CN111476860B - Image reconstruction method, image reconstruction device, computer equipment and storage medium - Google Patents
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Abstract
The application relates to an image reconstruction method, an image reconstruction device, a computer device and a storage medium, wherein the image reconstruction method comprises the following steps: acquiring fan-shaped beam data of an object to be scanned; rearranging the fan-shaped beam data to obtain parallel beam data; respectively distributing corresponding weights for each ray in the parallel beam data; and reconstructing according to the parallel beam data after the weight distribution to obtain a reconstructed image. And weight is distributed to each ray in the parallel beam data, so that the influence of damaged data on a reconstructed image when a bulb tube is ignited can be reduced during image reconstruction, namely, the reconstructed image without artifacts can be obtained by distributing the weight. Therefore, rescanning is not needed, waste of contrast agent is avoided, and the radiation dose of a patient is reduced.
Description
Technical Field
The present application relates to the field of medical devices, and in particular, to an image reconstruction method, apparatus, computer device, and storage medium.
Background
The computer tomography device (CT, computed Tomography) scans the human body with X-rays from a plurality of directions with a certain thickness, the attenuated X-rays are converted into visible light by a detector, then the visible light is converted into an electric signal, and finally the electric signal is subjected to analog-digital conversion and then the computer device is subjected to image reconstruction to obtain a final CT image. In CT scanning, a tube generating X-rays may be ignited at any time, and once the ignition occurs, the detector cannot receive a normal projection signal, or the detector fails, and cannot receive a normal projection signal at certain angles. When the normal projection signals cannot be received and the image is finally reconstructed, the image can show data missing artifacts, and the data missing artifacts are particularly embodied as serious bar artifacts or arc artifacts.
In the case of a bulb strike or a detector failure, the conventional technology needs to stop the bulb paying-off and rescan. However, in clinical applications, rescanning can result in wastage of contrast medium and increased radiation dose to the patient in a variety of settings such as perfusion, cardiac coronary imaging, etc.
Disclosure of Invention
The embodiment of the application provides an image reconstruction method, an image reconstruction device, computer equipment and a storage medium, which at least solve the problems of contrast agent waste and increased radiation dose of a patient in the related technology.
In a first aspect, an embodiment of the present application provides an image reconstruction method, including: acquiring fan-shaped beam data of an object to be scanned; rearranging the fan-shaped beam data to obtain parallel beam data; respectively distributing corresponding weights for each ray in the parallel beam data; and reconstructing according to the parallel beam data after the weight distribution to obtain a reconstructed image.
In some embodiments, the rearranging the fan beam data to obtain parallel beam data includes: acquiring fan-beam data; obtaining the corresponding relation between the fan-shaped beam data and the parallel beam data according to the detector parameters; and obtaining parallel beam data according to the corresponding relation and the fan-shaped beam data.
In some embodiments, the assigning a respective weight to each ray in the parallel beam data comprises: acquiring a detector row corresponding to each ray; the weight of rays corresponding to the detector rows at the geometric center is set as a first weight, and the weights of rays corresponding to the detector rows at the two sides of the geometric center are sequentially reduced.
In some embodiments, the assigning a respective weight to each ray in the parallel beam data comprises: acquiring the corresponding relation between all rays and the fan-shaped beam data according to the corresponding relation between the fan-shaped beam data and the parallel beam data; and distributing corresponding weights for the rays according to the fan-shaped beam data corresponding to the rays.
In some embodiments, the assigning the respective weights to the rays according to fan beam data corresponding to the rays includes: the fan beam data includes corrupted fan beam data and full fan beam data; if the ray corresponds to the damaged fan-shaped beam data, setting the weight of the ray as a first weight; if the ray corresponds to the complete fan-shaped beam data, setting the weight of the ray as a second weight; the value of the second weight is greater than the value of the first weight.
In some embodiments, the assigning the respective weights to the rays according to fan beam data corresponding to the rays includes: the fan-shaped beam data comprise damaged fan-shaped beam data and complete fan-shaped beam data, rays corresponding to the damaged fan-shaped beam data are taken as first-class rays, and rays corresponding to the complete fan-shaped beam data are taken as second-class rays; setting the weight of the first type of rays as a first weight; setting the weight of the second type of rays in a preset range around the first type of rays to gradually increase from the first weight to the second weight; and setting the weights of the rest second type rays as second weights.
In some embodiments, reconstructing the image according to the weighted parallel scan data includes: and performing filtering back projection on the parallel scanning data after the weight allocation to obtain a reconstructed image.
In a second aspect, an embodiment of the present application provides an image reconstruction apparatus, including: the acquisition module is used for acquiring fan-shaped beam data of an object to be scanned; the rearrangement module is used for rearranging the fan-shaped beam data to obtain parallel beam data; the weight distribution module is used for distributing corresponding weights to each ray in the parallel beam data respectively; and the reconstruction module is used for reconstructing according to the parallel scanning data after the weight distribution to obtain a reconstructed image.
In a third aspect, an embodiment of the present application provides a computer device, including a memory, a processor, and a computer program stored on the memory and executable on the processor, where the processor implements the image reconstruction method as described in any one of the above when executing the computer program.
In a fourth aspect, embodiments of the present application provide a computer readable storage medium having stored thereon a computer program which when executed by a processor implements a method of image reconstruction as described in any of the above.
Compared with the related art, the method and the device have the advantages that firstly, the fan-shaped beam data of the object to be scanned are obtained, the fan-shaped beam data are rearranged to obtain parallel beam data, then, each ray in the parallel beam data is correspondingly assigned with a weight, and finally, reconstruction is carried out according to the parallel beam data after the weight is assigned to obtain a reconstructed image. And weight is distributed to each ray in the parallel beam data, so that the influence of damage data caused by bulb tube ignition or detector faults on a reconstructed image can be reduced during image reconstruction, namely, the reconstructed image without artifacts can be obtained by distributing the weight. Therefore, rescanning is not needed, waste of contrast agent is avoided, and the radiation dose of a patient is reduced.
The details of one or more embodiments of the application are set forth in the accompanying drawings and the description below to provide a more thorough understanding of the other features, objects, and advantages of the application.
Drawings
The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this specification, illustrate embodiments of the application and together with the description serve to explain the application and do not constitute a limitation on the application. In the drawings:
FIG. 1 is a flow chart of an image reconstruction method in one embodiment;
FIG. 2 is a flow diagram of a method for assigning weights to parallel beam data in one embodiment;
FIG. 3 is a reconstructed image of one embodiment taken prior to correction;
FIG. 4 is a reconstructed image after correction in one embodiment;
FIG. 5 is a block diagram of an image reconstruction apparatus in one embodiment;
fig. 6 is a schematic diagram of a hardware structure of a computer device in one embodiment.
Detailed Description
The present application will be described and illustrated with reference to the accompanying drawings and examples in order to make the objects, technical solutions and advantages of the present application more apparent. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the application. All other embodiments, which can be made by a person of ordinary skill in the art based on the embodiments provided by the present application without making any inventive effort, are intended to fall within the scope of the present application.
It is apparent that the drawings in the following description are only some examples or embodiments of the present application, and it is possible for those of ordinary skill in the art to apply the present application to other similar situations according to these drawings without inventive effort. Moreover, it should be appreciated that while such a development effort might be complex and lengthy, it would nevertheless be a routine undertaking of design, fabrication, or manufacture for those of ordinary skill having the benefit of this disclosure, and thus should not be construed as having the benefit of this disclosure.
Reference in the specification to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the application. The appearances of such phrases in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. It is to be expressly and implicitly understood by those of ordinary skill in the art that the described embodiments of the application can be combined with other embodiments without conflict.
Unless defined otherwise, technical or scientific terms used herein should be given the ordinary meaning as understood by one of ordinary skill in the art to which this application belongs. The terms "a," "an," "the," and similar referents in the context of the application are not to be construed as limiting the quantity, but rather as singular or plural. The terms "comprising," "including," "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, article, or apparatus that comprises a list of steps or modules (elements) is not limited to only those steps or elements but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus. The terms "connected," "coupled," and the like in connection with the present application are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. The term "plurality" as used herein means two or more. "and/or" describes an association relationship of an association object, meaning that there may be three relationships, e.g., "a and/or B" may mean: a exists alone, A and B exist together, and B exists alone. The character "/" generally indicates that the context-dependent object is an "or" relationship. The terms "first," "second," "third," and the like, as used herein, are merely distinguishing between similar objects and not representing a particular ordering of objects.
A computed tomography apparatus (CT) generally comprises a gantry, a scan table and a console for operation by a physician. One side of the frame is provided with a bulb, and one side opposite to the bulb is provided with a detector. The console is a computer device that controls the bulb and the detector to scan. The computer equipment is also used for receiving the data acquired by the detector, processing and reconstructing the data, and finally forming a CT image. When the CT is used for scanning, a patient lies on the scanning bed, the scanning bed sends the patient into the aperture of the frame, the console controls the frame to rotate at high speed, the bulb arranged on the frame sends out X rays, the X rays penetrate through the patient to be received by the detector to form data, the data are transmitted to the computer equipment, and the computer equipment performs preliminary processing and image reconstruction on the data to obtain CT images.
The CT bulb is actually a large high vacuum cathode ray diode, and the working process is as follows: the cathode filament is heated by 12V current and generates free electron cloud, 40 kV high-voltage potential is added to the cathode and anode at the moment, the potential difference is increased suddenly, the free electron beam in an active state is driven by a high-voltage electric field, the cathode impacts the anode target disc at a high speed, energy conversion occurs, and about l% of electric energy forms x-rays and is emitted by the window; 99% of the electric energy is converted into heat energy and is emitted by the heat radiation system.
The bulb discharge spark occupies a high proportion of the bulb damage. However, the ignition is a general concept, and the reasons and the manifestations of the ignition of the bulb are very various. Bulb firing can be divided into: the in-die discharge and the out-die discharge are divided into the sparking caused by the locking of the rotary anode and the sparking caused by the normal operation of the rotary anode. In principle, the bulb firing includes the following reasons: 1. the insulation degree of the circulating cooling oil is reduced; 2. die cracking; 3. the vacuum degree of the tube core is reduced; 4. the anode target surface is damaged; 5. the inverter of the high-voltage system of the machine is short-circuited; 6. the insulation degree of a high-voltage cathode and anode output module of the machine is not high; 7. high voltage multiplier failure, etc.
The embodiment also provides an image reconstruction method. Fig. 1 is a schematic flow chart of an image reconstruction method in one embodiment, as shown in fig. 1, the flow chart includes the following steps:
step S102, fan-beam data of an object to be scanned is acquired.
Specifically, the object to be scanned is scanned by the computer tomography equipment, so that the scanning data corresponding to the object to be scanned can be obtained, and the obtained scanning data is fan-shaped beam data because the rays emitted by the bulb tube have wider fan-shaped angles in the scanning process. The obtained fan-shaped beam data can be obtained directly after scanning an object to be scanned by the computer tomography equipment; the computer tomography equipment can also scan the object to be scanned, store the scanned fan-shaped beam data into the memory, and acquire the corresponding fan-shaped beam data from the memory when the fan-shaped beam data are needed. The object to be scanned comprises: human body, mold body, etc.
And step S104, rearranging the fan-shaped beam data to obtain parallel beam data.
Specifically, based on imaging reconstruction theory, image reconstruction of CT is performed based on parallel beam data. Therefore, an important process in image reconstruction is to rearrange scanned fan beam data to obtain parallel beam data. The rearrangement is to interpolate in the projection view angle direction to obtain a group of parallel sampling data with uneven interval, then interpolate along the detector channel direction to obtain parallel beam data with even interval. The image reconstruction is carried out through the reconstructed parallel beam data, the reconstruction algorithm is more concise, and the image speed obtained by reconstruction is faster. The rearrangement firstly needs to acquire the mapping relation between the fan-shaped beam data and the parallel beam data in geometry, and then rearranges the fan-shaped beam data according to the mapping relation to obtain corresponding parallel beam data. More specifically, fan-shaped beam data are acquired, and the corresponding relation between the fan-shaped beam data and parallel beam data is obtained according to the detector parameters; and obtaining parallel beam data according to the corresponding relation and the fan-shaped beam data. Wherein the detector parameters include: detector parameters and geometry parameters; wherein the detector parameters include the number of detectors, the detector cell size, etc.; the geometric parameters include: the distance between the detector units, the distance between the bulb and the detector, etc., are all conventional parameters in the art, and will not be described in detail herein. And sampling the fan-shaped beam according to the parameters of the detector to obtain the corresponding relation between the fan-shaped beam data and the parallel beam data. And according to the corresponding relation, the rays with the same absolute angle in the fan-shaped beam data are placed under the same parallel beam data to form parallel beam data. All rays of the same absolute angle are included in the parallel beam data, i.e. all rays in the parallel beam are parallel. Each ray in the parallel beam data corresponds to fan beam data prior to rebinning.
Step S106, each ray in the parallel beam data is respectively assigned with a corresponding weight.
Specifically, since each ray in the parallel beam data corresponds to the fan beam data before rearrangement, a corresponding weight can be assigned to a corresponding ray according to the fan beam data to which each ray corresponds. Each ray is data acquired by the detector unit, and a weight is assigned to each ray, namely, the data acquired by the detector unit is assigned with a weight. For example, during a CT scan, fan beam data under a field of view may be corrupted due to equipment, environment, or the object being scanned. The damaged data can be marked while the CT equipment scans. That is, the scanned fan beam data includes damaged data and complete data, and the damaged data has corresponding labels. Wherein the damage data includes two cases: continuous damage data and intermittent damage data; wherein the continuous damage data is a damage condition of fan beam data of a certain continuous angle, for example, the fan beam data scanned at 10-20 degrees are damaged in the 360-degree scanning process. The intermittent damaged data is the damaged data of multiple sections in the whole scanning process, and complete data exists among the damaged data, for example, the damaged data appears in the fan-shaped beam data scanned at 10-20 degrees in the 360-degree scanning process, the complete data appears in the fan-shaped beam data scanned at 20-100 degrees, and the damaged data appears in the fan-shaped beam data scanned at 100-120 degrees. The intermittent damaged data is illustrated by taking two sections as an example, and multiple sections of damaged data may occur in the whole scanning process in practical application. Acquiring all rays in the parallel beam data; and distributing corresponding weights to all the rays according to a preset rule. Specifically, each ray in the parallel beam data corresponds to fan beam data before rearrangement, and when a weight is assigned to each ray, a ray weight corresponding to damaged data is set to a low weight, and a ray weight corresponding to complete data is set to a high weight. Therefore, when the parallel beam data with the weight is used for reconstruction, the influence of the damaged data on the reconstructed image can be eliminated, and the purpose of eliminating the artifact is further achieved.
In one embodiment, assigning a respective weight to each ray in the parallel beam data includes: acquiring a detector row corresponding to each ray; the weight of rays corresponding to the detector rows at the geometric center is set as a first weight, and the weights of rays corresponding to the detector rows at the two sides of the geometric center are sequentially reduced. Specifically, the detector includes a plurality of rows of detectors, the detector row located at the geometric center is relative to the detector row located at the geometric edge position, the sensitivity of the received data is higher, the accuracy is higher, and the received data amount is larger, so in this embodiment, the ray weight corresponding to the detector row at the geometric center is set to the highest weight, and the ray weights corresponding to the detector rows sequentially arranged from the geometric center to the two sides sequentially decrease. For example: the CT equipment comprises 120 rows of detectors, wherein the 60 th detector row and the 61 st detector row are the detector rows at the geometric center position, and the ray weight corresponding to the two rows of detectors is set to be 1; setting the ray weight corresponding to the 59-1 th detector row to be gradually reduced from 1 to 0.1; the ray weights corresponding to the 62-120 detector rows are set to decrease from 1 to 0.1 in sequence.
And S108, reconstructing according to the parallel beam data with the assigned weights to obtain a reconstructed image.
Specifically, the parallel scanning data after the weight allocation is subjected to filtering back projection to obtain a reconstructed image. By weight distribution, the influence of the damaged data on the reconstructed image is reduced, and the image artifact caused by the damaged data is eliminated.
The method comprises the steps of firstly obtaining fan-shaped beam data of an object to be scanned, rearranging the fan-shaped beam data to obtain parallel beam data, then distributing weights to each ray in the parallel beam data correspondingly, and finally reconstructing according to the parallel beam data with the weights distributed to obtain a reconstructed image. The image reconstruction method in the above embodiment can be applied to any part of any human body, for example, the head, the chest, the liver, the lung, and the like. And weight is distributed to each ray in the parallel beam data, so that the influence of damaged data on a reconstructed image when a bulb tube is ignited can be reduced during image reconstruction, namely, the reconstructed image without artifacts can be obtained by distributing the weight. Therefore, rescanning is not needed, waste of contrast agent is avoided, and the radiation dose of a patient is reduced.
The embodiment also provides a method for distributing weights to parallel beam data. FIG. 2 is a flow chart of a method for assigning weights to parallel beam data according to one embodiment, as shown in FIG. 2, the flow includes the following steps:
step S202, obtaining the correspondence between all the rays and the fan-shaped beam data according to the correspondence between the fan-shaped beam data and the parallel beam data.
Specifically, when the fan-beam data is rearranged into parallel-beam data, the correspondence between the fan-beam data and the parallel-beam data is obtained. Wherein, the correspondence between fan-beam data and parallel beam data includes: and each ray in the parallel beam data is in corresponding relation with the fan-shaped beam data. Each ray in the parallel beam data comes from the fan-shaped beam data, and a corresponding relation exists between each ray and the fan-shaped beam data where the ray exists before.
Step S204, corresponding weights are distributed to the rays according to the fan-shaped beam data corresponding to the rays.
Specifically, according to the corresponding relation between each ray in the parallel beam data and the fan-shaped beam data and the corresponding ray, the fan-shaped beam data corresponding to the ray is found, and according to the corresponding fan-shaped beam data, the weight is distributed for the corresponding ray.
In one embodiment, the fan beam data includes corrupted fan beam data and full fan beam data; if the ray corresponds to the damaged fan-shaped beam data, setting the weight of the ray as a first weight; if the ray corresponds to the complete fan-shaped beam data, setting the weight of the ray as a second weight; the value of the second weight is greater than the value of the first weight. During CT scanning, due to the fact that the bulb tube is ignited, the fan-shaped beam data obtained in the scanning time corresponding to the bulb tube ignition can be damaged, namely the fan-shaped beam data are damaged, the bulb tube is quickly restored after the bulb tube is ignited, and after restoration, complete data can be obtained, namely the complete fan-shaped beam data. During a CT scan, the damaged fan beam data is correspondingly marked. Therefore, when the parallel beam data is assigned with weight, whether the ray corresponds to damaged fan beam data or complete fan beam data is determined according to the corresponding relation between each ray in the parallel beam data and the fan beam data. If the ray corresponds to the damaged fan-shaped beam data, setting the weight of the ray as a first weight; if the ray corresponds to the complete fan-shaped beam data, the weight of the ray is set as a second weight. Wherein the weight value of the second weight is greater than the weight value of the first weight. The purpose is to reduce the proportion of damaged data in image reconstruction, so that the reconstructed image is clearer. For example: the first weight may be set to 0.3; the second weight may be set to 1, improving image quality by reducing the weight of corrupted data.
In one embodiment, the fan beam data includes damaged fan beam data and complete fan beam data, rays corresponding to the damaged fan beam data are taken as first type rays, and rays corresponding to the complete fan beam data are taken as second type rays; setting the weight of the first type of rays as a first weight; setting the weight of the second type of rays in a preset range around the first type of rays to gradually increase from the first weight to the second weight; and setting the weights of the rest second type rays as second weights. The method comprises the steps that rays in parallel beam data are taken as first-class rays, wherein the rays corresponding to damaged fan-shaped beam data are obtained when a corresponding bulb is ignited; and taking the rays corresponding to the obtained complete fan-shaped beam data as second-class rays. Setting the weight of the first type of rays as a first weight; setting a second type of rays in a certain range around the first type of rays to gradually increase from a first weight to a second weight; and setting the weights of the rest second type rays as second weights. The preset range is the number of rays. I.e. when a ray of the first type is present, a transition is smoothly made by the first weight of the ray of the first type to the second weight. For example, 15 rays are included in one parallel beam data in total, when the 7 th ray is the first type ray, the weight of the 7 th ray is set to 0.3, the second type ray in the range of 4 rays around the 7 th ray is selected, the weight of 5 rays is set to be increased from 0.3 to 1, the 6 th and 8 th rays are set to 0.35, and the 5 th and 9 th rays are set to 0.5; the 4 th and 10 th rays are set to 0.7, the 3 rd and 11 th rays are set to 1, and the weights of the remaining 1 st, 2 nd, 12 th, 13 th, 14 th and 15 th rays are set to 1. The more the number of rays in the preset range is, the smoother the curve from the first weight to the second weight is gradually increased, and finally, the reconstructed image is clear. The foregoing is merely illustrative, and not intended to be limiting, and the weights are set according to actual situations in actual applications.
According to the method for distributing the weights for the parallel beam data, the weights as small as possible are set for the damaged data, so that the reconstructed image can be clearer when the image is finally reconstructed.
In one embodiment, in the practical application process, for one abdominal spiral scan, the collimation width is set to 40mm, the pitch is 0.9875, and the rotation speed of the bulb tube is 0.5s for one circle and 1200 visual fields are set. Assume that the number of fields of view corresponding to the damaged fan beam data is 30 out of 1200 fields of view. The reconstruction conditions were: the visual field is 350mm, the matrix size is 512 x 512, and the image thickness is 3mm. The image obtained before using the method provided by the above embodiment is shown in fig. 3, and the image obtained after using the method provided by the above embodiment is shown in fig. 4, it is obvious that the streak artifact caused by the damaged fan beam data is greatly reduced after using the method provided by the above embodiment.
It should be noted that the steps illustrated in the above-described flow or flow diagrams of the figures may be performed in a computer system, such as a set of computer-executable instructions, and that, although a logical order is illustrated in the flow diagrams, in some cases, the steps illustrated or described may be performed in an order other than that illustrated herein.
The present embodiment also provides an image reconstruction device, which is used to implement the foregoing embodiments and preferred embodiments, and will not be described in detail. As used below, the terms "module," "unit," "sub-unit," and the like may be a combination of software and/or hardware that implements a predetermined function. While the means described in the following embodiments are preferably implemented in software, implementation in hardware, or a combination of software and hardware, is also possible and contemplated.
Fig. 5 is a block diagram of an image reconstruction apparatus according to an embodiment, as shown in fig. 5, the apparatus includes: the system comprises an acquisition module 100, a rearrangement module 200, a weight distribution module 300 and a reconstruction module 400.
An acquisition module 100 for acquiring fan-beam data of an object to be scanned;
a rearrangement module 200, configured to rearrange the fan-shaped beam data to obtain parallel beam data;
a weight distribution module 300, configured to distribute a corresponding weight to each ray in the parallel beam data;
the reconstruction module 400 is configured to reconstruct according to the parallel scan data after the weight is assigned, so as to obtain a reconstructed image.
The rearrangement module 200 is further configured to obtain a detector parameter, sample the fan-shaped beam data according to the detector parameter, and obtain a correspondence between the fan-shaped beam data and the parallel beam data; and obtaining parallel beam data according to the corresponding relation and the fan-shaped beam data.
The weight distribution module 300 is further configured to obtain a detector row that receives each ray correspondingly; the weight of rays corresponding to the detector rows at the geometric center is set as a first weight, and the weights of rays corresponding to the detector rows at the two sides of the geometric center are sequentially reduced. .
The weight distribution module 300 is further configured to obtain, according to the correspondence between the fan-shaped beam data and the parallel beam data, the correspondence between all the rays and the fan-shaped beam data; and distributing corresponding weights for the rays according to the fan-shaped beam data corresponding to the rays.
The weight distribution module 300 is further configured to set the weight of the ray to a first weight if the ray corresponds to damaged fan beam data; if the ray corresponds to the complete fan-shaped beam data, setting the weight of the ray as a second weight; the value of the second weight is greater than the value of the first weight.
The weight distribution module 300 is further configured to set a weight of the first type of ray as a first weight; setting the weight of the second type of rays in a preset range around the first type of rays to gradually increase from the first weight to the second weight; and setting the weights of the rest second type rays as second weights.
The reconstruction module 400 is further configured to perform filtered back projection on the parallel scan data after the weight is assigned, so as to obtain a reconstructed image.
The above-described respective modules may be functional modules or program modules, and may be implemented by software or hardware. For modules implemented in hardware, the various modules described above may be located in the same processor; or the above modules may be located in different processors in any combination.
In addition, the image reconstruction method according to the embodiment of the present application described in connection with fig. 1 may be implemented by a computer device. Fig. 6 is a schematic diagram of a hardware structure of a computer device according to an embodiment of the present application.
The computer device may include a processor 81 and a memory 82 storing computer program instructions.
In particular, the processor 81 may comprise a Central Processing Unit (CPU), or an application specific integrated circuit (Application Specific Integrated Circuit, abbreviated as ASIC), or may be configured as one or more integrated circuits that implement embodiments of the present application.
Memory 82 may include, among other things, mass storage for data or instructions. By way of example, and not limitation, memory 82 may comprise a Hard Disk Drive (HDD), floppy Disk Drive, solid state Drive (Solid State Drive, SSD), flash memory, optical Disk, magneto-optical Disk, tape, or universal serial bus (Universal Serial Bus, USB) Drive, or a combination of two or more of the foregoing. The memory 82 may include removable or non-removable (or fixed) media, where appropriate. The memory 82 may be internal or external to the data processing apparatus, where appropriate. In a particular embodiment, the memory 82 is a Non-Volatile (Non-Volatile) memory. In a particular embodiment, the Memory 82 includes Read-Only Memory (ROM) and random access Memory (Random Access Memory, RAM). Where appropriate, the ROM may be a mask-programmed ROM, a programmable ROM (PROM for short), an erasable PROM (Erasable Programmable Read-Only Memory for short), an electrically erasable PROM (Electrically Erasable Programmable Read-Only Memory for short EEPROM), an electrically rewritable ROM (Electrically Alterable Read-Only Memory for short EAROM) or a FLASH Memory (FLASH) or a combination of two or more of these. The RAM may be a Static Random-Access Memory (SRAM) or a dynamic Random-Access Memory (DRAM) where appropriate, and the DRAM may be a fast page mode dynamic Random-Access Memory (Fast Page Mode Dynamic Random Access Memory, FPMDRAM), an extended data output dynamic Random-Access Memory (Extended Date Out Dynamic Random Access Memory, EDODRAM), a synchronous dynamic Random-Access Memory (SDRAM), or the like.
Memory 82 may be used to store or cache various data files that need to be processed and/or communicated, as well as possible computer program instructions for execution by processor 81.
The processor 81 implements any of the image reconstruction methods of the above embodiments by reading and executing computer program instructions stored in the memory 82.
In some of these embodiments, the computer device may also include a communication interface 83 and a bus 80. As shown in fig. 6, the processor 81, the memory 82, and the communication interface 83 are connected to each other through the bus 80 and perform communication with each other.
The communication interface 83 is used to enable communication between modules, devices, units and/or units in embodiments of the application. Communication port 83 may also enable communication with other components such as: and the external equipment, the image/data acquisition equipment, the database, the external storage, the image/data processing workstation and the like are used for data communication.
Bus 80 includes hardware, software, or both, coupling components of the computer device to each other. Bus 80 includes, but is not limited to, at least one of: data Bus (Data Bus), address Bus (Address Bus), control Bus (Control Bus), expansion Bus (Expansion Bus), local Bus (Local Bus). By way of example, and not limitation, bus 80 may include a graphics acceleration interface (Accelerated Graphics Port), abbreviated AGP, or other graphics Bus, an enhanced industry standard architecture (Extended Industry Standard Architecture, abbreviated EISA) Bus, a Front Side Bus (FSB), a HyperTransport (HT) interconnect, an industry standard architecture (Industry Standard Architecture, ISA) Bus, a wireless bandwidth (InfiniBand) interconnect, a Low Pin Count (LPC) Bus, a memory Bus, a micro channel architecture (Micro Channel Architecture, abbreviated MCa) Bus, a peripheral component interconnect (Peripheral Component Interconnect, abbreviated PCI) Bus, a PCI-Express (PCI-X) Bus, a serial advanced technology attachment (Serial Advanced Technology Attachment, abbreviated SATA) Bus, a video electronics standards association local (Video Electronics Standards Association Local Bus, abbreviated VLB) Bus, or other suitable Bus, or a combination of two or more of the foregoing. Bus 80 may include one or more buses, where appropriate. Although embodiments of the application have been described and illustrated with respect to a particular bus, the application contemplates any suitable bus or interconnect.
The computer device may execute the image reconstruction method according to the embodiment of the present application based on the acquired computer instructions, thereby implementing the image reconstruction method described in connection with fig. 1.
In addition, in connection with the image reconstruction method in the above embodiment, the embodiment of the present application may be implemented by providing a computer readable storage medium. The computer readable storage medium has stored thereon computer program instructions; the computer program instructions, when executed by a processor, implement any of the image reconstruction methods of the above embodiments.
The technical features of the above-described embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above-described embodiments are not described for brevity of description, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description.
The above examples illustrate only a few embodiments of the application, which are described in detail and are not to be construed as limiting the scope of the application. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the application, which are all within the scope of the application. Accordingly, the scope of protection of the present application is to be determined by the appended claims.
Claims (8)
1. An image reconstruction method, comprising:
acquiring fan-shaped beam data of an object to be scanned;
rearranging the fan-shaped beam data to obtain parallel beam data;
respectively distributing corresponding weights for each ray in the parallel beam data;
reconstructing according to the parallel beam data after weight distribution to obtain a reconstructed image;
the assigning a respective weight to each ray in the parallel beam data includes:
acquiring the corresponding relation between all rays and the fan-shaped beam data according to the corresponding relation between the fan-shaped beam data and the parallel beam data;
according to the fan-shaped beam data corresponding to the rays, corresponding weights are distributed to the rays;
the fan beam data includes corrupted fan beam data and full fan beam data;
the assigning the corresponding weight to the ray according to the fan-shaped beam data corresponding to the ray comprises:
if the ray corresponds to the damaged fan-shaped beam data, setting the weight of the ray to be low;
if the ray corresponds to the complete fan-shaped beam data, setting the weight of the ray to be high weight; the high weight value is greater than the low weight value.
2. The image reconstruction method according to claim 1, wherein the rearranging the fan-beam data to obtain parallel-beam data includes:
acquiring fan-beam data;
obtaining the corresponding relation between the fan-shaped beam data and the parallel beam data according to the detector parameters;
and obtaining parallel beam data according to the corresponding relation and the fan-shaped beam data.
3. The image reconstruction method according to claim 2, wherein said assigning a respective weight to each ray in the parallel beam data comprises:
acquiring a detector row corresponding to each ray;
the weight of rays corresponding to the detector rows at the geometric center is set as a first weight, and the weights of rays corresponding to the detector rows at the two sides of the geometric center are sequentially reduced.
4. The image reconstruction method according to claim 1, wherein said assigning respective weights to the rays according to fan-beam data corresponding to the rays comprises: taking the ray corresponding to the damaged fan-shaped beam data as a first type ray, and taking the ray corresponding to the complete fan-shaped beam data as a second type ray;
setting the weight of the first type of rays as a first weight;
setting the weight of the second type of rays in a preset range around the first type of rays to gradually increase from the first weight to the second weight;
and setting the weights of the rest second type rays as second weights.
5. The image reconstruction method according to claim 1, wherein reconstructing from the weighted parallel scan data to obtain a reconstructed image comprises:
and performing filtering back projection on the parallel scanning data after the weight allocation to obtain a reconstructed image.
6. An image reconstruction apparatus, comprising:
the acquisition module is used for acquiring fan-shaped beam data of an object to be scanned;
the rearrangement module is used for rearranging the fan-shaped beam data to obtain parallel beam data;
the weight distribution module is used for distributing corresponding weights to each ray in the parallel beam data respectively;
the reconstruction module is used for reconstructing according to the parallel scanning data after the weight distribution to obtain a reconstructed image;
the weight allocation module is also used for the weight allocation module,
acquiring the corresponding relation between all rays and the fan-shaped beam data according to the corresponding relation between the fan-shaped beam data and the parallel beam data;
according to the fan-shaped beam data corresponding to the rays, corresponding weights are distributed to the rays;
the fan beam data includes corrupted fan beam data and full fan beam data;
if the ray corresponds to the damaged fan-shaped beam data, setting the weight of the ray to be low;
if the ray corresponds to the complete fan-shaped beam data, setting the weight of the ray to be high weight; the high weight value is greater than the low weight value.
7. A computer device comprising a memory, a processor and a computer program stored on the memory and executable on the processor, characterized in that the processor implements the image reconstruction method according to any one of claims 1 to 5 when executing the computer program.
8. A computer-readable storage medium, on which a computer program is stored, characterized in that the program, when being executed by a processor, implements the image reconstruction method as claimed in any one of claims 1 to 5.
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