CN109242923A - A kind of system and method for iterative approximation - Google Patents

A kind of system and method for iterative approximation Download PDF

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Publication number
CN109242923A
CN109242923A CN201810956684.0A CN201810956684A CN109242923A CN 109242923 A CN109242923 A CN 109242923A CN 201810956684 A CN201810956684 A CN 201810956684A CN 109242923 A CN109242923 A CN 109242923A
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China
Prior art keywords
image
outer ring
seeds picture
exposure mask
air exposure
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CN201810956684.0A
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CN109242923B (en
Inventor
斯坦尼斯拉夫·萨比奇
孙昊桦
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Shanghai United Imaging Healthcare Co Ltd
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Shanghai United Imaging Healthcare Co Ltd
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Priority to CN201810956684.0A priority Critical patent/CN109242923B/en
Priority to US16/206,167 priority patent/US10977840B2/en
Publication of CN109242923A publication Critical patent/CN109242923A/en
Priority to US17/221,012 priority patent/US11481935B2/en
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    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
    • G06T11/00—2D [Two Dimensional] image generation
    • G06T11/003—Reconstruction from projections, e.g. tomography
    • G06T11/005—Specific pre-processing for tomographic reconstruction, e.g. calibration, source positioning, rebinning, scatter correction, retrospective gating
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
    • G06T11/00—2D [Two Dimensional] image generation
    • G06T11/003—Reconstruction from projections, e.g. tomography
    • G06T11/006—Inverse problem, transformation from projection-space into object-space, e.g. transform methods, back-projection, algebraic methods
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
    • G06T11/00—2D [Two Dimensional] image generation
    • G06T11/003—Reconstruction from projections, e.g. tomography
    • G06T11/008—Specific post-processing after tomographic reconstruction, e.g. voxelisation, metal artifact correction

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • General Physics & Mathematics (AREA)
  • Theoretical Computer Science (AREA)
  • Algebra (AREA)
  • Mathematical Analysis (AREA)
  • Mathematical Optimization (AREA)
  • Mathematical Physics (AREA)
  • Pure & Applied Mathematics (AREA)
  • Image Processing (AREA)

Abstract

This application involves a kind of system and method for iterative approximation.The available initial data detected by imaging device of the system and method；Drawing of seeds picture is generated by executing filtered back projection to the initial data；It can be by determining that the drawing of seeds picture after correcting, the outer ring background can indicate the background of outer ring from outer ring background is subtracted in the drawing of seeds picture, the outer ring can correspond to the region between the visual field of the imaging device and the machine frame hole of the imaging device；And can based on after the correction drawing of seeds picture and the initial data by executing iterative approximation rebuild at least one image.

Description

A kind of system and method for iterative approximation
Technical field
This application involves image reconstructions by the application, relate more specifically to a kind of system and method for iterative approximation.
Background technique
Non-invasive imaging technique can obtain the image data of the internal structure of object, without executing intrusion to object Property process.The imaging techniques such as computed tomography (CT), positron emission computerized tomography (PET), magnetic resonance imaging (MRI) benefit Image data is obtained with various physical principles and the image of object is provided.The method of image reconstruction first is that iterative approximation.Repeatedly Generation, which rebuilds, to be referred to by being repeated according to the matched quality between measurement data and the analogue measurement currently estimated from image Existing estimation is adjusted to form the technology of image.However, iterative reconstruction technique is usually computationally intensive and time-consuming.Slowly weight Building speed is one of ultimate challenge of iterative approximation.Therefore, it is desirable to which Accelerated iteration is rebuild.
Summary of the invention
A kind of system and method for being designed to provide iterative approximation of the application, subtract outer ring background from drawing of seeds picture Drawing of seeds picture after correction can be generated is iterated based on the drawing of seeds picture after correction and rebuilds the speed that can accelerate iterative approximation Degree.
To achieve the above object of the invention, technical solution provided by the present application is as follows:
According to the one aspect of the application, a kind of method of iterative approximation is provided, the method can be used for rebuilding figure Picture, the method may include the initial data that acquisition is detected by imaging device；By executing filtering to the initial data Back projection generates drawing of seeds picture；By determining the drawing of seeds picture after correcting from outer ring background is subtracted in the drawing of seeds picture, The outer ring background can indicate the background of outer ring, the outer ring can correspond to the imaging device the visual field and the imaging Region between the machine frame hole of equipment；And based on after the correction drawing of seeds picture and the initial data by execute iteration It rebuilds to rebuild at least one image.
In some embodiments, the drawing of seeds picture may include the first element of at least one of cartesian coordinate system, Each first element can be pixel or voxel, by determining the kind after correcting from outer ring background is subtracted in the drawing of seeds picture Subgraph may include: to be become by executing the first coordinate of the drawing of seeds picture from the cartesian coordinate system to polar coordinate system It changes, determines the intermediate image including at least one second element in the polar coordinate system；Described in from the polar coordinate system At least one second element for corresponding to the outer ring is extracted at least one second element；Based on described in the polar coordinate system Second element after at least one described extraction is divided at least one set by the position of the second element after at least one extraction, Second element after every group of extraction corresponds to a sub-regions of the outer ring；Based on second yuan after at least one set of extraction Element generates background image corresponding with the outer ring background in the cartesian coordinate system；And from the drawing of seeds picture The background image corresponding to the outer ring background is subtracted, to obtain the drawing of seeds picture after the correction.
In some embodiments, it based on the second element after at least one set of extraction, generates and the cartesian coordinate The corresponding background image of the outer ring background in system may include: to determine the outer ring along the radial direction of the polar coordinate system At least one reference value in each subregion；By execute described in from the polar coordinate system to the cartesian coordinate system to Second coordinate transform of the second element after a few extraction, determines including at least one third in the cartesian coordinate system The initial circular image of element, the initial circular image correspond to the outer ring；And it is modified by executing homogenization operation The initial circular image corresponds to the background image of the outer ring background to obtain.
In some embodiments, at least one extraction described in from the polar coordinate system to the cartesian coordinate system is executed Second coordinate transform of second element afterwards may further include: based at least one described reference value to it is described at least one Second element after transformed extraction executes interpolation operation.
In some embodiments, it is described at least one extraction after second element along the polar coordinate system the radial direction Distribution at least one row, at least one in each subregion of the outer ring is determined along the radial direction of the polar coordinate system A reference value may include: every a line of each subregion and described at least a line for the outer ring, in every height Every a line middle finger in region determines the intermediate value of the second element after the extraction as the described each of each subregion Capable reference value；Or determine a part of the second element after extracting described in described every a line of each subregion, And specify described every a line as each subregion of average value of the part of the second element after the extraction The part of reference value, the second element after the extraction has the element value in particular range.
In some embodiments, the initial circular image is modified by executing homogenization operation to obtain corresponding to described The background image of outer ring background may include: by making at least one third element phase described in the initial circular image The center of the outer ring is rotated at least once, and rotates an angle in each rotation, to generate at least one rotation Circular image after turning；It is stacked by being superimposed the initial circular image and at least one described postrotational circular image next life Add image；And by normalizing the superimposed image, generate the background image corresponding with the outer ring background.
In some embodiments, the initial circular image is modified by executing homogenization operation to obtain corresponding to described The background image of outer ring background may include: make at least one described third element of the initial circular image carry out to Few primary rotation, wherein at least one third element described in the initial circular image is relative to institute in each rotation When stating center one angle of rotation of outer ring, postrotational circular image is generated；By being superimposed the initial circular image and institute Postrotational circular image is stated to generate superimposed image；And specifying the superimposed image is the initial circular image；And By normalizing the superimposed image, the background image corresponding with the outer ring background is generated.
It in some embodiments, can be at least one described postrotational circle before generating the superimposed image At least one of image executes interpolation arithmetic.
It in some embodiments, can be at least one described postrotational circle before generating the superimposed image At least one of image executes interpolation arithmetic.
In some embodiments, generating drawing of seeds picture may include: by executing filtered back projection to the initial data To generate initial pictures；And down-sampled the drawing of seeds picture is determined by executing to the initial pictures.
In some embodiments, it may include: down-sampled to initial data execution for generating drawing of seeds picture；And pass through Filtered back projection is executed to the down-sampled initial data to generate the drawing of seeds picture.
In some embodiments, the initial data can be from least one angular collection, and generating drawing of seeds picture can To include: one of the initial data for selecting to collect from a part of at least one angle from the initial data Point；And filtered back projection is executed to generate the drawing of seeds picture by the selected part to the initial data.
In some embodiments, the drawing of seeds picture may include at least one element, at least one element it is every A element can be pixel or voxel, by determining the drawing of seeds picture after correcting from outer ring background is subtracted in the drawing of seeds picture It may include: that at least one element for corresponding to the initial circular image of the outer ring is extracted from least one described element； By rotating the element after at least one described extraction at least once relative to the center of the outer ring, and rotating every time One angle of middle rotation, to generate at least one postrotational circular image, the angle is less than 360 °；Based on the initial circle Shape image and at least one described postrotational circular image generate the background image for corresponding to the outer ring background；And from institute The background image subtracted in drawing of seeds picture corresponding to the outer ring background is stated, to obtain the drawing of seeds picture after the correction.
In some embodiments, it is generated based on the initial circular image and at least one described postrotational circular image Background image corresponding to the outer ring background may include: by being superimposed the initial circular image and at least one described rotation Circular image after turning generates superimposed image；And it by normalizing the superimposed image, generates and the outer ring background pair The background image answered.
In some embodiments, at least one at least one described postrotational circular image can be modified by interpolation It is a.
According to further aspect of the application, a kind of system of iterative approximation is provided, the system can be used for rebuilding Image, the system may include: at least one processor；And it is configured as the memory of store instruction, wherein work as execution When described instruction, at least one described processor can be used for: obtain the initial data detected by imaging device；By to institute It states initial data and executes filtered back projection to generate drawing of seeds picture；It is determined by subtracting outer ring background from the drawing of seeds picture Drawing of seeds picture after correction, the outer ring background indicate the background of outer ring, and the outer ring corresponds to the visual field of the imaging device Region between the machine frame hole of the imaging device；And based on after the correction drawing of seeds picture and the initial data it is logical Execution iterative approximation is crossed to rebuild at least one image.
According to further aspect of the application, a kind of system of iterative approximation is provided, the system can be used for rebuilding Image, the system may include obtaining module, drawing of seeds picture generation module, drawing of seeds picture correction module and rebuilding module；Institute It states and obtains module for obtaining the initial data detected by imaging device；The drawing of seeds picture generation module is used for by institute It states initial data and executes filtered back projection to generate drawing of seeds picture；The drawing of seeds picture correction module is used for by from the seed Outer ring background is subtracted in image to determine that the drawing of seeds picture after correction, the outer ring background indicate the background of outer ring, the outer ring Corresponding to the region between the visual field of the imaging device and the machine frame hole of the imaging device；And the reconstruction module is used for Based on after the correction drawing of seeds picture and the initial data by executing iterative approximation rebuild at least one image.
According to further aspect of the application, a kind of computer readable storage medium is provided, the storage medium can be with Computer instruction is stored, when the computer instruction executes, the method that executes the iterative approximation
Because the technical solution more than using, the application have following technical effect that
One, drawing of seeds picture is corrected by removing outer ring background from drawing of seeds picture, it is possible to reduce or eliminate drawing of seeds picture Offset；
Two, iteration speed can be accelerated by being iterated reconstruction using the drawing of seeds picture after correction, and improve reconstruction image Quality.
Supplementary features will be set forth in part in the description which follows, by studying the following drawings, for the technology of this field The supplementary features are it will be apparent that can be understood by the production or operation of embodiment described additional for personnel Feature.Feature in the present invention can by practice or using the method, means or combinations thereof that are described below in detail each side Face is achieved and obtained.
Detailed description of the invention
The application will be further described below in conjunction with exemplary embodiment.These exemplary embodiments will be carried out by attached drawing Detailed description.The drawings are not drawn to scale.These embodiments are non-limiting exemplary embodiment, under a variety of views of attached drawing Embodiment in, similar number indicates similar structure, and wherein:
Fig. 1 is the schematic diagram of the exemplary imaging system according to shown in some embodiments of the present application；
Fig. 2 be can be used for realizing according to shown in some embodiments of the present application processing equipment calculating equipment it is exemplary The schematic diagram of hardware and or software component；
Fig. 3 is the example hardware and/or component software of the mobile device according to shown in some embodiments of the present application Schematic diagram；
Fig. 4 is the schematic diagram of the exemplary processing devices according to shown in some embodiments of the present application；
Fig. 5 is the process that the example process of at least one image is rebuild according to shown in some embodiments of the present application Figure；
Fig. 6 is the flow chart that the example process of air exposure mask is generated according to shown in some embodiments of the present application；
Fig. 7 A-7D is the schematic diagram of the exemplary drawing of seeds picture of the object according to shown in some embodiments of the present application；
Fig. 8 A-8D is the schematic diagram of the exemplary drawing of seeds picture of the object according to shown in some embodiments of the present application；
Fig. 9 is the flow chart that the example process of air exposure mask is modified according to shown in some embodiments of the present application；
Figure 10 A is the schematic diagram that the example process of air exposure mask is generated according to shown in some embodiments of the present application；
Figure 10 B is the schematic diagram that the example process of air exposure mask is generated according to shown in some embodiments of the present application；
Figure 11 A shows the air exposure mask drawing of seeds picture corresponding to air exposure mask described in Figure 10 A；
Figure 11 B shows the air exposure mask drawing of seeds picture corresponding to air exposure mask described in Figure 10 B；
Figure 12 A is the schematic diagram that the example process of air exposure mask is generated according to shown in some embodiments of the present application；
Figure 12 B is the signal that the another exemplary process of air exposure mask is generated according to shown in some embodiments of the present application Figure；
Figure 13 A and 13B are the examples for not having a part of object of truncation according to shown in some embodiments of the present application Property air exposure mask drawing of seeds picture；
Figure 13 C is shown based on anti-with the exemplary filter of the identical Raw Data Generation of same target in Figure 13 A and 13B Project drawing of seeds picture；
Figure 13 D and 13E are showing for another part of the object with truncation according to shown in some embodiments of the present application Example property air exposure mask drawing of seeds picture；
Figure 13 F is shown based on anti-with the exemplary filter of the identical Raw Data Generation of same target in Figure 13 D and 13E Project drawing of seeds picture；
Figure 14 A is the process that the example process of at least one image is rebuild according to shown in some embodiments of the present application Figure；
Figure 14 B is the schematic diagram of the exemplary outer ring according to shown in some embodiments of the present application；
Figure 15 is the schematic diagram of the exemplary drawing of seeds picture correction module according to shown in some embodiments of the present application；
Figure 16 is the example process of the drawing of seeds picture after the generation correction according to shown in some embodiments of the present application Flow chart；
Figure 17 is the flow chart that the example process of background image is generated according to shown in some embodiments of the present application；
Figure 18 is the schematic diagram of the exemplary drawing of seeds picture of the object according to shown in some embodiments of the present application；
Figure 19 is the schematic diagram of the exemplary intermediate image of the object according to shown in some embodiments of the present application；
Figure 20 shows the schematic diagram of multiple reference values in the 4th subregion in multiple rows；
Figure 21 A is the schematic diagram of the exemplary initial circular image according to shown in some embodiments of the present application；
Figure 21 B is the schematic diagram of the exemplary background image according to shown in some embodiments of the present application；
Figure 22 is the process that the example process of initial circular image is modified according to shown in some embodiments of the present application Figure；
Figure 23 is the signal that the example process of initial circular image is modified according to shown in some embodiments of the present application Figure；
Figure 24 is the process that the example process of initial circular image is modified according to shown in some embodiments of the present application Figure；And
Figure 25 is the signal that the example process of initial circular image is modified according to shown in some embodiments of the present application Figure.
Specific embodiment
In the following description, detail is illustrated by example in order to provide the comprehensive understanding to present disclosure.It is aobvious and easy Insight, for those skilled in the art, the application can be implemented in the case where not using the details.In other situations Under, in order to avoid unnecessarily obscuring some aspects of the application, the application is with many institutes of relatively high hierarchy description Known method, program, system, component and/or circuit.For those of ordinary skill in the art, the application is disclosed The various modifications that carry out of embodiment be it will be apparent that and the general rule that is defined herein without departing substantially from spirit herein and In the case where range, it can be adapted for other embodiments and application.Therefore, the application be not limited to shown in embodiment, but want Meet and the consistent widest range of claim.
Term used herein is only used for description certain exemplary embodiments, does not limit the scope of the application.Such as " one " used in this application, "one", " described ", the words such as "the" not refer in particular to odd number, may also comprise plural form, unless Context clearly prompts exceptional situation.It is also understood that the terms "include", "comprise" only prompt to exist as in the present specification The feature, entirety, step, operation, component and/or component, but presence is not precluded or adds at least one other feature, whole The case where body, step, operation, component, component and/or combination thereof.
It should be understood that terms used herein " system ", " unit ", " module " and/or " block " are for by ascending order The method for distinguishing the different component of different stage, element, component, part or component.However, if phase may be implemented in other expression Same purpose then can replace the word by other expression.
In general, " module ", " unit " and/or " block " in the application refer to being stored in hardware, patrolling in firmware Volume or one group of software instruction." module ", " unit " and/or " block " referred herein can be held by software and/or hardware modules Row can also be stored in any computer-readable non-provisional medium or other storage equipment.In some embodiments In, software module/unit/block can be compiled and be connected in an executable program.Here software module can be right Itself or other modules/unit/block transmitting information respond, and/or can detect certain events or interruption When respond.Be configured as calculate equipment (for example, processor 210 shown in Fig. 2) on execute software module/unit/ The computer that block may be provided in such as CD, digital video disc, flash drive, disk or any other tangible medium can It reads on medium, or (can store in compressed package or installation kit as number downloading, need to install before execution, decompression Contracting or decryption).Here software code can be set by the part or all of storage for being stored in the calculating equipment for executing operation In standby, and apply among the operation for calculating equipment.Software instruction can be implanted in firmware, such as erasable programmable is read-only Memory (EPROM).It will be further understood that hardware module/unit/block may include connection logic module, such as door and Trigger, and/or may include programmable unit, such as programmable gate array or processor.Module/unit described herein/ Block or computing device functionality may be embodied as software module/unit/block, but can be indicated with hardware or firmware.In general, Module/unit/block described herein refers to logic module/unit/block, can be combined with other module/unit/blocks or by It is divided into submodule/subelement/sub-block, physical organization or storage but regardless of them.
It should be appreciated that when a unit, engine, module or block " being located at ", " being connected to " or " being coupled to " another unit, drawing It holds up, module or when block, unless the context is clearly stated, these units, engine, module or block can directly be located at, be connected to Or it is coupled to or is communicated to another unit, engine, module or block, there may also be other temporary locations, engine, module or blocks. In this application, term "and/or" may include any one of entry listed by least one correlation or combinations thereof.
After considering the description content as the attached drawing of the application a part, the feature and feature of the application and operation Method, the function of the coherent element of structure, the combination of each section, manufacture economy become apparent.However, should manage Solution, the purpose that attached drawing is merely to illustrate that and describes, it is no intended to limit scope of the present application.It should be understood that attached drawing is simultaneously Not in proportion.
The one aspect of the application is related to the system and method for Accelerated iteration reconstruction.It can be by executing iterative approximation next life At at least one image.Each of at least one image may include at least one element.Element can be pixel or body Element.For Accelerated iteration reconstruction, which can be generated air exposure mask, which can only include indicating air Element.The element for indicating air can be ignored in iterative approximation, this can be rebuild with Accelerated iteration.It is covered to generate air Film, the available initial data detected by imaging device from least one angle of the system and method.The system and method It can be by the way that the smallest initial data in a part of initial data or modified data be appointed as at least one image The backprojected value of each element execute minimum value back projection (BP), and based on it is relevant at least one element at least one Backprojected value generates air exposure mask drawing of seeds picture (or second seed image).The system and method can be by being based on threshold value to sky Gas exposure mask drawing of seeds picture (or second seed image) executes threshold process, and to generate air exposure mask, (also referred to as the first air is covered Film).In order to execute iterative approximation, which can also be by executing filtered back projection's (FBP) next life to initial data At drawing of seeds picture (also referred to as initial pictures estimation).The system and method can (or initial pictures be estimated based on drawing of seeds picture Meter), air exposure mask (or first air exposure mask) and initial data at least one image is generated by execution iterative approximation.
Alternatively or additionally, in general, drawing of seeds picture (that is, initial pictures estimation) may include due to lacking in outer ring Data and the offset occurred.In order to compensate for the offset, it may be necessary to execute more iterative approximation.However, disclosed herein System and method can be rebuild come Accelerated iteration (that is, reducing the iteration time of iterative approximation by generating the drawing of seeds picture after correcting Number).The system and method can be by determining the drawing of seeds picture after correcting from outer ring background is subtracted in drawing of seeds picture.Outer ring back Scape can correspond to the background of outer ring.The outer ring can correspond to the machine frame hole of (scanning) visual field (FOV) and imaging device Between region.The system and method can based on after correction drawing of seeds picture and initial data by execute iterative approximation next life At at least one image.
Fig. 1 is the schematic diagram of the exemplary imaging system according to shown in some embodiments of the present application.Imaging system 100 can Including computer tomography (CT) system, computer tomography angiography (CTA) system, positron emission tomography (PET) system, single photon emission computed tomography (SPECT) system, magnetic resonance imaging (MRI) system etc., or combinations thereof. In some embodiments, medical image system can be used alone.In some embodiments, the medical image system can be made For multimodal systems (for example, PET-CT system) use.
As shown in Figure 1, imaging system 100 may include imaging device 110, network 120, at least one terminal 130, processing Equipment 140 and storage equipment 150.Component in imaging system 100 can connect in various ways.Only as an example, imaging is set Standby 110 can be connected to processing equipment 140 by network 120.It is set in another example imaging device 110 can be directly connected to processing Standby 140, as shown in connection imaging device 110 and the dotted line four-headed arrow of processing equipment 140.In another example storage equipment 150 can be with Processing equipment 140 is connected to directly or by network 120.For another example terminal 130 can be directly (such as connection terminal 130 and processing Shown in the dotted line four-headed arrow of equipment 140) or processing equipment 140 is connected to by network 120.
By taking CT system as an example, imaging device 110 may include rack 111, detector module 112, radiation source 113 and scan table 114.Detector module 112 and radiation source 113 can be relatively mounted in rack 111.Object can be placed on scan table On 114 and it is moved in the sense channel of imaging device 110.The object can be biological object (for example, patient, animal) Or abiology object (for example, artificial objects).In this application, " object " and " target " is used interchangeably.For the ease of saying It is bright, introduce coordinate system shown in FIG. 1.The coordinate system may include X-axis, Y-axis and Z axis.Z axis can refer to object along its shifting Enter and/or remove imaging device 110 sense channel direction.X-axis and Y-axis can form the plane perpendicular to Z axis.
Radiation source 113 can emit radiation ray to scan the object being placed on scan table 114.The radiation ray can Including X-ray, gamma-rays, alpha ray, ultraviolet light, laser, neutron, proton etc., or combinations thereof.Detector module 112 can receive Across the radiation ray of object.In some embodiments, detector module 112 may include at least one detector, can arrange In channel direction and line direction.The detector may include scintillation detector (for example, cesium iodide detector) or gas inspection Survey device.
Network 120 can promote the exchange of information and/or data.In some embodiments, at least the one of imaging system 100 A component (for example, imaging device 110, terminal 130, processing equipment 140 or storage equipment 150) can will be at by network 120 As in system 100 information and/or data be sent to another component.For example, processing equipment 140 can via network 120 from Imaging device 110 obtains initial data relevant to object.In another example processing equipment 140 can be used for via network 120 Air exposure mask is generated, drawing of seeds picture is corrected, rebuilds the user instruction of at least one image etc..In some embodiments, network 120 It can be any one in cable network or wireless network, or combinations thereof.Network 120 can be and/or including public network (e.g., internet), dedicated network (e.g., local area network (LAN), wide area network (WAN)), cable network (e.g., Ethernet), wireless network (e.g., 802.11 networks, Wi-Fi network), cellular network (e.g., long term evolution (LTE) network), frame-relay network, virtual private Network (" VPN "), satellite network, telephone network, router, hub, interchanger, server computer and/or its any group It closes.Only as an example, network 120 may include cable system, cable network, fiber optic network, telecommunication network, Intranet, Internet, local area network (LAN), wide area network (WAN), WLAN (WLAN), it is Metropolitan Area Network (MAN) (MAN), wide area network (WAN), public Telephone-switching network (PSTN), bluetoothTMNetwork, purple honeybeeTMNetwork, near-field communication (NFC) network etc., or any combination thereof.One In a little embodiments, network 120 may include at least one network exchange point.For example, network 120 may include wired or wireless net Network access point, such as base station and/or internet exchange point, at least one component of imaging system 100 can be accessed by these Point is connected to network 120 to exchange data and/or information.
Terminal 130 may include mobile device 130-1, tablet computer 130-2, laptop computer 130-3 etc. or its Any combination.In some embodiments, mobile device 130-1 may include that smart home device, wearable device, intelligent mobile are set Standby, virtual reality device, augmented reality equipment etc., or any combination thereof.In some embodiments, smart home device can wrap Intelligent illumination device, the control equipment of intelligent electric appliance, intelligent monitoring device, smart television, intelligent camera, intercom etc. are included, Or any combination thereof.In some embodiments, wearable device may include bracelet, footgear, glasses, the helmet, wrist-watch, clothing, Knapsack, accessory etc., or any combination thereof.In some embodiments, Intelligent mobile equipment may include that smart phone, individual digital help (PDA), game station, navigation equipment, point of sale (POS) equipment etc. are managed, or any combination thereof.In some embodiments, virtually Real world devices and/or augmented reality equipment may include virtual implementing helmet, virtual reality glasses, virtual reality eyeshade, enhancing The real helmet, augmented reality glasses, augmented reality eyeshade etc., or any combination thereof.For example, virtual reality device and/or enhancing Real world devices may include Google Glass, Oculus Rift, HoloLens or Gear VR etc..In some embodiments, eventually End 130 can remotely operate imaging device 110.In some embodiments, terminal 130 can be set by being wirelessly connected operation imaging Standby 110.In some embodiments, terminal 130 can receive information input by user and/or instruction, and via network 120 Imaging device 110 or processing equipment 140 are sent by the received information of institute and/or instruction.In some embodiments, terminal 130 It can receive information and/or data from processing equipment 140.In some embodiments, terminal 130 can be processing equipment 140 a part.In some embodiments, it is convenient to omit terminal 130.
In some embodiments, processing equipment 140 can handle from imaging device 110, terminal 130 or storage equipment 150 The data of acquisition.For example, processing equipment 140 can be based on the Raw Data Generation drawing of seeds picture detected by imaging device 110 And/or air exposure mask.In another example processing equipment 140 can correct drawing of seeds picture to determine the drawing of seeds picture after correction.Example again Such as, processing equipment 140 can rebuild at least one figure by executing iterative approximation based on the user instruction obtained from terminal 130 Picture.Processing equipment 140 can be central processing unit (CPU), digital signal processor (DSP), system level chip (SoC), micro- Controller unit (MCU) etc., or any combination thereof.In some embodiments, processing equipment 140 can be individual server or clothes Business device group.The server group can be centralization, be also possible to distributed.In some embodiments, processing equipment 140 It can be local or remote.For example, processing equipment 140 can be accessed via network 120 be stored in imaging device 110, end Information and/or data in end 130 and/or storage equipment 150.It is set in another example processing equipment 140 can be directly connected to imaging Standby 110, terminal 130 and/or storage equipment 150, to access the information and/or data of storage.In some embodiments, processing is set Standby 140 can implement in cloud platform.Only as an example, the cloud platform may include private clound, public cloud, mixed cloud, society Qu Yun, distribution clouds, internal cloud, cloudy etc., or any combination thereof.In some embodiments, processing equipment 140 can be in the application In implement in the calculating equipment 200 shown in Fig. 2 at least one component.
Storage equipment 150 can store data and/or instruction.In some embodiments, storage equipment 150 can store from The data that terminal 130 and/or processing equipment 140 obtain.In some embodiments, storage equipment 150 can store processing equipment 140 executable or data and/or instruction for executing illustrative methods described in this application.In some embodiments, it deposits Storage equipment 150 may include mass storage, removable memory, volatile read-write memory, read-only memory (ROM) etc., Or any combination thereof.Illustrative mass storage may include disk, CD, solid magnetic disc etc..It is illustrative removable Memory may include flash drive, floppy disk, CD, memory card, compression dish, tape etc..Illustrative read-write volatile storage Device may include random access memory (RAM).Illustrative random access memory may include dynamic random access memory (DRAM), Double Data Rate Synchronous Dynamic Random Access Memory (DDR SDRAM), static random access memory (SRAM), lock Fluid random access memory (T-RAM) and zero capacitance random access memory (Z-RAM) etc..Illustrative read-only memory can To include mask ROM (MROM), programmable read only memory (PROM), Erasable Programmable Read Only Memory EPROM (PEROM), electrically erasable programmable read-only memory (EEPROM), compact disc read-only memory (CD-ROM) and digital versatile disc Read memory etc..In some embodiments, the storage equipment 150 can be implemented on platform beyond the clouds.Only as an example, cloud is flat Platform may include private clound, public cloud, mixed cloud, community cloud, distribution clouds, internal cloud, cloudy etc., or any combination thereof.
In some embodiments, storage equipment 150 may be coupled to network 120 with imaging system 100 (for example, terminal 130, processing equipment 140) at least one component communicated.At least one component in imaging system 100 can be via Network 120 accesses the data or instruction being stored in storage equipment 150.In some embodiments, storage equipment 150 can at As at least one component (for example, terminal 130, processing equipment 140) of system 100 is directly connected to or communicates.In some embodiments In, storage equipment 150 can be a part of processing equipment 140.
Fig. 2 is the calculating equipment 200 that can be used for realizing processing equipment 140 according to shown in some embodiments of the present application The schematic diagram of example hardware and/or component software.As shown in Fig. 2, calculating equipment 200 may include processor 210, memory 220, input/output (I/O) 230 and communication port 240.
Processor 210 can cause processing equipment 140 when executing the instruction with computer instructions (program code) The function of processing equipment 140 is executed according to technology described herein.The computer instruction may include executing the application institute The instruction for the specific function stated, such as routine, programs, objects, component, signal, data structure, process, module and function.One In a little embodiments, processor 210 be can handle from imaging device 110, terminal 130, storage equipment 150 and/or imaging system 100 Any other component obtain data and/or image.For example, processor 210 can be based on being detected by imaging device 110 Raw Data Generation air exposure mask.In another example processor 210 can correct kind by subtracting outer ring background from drawing of seeds picture Subgraph.In another example processor 210 can rebuild at least one image by executing iterative approximation.In some embodiments, locate Managing device 210 may include at least one hardware processor, such as microcontroller, microprocessor, reduced instruction set computing device (RISC), specific integrated circuit (ASIC), dedicated instruction set processor ASIP), central processing unit (CPU), graphics process list Member (GPU), physical processing unit (PPU), micro controller unit, digital signal processor (DSP), field programmable gate array (FPGA), Advance RISC Machine (ARM), programmable logic device (PLD), any circuit for being able to carry out at least one function or Processor etc., or any combination thereof.
Just to illustrate, calculates in equipment 200 and only describe a processor.But it should be noted that in the application Calculating equipment 200 can also include multiple processors.Therefore, such as the operation described in this application executed by a processor And/or method and step can also be combined or be individually performed by multiple processors.For example, if calculating equipment 200 in the application Processor implementation procedure A and process B, then it should be understood that process A and process B can also by two in calculating equipment 200 or more Mostly different processors collectively or individually executes (for example, first processor implementation procedure A and second processor executed Journey B or first processor and the common implementation procedure A and B of second processor).
Memory 220 can store from any of imaging device 110, terminal 130, storage equipment 150 or imaging system 100 The data/information that other assemblies obtain.In some embodiments, memory 220 may include mass storage, move and deposit Reservoir, volatile read-write memory, read-only memory (ROM) etc., or any combination thereof.For example, mass storage can wrap Include disk, CD, solid magnetic disc etc..Removable memory may include flash drive, floppy disk, CD, memory card, compression Dish, tape etc..Volatile read-write memory may include random access memory (RAM).Random access memory may include Dynamic random access memory (DRAM), Double Data Rate Synchronous Dynamic Random Access Memory (DDR SDRAM), static random are deposited Access to memory (SRAM), thyristor random access memory (T-RAM) and zero capacitance (Z-RAM) etc..Read-only memory can wrap Include mask ROM (MROM), programmable read only memory (PROM), Erasable Programmable Read Only Memory EPROM (PEROM), Electrically erasable programmable read-only memory (EEPROM), compact disc read-only memory (CD-ROM) and digital versatile disc read-only memory Deng.In some embodiments, memory 220 can store at least one program and/or instruction is described in this application with executing Illustrative methods.For example, memory 220 can store the program for processing equipment 140 (for example, executable with computer The form of instruction) to generate air exposure mask.In another example memory 220 can store for processing equipment 140 program (for example, In the form of computer executable instructions) to correct drawing of seeds picture.For another example memory 220 can store for processing equipment 140 program (for example, in the form of computer executable instructions), for rebuilding at least one figure by executing iterative approximation Picture.
Input/output 230 can input or output signal, data, and/or information.In some embodiments, input/defeated It 230 can enable a user to interact with processing equipment 140 out.In some embodiments, input/output 230 may include defeated Enter equipment and output equipment.Exemplary input devices may include keyboard, mouse, touch screen, microphone etc. or its any group It closes.Exemplary output device may include showing equipment, loudspeaker, printer, projector etc., or any combination thereof.It is exemplary Display equipment may include liquid crystal display (LCD), aobvious based on the display of light emitting diode (LED), flat-panel monitor, curved surface Show device, television equipment, cathode-ray tube (CRT) etc., or any combination thereof.
Communication port 240 may be coupled to network (for example, network 120) to promote data communication.Communication port 240 can be with Connection is established between processing equipment 140 and imaging device 110, terminal 130 or storage equipment 150.Connection can be wired company It connects, be wirelessly connected, or combinations thereof, to realize data transmission and reception.Wired connection may include cable, optical cable, telephone wire etc., Or any combination thereof.Wireless connection may include bluetooth, Wi-Fi, WiMAX, WLAN, ZigBee, mobile network (for example, 3G, 4G, 5G etc.) etc., or combinations thereof.In some embodiments, communication port 240 can be standardized port, such as RS232, RS485 Deng.In some embodiments, communication port can be the communication port specially designed.For example, communication port 240 can be according to number Word imaging is designed with medical communication (DICOM) agreement.
Fig. 3 is the example hardware and/or component software of the mobile device 300 according to shown in some embodiments of the present application Schematic diagram.As shown in figure 3, mobile device 300 may include communications platform 310, display 320, graphics processing unit (GPU) 330, central processing unit (CPU) 340, input/output 350, memory 360 and memory 390.In some embodiments, any Other suitable components, including but not limited to system bus or controller (not shown) also may include in mobile device 300. In some embodiments, operating system 370 (e.g., iOS, Android, Windows Phone etc.) and at least one using 380 can To be loaded into memory 360 from memory 390, to be executed by CPU 340.Using 380 may include browser or it is any its His suitable mobile application, for information related with image procossing or other information to be received and presented from processing equipment 140.With The interaction of family and information flow can realize by input/output 350, and by network 120 be supplied to processing equipment 140 and/or The other assemblies of imaging system 100.
In order to implement various modules, unit and its function described herein, computer hardware platforms can be used as the application Described at least one element hardware platform.Hardware elements, operating system and the programming language of this computer are substantially It is conventional, and assumes these technologies familiar to those skilled in the art so that these technologies adapt to iteration as described in the present application The acceleration of reconstruction.Computer with user interface element can be used for implementing personal computer (PC) or other kinds of work It stands or terminal device, if suitably programmed, computer can also act as server.It is considered that those skilled in the art are to this The general operation of the structure of sample, program and this kind of computer equipment is all known, therefore all attached drawings all do not need volume yet Outer explanation.
Fig. 4 is the schematic diagram of the exemplary processing devices according to shown in some embodiments of the present application.Processing equipment 140 can To implement (for example, processor 210 as shown in Figure 2 or CPU 340 as shown in Figure 3) on calculating equipment 200.Processing equipment 140 may include obtaining module 402, drawing of seeds picture generation module 404, air exposure mask generation module 406, rebuilding 408 and of module Drawing of seeds picture correction module 410.
Obtaining module 402 can be configured as acquisition information related with imaging system 100.The information may include scanning number According to (for example, initial data), image data etc., or any combination thereof.For example, it is available by imaging device to obtain module 402 The initial data that (for example, imaging device 100) is detected from least one angle.The initial data can reflect across object Radiation ray (for example, X-ray) dampening information, and be commonly used for generating relevant to object at least one figure Picture.Initial data may include at least one set of data corresponding at least one angle.One group collected under a certain angle is former Beginning data are referred to as view.In some embodiments, obtaining module 402 can be from least one group of imaging system 100 Part (such as imaging device 100, terminal (for example, terminal 130), storage equipment (for example, storage equipment 150) etc.) obtains original number According to.Alternatively or additionally, initial data can be obtained from external source via network 120 by obtaining module 402.For example, obtaining Module 402 can obtain initial data from medical data base.
Drawing of seeds picture generation module 404, which can be configured as, generates drawing of seeds picture (also referred to as the first drawing of seeds picture).One In a little embodiments, the first drawing of seeds picture can provide initial pictures estimation for iterative approximation.In some embodiments, drawing of seeds picture Generation module 404 can generate first by executing filtered back projection (FBP) to the initial data obtained by acquisition module 402 Drawing of seeds picture.In the operation of exemplary filter back projection, drawing of seeds picture generation module 404 can be at least one set of (for example, every Group) initial data executes filtering.In some embodiments, can be used such as high-pass filter, slope filter or its What combination is to execute filtering.In some embodiments, every group of initial data (also referred to as each view) can in filter Core carries out convolution to generate view-filtered.Drawing of seeds picture generation module 404 can execute back projection at least one view-filtered To rebuild the first drawing of seeds picture.
Air exposure mask generation module 406, which can be configured as, generates air exposure mask (also referred to as the first air exposure mask).First Air exposure mask can be used for distinguishing the element of element and/or the air not indicated that air is indicated in image.In some embodiments, Air exposure mask generation module 406 can be by executing minimum value back projection (BP) to the initial data obtained by acquisition module 402 To determine the first air exposure mask.Specifically, it is anti-can to execute minimum value to each element of image for air exposure mask generation module 406 Projection, to determine backprojected value relevant to each element of image.Each element of image can refer in the image to be rebuild Each element, and can correspond to the spatial point of object.Air exposure mask generation module 406 can be based on and correspond to object At least one element at least one relevant backprojected value of at least one spatial point generate second seed image (also referred to as Air exposure mask drawing of seeds picture).Air exposure mask generation module 406 can be based further on threshold value (that is, second threshold) and pass through to Two drawing of seeds picture execute threshold process to generate the first air exposure mask.It can be in this Shen about the details for generating the first air exposure mask Please find (for example, Fig. 6 and its description) elsewhere.
In some embodiments, air exposure mask generation module 406 can be additionally configured to the first air exposure mask of modification.Example Such as, air exposure mask generation module 406 can be based on the first air exposure mask and the second air exposure mask by executing logical operation (also referred to as For Boolean calculation) modify the first air exposure mask.Specifically, air exposure mask generation module 406 can to the first air exposure mask and Second air exposure mask executes inclusive-OR operation and/or "and" operation to modify the first air exposure mask.It in some embodiments, can be with base The second air exposure mask is generated by executing threshold process to the first drawing of seeds picture in threshold value (that is, third threshold value).In some realities It applies in example, the second air exposure mask can be different from the first air exposure mask.In some embodiments, the second air exposure mask can be used for repairing Change the first air exposure mask.In another example air exposure mask generation module 406 can be by executing morphology operations to the first air exposure mask To modify the first air exposure mask.Morphology operations may include erosion operation, dilation operation, opening operation, closed operation etc. or its What is combined.The details of modification about the first air exposure mask can be in the finding of the application (for example, Fig. 9 and its retouching elsewhere It states).
Reconstruction module 408, which can be configured as by executing iterative approximation, rebuilds at least one image.Exemplary iterative Algorithm for reconstructing may include that adaptively statistics iterative approximation (ASiR), iterative approximation (MBiR), image space based on model change In generation, rebuilds (iRIS), the iterative approximation (SAFIRE) based on initial data, iterative approximation (DMBiR) based on dual model, adaptive Iteration dosage is answered to reduce (AIDR) iterative approximation, IMR etc., or any combination thereof.In some embodiments, rebuilding module 408 can To rebuild at least one figure by executing iterative approximation based on the first drawing of seeds picture, the first air exposure mask and/or initial data Picture.Alternatively, rebuild module 408 can based on after correction drawing of seeds picture and initial data by execute iterative approximation come rebuild to A few image.Details about image reconstruction can finding elsewhere (for example, the operation of process 500 in the application 507, the operation 1407 of process 1400, and its description).
Drawing of seeds picture correction module 410 can be configured as correction and/or modification drawing of seeds picture (for example, the first drawing of seeds Picture) to determine the drawing of seeds picture after correction.In some embodiments, drawing of seeds picture correction module 410 can be to drawing of seeds picture (example Such as, the first drawing of seeds picture) execute low-pass filtering.For example, drawing of seeds picture correction module 410 can execute two to the first drawing of seeds picture Tie up low-pass filtering.In another example drawing of seeds picture correction module 410 can be in the logical of at least one detector of detector module 112 One-dimensional low-pass filtering is executed on road direction.Alternatively or additionally, drawing of seeds picture correction module 410 can be from drawing of seeds picture Outer ring background is subtracted in (for example, first drawing of seeds picture) to determine the drawing of seeds picture after correction.Outer ring background can correspond to outer The background of ring.Outer ring can correspond to imaging device 110 (scanning) visual field (FOV) and imaging device 110 machine frame hole it Between region.The details of correction about drawing of seeds picture can finding elsewhere (for example, the behaviour of process 900 in the application Make 901, the operation 1405 of process 1400, process 1600, and its description).
It should be noted that above description provides for illustration purposes only, it is no intended to limit scope of the present application.For For those skilled in the art, various modifications and variations can be made according to the description of the present application.However, These modifications and variations are without departing from scope of the present application.For example, processing equipment 140 can also be including memory module (in Fig. 4 not It shows).Memory module can be configured as the data that storage is generated by processing equipment 140.In some embodiments, two or more Multiple modules (or unit) can be combined into individual module (or unit).For example, drawing of seeds picture generation module 404 and drawing of seeds picture Correction module 410 can be combined into individual module.The individual module can be configured as generation and/or modification drawing of seeds picture.It can Selection of land or additionally, any one module can be divided into two or more units (or subelement).For example, air exposure mask is raw Two units are segmented at module 406.One of unit, which can be configured as, generates air exposure mask (for example, the first air Exposure mask), another unit can be configured as modification air exposure mask (for example, first air exposure mask).
Fig. 5 is according to shown in some embodiments of the present application for rebuilding the stream of the example process of at least one image Cheng Tu.In some embodiments, implement in the imaging system 100 that at least one operation of process 500 can be shown in Fig. 1. For example, process 500 can be stored in storage equipment 150 and/or memory 220 in the form of instruction (for example, application program), And by processing equipment 140 (for example, the processor 210, movement as shown in Figure 3 in calculating equipment 200 as shown in Figure 2 are set Standby 300 CPU 340, at least one module of processing equipment 140 as shown in Figure 4 etc.) it calls and/or executes.In another example mistake The a part of of journey 500 can implement on imaging device 110.The operation of shown process presented below is intended to illustrate.Some In embodiment, process 500 can add at least one operation bidirectional not described when implementing, and/or delete at least one this The described operation in place.In addition, the sequence of process 500 and operations described below shown in Fig. 5 and without restriction.
In operation 501, processing equipment 140 (for example, obtain module 402) it is available by imaging device (for example, imaging Equipment 110) initial data that is detected from least one angle (also referred to as projection angle).In some embodiments, former Beginning data are properly termed as data for projection.Initial data can reflect the decaying letter of the radiation ray (for example, X-ray) across object Breath, and be commonly used for generating at least one image relevant to object.In some embodiments, initial data can be by Imaging device 110 is detected and/or is collected from least one angle.Initial data may include it is corresponding at least one angle extremely Few one group of data.In some embodiments, the one group of initial data collected under a certain angle is referred to as view.For example, Imaging device 110 (for example, CT imaging device) can execute the scanning of object by using x-ray bombardment object.It is scanning Period, radiation source 113 and detector module 112 can rotate together with the Z axis with rack 111, to scan from different perspectives pair As.Z axis can be the axis along the scanning channel of rack 111 from the front side of rack 111 to rear side.
In some embodiments, projection angle can refer to the rotation center by connection radiation source 113 and rack 111 line and The angle that coordinate system (for example, X-axis as shown in Figure 1, Y-axis) is formed.In some embodiments, which can be from initial angle It is changed in the range of degree and stop angle.Start angle can correspond to radiation source 113 and start to emit radiation ray and detect Device module 112 start detect initial data when radiation source 113 position.Stop angle can correspond to the stopping of radiation source 113 The position of radiation source 113 when transmitting radiation ray and the stopping detection initial data of detector module 112.Start angle can be with It is 0 °, 5 °, 10 °, 20 ° etc..Stop angle can be greater than start angle, for example, 180 °, 210 °, 270 °, 360 ° etc..? In some embodiments, when rack 111 rotates, radiation source 113 can be continuously to object transmitting radiation ray (for example, X be penetrated Line).In some embodiments, detector module 112 can be collected corresponding to multiple angles (for example, range is from 0 ° to 360 ° 1200 or 2400 angles) multiple groups initial data.Alternatively, radiation source 113 can be intermittently to right when rack 111 rotates As emitting radiation ray (for example, X-ray).In some embodiments, radiation source 113 can with special angle interval (for example, 1 °, 2 °, 5 °, 10 ° etc.) to object emit radiation ray (for example, X-ray).For example, angle interval can be 1 ° and angle model It encloses and can be 0 ° -360 °, therefore, detector module 112 can collect 360 groups of initial data (also referred to as 360 views).Example again Such as, angle interval can be 0.5 ° and angular range can be 0 ° -360 °, and therefore, detector module 112 can collect 720 Group initial data (also referred to as 720 views).
In some embodiments, obtain module 402 can from least one component of imaging system 100 (such as imaging is set Standby 110, terminal (for example, terminal 130), storage equipment (for example, storage equipment 150) etc.) obtain initial data.Alternatively or Additionally, initial data can be obtained from external source via network 120 by obtaining module 402.It can be from for example, obtaining module 402 Medical data base obtains initial data.
In operation 503, the first drawing of seeds is can be generated in processing equipment 140 (for example, drawing of seeds picture generation module 404) Picture.In some embodiments, drawing of seeds picture generation module 404 can be by executing filter to the initial data obtained in operation 501 Wave back projection (FBP) generates the first subgraph.In some embodiments, filtered back projection can refer to from initial data (or Data for projection) reconstruction image technology, handle projector space in data and by each element in image space (here Also referred to as pictorial element) the value image that is determined as that treated a part linear combination.The a part for data that treated It can be obtained from multiple points in projector space, pictorial element contributes these points in forward projection.Pictorial element can be with Correspond to the pixel or voxel of the spatial point of object.The value of pictorial element can be to decline with radiation ray (such as X-ray) Subtract the relevant data of coefficient, the radiation ray passes through the additional space point of object from least one angle.
In the operation of exemplary filter back projection, drawing of seeds picture generation module 404 can be at least one set of (for example, every group) Initial data executes filtering.In some embodiments, high-pass filter, slope filter etc. or its any group can be used It closes to execute filtering.In some embodiments, every group of initial data (also referred to as each view) can with the kernel of filter into Row convolution is to generate filtered view.Drawing of seeds picture generation module 404 can execute at least one filtered view anti- Projection is to rebuild the first drawing of seeds picture.
In some embodiments, the first drawing of seeds picture further can be modified and/or correct to determine the first modified Subgraph.In some embodiments, drawing of seeds picture correction module 410 can execute low-pass filtering to the first drawing of seeds picture.It can replace Generation ground or additionally, drawing of seeds picture correction module 410 can be modified by subtracting outer ring background from the first drawing of seeds picture and/ Or the first drawing of seeds picture of correction.More descriptions of modification and/or correction about the first drawing of seeds picture can the application its He finds in place (for example, the operation 901 of process 900, the operation 1405 of process 1400, process 1600 and its associated description).
In operation 505, processing equipment 140 (for example, air exposure mask generation module 406) can be based in operation 501 The initial data of acquisition determines the first air exposure mask.In some embodiments, air exposure mask may include at least one to spoke Ray (for example, X-ray) has the element of zero attenuation.There is zero attenuation to radiation ray or relatively low (for example, negligible ) element of decaying can indicate air.Each of at least one element can be pixel or voxel.First air exposure mask can For distinguishing the element of expression air in image (for example, first drawing of seeds picture determined in operation 503) and not indicating air Element.First air exposure mask can be bianry image.Only as an example, indicating the member of air in the first air exposure mask Element can have the first value, without indicating that the element (for example, object) of air can have second value.First value and second value may not Together.For example, the first value can be 1, and second value can be 0.In another example the first value can be 0, and second value can be 1.Only These values are provided for purposes of illustration, it is no intended to limit scope of the present application.
In some embodiments, air exposure mask generation module 406 can determine the first air exposure mask based on initial data.Only As an example, air exposure mask generation module 406 can each element (also referred to as pictorial element) to image execute minimum It is worth back projection (BP), to determine backprojected value relevant to each element of image.Each element of image can refer to and rebuild Image in each element, and can correspond to the spatial point of object.Air exposure mask generation module 406 can based on it is right Second seed figure should be generated at least one relevant backprojected value of at least one element of at least one spatial point of object As (also referred to as air exposure mask drawing of seeds picture).Air exposure mask generation module 406 can be based further on second threshold and pass through to Two drawing of seeds picture execute threshold process to generate the first air exposure mask.Second threshold can be relevant to imaging system 100 silent Recognize value or empirical value.In some embodiments, second threshold can be arranged according to the default setting of imaging system 100, or It is preset by user or operator by terminal 130.It should be noted that in some embodiments, be different from filtered back projection and operate, it is empty Gas exposure mask generation module 406 can not need to execute filtering to initial data before executing the operation of minimum value back projection, with true Fixed first air exposure mask.In some embodiments, the filtering processing in filtered back projection is (for example, used in filtered back projection Ramp filter) low frequency component in initial data can be inhibited and enhance high fdrequency component.In addition, filtered back projection operation to cut Disconnected sensitivity.In some embodiments, the data value at position, which is truncated, sharply to be declined.That is, filtering may Steeply rising for data value is generated, near cutoff edge so as to cause the band-like puppet of white bars is shown as in result images Shadow.In addition, gibbs artifact may be propagated towards the center of result images, to reduce whole picture quality.In minimum value It, can be based on each to determine from the minimum initial data in the initial data that at least one angle detects in back projection's operation The value of element.Therefore, which may not be influenced by artifact, moreover, the operation of minimum value back projection may be insensitive to being truncated.It closes Operated in minimum value back projection and more descriptions based on Raw Data Generation the first air exposure mask can the application other Find (for example, Fig. 6 and its associated description) in place.
Alternatively, or in addition, air exposure mask generation module 406 can based on initial data and (modified) the first Subgraph determines the first air exposure mask.Only as an example, air exposure mask generation module 406 can be based on as described above original Data determine the first air exposure mask.Air exposure mask generation module 406 can be generated based on (modified) first drawing of seeds picture Second air exposure mask, for example, being generated based on third threshold value by executing threshold process to (modified) first drawing of seeds picture Second air exposure mask.Third threshold value can be default value relevant to imaging system 100 or empirical value.In some embodiments, Third threshold value can be arranged according to the default setting of imaging system 100, or can be by user or operator via terminal 130 To preset.Third threshold value can be identical or different with second threshold.Only as an example, for (modified) the first drawing of seeds picture Element, the value (also referred to as element value) of element can be compared by air exposure mask generation module 406 with third threshold value.Response It is less than third threshold value in the element value of the first drawing of seeds picture of determination (modified), air exposure mask generation module 406 can be by the One value distributes to the corresponding element of the second air exposure mask (that is, corresponding to the second of the element of (modified) first drawing of seeds picture The element of air exposure mask).Element value in response to the first drawing of seeds picture of determination (modified) is more than third threshold value, air exposure mask Second value can be distributed to the corresponding element of the second air exposure mask by generation module 406.It should be noted that in response to determination (modification The element value of the first drawing of seeds picture is equal to third threshold value afterwards), and air exposure mask generation module 406 can be by the first value or second value Distribute to the corresponding element of second air exposure mask.For example, the first value can be distributed for the corresponding element of the second air exposure mask.Again For example, second value can be distributed for the corresponding element of the second air exposure mask.When each in all elements of the second air exposure mask It is a when being all given particular value (the first value or second value), the second air exposure mask can be generated.
Air exposure mask generation module 406 can be based on the first air exposure mask and the second air exposure mask by executing logical operation (also referred to as Boolean calculation) modifies the first air exposure mask.About raw based on initial data and (modified) first drawing of seeds picture At more descriptions of the first air exposure mask (for example, Fig. 9 and its associated description) can be found elsewhere in the application.
In operation 507, processing equipment 140 (for example, rebuilding module 408) can be based on the first drawing of seeds picture, the first sky Gas exposure mask and/or initial data rebuild at least one image by executing iterative approximation.In some embodiments, at least one Image may include 3D rendering or body image.Each of at least one image may include at least one element.Each element It can be pixel or voxel.First drawing of seeds picture can provide initial pictures estimation in iterative approximation at least one image.
In some embodiments, iterative approximation may include at least one forward projection and/or at least one back projection.It is grasping Making the first air exposure mask determined in 505 can be used in the forward projection and the back projection.For example, the first air exposure mask It may include the element for indicating air and the element (for example, object) for not indicating air.Indicate that the element of air can have the One value (for example, 0), without indicating that the element of air can have second value (for example, 1).In forward projection and/or back projection It can be omitted the element for indicating air in iterative approximation.By using the first air exposure mask, can be rebuild with Accelerated iteration.It is exemplary Iterative reconstruction algorithm may include adaptive statistics iterative approximation (ASiR), the iterative approximation (MBiR) based on model, image sky Between iterative approximation (iRIS), the iterative approximation (SAFIRE) based on initial data, iterative approximation (DMBiR) based on dual model, Adaptive iteration dosage reduces (AIDR) iterative approximation, IMR etc., or any combination thereof.
In some embodiments, the first air exposure mask can be updated in the primary or above iteration of iterative approximation.Only make For example, the first air exposure mask can be generated based on the first drawing of seeds picture.Can be updated in the iteration of iterative approximation Therefore one drawing of seeds picture can update the first air exposure mask based on updated first drawing of seeds picture in the iteration.
It should be noted that the above description about process 500 is to provide for purposes of illustration, it is no intended to which limitation is originally The range of application.For those of ordinary skill in the art, various repair can be made according to the description of the present application Just and change.However, these modifications and variations are without departing from scope of the present application.It in some embodiments, can be to original number It is down-sampled according to executing.The first air exposure mask can be determined based on the initial data after down-sampled.It alternatively or additionally, can be with The first (or second) drawing of seeds picture is executed down-sampled.It can be according to the first (or second) drawing of seeds picture after down-sampled at least One block of pixels determines the first air exposure mask.Each of at least one block of pixels may include N × M pixel, for example, 3 × 2 pixels, 4 × 4 pixels, 4 × 6 pixels etc..Digital N can refer to the quantity (or counting) of the row of block of pixels, digital M It can refer to the quantity (or counting) of the column of block of pixels.In some embodiments, morphology can be executed on the first air exposure mask Operation is to modify the first air exposure mask.Morphology operations may include erosion operation, dilation operation etc., or any combination thereof.? In some embodiments, the first air exposure mask can be used for image procossing, image segmentation, image denoising etc..
In some embodiments, air exposure mask generation module 406 can be determined based on (modified) the first drawing of seeds picture First air exposure mask.Air exposure mask generation module 406 can be passed through based on first threshold to (modified) the first drawing of seeds picture Threshold process is executed to determine the first air exposure mask.First threshold can be identical or different with second threshold or third threshold value.? It is raw based on (modified) first drawing of seeds picture herein if first threshold is identical as third threshold value in some embodiments At the first air exposure mask can be identical as above-mentioned second air exposure mask.
Fig. 6 is the flow chart that the example process of air exposure mask is generated according to shown in some embodiments of the present application.? In some embodiments, implement in the imaging system 100 that at least one operation of process 600 can be shown in Fig. 1.For example, mistake Journey 600 can be stored in storage equipment 150 and/or memory 220 in the form of instruction (for example, application program), and by Processing equipment 140 (for example, the processor 210 of calculating equipment 200 as shown in Figure 2, mobile device 300 as shown in Figure 3 CPU 340, at least one module of processing equipment 140 as shown in Figure 4 etc.) it calls and/or executes.In another example process 600 A part can be implemented on imaging device 110.The operation of shown process presented below is intended to illustrate.In some embodiments In, process 600 can add at least one operation bidirectional not described when implementing, and/or delete at least one this place and retouch The operation stated.In addition, the operation order of process 600 shown in Fig. 6 and operations described below are sequentially and without restriction.? It, can be according to the operation 505 of 600 implementation procedure 500 of process in some embodiments.
Operation 601 in, processing equipment 140 (for example, air exposure mask generation module 406) can to initial data (for example, The initial data obtained in 501) execute low-pass filtering.Initial data can be by least one detection of detector module 112 Device detection.At least one detector can be arranged along channel direction and line direction.In some embodiments, air exposure mask generates mould Block 406 can execute one-dimensional (1D) low-pass filtering to initial data in channel direction before executing minimum value back projection.Or Person, air exposure mask generation module 406 can before executing minimum value back projection in channel direction and line direction to original number According to executing two dimension (2D) low-pass filtering.In some embodiments, it is convenient to omit operation 601.Air exposure mask generation module 406 can be with It omits the filtering to initial data and minimum value back projection directly is executed to initial data.
In operation 603, processing equipment 140 (for example, air exposure mask generation module 406) can be by specifying initial data Or the smallest initial data of a part of modified data is come as the backprojected value of each element of at least one image Execute minimum value back projection.The part of initial data can be related to each element and is detected from least one angle 's.Modified data can be generated based on initial data by interpolation.
Only as an example, each element of image can correspond to the spatial point of object.The radiation emitted from radiation source 113 Ray (for example, X-ray) can pass through the spatial point of object from least one angle and be detected by detector module 112. Air exposure mask generation module 406 can compare the initial data relevant to each element detected, and the original that will test Substantially the smallest initial data in beginning data is appointed as the backprojected value of each element.In some embodiments, from least The radiation ray for the spatial point that special angle in one angle passes through object may not be directly by the inspection of detector module 112 Device is surveyed to detect.For example, radiation ray can irradiate on gap between the two detectors.Data corresponding to radiation ray (also referred to as modified data) can be original based on detecting at two or more angles adjacent with special angle Data are generated by interpolation.Interpolation may include nearest neighbor pixels interpolation, linear interpolation etc..
In operation 605, processing equipment 140 (for example, air exposure mask generation module 406) can be based on first at least one Element relevant at least one backprojected value generates second seed image.Each element at least one element can be passed through Backprojected value is distributed to generate second seed image (also referred to as air exposure mask drawing of seeds picture).With generated based on filtered back projection First drawing of seeds picture is different, and second seed image, which can be by executing minimum value back projection to initial data, to be generated.? In some embodiments, second seed image cannot reflect the actual attenuation information of radiation ray, and second seed image is not It can be used as the initial pictures estimation of iterative approximation.
In operation 607, processing equipment 140 (for example, air exposure mask generation module 406) can be passed through based on second threshold Threshold process is executed to second seed image to generate the first air exposure mask.In some embodiments, the first air exposure mask is available The element of air is indicated in differentiation second seed image and/or does not indicate the element of air (for example, indicating the member of non-air Element).It only as an example, in the first air exposure mask, indicates that the element of air can have the first value (for example, 0), and indicates non-empty The element of gas can have second value (for example, 1).
In some embodiments, for the element of second seed image, air exposure mask generation module 406 can be by element Value (also referred to as element value) is compared with second threshold.Indicate that the element of air may be than not indicating the element of air with low Radiation ray dampening information.In response to determining that the element value of second seed image is less than second threshold, air exposure mask generates mould First value can be distributed to the corresponding element of the first air exposure mask (that is, corresponding to the of the element of second seed image by block 406 The element of one air exposure mask).In response to determining that the element value of second seed image is more than second threshold, air exposure mask generation module 406 can distribute to second value the corresponding element of the first air exposure mask.It should be noted that in response to determining second seed image Element value is equal to second threshold, and the first value or second value can be distributed to the first air exposure mask by air exposure mask generation module 406 Corresponding element.For example, the first value can be distributed for the corresponding element of the first air exposure mask.In another example can be the first air The corresponding element of exposure mask distributes second value.When each of all elements of the first air exposure mask are all given particular value ( One value or second value) when, the first air exposure mask can be generated.Second threshold can be default value relevant to imaging system 100 Or empirical value.
It should be noted that the above description about process 600 is to provide for purposes of illustration, and be not intended to be limited to Scope of the present application.For those of ordinary skill in the art, it can be made various according to the description of the present application Modifications and variations.However, these modifications and variations are without departing from scope of the present application.In some embodiments, minimum is being executed It is worth before back projection, processing equipment 140 can execute wave absorption operation to (filtered) initial data.Wave absorption operation, which can refer to, repairs Change the operation of at least one a reference value.In the operation of exemplary wave absorption, its a reference value can be less than reference value by processing equipment 140 A part of initial data be converted to reference value (for example, by negative be converted to 0).
Fig. 7 A-7D is the schematic diagram of the exemplary drawing of seeds picture of the object according to shown in some embodiments of the present application.Figure Drawing of seeds picture shown in 7A-7D is based on the identical Raw Data Generation not being truncated.Fig. 7 A and 7C are shown not Same image under same window width (WW) and window position (WL), being also referred to as the first drawing of seeds picture in this application, (or filtering is anti-throws Shadow drawing of seeds picture).Fig. 7 B and 7D show the same image under different window widths (WW) and window position (WL), in this application Referred to as second seed image (or air exposure mask drawing of seeds picture).In some embodiments, the window width (WW) of image can influence The contrast of image, the window position (WL) of image can influence the brightness of image.First drawing of seeds picture shown in Fig. 7 A and 7C ( It is filtered back projection's drawing of seeds picture) it is to be generated according to Feldkamp-Davis-Kress (FDK) algorithm.FDK algorithm is a kind of Filter back-projection algorithm.Second seed image shown in Fig. 7 B and 7D (and air exposure mask drawing of seeds picture) is according to the application Described in minimum value backprojection algorithm generate.First area 701 shown in Fig. 7 A indicates object, second area 703 (that is, other regions) indicate background information (for example, air, bed board etc.).Similarly, 702 table of first area shown in Fig. 7 B Show object, and second area 704 (that is, other regions) indicates background information (for example, air, bed board etc.).
The first profile for multiple elements that filtered back projection's drawing of seeds picture is expert at 705 is shown in Fig. 7 A.Show in Fig. 7 B The second profile of multiple elements that air exposure mask drawing of seeds picture is expert at 706 is gone out.Row 706 has position corresponding with row 705 It sets (that is, row 705 and row 706 can weigh if filtered back projection's drawing of seeds picture and air exposure mask drawing of seeds picture are aligned and are overlapped It closes).The element value (for example, gray value) of first profile reflection row 705.Second profile reflects the element value of row 706 (for example, ash Angle value).Element value near 0 likely corresponds to air.Element value near 0 in first profile is (with solid line circle mark in Fig. 7 A Note) it is fluctuation, it means that and the variation of the element value near 0 in row 705 is relatively apparent.Near 0 in second profile Element value (being marked in Fig. 7 B with dashed circle) is smooth, it means that the variation of the element value near 0 in row 706 is relatively It is small.If to filtered back projection's drawing of seeds picture and air exposure mask drawing of seeds picture execution threshold process to generate air exposure mask respectively, Because threshold processing operations, which are more likely to be fluctuated by element value, to be influenced, then the air exposure mask generated based on air exposure mask drawing of seeds picture It may be more more acurrate than filtered back projection drawing of seeds picture.
In order to compare the first drawing of seeds picture and second seed image, the first drawing of seeds picture and second seed image are displayed on Under identical window width and window position.Specifically, as shown in figs. 7 c and 7d, window width can be 100 Heng Shi units (HU), and window position can be 0HU.As seen in figure 7 c, the element in first area 701 has relatively high element value and is shown as white.Second area 703 In element have and relatively low element value and appear dimmed.Similarly, as illustrated in fig. 7d, the element in first area 702 With relatively high element value and it is shown as white.Element in second area 704 has relatively low element value and display For grey.The element value of second area 703 is non-uniform, and the element value of second area 704 is uniform.That is, Second seed image can provide the clear profile of object, and the noise in second seed image can be minimized, this can be with Promote to divide or distinguish air section and non-air region (for example, object) by threshold process.It in some embodiments, can be with Air exposure mask is generated by executing threshold process to second seed image.
Fig. 8 A-8D is the schematic diagram of the exemplary drawing of seeds picture of the object according to shown in some embodiments of the present application.Figure Drawing of seeds picture shown in 8A-8D is based on the identical Raw Data Generation with truncation.If object extends to imaging and sets Except standby 110 (scanning) visual field (FOV), then truncation can be introduced in cross sectional reconstruction.Fig. 8 A and 8C are shown in difference Same image under window width (WW) and window position (WL) is also referred to as the first drawing of seeds picture (and filtered back projection in this application Drawing of seeds picture).Fig. 8 B and 8D show the same image under different window widths (WW) and window position (WL), are also referred to as in this application For second seed image (and air exposure mask drawing of seeds picture).First drawing of seeds picture shown in Fig. 8 A and 8C (and filtering is anti- Projection drawing of seeds picture) it can be generated according to Feldkamp-Davis-Kress (FDK) algorithm.FDK algorithm, which is that a kind of filtering is anti-, to be thrown Shadow algorithm.Second seed image shown in Fig. 8 B and 8D (and air exposure mask drawing of seeds picture) can be described according in the application Minimum value backprojection algorithm generate.First area 801 shown in Fig. 8 A indicates object, and second area 803 is (that is, other areas Domain) indicate background information (for example, air, bed board etc.).Similarly, the expression of first area 802 shown in Fig. 8 B object, second Region 804 (that is, other regions) indicates background information (for example, air, bed board etc.).
The first profile for multiple elements that filtered back projection's drawing of seeds picture is expert at 805 is shown in Fig. 8 A.Show in Fig. 8 B The second profile of multiple elements that air exposure mask drawing of seeds picture is expert at 806 is gone out.Row 806 has position corresponding with row 805 Set (that is, row 805 and row 806 can be overlapped if the first drawing of seeds picture and second seed image alignment and be overlapped).The first round Exterior feature reflects the element value (for example, gray value) of row 805.Second profile reflects the element value (for example, gray value) of row 806.0 Neighbouring element value likely corresponds to air.Element value (being marked in Fig. 8 A with solid line circle) near 0 in first profile is wave Dynamic, it means that the variation of the element value near 0 in row 805 is relatively obvious.Element value (Fig. 8 B near 0 in second profile It is middle to be marked with dashed circle) it is smooth, it means that and the variation of the element value near 0 in row 806 is relatively small.In addition, by In data truncation, the value of the element of the boundary between air and object in first profile may suddenly change (such as figure Shown in arrow 807 in 8A).
In some embodiments, in order to compare the first drawing of seeds picture and second seed image, the first drawing of seeds picture and second Drawing of seeds picture may be displayed under identical window width and window position.Specifically, as shown in figures 8 c and 8d, window width can be 100HU, window Position can be 0HU.As shown in Figure 8 C, the element in first area 801 has relatively high element value and is shown as white.It should Note that a part of the element value in second area 803 is higher than the element value of air due to data truncation.Therefore, it is difficult to Divide or distinguish air and object in one drawing of seeds picture.As in fig. 8d, the element in first area 802 has relatively high Element value is simultaneously shown as white.Element in second area 804 has relatively low element value and appears dimmed.Second area 804 element value is uniform, therefore convenient for dividing or distinguishing air and object in second seed image.That is, working as It, can be with according to the second seed image that minimum value backprojection algorithm described in this application generates when occurring or executing data truncation Air exposure mask is more easily generated, and air exposure mask generated can be more acurrate.
Fig. 9 is showing for modification air exposure mask (for example, first air exposure mask) according to shown in some embodiments of the present application The flow chart of example property process.In some embodiments, the imaging system that at least one operation of process 900 can be shown in Fig. 1 Implement in system 100.For example, process 900 can be stored in the form of instruction (for example, application program) storage equipment 150 and/or In memory 220, and by processing equipment 140 (for example, processor 210, such as Fig. 3 in calculating equipment 200 as shown in Figure 2 Shown in the CPU 340 of mobile device 300, at least one module of processing equipment 140 as shown in Figure 4 etc.) call and/or hold Row.In another example a part of of process 900 can implement on imaging device 110.The operation of shown process presented below is intended to Explanation.In some embodiments, process 900 can add at least one operation bidirectional not described when implementing, and/or delete At least one operation described herein.In addition, the operation order of process 900 and operations described below shown in Fig. 9 Sequence is simultaneously without restriction.It in some embodiments, can be according to the operation 505 of 900 implementation procedure 500 of process.
In operation 901, processing equipment 140 (for example, drawing of seeds picture correction module 410) can be by from the first drawing of seeds Outer ring background is subtracted as in and/or low-pass filtering is executed to the first drawing of seeds picture to modify the first drawing of seeds picture.
In some embodiments, drawing of seeds picture correction module 410 can execute low-pass filtering to the first drawing of seeds picture.Example Such as, drawing of seeds picture correction module 410 can be in the channel direction of at least one detector of detector module 112 to the first Subgraph executes one-dimensional (1D) low-pass filtering.In another example drawing of seeds picture correction module 410 can detector module 112 extremely Two dimension (2D) low-pass filtering is executed to the first drawing of seeds picture in the channel direction of a few detector and on line direction.Two-dimensional filtering The size of device can be, for example, 5 × 5,10 × 10 etc..In some embodiments, drawing of seeds picture correction module 410 can pass through Outer ring background is subtracted from the first drawing of seeds picture to modify the first drawing of seeds picture.Outer ring can correspond to (sweeping for imaging device 110 Retouch) region between the visual field (FOV) and the machine frame hole of imaging device 110.Modification and/or correction about the first drawing of seeds picture It is more description can be found elsewhere (for example, the operation 1405 of process 1400, process 1600 and its phase in the application Close description).
In operation 903, processing equipment 140 (for example, air exposure mask generation module 406) can be passed through based on third threshold value Threshold process is executed to (modified) first drawing of seeds picture to generate the second air exposure mask.Second air exposure mask can be two-value Image, including the element with the first value and with the element of second value.In some embodiments, the element with the first value can To indicate air, the element with second value can indicate other regions (for example, object) of image.In some embodiments, Second air exposure mask can be different from the first air exposure mask (that is, at least one element of the second air exposure mask can be with the first sky The corresponding element of gas exposure mask is different).In some embodiments, the second air exposure mask can be used for modifying the first air exposure mask.One In a little embodiments, it is convenient to omit operation 901, it can be based on third threshold value by executing threshold process next life to the first drawing of seeds picture At the second air exposure mask.
In some embodiments, for the element of (modified) the first drawing of seeds picture, air exposure mask generation module 406 can The value of element to be compared with third threshold value.It is less than in response to the value of the element of the first drawing of seeds picture of determination (modified) First value can be distributed to the corresponding element of the second air exposure mask (that is, corresponding by third threshold value, air exposure mask generation module 406 In the element of the second air exposure mask of the element of (modified) first drawing of seeds picture).In response to determination (modified) first The value of the element of drawing of seeds picture is more than third threshold value, and second value can be distributed to the second air by air exposure mask generation module 406 The corresponding element of exposure mask.It should be noted that being equal to third threshold in response to the value of the element of the first drawing of seeds picture of determination (modified) First value or second value can be distributed to the corresponding element of the second air exposure mask by value, air exposure mask generation module 406.For example, The first value can be distributed for the corresponding element of the second air exposure mask.In another example can be the corresponding element point of the second air exposure mask With second value.When each element of the second air exposure mask is given particular value (the first value or second value), second can produce Air exposure mask.Third threshold value can be default value relevant to imaging system 100 or empirical value.In some embodiments, third Threshold value can be arranged according to the default setting of imaging system 100, or be preset by user or operator via terminal 130.
In operation 905, processing equipment 140 (for example, air exposure mask generation module 406) can be based on the first air exposure mask (also referred to as boolean transports by executing logical operation for (for example, the first air exposure mask generated in operation 607) and the second air exposure mask Calculate) modify the first air exposure mask.In some embodiments, air exposure mask generation module 406 can be to the first air exposure mask and Two air exposure masks execute inclusive-OR operation or "and" operation.In some embodiments, the first air exposure mask and the second air exposure mask be all It can be bianry image.Only as an example, in the first air exposure mask and the second air exposure mask, indicate that the element of air can have First value, and second value can be had by indicating the element in other regions (for example, object).First value and second value may be different.Example Such as, the first value can be 1, and second value can be 0.In another example the first value can be 0, and second value can be 1.Merely for The purpose of explanation provides these values, and is not intended to be limited to scope of the present application.
Only as an example, when modifying the first air exposure mask, air exposure mask generation module 406, which can choose, executes "and" fortune It calculates.That is, air exposure mask generation module 406 can be to pair in the element and the second air exposure mask in the first air exposure mask Element is answered to execute "and" operation.In another example air exposure mask generation module 406, which can choose, to be held when modifying the first air exposure mask Row inclusive-OR operation.That is, air exposure mask generation module 406 can in the first air exposure mask element and the second air cover Corresponding element in film executes inclusive-OR operation.The selection mode can determine by the default setting of imaging system 100, or Person is default via terminal 130 by user or adjusts.
Only as an example, indicating that the value of the element of air can be 0 in the first air exposure mask and the second air exposure mask, and the Indicate that the value of the element in other regions can be 1 in one air exposure mask and the second air exposure mask.If executing inclusive-OR operation, repair Do not indicate that the quantity (or counting) of the element of air can increase relative to the first air exposure mask in the first air exposure mask after changing, Correspondingly, indicate that the quantity (or counting) of the element of air can relative to the first air exposure mask in modified first air exposure mask It can be reduced.Therefore, the iterative approximation based on modified first air exposure mask may be than changing based on original first air exposure mask Generation, which rebuilds, is related to more pixels, to increase the calculating cost of reconstruction.Alternatively, if executing "and" operation, modified the Do not indicate that the quantity (or counting) of the element of air is likely to reduced relative to the first air exposure mask in one air exposure mask, correspondingly, Indicate that the quantity (or counting) of the element of air can increase relative to the first air exposure mask in modified first air exposure mask. Therefore, it can be rebuild based on modified first air exposure mask with Accelerated iteration.
As another example, indicate that the value of the element of air can be 1 in the first air exposure mask and the second air exposure mask, And do not indicate that the value of the element of air can be 0 in the first air exposure mask and the second air exposure mask.If executing inclusive-OR operation, Indicate that the quantity (or counting) of the element of air can increase relative to the first air exposure mask in modified first air exposure mask, Correspondingly, do not indicate the quantity (or counting) of the element of air relative to the first air exposure mask in modified first air exposure mask It is likely to reduced.Therefore, it can be rebuild based on modified first air exposure mask with Accelerated iteration.Alternatively, if executing "and" operation, Then indicate that the quantity (or counting) of the element of air may subtract relative to the first air exposure mask in modified first air exposure mask It is few, correspondingly, do not indicate the quantity (or counting) of the element of air relative to the first air in modified first air exposure mask Exposure mask can increase.Therefore, the iterative approximation based on modified first air exposure mask may be than being covered based on original first air The iterative approximation of film is related to more pixels, to increase the calculating cost of reconstruction.
In operation 907, processing equipment 140 (for example, air exposure mask generation module 406) can be empty to modified first Gas exposure mask executes morphology operations.In some embodiments, morphology operations may include erosion operation, dilation operation, opening operation, Closed operation etc., or any combination thereof.In some embodiments, air exposure mask generation module 406 can be executed based on structural element Morphology operations.Structural element can be relatively small bianry image (that is, the relatively small square of pixel or voxel composition Battle array each has 1 or 0 value).In some embodiments, the size of structural element can be less than air exposure mask.In some implementations In example, the size of structural element can be 3 × 4,5 × 5,10 × 10 etc..In some embodiments, the starting point of structural element can be with It is one in pixel or voxel.In some embodiments, the value of the starting point of structural element can be 1.In some embodiments, Modified first air exposure mask can be still bianry image, including have the first value (for example, 0) and second value (for example, 1) Element.Air exposure mask generation module 406 can execute morphology operations to modified first air exposure mask.
It should be noted that the above description about process 900 is to provide for purposes of illustration, it is no intended to which limitation is originally The range of application.For those of ordinary skill in the art, various repair can be made according to the description of the present application Just and change.However, these modifications and variations are without departing from scope of the present application.In some embodiments, it is convenient to omit operation 907.In some embodiments, in operation 905 the modified first air exposure mask that generates or generated in operation 907 into First air exposure mask of one step modification, can substitute the first air exposure mask generated in operation 505, in operation 507 Shown in iterative approximation to accelerate image reconstruction.
Figure 10 A is the schematic diagram that the example process of air exposure mask is generated according to shown in some embodiments of the present application. At least one air exposure mask can be generated by executing different operations to initial data.
Only as an example, as shown in Figure 10 A, processing equipment 140 can be executed in initial data minimum value back projection with Air exposure mask drawing of seeds picture V1 is generated, threshold value T1 is based further on and threshold process is executed to air exposure mask drawing of seeds picture V1, with true Determine air exposure mask I.More descriptions of generation about air exposure mask I can finding elsewhere (for example, Fig. 6 in the application Shown in operation 603 to 607 and its description).Threshold value T1 can be, for example, default value relevant to imaging system 100 or warp Test value.
In another example processing equipment 140 can execute wave absorption operation to initial data first, the initial data after wave absorption is held Row minimum value back projection is based further on threshold value T2 and holds to air exposure mask drawing of seeds picture V2 to generate air exposure mask drawing of seeds picture V2 Row threshold process, to determine air exposure mask II.More descriptions of generation about air exposure mask II can the application other Find (for example, process 600 shown in Fig. 6 and its description) in place.Threshold value T2 can be, for example, related to imaging system 100 Default value or empirical value.
For another example processing equipment 140 can execute one-dimensional (1D) low-pass filtering to initial data in channel direction, to filter Initial data after wave executes minimum value back projection to generate air exposure mask drawing of seeds picture V3, is based further on threshold value T3 to air Exposure mask drawing of seeds picture V3 executes threshold process, to determine air exposure mask III.More descriptions of generation about air exposure mask III (for example, process 600 shown in Fig. 6 and its description) can be found elsewhere in the application.Threshold value T3 can be, example Such as, default value relevant to imaging system 100 or empirical value.
For another example processing equipment 140 can execute one-dimensional (1D) low-pass filtering to initial data in channel direction, to filter Initial data after wave executes wave absorption operation, executes minimum value back projection to the initial data after wave absorption to generate air exposure mask kind Subgraph V4 is based further on threshold value T4 and executes threshold process to air exposure mask drawing of seeds picture V4, to determine air exposure mask IV.It closes It can be found elsewhere (for example, process shown in Fig. 6 in the application in more descriptions of the generation of air exposure mask IV 600 and its description).Threshold value T4 can be, for example, default value relevant to imaging system 100 or empirical value.
For another example processing equipment 140 can execute two dimension (2D) low pass to initial data in channel direction and line direction Filtering executes minimum value back projection to filtered initial data to generate air exposure mask drawing of seeds picture V5, is based further on threshold Value T5 executes threshold process to air exposure mask drawing of seeds picture V5, to determine air exposure mask V.Generation about air exposure mask V is more More descriptions can find (for example, process 600 shown in Fig. 6 and its description) in the application elsewhere.Threshold value T5 can be with It is, for example, default value relevant to imaging system 100 or empirical value.
For another example processing equipment 140 can execute two dimension (2D) low pass to initial data in channel direction and line direction Filtering, executes wave absorption operation to filtered initial data, executes minimum value back projection to the initial data after wave absorption to generate Air exposure mask drawing of seeds picture V6 is based further on threshold value T6 and executes threshold process to air exposure mask drawing of seeds picture V6, empty to determine Gas exposure mask VI.More descriptions of generation about air exposure mask VI can finding elsewhere (for example, in Fig. 6 in the application Shown in process 600 and its description).Threshold value T6 can be, for example, default value relevant to imaging system 100 or empirical value.? In some embodiments, all threshold value T1-T6 can be identical.In some embodiments, at least two threshold values of threshold value T1-T6 can be with It is identical.In some embodiments, at least two threshold values of threshold value T1-T6 can be different.In some embodiments, institute There is threshold value T1-T6 different from each other.
Figure 10 B is the schematic diagram that the example process of air exposure mask is generated according to shown in some embodiments of the present application. As shown in Figure 10 B, processing equipment 140 can to initial data execute filtered back projection to generate filtered back projection's drawing of seeds picture, And threshold process is executed to filtered back projection's drawing of seeds picture to generate the second air exposure mask based on threshold value T.Used in Figure 10 B Initial data is identical as the initial data in Figure 10 A.Threshold value T can be, for example, default value relevant to imaging system 100 or Empirical value.Processing equipment 140 can by air exposure mask I (referring to Figure 10 A) and the second air exposure mask execute Boolean calculation come It determines air exposure mask HI, determine sky by executing Boolean calculation to air exposure mask II (referring to Figure 10 A) and the second air exposure mask Gas exposure mask HII, determine that air is covered by executing Boolean calculation to air exposure mask III (referring to Figure 10 A) and the second air exposure mask Film HIII, air exposure mask is determined by executing Boolean calculation to air exposure mask IV (referring to Figure 10 A) and the second air exposure mask HIV, air exposure mask HV is determined by executing Boolean calculation to air exposure mask V (referring to Figure 10 A) and the second air exposure mask and is led to It crosses to Boolean calculation is executed on air exposure mask VI (see Figure 10 A) and the second air exposure mask and determines air exposure mask HVI.About air More descriptions of the generation of exposure mask HI-HVI can finding elsewhere (for example, operating 903 shown in Fig. 9 in the application With 905, and its description).
Figure 11 A shows the air exposure mask drawing of seeds picture corresponding to air exposure mask described in Figure 10 A.Air exposure mask seed Image (that is, air exposure mask drawing of seeds picture V1-V6) can the generation of the process according to shown in Figure 10 A.By to air exposure mask kind Subgraph carries out threshold process, and corresponding air exposure mask can be generated.As shown in Figure 11 A, the air corresponding to air exposure mask I is covered Film drawing of seeds picture is referred to as air exposure mask drawing of seeds picture I, the air exposure mask drawing of seeds picture referred to as sky corresponding to air exposure mask II Gas exposure mask drawing of seeds picture II, it is referred to as air exposure mask drawing of seeds picture corresponding to the air exposure mask drawing of seeds picture of air exposure mask III III, corresponding to air exposure mask IV air exposure mask drawing of seeds picture be referred to as air exposure mask drawing of seeds picture IV, correspond to air exposure mask The air exposure mask drawing of seeds picture of V is referred to as air exposure mask drawing of seeds picture V, the air exposure mask drawing of seeds picture corresponding to air exposure mask VI Referred to as air exposure mask drawing of seeds picture VI.Air exposure mask drawing of seeds picture I-VI is generated based on the data of truncation.If object extends To except (scanning) visual field (FOV) of imaging device 110, then data truncation may be introduced.Due to data truncation, covered in air Striped is introduced in film drawing of seeds picture (for example, in solid line and dashed circle in air exposure mask drawing of seeds picture I-VI in Figure 11 A Striped).Air exposure mask drawing of seeds picture VI includes less striped (for example, striped in solid line), this can accelerate to pass through threshold Value processing is to divide or distinguish air section and non-air region.
Figure 11 B shows the air exposure mask drawing of seeds picture corresponding to air exposure mask described in Figure 10 B.Air exposure mask seed Image can modify air exposure mask drawing of seeds picture I-VI by using filtered back projection's drawing of seeds picture to generate.By being covered to air Film drawing of seeds picture executes threshold process, and corresponding air exposure mask can be generated.As shown in Figure 11 B, corresponding to air exposure mask HI's Air exposure mask drawing of seeds picture is referred to as air exposure mask drawing of seeds picture HI, the air exposure mask drawing of seeds picture corresponding to air exposure mask HII Referred to as air exposure mask drawing of seeds picture HII, it is referred to as air exposure mask corresponding to the air exposure mask drawing of seeds picture of air exposure mask HIII Drawing of seeds picture HIII, it is referred to as air exposure mask drawing of seeds picture HIV, right corresponding to the air exposure mask drawing of seeds picture of air exposure mask HIV Air exposure mask drawing of seeds picture HV should be referred to as, corresponding to air exposure mask HVI's in the air exposure mask drawing of seeds picture of air exposure mask HV Air exposure mask drawing of seeds picture is referred to as air exposure mask drawing of seeds picture HVI.As shown in Figure 11 B, air exposure mask drawing of seeds picture HI-HVI Striped in middle solid line circle is reduced relative to the striped in the air exposure mask drawing of seeds picture I-VI in Figure 11 A.Air exposure mask kind Striped in contrast of fringes air exposure mask drawing of seeds picture I-VI in dashed circle in subgraph HI-HVI is reduced.Air exposure mask kind Subgraph HVI has least striped, and provides the clear profile of object.Therefore, air exposure mask drawing of seeds picture HVI can be effective Ground identifies the air section polluted by striped, and identifies the object for having similar HU with air section.
Figure 12 A is the schematic diagram that the example process of air exposure mask is generated according to shown in some embodiments of the present application. As illustrated in fig. 12, processing equipment 140 can execute filtered back projection to initial data to generate the first drawing of seeds picture.Processing is set Standby 140 can modify the first drawing of seeds picture by subtracting outer ring background from the first drawing of seeds picture, to optimize the first drawing of seeds Picture.Processing equipment 140 can execute two dimension (2D) low-pass filtering to the first drawing of seeds picture to reduce jail-bar artifacts.Due to projection line Between interpolation, there may be jail-bar artifacts during back projection.The presence of jail-bar artifacts may cause to fault feature Erroneous judgement.Therefore, it may be desirable for reducing jail-bar artifacts in some embodiments.It is for illustration purposes only, two dimensional filter Size can be 5 × 5.Processing equipment 140 be also based on threshold value T to it is modified (that is, optimization after and/or filtering after ) the first drawing of seeds picture execute threshold process to generate air exposure mask VII.First threshold T can be, for example, and imaging system 100 relevant default values or empirical value.For example, threshold value T can be 30HU when initial data includes CT data.Processing equipment 140 can also execute morphology operations to air exposure mask VII, and can determine modified air exposure mask VII.For example, place Two-dimensional swelling operation can be executed to air exposure mask VII by managing equipment 140.The ruler of the structural element used in two-dimensional swelling operation It is very little to can be 10 × 10, it is much smaller than the size of air exposure mask VII.
Figure 12 B is the signal that the another exemplary process of air exposure mask is generated according to shown in some embodiments of the present application Figure.As shown in Figure 12 B, processing equipment 140 can execute filtered back projection to initial data to generate the first drawing of seeds picture.Figure Initial data used in 12B is identical as the initial data in Figure 12 A.Processing equipment 140 can be by from the first drawing of seeds picture In subtract outer ring background to modify the first drawing of seeds picture, to optimize the first drawing of seeds picture.Processing equipment 140 can be to the first seed Image executes two dimension (2D) low-pass filtering to reduce jail-bar artifacts.It, can during back projection due to the interpolation between projection line Jail-bar artifacts can be generated.The presence of jail-bar artifacts may cause the erroneous judgement to fault feature.Therefore, subtract in some embodiments Few jail-bar artifacts may be desirable.It is for illustration purposes only, the size of two dimensional filter can be 5 × 5.Processing equipment 140 Can based on first threshold T1 to it is modified (that is, optimization after and/or it is filtered) the first drawing of seeds picture execute threshold value at Reason is to generate the second air exposure mask.First threshold T1 can be, for example, default value relevant to imaging system 100 or empirical value. For example, first threshold T1 can be 30HU when initial data includes CT data.Meanwhile processing equipment 140 can be to original number According to executing two dimension (2D) low-pass filtering, and minimum value back projection is executed to generate second of subgraph to filtered initial data Picture.Processing equipment 140 is also based on second threshold T2 and executes threshold process to second seed image, is covered with generating the first air Film.Second threshold T2 can be, for example, default value relevant to imaging system 100 or empirical value.For example, second threshold T2 can To be 0.Processing equipment 140 can execute Boolean calculation to the first air exposure mask and the second air exposure mask.For example, processing equipment 140 can determine modified first air exposure mask by executing inclusive-OR operation to the first air exposure mask and the second air exposure mask (for example, air exposure mask VIII).After inclusive-OR operation, do not indicated in air exposure mask VIII the element of air quantity (or meter Number) it can increase relative to air exposure mask VII.In some embodiments, processing equipment 140 can also hold air exposure mask VIII Row morphology operations, and can determine modified air exposure mask VIII.For example, processing equipment 140 can be to air exposure mask VIII executes closed operation (first dilation operation, post-etching operation).The size of the structural element used in closed operation can be 10 × 10, this is much smaller than the size of air exposure mask VIII.
Figure 13 A and 13B are the examples for not having a part of object of truncation according to shown in some embodiments of the present application Property air exposure mask drawing of seeds picture.Air exposure mask drawing of seeds picture shown in Figure 13 A is that the process according to shown in Figure 12 A generates 's.By carrying out threshold process to air exposure mask drawing of seeds picture VII, corresponding air exposure mask VII can be generated.Institute in Figure 13 B The air exposure mask drawing of seeds picture shown is that the process according to shown in Figure 12 B generates.By to air exposure mask drawing of seeds picture VIII Threshold process is carried out, corresponding air exposure mask VIII can be generated.Figure 13 C, which is shown, to be based on and same target in Figure 13 A and 13B Identical Raw Data Generation exemplary filter back projection drawing of seeds picture.Filtered back projection's drawing of seeds picture shown in Figure 13 C It is to be generated according to filter back-projection algorithm.
Figure 13 D and 13E are showing for another part of the object with truncation according to shown in some embodiments of the present application Example property air exposure mask drawing of seeds picture.Similar to air exposure mask shown in air exposure mask drawing of seeds picture VII, Figure 13 D in Figure 13 A Drawing of seeds picture VII' is that the process according to shown in Figure 12 A generates.Similar in air exposure mask drawing of seeds picture VIII, Figure 13 E Shown in air exposure mask drawing of seeds picture VIII' be that the process according to shown in Figure 12 B generates.Figure 13 F, which is shown, to be based on and figure The exemplary filter back projection drawing of seeds picture of the identical Raw Data Generation of same target in 13D and 13E.Shown in Figure 13 F Filtered back projection's drawing of seeds picture is generated according to filter back-projection algorithm.
As illustrated in figures 13 a and 13b, background information can be efficiently identified in air exposure mask drawing of seeds picture VII and VIII (for example, bed board, air) and object.Air exposure mask drawing of seeds picture VII includes the hole (example between the area-of-interest of object Such as, corresponding to each hole of air section), and air exposure mask drawing of seeds picture VIII includes the air zone of lesser amt (or counting) It domain and can more be connected to.It as shown in figures 13 d and 13e, can be in air exposure mask drawing of seeds picture VII' and air exposure mask kind Background information (for example, bed board, air) and object are efficiently identified in subgraph VIII'.Air exposure mask drawing of seeds picture VII' packet It is contained in the hole each hole of air section (for example, correspond to) between the area-of-interest of object, and air exposure mask drawing of seeds picture VIII' includes the air section of smaller amounts (or counting) and can more be connected to.Therefore, it is based on air exposure mask VIII The iteration weight of (for example, the air exposure mask generated based on air exposure mask drawing of seeds picture VIII' or air exposure mask drawing of seeds picture VIII) Building may be than being based on air exposure mask VII (for example, raw based on air exposure mask drawing of seeds picture VII' or air exposure mask drawing of seeds picture VII At air exposure mask) iterative approximation to can be calculation amount bigger and safer.
Figure 14 A is the process that the example process of at least one image is rebuild according to shown in some embodiments of the present application Figure.In some embodiments, implement in the imaging system 100 that at least one operation of process 1400 can be shown in Fig. 1.Example Such as, process 1400 can be stored in storage equipment 150 and/or memory 220 in the form of instruction (for example, application program), And by processing equipment 140 (for example, the processor 210 of calculating equipment 200 as shown in Figure 2, mobile device as shown in Figure 3 300 CPU 340, at least one module of processing equipment 140 as shown in Figure 4 etc.) it calls and/or executes.In another example process 1400 a part of can implement on imaging device 110.The operation of shown process presented below is intended to illustrate.In some realities It applies in example, process 1400 can add at least one operation bidirectional not described when implementing, and/or delete at least one herein Described operation.In addition, process 1400 as shown in Figure 14 A and operation described below sequence is not limiting.
In operation 1401, processing equipment 140 (for example, obtain module 402) it is available by imaging device (for example, at As equipment 110) initial data that detects.The initial data can reflect the radiation ray (for example, X-ray) across object Dampening information, and be commonly used for generating relevant to object at least one image.In some embodiments, can by As equipment 110 detects and/or collect initial data from least one angle.Initial data may include corresponding at least one angle At least one set of data.In some embodiments, view is alternatively referred to as from one group of initial data that equal angular is collected.About original More descriptions of beginning data can finding elsewhere (for example, the operation 501 of process 500 and its correlation are retouched in the application It states).
In some embodiments, obtain module 402 (can set from least one component of imaging system 100 for example, being imaged Standby 110, terminal (for example, terminal 130), storage equipment (for example, storage equipment 150) etc.) obtain initial data.Optionally or separately Other places, initial data can be obtained from external source via network 120 by obtaining module 402.For example, obtaining module 402 can take up a job as a doctor It learns database and obtains initial data.
In operation 1403, drawing of seeds picture is can be generated in processing equipment 140 (for example, drawing of seeds picture generation module 404).? In some embodiments, drawing of seeds picture generation module 404 can be by executing filtering to the initial data obtained in operation 1401 Back projection generates drawing of seeds picture.Drawing of seeds picture may include at least one element.Each element can be the sky corresponding to object Between the pixel put or voxel.In the operation of exemplary filter back projection, drawing of seeds picture generation module 404 can be at least one set (for example, every group) initial data executes filtering.In some embodiments, such as high-pass filter, slope filter can be used Deng or any combination thereof execute filtering.In some embodiments, every group of initial data (also referred to as each view) can be with filter The kernel of wave device carries out convolution to generate view-filtered.Drawing of seeds picture generation module 404 can hold at least one view-filtered Row back projection is to rebuild the first drawing of seeds picture.
In operation 1405, processing equipment 140 (for example, drawing of seeds picture correction module 410) can be by from drawing of seeds picture In subtract outer ring background determine correction after drawing of seeds picture.Outer ring background likely corresponds to the background of outer ring.Outer ring can be right It should be in the region between (scanning) visual field (FOV) of imaging device 110 and the machine frame hole of imaging device 110.
As shown in Figure 14B, when object 1453 is imaged in imaging device 110, object 1453 can be located at imaging and set In standby 110 machine frame hole 1451.Imaging device 110 can have the visual field 1452 of scanning in machine frame hole 1451.The view of scanning Open country 1452 can define the two dimension of image or the size of 3D region.The visual field of scanning may include with area-of-interest (ROI) image-region.In some embodiments, if object 1453 have relatively large size, one of object 1453 Divide (for example, shadow region 1455) to extend to except the visual field 1452 of scanning, and extends in outer ring 1454.The view of scanning The center of open country 1452 and the center of machine frame hole 1451 can be overlapped at the O of center.Machine frame hole 1451 and scanning the visual field 1452 it Between region be properly termed as outer ring 1454.The center of outer ring 1454 is also possible to center O.In some embodiments, outer ring 1454 In the image information (including background information) of part (for example, shadow region 1455) of object 1453 iterative approximation can be used in At least one forward projection in reconstruction image.In some embodiments, due to lacking and the object 1453 in outer ring 1454 The relevant data in part, offset may be introduced in image after reconstruction.The offset may include image background (for example, Air) offset, the reconstruction deviation of part (for example, shadow region 1455) of object 1453 in outer ring of CT value etc.. In some embodiments, it may be desired to from outer ring background (that is, background information in outer ring 1454) is subtracted in drawing of seeds picture with life At the drawing of seeds picture after correction.In some embodiments, the drawing of seeds picture after correction can be generated according to process 1600, here not It repeats.
In operation 1407, processing equipment 140 (for example, rebuilding module 408) can rebuild at least one image.Some In embodiment, rebuilding module 408 can be based on the drawing of seeds picture after the correction determined in operation 1405 and in operation 1401 The initial data of acquisition rebuilds at least one image by executing iterative approximation.In some embodiments, at least one image It may include 3D rendering (or body image).Each image at least one image may include at least one element.At least one Each element in a element can be pixel or voxel.
In some embodiments, iterative approximation may include at least one forward projection and at least one back projection.After correction Drawing of seeds picture can in iterative approximation at least one image provide initial pictures estimation.By being determined from operation 1403 Drawing of seeds picture in subtract outer ring background, it is possible to reduce or eliminate correction after drawing of seeds picture offset.That is, after correction Drawing of seeds picture may include it is relatively small number of offset or do not deviate.Therefore, based on the iteration weight of the drawing of seeds picture after correction The number of iterations can be reduced by building, and the efficiency of iterative approximation can be improved in this.Furthermore it is possible to improve at least one image of reconstruction Quality.Exemplary iterative algorithm for reconstructing may include adaptive statistics iterative approximation (ASiR), the iterative approximation based on model (MBiR), image space iterative approximation (iRIS), the iterative approximation (SAFIRE) based on initial data, the iteration based on dual model (DMBiR), adaptive iteration dosage reduction (AIDR) iterative approximation, IMR etc. are rebuild, or any combination thereof.
It should be noted that the above description about process 1400 is to provide for purposes of illustration, and be not intended to limit Scope of the present application processed.For those of ordinary skill in the art, it can be made various according to the description of the present application Modifications and variations.However, these modifications and variations are without departing from scope of the present application.In some embodiments, drawing of seeds picture Generation module 404 can generate initial pictures by executing filtered back projection to initial data, and by initial pictures It executes and down-sampled determines drawing of seeds picture.Alternatively, drawing of seeds picture generation module 404 can be down-sampled to initial data execution, and Drawing of seeds picture is generated by executing filtered back projection to down-sampled initial data.Alternatively, drawing of seeds picture generation module 404 can A part with the initial data for selecting a part from least one angle to collect, and pass through the selected part to initial data Filtered back projection is executed to generate drawing of seeds picture.
Figure 15 is the schematic diagram of the exemplary drawing of seeds picture correction module according to shown in some embodiments of the present application.Seed Image correction module 410 can be implemented on calculating equipment 200 (for example, processor 210 as shown in Figure 2 or as shown in Figure 3 CPU 340).Drawing of seeds picture correction module 410 may include coordinate transformation unit 1502, element extraction unit 1504, element stroke Sub-unit 1506, background image generation unit 1508 and image subtraction unit 1510.
Coordinate transformation unit 1502 can be configured as the coordinate transform for executing image or the element in image.It is only used as and shows Example, coordinate transformation unit 1502 can execute from the first coordinate system (for example, cartesian coordinate system) to the second coordinate system (for example, Polar coordinate system) first coordinate transform of drawing of seeds picture determine intermediate image.Drawing of seeds picture may include in the first coordinate system At least one first element, and intermediate image may include at least one second element in the second coordinate system.Each One element or second element can be pixel or voxel.In some embodiments, intermediate image and drawing of seeds picture can have The essentially identical image information expressed in different coordinates.
Element extraction unit 1504 can be configured as extracts at least one element from image.Only as an example, element Extraction unit 1504 can be extracted from least one second element in the second coordinate system (that is, polar coordinate system) corresponds to outer ring At least one second element.In some embodiments, element extraction unit 1504 can determine the scan vision of imaging device 110 The first maximum polar diameter and machine frame hole the second maximum polar diameter.Element extraction unit 1504 can be by the first maximum polar diameter and second Region between maximum polar diameter is determined as outer ring.Element extraction unit 1504 can be extracted positioned at least one of outer ring second Element.
Element division unit 1506 can be configured as second yuan after extracting based at least one of second coordinate system At least one second element after extracting is divided at least one set by the position of element.Second element after every group of extraction can correspond to In a sub-regions of outer ring.In some embodiments, the after element division unit 1506 can be extracted according at least one At least one second element after extracting is divided at least one set by the polar angle of Was Used.In some embodiments, element divides Unit 1506 can uniformly or non-uniformly divide the second element after at least one extraction.
Background image generation unit 1508 can be configured as to be generated and the based on the second element after at least one set of extract The corresponding background image of outer ring background in one coordinate system.In some embodiments, background image can reflect corresponding to outer The background information (for example, air) of ring.The details of generation about background image can find (example in the application elsewhere Such as, the operation 1607 of process 1600, process 1700, and its description).
Image subtraction unit 1510 can be configured as the background image subtracted from drawing of seeds picture corresponding to outer ring background, With the drawing of seeds picture after being corrected.In some embodiments, background image may include the background information (example reflected in outer ring Such as, the element value of air) multiple elements.In some embodiments, background image is alternatively referred to as outer ring background.Image subtraction list The element value that member 1510 can subtract outer ring background from drawing of seeds picture, with the drawing of seeds picture after being corrected.Kind after correction Subgraph may include outer ring background more less than primordial seed image.In some embodiments, the drawing of seeds picture after correction can Not include outer ring background.
It should be noted that above description provides for illustration purposes only, it is no intended to limit scope of the present application.For For those skilled in the art, various modifications and variations can be made according to the description of the present application.However, These modifications and variations are without departing from scope of the present application.In some embodiments, drawing of seeds picture correction module 410 may also include Storage unit (is not shown) in Figure 15.It is raw by the unit of drawing of seeds picture correction module 410 that storage unit can be configured as storage At data.
Figure 16 is the example process of the drawing of seeds picture after the generation correction according to shown in some embodiments of the present application Flow chart.In some embodiments, real in the imaging system 100 that at least one operation of process 1600 can be shown in Fig. 1 It applies.For example, process 1600 can be stored in storage equipment 150 and/or memory in the form of instruction (for example, application program) In 220, and by processing equipment 140 (for example, the processor 210 of calculating equipment 200 as shown in Figure 2, shifting as shown in Figure 3 The CPU 340 of dynamic equipment 300, at least one module of processing equipment 140 as shown in Figure 4 etc.) it calls and/or executes.Example again Such as, a part of of process 1600 can implement on imaging device 110.The operation of shown process presented below is intended to illustrate. In some embodiments, process 1600 can add at least one operation bidirectional not described when implementing, and/or delete at least One operation described herein.In addition, operation order and operations described below in process 1600 shown in Figure 16 Sequence is simultaneously without restriction.It in some embodiments, can be according to the operation 1405 of 1600 implementation procedure 1400 of process.
In operation 1601, processing equipment 140 (for example, coordinate transformation unit 1502) can be based in drawing of seeds picture determination Between image.In some embodiments, drawing of seeds picture may include the first element of at least one of first coordinate system.Intermediate image It may include at least one second element in the second coordinate system.Each first element can be pixel or voxel.Each second Element can be pixel or voxel.Coordinate transformation unit 1502 can be by executing from the first coordinate system to the kind of the second coordinate system First coordinate transform of subgraph generates intermediate image.
In some embodiments, the first coordinate system can be cartesian coordinate system, and the second coordinate system can be polar coordinate system. In some embodiments, the origin of the origin of the first coordinate system and/or the second coordinate system can be located at the position of the machine frame hole of rack 111 It sets.For example, the origin of the origin of the first coordinate system and the second coordinate system can be overlapped and all be overlapped with the center of outer ring (as schemed Shown in 18).
Figure 18 is the schematic diagram of the exemplary drawing of seeds picture of the object according to shown in some embodiments of the present application.Described kind Subgraph is two-dimentional (2D) image.As shown in figure 18, outer ring refers between the machine frame hole of imaging device 110 and the visual field of scanning Region.As shown in figure 18, object 1804 is located in the visual field 1803 of scanning.Outer ring background 1802 includes background information, background letter Breath includes air, bed board information etc., or any combination thereof.Drawing of seeds picture shown in Figure 18 indicates in orthogonal coordinate system.Flute The trunnion axis of karr coordinate system is the X-axis in Figure 18, and the vertical axis of cartesian coordinate system is the Y-axis in Figure 18.Cartesian coordinate The origin O of system is overlapped with the center of outer ring.
Figure 19 is the schematic diagram of the exemplary intermediate image of the object according to shown in some embodiments of the present application.Middle graph It seem to carry out what the first coordinate transform determined according to drawing of seeds picture shown in Figure 18.Intermediate image shown in Figure 19 is located at pole In coordinate system.The origin O of polar coordinate system also is located at the center of outer ring.The trunnion axis of polar coordinate system is the polar angle θ in Figure 19, and pole is sat The vertical axis of mark system is the polar diameter r in Figure 19.
In some embodiments, intermediate image and drawing of seeds picture can have expressed in different coordinates it is essentially identical Image information.In some embodiments, at least one second element in the second coordinate system can not correspond directly to first The first element of at least one of coordinate system.For example, second element can have between two the first elements in drawing of seeds picture There is corresponding position (that is, a part that the corresponding position of second element can take up each of two first elements).Cause This, in some embodiments, the element value of the second element in the second coordinate system can be based at least two in the first coordinate system The element value of a first element is determined by interpolation.
In operation 1603, processing equipment 140 (for example, element extraction unit 1504) can from the second coordinate system to A few second element extracts at least one second element for corresponding to outer ring.In some embodiments, element extraction unit 1504 can determine the second maximum polar diameter of the first maximum polar diameter in the visual field of the scanning of imaging device 110 and machine frame hole.Element Region between first maximum polar diameter and the second maximum polar diameter can be determined as outer ring by extraction unit 1504.Element extraction unit 1504 can extract at least one second element positioned at outer ring.It is only as an example, as shown in figure 19, the maximum in the visual field of scanning Polar diameter r2 can be 500 millimeters, and the maximum polar diameter r3 of the machine frame hole of imaging device 110 can be 700 millimeters.R2=500 Region (for example, by region of dotted line instruction) between millimeter and r3=700 millimeter can be designated as outer ring, therefore, can be with Extract at least one second element in the region.
In operation 1605, processing equipment 140 (for example, element division unit 1506) can be based in the second coordinate system At least one second element after extracting is divided at least one set by the position of the second element after at least one extraction.Every group mentions Second element after taking can correspond to a sub-regions of outer ring.In some embodiments, element division unit 1506 can be with At least one second element after extracting is divided at least one set according to the polar angle of at least one second element after extracting.? In some embodiments, element division unit 1506 can uniformly or non-uniformly divide second yuan after at least one extraction Element.Only as an example, as shown in figure 19, four can be divided evenly into corresponding to the second element after multiple extractions of outer ring Group, that is, first group, second group, third group and the 4th group.The polar angle of second element can be in 0 ° -90 ° of range in first group It is interior, indicate the first subregion 1902 of outer ring.The polar angle of second element can indicate in the range of 90 ° -180 ° in second group Second subregion 1904 of outer ring.The polar angle of second element can indicate outer ring in the range of 180 ° -270 ° in third group Third subregion 1906.The polar angle of second element in the range of 270 ° -360 °, can indicate the 4th son of outer ring in 4th group Region 1908.It should be noted that in some embodiments, the second element after at least one extraction can be divided into other quantity The group of (or counting), for example, 5 groups, 8 groups, 10 groups etc..In some embodiments, it can be divided to according at least one mode Second element after a few extraction, at least one described mode can be arranged according to the default setting of imaging system 100, or Person is preset by user or operator via terminal 130.
In operation 1607, processing equipment 140 (for example, background image generation unit 1508) can be mentioned based at least one set Second element after taking generates background image corresponding with the outer ring background in the first coordinate system.In some embodiments, it carries on the back Scape image can reflect the background information (for example, air) corresponding to outer ring.
In some embodiments, background image generation unit 1508 can along the second coordinate system first direction (for example, Radially) determine at least one reference value in each subregion of outer ring.Background image generation unit 1508 can pass through execution Second yuan after from the second coordinate system (that is, polar coordinate system) at least one extraction of the first coordinate system (i.e. flute card and coordinate system) Second coordinate transform of element determines the initial circular image including at least one third element in the first coordinate system.Initial circle Shape image can correspond to outer ring.Background image generation unit 1508 can further be modified by executing homogenization operation initial Circular image corresponds to the background image of outer ring background to obtain.In some embodiments, homogenization operation may include rotation process, Overlap-add operation and normalization operation.More descriptions of generation about background image can finding elsewhere in the application (for example, Figure 17, Figure 22 and Figure 24 and its associated description).
In operation 1609, processing equipment 140 (for example, image subtraction unit 1510) can subtract pair from drawing of seeds picture It should be in the background image of outer ring background, with the drawing of seeds picture after being corrected.In some embodiments, background image may include Reflect at least one element of the background information (for example, element value of air) in outer ring.In some embodiments, background image Alternatively referred to as outer ring background.Image subtraction unit 1510 can subtract the element value of outer ring background from drawing of seeds picture, to obtain Drawing of seeds picture after correction.Drawing of seeds picture after correction may include outer ring background more less than primordial seed image.Some In embodiment, the drawing of seeds picture after correction can not include outer ring background.
It should be noted that the above description about process 1600 is to provide for purposes of illustration, it is no intended to limit Scope of the present application.For those of ordinary skill in the art, it can be made various according to the description of the present application Modifications and variations.However, these modifications and variations are without departing from scope of the present application.In some embodiments, operation 1603 and/ Or operation 1601 can execute in different ways.Only as an example, processing equipment 140 can be from the first coordinate system at least One the first element extraction corresponds at least one first element of outer ring.Processing equipment 140 can also be performed from the first coordinate It is the first coordinate transform to the first element after at least one extraction of the second coordinate system, after determining at least one extraction Second element.
In some embodiments, it is convenient to omit operation 1601, the drawing of seeds picture after generating correction can not need coordinate change It changes.Only as an example, processing equipment 140 can extract at least one element of the initial circular image corresponding to outer ring, and lead to The element crossed after extracting at least one rotates at least once relative to the center of outer ring, and rotates one in each rotation Angle, to generate at least one postrotational circular image.In some embodiments, angle is smaller than 360 °.In some implementations In example, processing equipment 140 can modify at least one of at least one postrotational circular image by interpolation.Processing is set Standby 140 can generate the Background for corresponding to outer ring background based on initial circular image and at least one postrotational circular image Picture.For example, processing equipment 140 can be stacked by superposition initial circular image and at least one postrotational circular image next life Add image, and background image corresponding with outer ring background is generated by normalization superimposed image.Processing equipment 140 can be from seed The background image corresponding to outer ring background is subtracted in image, with the drawing of seeds picture after being corrected.
Figure 17 is the flow chart that the example process of background image is generated according to shown in some embodiments of the present application.? In some embodiments, implement in the imaging system 100 that at least one operation of process 1700 can be shown in Fig. 1.For example, mistake Journey 1700 can be stored in storage equipment 150 and/or memory 220 in the form of instruction (for example, application program), and by Processing equipment 140 (for example, the processor 210 of calculating equipment 200 as shown in Figure 2, mobile device 300 as shown in Figure 3 CPU 340, at least one module of processing equipment 140 as shown in Figure 4 etc.) it calls and/or executes.In another example process 1700 A part of can implement on imaging device 110.The operation of shown process presented below is intended to illustrate.In some embodiments In, process 1700 can add at least one operation bidirectional not described when implementing, and/or delete at least one this place and retouch The operation stated.In addition, the operation order of process 1700 and the sequence of operations described below shown in Figure 17 are not limited System.It in some embodiments, can be according to the operation 1607 of 1700 implementation procedure 1600 of process.
In operation 1701, processing equipment 140 (for example, background image generation unit 1508) can be along the second coordinate system First direction determine at least one reference value in each subregion of outer ring.The first direction of second coordinate system can refer to diameter To (for example, radial direction as shown in figure 19).In some embodiments, the second element after at least one extraction can be along second The first direction distribution of coordinate system is at least one row.Reference value can be the member of the second element after the extraction at least a line The intermediate value (or average value, maximum value, minimum value etc.) of element value.Each reference value can correspond to a line at least a line.Often A row can correspond to a specific polar diameter (for example, polar diameter can be in the range of 500-700 millimeter as shown in figure 19). Therefore, at least one reference value and polar diameter of outer ring can have particular kind of relationship as shown in figure 20.
In some embodiments, for each subregion of outer ring and in every a line of at least a line, background image Generation unit 1508 can refer to the intermediate value of the second element after fixed extract as each sub-district in every a line of each subregion The reference value of every a line in domain.Intermediate value (also referred to as median) can be after the extraction in every a line by each subregion Higher half and its of the element value of Was Used are relatively at half the value separated.Only as an example, if there is from small to large (or from Arrive greatly small) arrangement five element values (for example, the first element value, second element value, third element value, fourth element value, the 5th Element value), then third element value can be intermediate value.In some embodiments, the second element after indicating the extraction of background information Quantity (or count) can be more than indicate the quantity (or counting) of the second element after the extraction of information relevant to object, therefore Intermediate value can be the element value of background information.Only as an example, as shown in figure 19, for the 4th subregion 1908 and row r4, carrying on the back Scape image generation unit 1508 can be according to corresponding element value to second yuan after extracting in the row r4 of the 4th subregion 1908 Element is ranked up.Background image generation unit 1508 can determine the after extracting based on the second element after the extraction after sequence The intermediate value of Was Used, and intermediate value is appointed as the reference value of the row r4 of the 4th subregion 1908 (for example, element value shown in Figure 20 C1).Figure 20 shows the schematic diagram of multiple reference values in the 4th subregion 1908 in multiple rows.As shown in figure 20, Mei Gecan Examining value can correspond to a line.Each reference value can be in the second element after the extraction in the row of the 4th subregion 1908 Value.For example, reference value C1 can be the intermediate value of the second element after the extraction in the row r4 of the 4th subregion 1908.
Alternatively, or in addition, each subregion for outer ring and in every a line of at least a line, background image Generation unit 1508 can determine a part of the second element after the extraction in every a line of each subregion.After extraction The part of Was Used can have the element value in particular range.Element value in particular range can indicate background information, Such as air.Only as an example, subregion for outer ring and in a line of at least a line, background image generation unit 1508 The element value of the second element after extracting in the row of subregion can be determined whether in the particular range.In response to determination The element value of second element after extracting in the row of subregion is beyond the particular range (that is, the second element after extracting Can indicate information relevant to object), background image generation unit 1508 can not consider the extraction when determining reference value Second element afterwards.The element value of second element after extracting in the row in response to determining subregion is in the particular range Interior (that is, the second element after extracting can indicate background information (for example, air)), background image generation unit 1508 can be Second element after considering the extraction when determining reference value.Background image generation unit 1508 can be in each of each subregion Determine a part of the second element after extracting (that is, second after at least one extraction of element value in particular range in row Element) and determine extract after second element the part element value average value.Background image generation unit 1508 can The average value of the part of the second element after extracting to be appointed as to the reference value of every row of each subregion.
In operation 1703, processing equipment 140 (for example, background image generation unit 1508) can be by executing from second Second element after coordinate system (that is, polar coordinate system) at least one extraction of the first coordinate system (that is, cartesian coordinate system) The second coordinate transform, to determine the initial circular image including at least one third element in the first coordinate system.Some In embodiment, initial circular image can correspond to outer ring.It in some embodiments, can be based at least one parameter value come really At least one element value of at least one fixed third element, and at least one element value of at least one third element and kind The element value of corresponding first element in subgraph is different.
Only as an example, Figure 21 A is showing for the exemplary initial circular image according to shown in some embodiments of the present application It is intended to.The initial circular image can be generated according to the second coordinate transform of at least one second element after extracting.Such as figure Shown in 21A, initial circular image may include four parts, i.e. first part 2102, second part 2104,2106 and of Part III Part IV 2108.First part 2102 can correspond to the first subregion 1902.Second part 2104 can correspond to second Subregion 1904.Part III 2106 can correspond to third subregion 1906.Part IV 2108 can correspond to the 4th son Region 1908.Initial circular image may include at least one third element.It can be based at least one of respective sub-areas Reference value determines the element value of the third element in each part.For example, can be based in the first subregion 1902 of outer ring At least one reference value determine the element value of the third element in first part 2102.
In some embodiments, after the second coordinate transform, the first part of the third element in initial circular image A part of second element after can corresponding directly to the extraction in intermediate image, therefore each of first part of third element Element value can be directly determined according to the relationship between reference value and polar diameter (as shown in figure 20), and therefore, reference value can be referred to It is set to each element value of the first part of third element.Alternatively, or in addition, third element in initial circular image Second part can not correspond directly to the second element after any extraction in intermediate image, therefore the second part of third element Each element value can be determined based on the relationship between reference value and polar diameter (as shown in figure 20) by interpolation.Therefore, exist In some embodiments, background image generation unit 1508 can be based at least two reference values to second after transformed extraction A part of element executes interpolation, to determine the element value of third element.Interpolation algorithm may include nearest neighbor pixels interpolation, line Property interpolation etc..
In operation 1705, processing equipment 140 (for example, background image generation unit 1508) can be by executing homogenizing behaviour Make to modify initial circular image to obtain the background image for corresponding to outer ring background.Background image can reflect related to outer ring Background information (for example, air).Figure 21 B is the signal of the exemplary background image according to shown in some embodiments of the present application Figure.Background image shown in Figure 21 B can be generated by modifying initial circular image shown in Figure 21 A.Such as Figure 21 B institute Show, the initial circular image in background image ratio Figure 21 A is more evenly.
In some embodiments, homogenization operation may include rotation process, overlap-add operation, normalization operation etc., or combinations thereof. For example, background image generation unit 1508 can be by making at least one third element of initial circular image relative to outer ring Center rotate at least once, and every time rotate when rotate an angle, to generate at least one postrotational circular image.It is logical Execution rotation process is crossed, reference value (for example, intermediate value) can be evenly distributed in radially on postrotational image.Only conduct Example, when at least one third element of initial circular image rotates one time, the position of at least one third element can be moved New position is moved to generate postrotational circular image.For being located at the third element of the initial circular image of first position, The element value of respective element in postrotational circular image positioned at first position may be with the third element of initial circular image Element value it is different.Background image generation unit 1508 can pass through superposition initial circular image and at least one postrotational circle Shape image generates superimposed image.Background image generation unit 1508 can also be corresponded to by normalization superimposed image to generate The background image of outer ring background.For example, background image generation unit 1508 can be each element in superimposed image (also referred to as Fourth element) divided by n+1, wherein n refers to the quantity (or counting) of number of revolutions or postrotational circular image.In another example background Image generation unit 1508 can be such that at least one third element of initial circular image is rotated at least once.It is revolving every time When turning, background image generation unit 1508 can be at center of at least one third element relative to outer ring of initial circular image When rotating an angle, postrotational circular image is generated, and pass through superposition initial circular image and postrotational circular image To generate another image.In each rotation, superimposed image can also be appointed as initial circle by background image generation unit 1508 Shape image.When completing to rotate at least once, background image generation unit 1508 can be generated by normalization superimposed image Background image corresponding to outer ring background.For example, background image generation unit 1508 can be by each element in superimposed image (that is, fourth element) is divided by 2n (n refers to number of revolutions) to generate background image.More descriptions of generation about background image can To find (for example, Figure 22 and Figure 24 and its associated description) elsewhere in the application.
Figure 22 is the process that the example process of initial circular image is modified according to shown in some embodiments of the present application Figure.In some embodiments, implement in the imaging system 100 that at least one operation of process 2200 can be shown in Fig. 1.Example Such as, process 2200 can be stored in storage equipment 150 and/or memory 220 in the form of instruction (for example, application program), And by processing equipment 140 (for example, the processor 210 of calculating equipment 200 as shown in Figure 2, mobile device as shown in Figure 3 300 CPU 340, at least one module of processing equipment 140 as shown in Figure 4 etc.) it calls and/or executes.In another example process 2200 a part of can implement on imaging device 110.The operation of shown process presented below is intended to illustrate.In some realities It applies in example, process 2200 can add at least one operation bidirectional not described when implementing, and/or delete at least one herein Described operation.In addition, the operation order of process 2200 and the sequence of operations described below shown in Figure 22 and being not added With limitation.It in some embodiments, can be according to the operation 1705 of 2200 implementation procedure 1700 of process.
In operation 2201, processing equipment 140 (for example, background image generation unit 1508) can be by making initial circular At least one third element of image relative to outer ring center rotation at least once, and every time rotate when rotate an angle Degree, to generate at least one postrotational circular image.Each postrotational circular image may include that at least one is postrotational Third element.The center of outer ring can be overlapped with the machine frame hole at the center in the visual field of scanning and/or imaging device 110.The angle Degree is smaller than 360 °.In some embodiments, the angle two or more times in rotation can be identical.Alternatively, not homogeneous Angle in several rotations can be different.For example, angle when rotating for the first time can be 30 °, when rotating for the second time Angle can be 45 °.Number of revolutions can be arranged according to the default setting of imaging system 100, or by user or operator It is preset via terminal 130.
As shown in figure 23, at least one postrotational circular image can be generated based on initial circular image.Figure 23 is root According to the schematic diagram for the example process for modifying initial circular image shown in some embodiments of the present application.As shown in figure 23, just Beginning circular image 2301 may include four parts.Postrotational circular image 2302 can be by making initial circular image for the first time 2301 relative to outer ring center O with 30 ° carry out rotation for the first time and generate.Second postrotational circular image 2303 can be with By generating initial circular image 2301 (alternatively, making first and rotate for second with 30 ° relative to the center O of outer ring Secondary postrotational circular image 2302 carries out second relative to the center O of outer ring with 30 ° and rotates).It should be noted that number of revolutions It provides for illustration purposes only, and is not intended to be limited to scope of the present application.Initial circular image 2301 can carry out it The rotation of his number, for example, 7 times, 10 times, it is 20 inferior.Initial circular image can same direction (for example, clockwise, It is rotated on counterclockwise).
In operation 2203, processing equipment 140 (for example, background image generation unit 1508) can be by being superimposed initial circle Shape image and at least one postrotational circular image generate new images (that is, superimposed image).In some embodiments, background Image generation unit 1508 can be superimposed in the third element in initial circular image and at least one postrotational circular image Corresponding postrotational third element.Superimposed image may include at least one fourth element.Each fourth element can be The summation of three elements and corresponding postrotational third element.Only as an example, as shown in figure 23, the initial circle of superposition can be passed through Shape image 2301, postrotational circular image 2302 generates new images with second of postrotational circular image 2303 for the first time 2304。
In some embodiments, background image generation unit 1508 can be at least one postrotational circular image At least one executes interpolation arithmetic.Specifically, background image generation unit 1508 can be at least one postrotational circular diagram The postrotational third element of picture executes interpolation arithmetic.Background image generation unit 1508 can be by being superimposed initial circular image With at least one (after interpolation) postrotational circular image generate new images (that is, superimposed image).
In operation 2205, processing equipment 140 (for example, background image generation unit 1508) can be superimposed by normalization Image generates the background image corresponding to outer ring background.Background image can reflect relevant to outer ring background information (for example, Air).
In some embodiments, background image generation unit 1508 can by each fourth element in superimposed image divided by N+1 (quantity (or counting) that n refers to number of revolutions or postrotational circular image).For example, if superimposed image is based on initial What circular image and 6 postrotational circular images generated, then background image generation unit 1508 can will be in superimposed image Each fourth element is divided by 7 to generate background image.It, can be based on initial circular image 2301, the in another example as shown in figure 23 Primary postrotational circular image 2302 generates superimposed image 2304 with second of postrotational circular image 2303.It can lead to It crosses and superimposed image 2304 (for example, fourth element in superimposed image 2304) is generated into background image 2305 divided by 3.
Figure 24 is the process that the example process of initial circular image is modified according to shown in some embodiments of the present application Figure.In some embodiments, implement in the imaging system 100 that at least one operation of process 2400 can be shown in Fig. 1.Example Such as, process 2400 can be stored in storage equipment 150 and/or memory 220 in the form of instruction (for example, application program), And by processing equipment 140 (for example, the processor 210 of calculating equipment 200 as shown in Figure 2, mobile device as shown in Figure 3 300 CPU 340, at least one module of processing equipment 140 as shown in Figure 4 etc.) it calls and/or executes.In another example process 2400 a part of can implement on imaging device 110.The operation of shown process presented below is intended to illustrate.In some realities It applies in example, process 2400 can add at least one operation bidirectional not described when implementing, and/or delete at least one herein Described operation.In addition, the operation order of process 2400 and the sequence of operations described below shown in Figure 24 and being not added With limitation.It in some embodiments, can be according to the operation 1705 of 2400 implementation procedure 1700 of process.
In operation 2401, processing equipment 140 (for example, background image generation unit 1508) can be in initial circular image At least one third element relative to outer ring center rotate an angle when, generate postrotational circular image.After rotation Circular image may include at least one postrotational third element.The center of outer ring can be located at the center in the visual field of scanning And/or the machine frame hole of imaging device 110.The angle is smaller than 360 °.
In operation 2403, processing equipment 140 (for example, background image generation unit 1508) can be by being superimposed initial circle Shape image and postrotational circular image generate new images (that is, superimposed image).In some embodiments, background image generates Unit 1508 can be superimposed corresponding postrotational in the third element in initial circular image and postrotational circular image Third element.Superimposed image may include at least one fourth element.Each fourth element can be corresponding third element and phase The summation for the postrotational third element answered.
In some embodiments, background image generation unit 1508 can execute interpolation fortune to postrotational circular image It calculates.Specifically, background image generation unit 1508 can execute the postrotational third element in postrotational circular image Interpolation arithmetic.Background image generation unit 1508 can pass through the postrotational circular diagram after superposition initial circular image and interpolation As generating new images (that is, superimposed image).
In operation 2405, processing equipment 140 (for example, background image generation unit 1508) may determine whether to meet item Part.The condition can with whether perform difference between two superimposed images in specified number of revolutions, twice continuous rotation Whether threshold value etc. or combinations thereof is less than associated.It should be noted that in some embodiments, when two in continuous rotation twice are folded When the difference between image being added to be equal to threshold value, background image generation unit 1508 can determine the condition of satisfaction, alternatively, background image is raw The condition of being unsatisfactory for can be determined at unit 1508.It is unsatisfactory for condition in response to determination, process 2400 can execute operation 2407.? In operation 2407, superimposed image can be appointed as initial circular by processing equipment 140 (for example, background image generation unit 1508) Image.Process 2400 can further execute operation 2401, and execution rotates next time.In some embodiments, different rotary time Several rotation angles can be identical or different.
Meet condition in response to determination, process 2400 can execute operation 2409.In operation 2409, processing equipment 140 (for example, background image generation unit 1508) can generate the Background corresponding to outer ring background by normalization superimposed image Picture.Background image can reflect background information (for example, air) relevant to outer ring.
In some embodiments, background image generation unit 1508 can by each fourth element in superimposed image divided by 2n (n refers to number of revolutions) is to generate background image.For example, if superimposed image is generated by executing 6 rotations, background Image generation unit 1508 can by each fourth element in superimposed image divided by 26 to generate background image.
Figure 25 is the signal that the example process of initial circular image is modified according to shown in some embodiments of the present application Figure.As shown in figure 25, it can execute and rotate twice.Initial circular image 2501 may include four parts.After rotating for the first time Circular image 2502 can be by making initial circular image 2501 relative to the center O of outer ring with 30 ° of progress first time rotations And it generates.Can by superposition initial circular image 2501 and postrotational circular image 2502 come generate the first new images (that is, First superimposed image) 2503.First superimposed image 2503 can be considered as initial circular image 2501 in next round rotation.The Circular image 2504 after secondary rotating can be by carrying out the first superimposed image 2503 with 15 ° relative to the center O of outer ring It rotates and generates for the second time.It can be generated by the first superimposed image 2503 of superposition and the second postrotational circular image 2504 Second new images (that is, second superimposed image) 2505.Background image can be generated by the second superimposed image 2505 of normalization 2506.It specifically, can be by the way that the second superimposed image 2505 (for example, fourth element in second of superimposed image 2505) be removed Background image 2506 is generated with 4.That is, moving radially in Figure 25 and being averagely applied to four sector image.
This application provides the system and method for the iterative approximation based on air exposure mask.It, can be with using the first air exposure mask Accelerated iteration is rebuild.Specifically, air exposure mask can be bianry image, can distinguish the element and not that air is indicated in image Indicate the element (for example, the element for indicating non-air) of air.Indicate that the element of air can be not involved in iterative approximation, this can be with Accelerate the speed of iterative approximation.Therefore, the high-precision air exposure mask that can distinguish air and non-air can promote iterative approximation And improve the quality of reconstruction image.It in this application, can be by executing minimum value back projection (in this application to initial data Description elsewhere) generate air exposure mask.By executing minimum value back projection, air exposure mask drawing of seeds picture can be generated (also referred to as second seed image).Regardless of whether truncation is introduced in the reconstruction, the air exposure mask generated based on minimum value back projection Drawing of seeds picture can provide the clear profile of object, this can promote to divide or distinguish air section and figure by threshold process The rest part of picture is to generate air exposure mask.Therefore, using minimum value back projection, the precision of air exposure mask can be improved.
For Accelerated iteration reconstruction, this application provides the drawing of seeds picture after correction.(after correction) drawing of seeds picture can be with Initial pictures estimation is provided for iterative approximation.In general, drawing of seeds picture may include occurring inclined due to lacking data in outer ring It moves (in the description elsewhere of the application).The offset can be reduced or eliminated by increasing the number of iterations of iterative approximation.? In the application, drawing of seeds picture can be corrected by subtracting outer ring background from drawing of seeds picture, to reduce or eliminate the offset.Cause This, can determine the initial pictures estimation (that is, drawing of seeds picture after correction) with good quality.Based on the drawing of seeds after correction The iterative approximation of picture can reduce the number of iterations, and the efficiency of iterative approximation can be improved in this, can also improve the matter of reconstruction image Amount.
It should be noted that in some embodiments, drawing of seeds picture and air exposure mask after correction can be same in iterative approximation When use, this can further speed up iterative approximation and improve the quality of reconstruction image.Only as an example, processing equipment 140 can To rebuild at least one image based on drawing of seeds picture, the first air exposure mask and/or the initial data after correction.
It should be noted that term " first ", " second ", " third ", " the 4th " etc. are only for the purposes of description without representing spy Fixed sequence or title.
Basic conception has been described above, it is clear that those skilled in the art, above-mentioned disclosure as just Example, and do not constitute the restriction to the application.Although do not clearly state herein, those skilled in the art may be to this Application is carry out various modifications, improves and is corrected.Such modification, improvement and amendment are proposed in this application, so such modification, It improves, correct the spirit and scope for still falling within the application example embodiment.
Meanwhile the application has used specific term to describe embodiments herein.For example, " one embodiment ", " a reality Apply example ", and/or " some embodiments " mean a certain feature relevant at least one embodiment of the application, structure or feature.Cause This, it should be highlighted that and it is noted that " embodiment " or " an implementation referred to twice or repeatedly in this specification in different location Example " or " alternate embodiment " are not necessarily meant to refer to the same embodiment.In addition, certain at least one embodiment of the application A little features, structure or characteristic can carry out combination appropriate.
In addition, it will be understood by those skilled in the art that the various aspects of the application can be by several with patentability Type or situation are illustrated and described, the combination or right including any new and useful process, machine, product or substance Their any new and useful improvement.Correspondingly, the various aspects of the application can completely by hardware execute, can be complete It is executed, can also be executed by combination of hardware by software (including firmware, resident software, microcode etc.).Hardware above or Software is referred to alternatively as " unit ", " module " or " system ".In addition, the various aspects of the application can be rendered as being located at least one Computer product in computer-readable media, the product are encoded with computer-readable program.
Non-transitory computer-readable signal media may include the data-signal propagated, wherein including computer-readable journey Sequence code, for example, in a base band or as carrier wave a part.Such transmitting signal can there are many forms, including electromagnetism shape Formula, light form etc. or any suitable combining form.Computer-readable signal media can be except computer readable storage medium Except any computer-readable medium, which can be by being connected to an instruction execution system, device or equipment with reality Now communicate, propagate or transmit the program for using.Program code in computer-readable signal media can be by any Suitable media are propagated, including the appropriate combination of radio, cable, fiber optic cables, RF etc. or any of above medium.
Computer program code needed for the operation of the application each section can use any one or more programming language, Including Object-Oriented Programming Languages such as Java, Scala, Smalltalk, Eiffel, JADE, Emerald, C++, C#, VB.NET, Python etc., conventional procedural programming language for example C language, Visual Basic, 2003 Fortran, Perl, COBOL 2002, PHP, ABAP, dynamic programming languages such as Python, Ruby and Groovy or other programming languages. Program code can run on the user computer completely or run on the user computer as independent software package or portion Operation on the user computer is divided partially to run or run on a remote computer or server on the remote computer completely. In the latter cases, remote computer can be connect by any latticed form with subscriber computer, for example, local area network (LAN) or Wide area network (WAN) is connected to outer computer (such as passing through internet) or makes in cloud computing environment or as service (SaaS) is serviced with such as software.
In addition, unless clearly stated in claim, the otherwise sequence of the processing element or sequence, digital alphabet Use or other titles use, be not intended to limit the sequence of the application process and method.Although passing through in above-mentioned disclosure Various examples discuss it is some it is now recognized that useful inventive embodiments, but it is to be understood that, such details only plays explanation Purpose, appended claims are not limited in the embodiment disclosed, on the contrary, claim is intended to cover and all meets this Shen Please embodiment spirit and scope amendment and equivalent combinations.For example, although system component described above can pass through hardware Equipment is implemented, but can also be only carried out by the solution of software, such as on existing server or mobile device Described system is installed.
Similarly, it is noted that in order to simplify herein disclosed statement, to help to implement at least one invention The understanding of example, above in the description of embodiments herein, sometimes by various features merger to one embodiment, attached drawing or In descriptions thereof.But this disclosure method is not meant to mention in aspect ratio claim required for the application object And feature it is more.On the contrary, the main body of invention should have feature more less than above-mentioned single embodiment.
In some embodiments, quantity, the property etc. for some embodiments of the application to be described and claimed as, should be by It is interpreted as being modified by term " about ", " approximation " or " substantially " in some cases.For example, unless otherwise stated, " about ", " approximation " or " substantially " can indicate ± 20% variation of the value of its description.Correspondingly, in some embodiments, specification and power Numerical parameter used in benefit requirement is approximation, and approximation feature according to needed for separate embodiment can change. In some embodiments, the method that numerical parameter is considered as defined significant digit and is retained using general digit.Although this Shen It please be used to confirm that Numerical Range and the parameter of its range range to be approximation, in a particular embodiment, such number in some embodiments Being set in for value is reported as precisely as possible in feasible region.
All patents, patent application, patent application publication and the other materials referred in the application (books, say by such as paper Bright book, publication, record, things and/or similar thing) it is fully incorporated the application by reference herein to reach All purposes, any prosecution paper trail relevant to above-mentioned file, or any of above file that conflicts inconsistent with this document Or except having any of above file of restriction effect to the extensive scope of claims relevant to this document sooner or later.Citing comes Say, if it is any be incorporated between the relevant description relevant with this document of material, definition and/or term use have it is any inconsistent Or conflict, then the description, definition and/or term use in this document should be preferential.
Finally, it will be understood that embodiment described herein is only to illustrate the principle of the embodiment of the present application.Other Deformation may also belong to scope of the present application.Therefore, as an example, not a limit, the alternative configuration of the embodiment of the present application is visual It is consistent with teachings of the present application.Correspondingly, embodiments herein is not limited only to the implementation that the application is clearly introduced and described Example.

Claims (18)

1. a kind of method of iterative approximation, the method is used for reconstruction image, which is characterized in that the described method includes:
Obtain the initial data detected by imaging device；
Drawing of seeds picture is generated by executing filtered back projection to the initial data；
By determining that the drawing of seeds picture after correcting, the outer ring background indicate outer from outer ring background is subtracted in the drawing of seeds picture The background of ring, the outer ring correspond to the region between the visual field of the imaging device and the machine frame hole of the imaging device；With And
Based on after the correction drawing of seeds picture and the initial data by executing iterative approximation rebuild at least one image.
2. the method for iterative approximation according to claim 1, which is characterized in that the drawing of seeds picture includes cartesian coordinate The first element of at least one of system, each first element is pixel or voxel, by subtracting outer ring from the drawing of seeds picture Background come determine correction after drawing of seeds picture include:
By executing the first coordinate transform of the drawing of seeds picture from the cartesian coordinate system to polar coordinate system, determination includes The intermediate image of at least one second element in the polar coordinate system；
Extracted at least one second element described in the polar coordinate system correspond to the outer ring at least one second Element；
Based on the position of the second element after at least one extraction described in the polar coordinate system, after at least one described extraction Second element be divided at least one set, the second element after every group of extraction correspond to the outer ring a sub-regions；
Based on the second element after at least one set of extraction, generate and the outer ring background pair in the cartesian coordinate system The background image answered；And
The background image corresponding to the outer ring background is subtracted, from the drawing of seeds picture to obtain the kind after the correction Subgraph.
3. the method for iterative approximation according to claim 2, which is characterized in that based on it is described it is at least one set of extract after the Was Used, generating background image corresponding with the outer ring background in the cartesian coordinate system includes:
At least one reference value in each subregion of the outer ring is determined along the radial direction of the polar coordinate system；
Pass through the second element after execution at least one extraction described in from the polar coordinate system to the cartesian coordinate system Second coordinate transform determines the initial circular image including at least one third element in the cartesian coordinate system, described Initial circular image corresponds to the outer ring；And
The initial circular image is modified by executing homogenization operation to obtain the background for corresponding to the outer ring background Image.
4. the method for iterative approximation according to claim 3, which is characterized in that execute from the polar coordinate system to the flute Second coordinate transform of the second element after at least one described extraction of karr coordinate system further comprises:
Interpolation operation is executed to the second element after at least one described transformed extraction based at least one described reference value.
5. the method for iterative approximation according to claim 3, which is characterized in that second yuan after at least one described extraction Element along the polar coordinate system the radial distribution at least one row, described along the polar coordinate system radial determines institute At least one reference value stated in each subregion of outer ring includes:
Every a line of each subregion and described at least a line for the outer ring,
The intermediate value of second element after referring to the fixed extraction in described every a line of each subregion is as described each The reference value of described every a line of subregion；Or
It determines a part of the second element after extracting described in described every a line of each subregion, and specifies described mention Reference value of the average value of the part of second element after taking as described every a line of each subregion, it is described to mention The part of second element after taking has the element value in particular range.
6. the method for iterative approximation according to claim 3, which is characterized in that modified by executing homogenization operation described Initial circular image with obtain correspond to the outer ring background the background image include:
By rotating at least one third element described in the initial circular image at least relative to the center of the outer ring Once, and in each rotation an angle is rotated, to generate at least one postrotational circular image；
Superimposed image is generated by being superimposed the initial circular image and at least one described postrotational circular image；And By normalizing the superimposed image, the background image corresponding with the outer ring background is generated.
7. the method for iterative approximation according to claim 3, which is characterized in that modified by executing homogenization operation described Initial circular image with obtain correspond to the outer ring background the background image include:
Rotate at least one described third element of the initial circular image at least once, wherein
In each rotation,
At least one third element described in the initial circular image rotates an angle relative to the center of the outer ring When, generate postrotational circular image；
Superimposed image is generated by being superimposed the initial circular image and the postrotational circular image；And
Specifying the superimposed image is the initial circular image；And
By normalizing the superimposed image, the background image corresponding with the outer ring background is generated.
8. the method for iterative approximation according to claim 6, which is characterized in that further comprise:
Before generating the superimposed image, interpolation is executed at least one of at least one described postrotational circular image Operation.
9. the method for iterative approximation according to claim 7, which is characterized in that further comprise:
Before generating the superimposed image, interpolation is executed at least one of at least one described postrotational circular image Operation.
10. the method for iterative approximation according to claim 1, which is characterized in that generating drawing of seeds picture includes:
Initial pictures are generated by executing filtered back projection to the initial data；And
Down-sampled the drawing of seeds picture is determined by executing to the initial pictures.
11. the method for iterative approximation according to claim 1, which is characterized in that generating drawing of seeds picture includes:
The initial data is executed down-sampled；And
The drawing of seeds picture is generated by executing filtered back projection to the down-sampled initial data.
12. the method for iterative approximation according to claim 1, which is characterized in that the initial data is from least one Angular collection, generating drawing of seeds picture includes:
The a part for the initial data collected from a part of at least one angle is selected from the initial data； And
Filtered back projection is executed by the selected part to the initial data to generate the drawing of seeds picture.
13. the method for iterative approximation according to claim 1, which is characterized in that the drawing of seeds picture includes at least one Element, each element of at least one element is pixel or voxel, by subtracting outer ring background from the drawing of seeds picture Come determine correction after drawing of seeds picture include:
At least one element for corresponding to the initial circular image of the outer ring is extracted from least one described element；
By rotating the element after at least one described extraction at least once relative to the center of the outer ring, and each An angle is rotated in rotation, to generate at least one postrotational circular image, the angle is less than 360 °；
It generates based on the initial circular image and at least one described postrotational circular image and corresponds to the outer ring background Background image；And
The background image corresponding to the outer ring background is subtracted, from the drawing of seeds picture to obtain the kind after the correction Subgraph.
14. the method for iterative approximation according to claim 13, which is characterized in that be based on the initial circular image and institute It states at least one postrotational circular image and generates and include: corresponding to the background image of the outer ring background
Superimposed image is generated by being superimposed the initial circular image and at least one described postrotational circular image；And
By normalizing the superimposed image, the background image corresponding with the outer ring background is generated.
15. the method for iterative approximation according to claim 13, which is characterized in that further comprise:
At least one of at least one described postrotational circular image is modified by interpolation.
16. a kind of system of iterative approximation, the system is used for reconstruction image characterized by comprising
At least one processor；And
Memory is configured as store instruction, wherein when executed, at least one described processor is used for:
Obtain the initial data detected by imaging device；
Drawing of seeds picture is generated by executing filtered back projection to the initial data；
By determining that the drawing of seeds picture after correcting, the outer ring background indicate outer from outer ring background is subtracted in the drawing of seeds picture The background of ring, the outer ring correspond to the region between the visual field of the imaging device and the machine frame hole of the imaging device；With And
Based on after the correction drawing of seeds picture and the initial data by executing iterative approximation rebuild at least one image.
17. a kind of system of iterative approximation, the system is used for reconstruction image, which is characterized in that including obtaining module, drawing of seeds As generation module, drawing of seeds picture correction module and rebuild module；
The acquisition module is for obtaining the initial data detected by imaging device；
The drawing of seeds picture generation module is used to generate drawing of seeds picture by executing filtered back projection to the initial data；
The drawing of seeds picture correction module is used for by determining the kind after correcting from outer ring background is subtracted in the drawing of seeds picture Subgraph, the outer ring background indicate the background of outer ring, the visual field and the imaging of the outer ring corresponding to the imaging device Region between the machine frame hole of equipment；And
It is described rebuild module be used for based on after the correction drawing of seeds picture and the initial data by execute iterative approximation come Rebuild at least one image.
18. a kind of computer readable storage medium, which is characterized in that the storage medium stores computer instruction, the calculating When machine instruction execution, the method for iterative approximation of the execution as described in claim 1-15 is any.
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