CN111445397A - Flat panel detector residual shadow correction method and device, storage medium and medical equipment - Google Patents
Flat panel detector residual shadow correction method and device, storage medium and medical equipment Download PDFInfo
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Abstract
The application provides a method and a device for correcting a residual image of a flat panel detector, a storage medium and medical equipment, which are used for quickly and accurately correcting the residual image of the flat panel detector. In the method, for any group of DR images subjected to saturation exposure before a current frame DR image, a residual image value of a bright field image remaining in the current frame DR image is determined according to a determined saturation exposure residual image compensation coefficient, a bright field image in the group of DR images and a determined final continuous saturation residual image attenuation curve; determining a residual shadow value of a bright field image of any group of DR images subjected to unsaturated exposure before according to the determined unsaturated exposure residual shadow compensation coefficient, the dark field image in the group of DR images and the determined final continuous unsaturated residual shadow attenuation curve; and then subtracting the sum of residual shadow values of bright-field images in all groups of DR images in the current frame DR image to obtain a residual shadow corrected DR image.
Description
Technical Field
The application relates to the technical field of medical images, in particular to a method and a device for correcting a residual image of a flat panel detector, a storage medium and medical equipment.
Background
With the continuous development of medical technology, digital X-ray imaging systems (DR imaging systems) are widely used, and flat panel detectors are key devices in DR imaging systems. The flat panel detector mainly comprises an amorphous silicon flat panel detector and an amorphous selenium flat panel detector according to materials, but the common problem is that the residual shadow is that under certain dosage exposure, the signal of the flat panel detector receiving X-rays does not disappear immediately but gradually attenuates and disappears along with the lapse of time due to the physical characteristics of the flat panel detector, if exposure is carried out again before the residual signal disappears, the shadow of the previous exposure, namely the so-called residual shadow, exists on an exposure image, and the residual shadow can cause misdiagnosis in clinical diagnosis.
In order to solve the problem of ghost of a flat panel detector, ghost can be removed by two methods, namely hardware and software at present, the ghost can be removed by hardware methods such as hardware design or improved process, but the cost can be greatly improved, the effect is not particularly ideal, the ghost can be removed by a software method, because the ghost is removed by the software method, the cost and the labor are saved, the flexibility is strong, and the ghost removing method can be suitable for all products made of the same material, so that the ghost is generally favored, but the software method in the related technology is high in algorithm complexity, consumes more time, is not particularly ideal in removing effect, and is extremely easy to cause excessive correction or insufficient correction.
Disclosure of Invention
In view of the above, the present application provides a method and an apparatus for correcting an afterimage of a flat panel detector, a storage medium and a medical device, which are used to correct an afterimage of a flat panel detector quickly and accurately.
In a first aspect, an embodiment of the present application provides a method for correcting a residual image of a flat panel detector, where the method includes:
obtaining a current frame DR image obtained by scanning a detected object and a plurality of groups of previous continuous DR images, wherein each group of DR images comprises a bright field image and a dark field image;
for any one of the plurality of groups of continuous DR images, judging whether the exposure corresponding to the group of DR images belongs to saturated exposure or unsaturated exposure;
if the image is in saturated exposure, determining a residual image value of a bright field image in the group of DR images remaining in the current frame DR image according to the determined saturated exposure residual image compensation coefficient, the bright field image in the group of DR images and the determined final continuous saturated residual image attenuation curve;
if the exposure is the unsaturated exposure, determining a residual image value of a bright field image in the group of DR images remaining in the current frame DR image according to the determined unsaturated exposure residual image compensation coefficient, the dark field image in the group of DR images and the determined final continuous unsaturated residual image attenuation curve;
and subtracting the sum of residual shadow values of bright-field images in all groups of DR images in the current frame DR image from the current frame DR image to obtain a residual shadow corrected DR image.
In a possible implementation manner, the determining of the final continuous saturation/non-saturation ghost attenuation curve includes the following steps:
collecting a dark field image before exposure;
collecting bright field images under the condition of no-load saturated exposure/unsaturated exposure, and collecting a dark field image at set time intervals in a set time period after exposure;
generating a discrete saturated/unsaturated afterimage attenuation curve according to the dark field image before exposure, the bright field image under the condition of no-load saturated exposure/unsaturated exposure and each dark field image after exposure;
and fitting the discrete saturated/unsaturated afterimage attenuation curve to obtain the final continuous saturated/unsaturated afterimage attenuation curve.
In a possible implementation manner, the fitting the discrete saturation/non-saturation afterimage attenuation curve to obtain the final continuous saturation/non-saturation afterimage attenuation curve includes:
fitting the discrete saturated/unsaturated afterimage attenuation curve to obtain an original continuous saturated/unsaturated afterimage attenuation curve;
determining a saturation/non-saturation attenuation time threshold corresponding to the original continuous saturated/non-saturation afterimage attenuation curve according to the original continuous saturated/non-saturation afterimage attenuation curve and a set threshold;
and correcting the original continuous saturated/unsaturated afterimage attenuation curve according to the saturated/unsaturated attenuation time threshold value to obtain the final continuous saturated/unsaturated afterimage attenuation curve.
In a possible implementation manner, the modifying the original continuous saturation/non-saturation afterimage attenuation curve according to the saturation/non-saturation attenuation time threshold includes:
when the ghost attenuation time is less than or equal to the saturation/non-saturation attenuation time threshold, maintaining the original continuous saturation/non-saturation ghost attenuation curve;
when the ghost attenuation time is larger than the saturation/non-saturation attenuation time threshold, replacing the ghost values of the points, which are larger than the attenuation time threshold, on the original continuous saturation/non-saturation ghost attenuation curve with the ghost values corresponding to the saturation/non-saturation attenuation time threshold.
In a possible implementation manner, the determining of the saturated exposure afterimage compensation coefficient includes the following steps:
collecting a first bright field image under the condition of no-load saturated exposure;
collecting a bright field image under the condition of saturated exposure with load;
collecting a second bright field image under the condition of no-load saturated exposure again;
determining an afterimage value in the second bright field image according to the undetermined saturated exposure afterimage compensation coefficient, the bright field image under the condition of loaded saturated exposure and the continuous saturated afterimage attenuation curve;
and subtracting the residual image value in the second bright field image from the second bright field image to approximate the first bright field image, and calculating the saturated exposure residual image compensation coefficient by reverse calculation.
In a possible implementation manner, the determining of the unsaturated exposure afterimage compensation coefficient includes the following steps:
collecting a third bright field image under the condition of no-load unsaturated exposure;
collecting a bright field image under the condition of non-saturated exposure with load and a dark field image after exposure;
collecting a fourth bright field image under the condition of no-load unsaturated exposure again;
determining an afterimage value in the fourth bright field image according to the to-be-determined unsaturated exposure afterimage compensation coefficient, the loaded unsaturated exposed dark field image and the continuous unsaturated afterimage attenuation curve;
and (4) subtracting the residual image value in the fourth bright field image from the fourth bright field image to approximate the third bright field image, and calculating the unsaturated exposure residual image compensation coefficient by reverse calculation.
In a second aspect, an embodiment of the present application further provides a device for correcting a flat panel detector residual image, which includes a module configured to execute the method for correcting a flat panel detector residual image in the first aspect or any possible implementation manner of the first aspect.
In a third aspect, this application further provides a storage medium, on which a computer program is stored, where the program is executed by a processor to implement the steps of the method for correcting the afterimage of the flat panel detector in the first aspect or any possible implementation manner of the first aspect.
In a fourth aspect, the present application further provides a medical apparatus, including a memory, a processor, and a computer program stored on the memory and executable on the processor, where the processor executes the program to implement the steps of the method for correcting the ghost of the flat panel detector in the first aspect or any possible implementation manner of the first aspect.
The technical scheme provided by the embodiment of the application at least has the following beneficial effects:
according to the technical scheme provided by the application, the residual shadow value of the saturated and exposed image remaining in the current frame DR image is determined according to the determined saturated and exposed residual shadow compensation coefficient, the bright field image in the group of DR images and the determined final continuous saturated and residual shadow attenuation curve for the image before the current frame DR image, and the residual shadow value of the unsaturated and exposed image remaining in the current frame DR image is determined according to the determined unsaturated and exposed residual shadow compensation coefficient, the dark field image in the group of DR images and the determined final continuous unsaturated and residual shadow attenuation curve for the image before the current frame DR image, namely, different models and parameters are respectively applied to different scanning conditions in the application to remove residual shadows, so that the residual shadow of the flat panel detector can be quickly and accurately corrected.
Drawings
Fig. 1 is a schematic flow chart of a method for correcting an afterimage of a flat panel detector according to an embodiment of the present disclosure;
fig. 2 is a schematic view of a first structure of an image sticking correction apparatus for a flat panel detector according to an embodiment of the present disclosure;
fig. 3 is a schematic diagram illustrating a second structure of the device for correcting an afterimage of a flat panel detector according to an embodiment of the present disclosure;
fig. 4 is a schematic structural diagram of a third image sticking correction apparatus of a flat panel detector according to an embodiment of the present disclosure;
fig. 5 is a schematic structural diagram of a medical device provided in an embodiment of the present application.
Detailed Description
Reference will now be made in detail to the exemplary embodiments, examples of which are illustrated in the accompanying drawings. When the following description refers to the accompanying drawings, like numbers in different drawings represent the same or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present application. Rather, they are merely examples of apparatus and methods consistent with certain aspects of the present application, as detailed in the appended claims.
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used in this application and the appended claims, the singular forms "a", "an", and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It should also be understood that the term "and/or" as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items.
It is to be understood that although the terms first, second, third, etc. may be used herein to describe various information, such information should not be limited to these terms. These terms are only used to distinguish one type of information from another. For example, first information may also be referred to as second information, and similarly, second information may also be referred to as first information, without departing from the scope of the present application. The word "if" as used herein may be interpreted as "at … …" or "when … …" or "in response to a determination", depending on the context.
The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application.
Referring to fig. 1, an embodiment of the present application provides a method for correcting a residual image of a flat panel detector, which may be used in a DR imaging system, and the method may include the following steps:
s101, obtaining a current frame DR image obtained by scanning a detected object and a plurality of groups of previous continuous DR images, wherein each group of DR images comprises a bright field image and a dark field image;
in this embodiment of the application, the multiple groups of continuous DR images refer to images acquired before a current frame DR image, for example, the current frame DR image acquired by this exposure is a bright-field image (or an nth frame bright-field image) acquired by nth exposure, and the multiple groups of continuous DR images may be a group of DR images acquired by 1 st exposure (including a 1 st frame bright-field image and a 1 st frame dark-field image) to a group of DR images acquired by n-1 st exposure (including an n-1 st frame bright-field image and an n-1 st frame dark-field image).
S102, judging whether the exposure corresponding to the group of DR images belongs to saturated exposure or unsaturated exposure for any group of the plurality of groups of continuous DR images;
in the embodiment of the application, when a DR image is collected, whether the secondary exposure is saturated exposure or unsaturated exposure can be judged according to the received X-ray signal, the corresponding mark is used for marking, and when ghost correction is carried out, the mark corresponding to the group of DR images can be inquired, so that whether the exposure corresponding to the group of DR images belongs to saturated exposure or unsaturated exposure can be determined.
S103, if the image is in saturated exposure, determining a residual image value of a bright field image in the group of DR images remaining in the current frame DR image according to the determined saturated exposure residual image compensation coefficient, the bright field image in the group of DR images and the determined final continuous saturated residual image attenuation curve;
s104, if the exposure is unsaturated exposure, determining an afterimage value of a bright field image in the group of DR images remaining in the current frame DR image according to the determined unsaturated exposure afterimage compensation coefficient, the dark field image in the group of DR images and the determined final continuous unsaturated afterimage attenuation curve;
and S105, subtracting the sum of residual shadow values of bright-field images in all groups of DR images in the current frame DR image to obtain a residual shadow corrected DR image.
In the embodiment of the present application, the afterimage value of the previous exposure image in the current frame DR image may be calculated by using the following formula (1), but is not limited to the following formula (1).
Wherein, Ghost (i) is the residual image value of the ith frame bright field image remaining in the current frame DR image, Kb is the unsaturated exposure compensation coefficient, Kc is the saturated exposure compensation coefficient, dark (i) is the image mean value of the ith frame dark field image, Bright (i) is the image mean value of the ith frame bright field image, L ag1(t) is a continuous unsaturated residual image attenuation curve, L ag2(t) is a continuous saturated residual image attenuation curve, and t is the image mean value of the ith frame bright field imagerefFor reference frame acquisition time, i.e. the time interval from the i-th frame bright-field image to the i-th frame dark-field image, tiAnd T is a saturated gray threshold value for the time interval from the ith frame bright-field image to the current frame DR image, Bright (i) < T indicates that the ith exposure is unsaturated exposure, and Right (i) ≧ T indicates that the ith exposure is saturated exposure. Therefore, if the ith exposure is the unsaturated exposure, the afterimage value can be calculated using the formula in the upper part in formula (1), and if the ith exposure is the saturated exposure, the afterimage value can be calculated using the formula in the lower part in formula (1).
In the embodiment of the present application, after determining the residual shadow value of the bright-field image remaining in the current frame DR image in each group of DR images, the residual shadow corrected DR image can be obtained by using the following formula (2).
The CaliImg is a DR image after image sticking correction, the coliimg is a current frame DR image (or a DR image before correction), and the N is that N frames of bright field images before the current frame DR image have residual image values in the current frame DR image.
In the embodiment of the present application, the continuous saturated/unsaturated afterimage attenuation curve and the saturated/unsaturated exposure afterimage compensation coefficient may be determined before the factory, or may be determined and stored after a user test, which is not limited in the present application.
In some embodiments, the determining the final continuous saturation ghost attenuation curve includes the following steps:
collecting a dark field image before exposure;
collecting a bright field image under the condition of no-load saturated exposure, and collecting a dark field image at a set time interval (delta t) within a set time period (for example, 90s) after exposure;
generating a discrete saturated afterimage attenuation curve according to the dark field image before exposure, the bright field image under the condition of no-load saturated exposure and each dark field image after exposure;
and fitting the discrete saturated residual image attenuation curve to obtain the final continuous saturated residual image attenuation curve.
In the embodiment of the present application, a discrete saturated afterimage attenuation curve L ag (n) may be generated according to the dark field image before exposure, the bright field image in the case of no-load saturated exposure, and each of the dark field images after exposure by using the following formula (3):
wherein Dark (0) is the image mean of the Dark field image before exposure, Dark (N) is the image mean of the Dark field image acquired at the nth time after exposure, Bright is the image mean of the Bright field image under the condition of no-load saturation exposure, and N is 1,2, …, N.
In some embodiments, the discrete saturated afterimage attenuation curve may be fitted to obtain an original continuous saturated afterimage attenuation curve, and then the original continuous saturated afterimage attenuation curve is used as a final continuous saturated afterimage attenuation curve.
In the embodiment of the present application, according to the geometric rule of the ghost attenuation curve, a dual-exponential model may be used to fit the discrete saturated ghost attenuation curve to obtain a final continuous saturated ghost attenuation curve, which may be represented by L ag (t) ═ a × exp (b × t) + c × exp (d × t), for example, where the parameters a, b, c, and d are determined according to the ghost values in the discrete saturated ghost attenuation curve.
In other embodiments, in order to improve the accuracy of the ghost correction, the fitting the discrete saturated ghost attenuation curve to obtain the final continuous saturated ghost attenuation curve includes:
fitting the discrete saturated residual image attenuation curve to obtain an original continuous saturated residual image attenuation curve;
determining a saturation attenuation time threshold corresponding to the original continuous saturated ghost attenuation curve according to the original continuous saturated ghost attenuation curve and a set threshold;
and correcting the original continuous saturated afterimage attenuation curve according to the saturated attenuation time threshold value to obtain the final continuous saturated afterimage attenuation curve.
In this embodiment, a saturation attenuation time threshold corresponding to the original continuous saturation residual image attenuation curve is determined according to the original continuous saturation residual image attenuation curve and a set threshold, for example, when a difference between residual image values of any two adjacent points is smaller than the set threshold after passing through a certain point on the original continuous saturation residual image attenuation curve, the point can be determined to be the saturation attenuation time threshold corresponding to the original continuous saturation residual image attenuation curve.
Generally, after a flat panel detector is exposed for a certain time, the afterimage value of the flat panel detector is basically stabilized at a constant value, the fitted afterimage attenuation curve is a function which is attenuated until the value is close to 0, if the afterimage attenuation time is greater than the saturation attenuation time threshold value, the afterimage value is continuously calculated according to the afterimage attenuation curve, the afterimage is not completely removed, and therefore, in order to improve the accuracy of afterimage correction, the original continuous saturated afterimage attenuation curve can be corrected.
In some embodiments, the modifying the original continuous saturation ghost attenuation curve according to the saturation attenuation time threshold includes:
when the ghost attenuation time is less than or equal to the saturation attenuation time threshold, keeping the original continuous saturated ghost attenuation curve;
and when the ghost attenuation time is greater than the saturation attenuation time threshold, replacing the ghost values of the points, which are greater than the attenuation time threshold, on the original continuous saturated ghost attenuation curve with the ghost values corresponding to the saturation attenuation time threshold.
In the embodiment of the present application, the original continuous saturated afterimage attenuation curve may be modified by the following formula (4):
wherein, tcIs the saturation decay time threshold.
In the embodiment of the present application, the method for determining the final continuous unsaturated afterimage attenuation curve is similar to the method for determining the final continuous saturated afterimage attenuation curve, and the final continuous unsaturated afterimage attenuation curve may be determined by referring to the method for determining the final continuous saturated afterimage attenuation curve.
In some embodiments, the determining the final continuous non-saturated ghost attenuation curve comprises the following steps:
collecting a dark field image before exposure;
collecting a bright field image under the condition of no-load unsaturated exposure, and collecting a dark field image at set time intervals in a set time period after exposure;
generating a discrete unsaturated afterimage attenuation curve according to the dark field image before exposure, the bright field image under the condition of no-load unsaturated exposure and each dark field image after exposure;
and fitting the discrete unsaturated afterimage attenuation curve to obtain the final continuous unsaturated afterimage attenuation curve.
In some embodiments, in order to improve the accuracy of the ghost correction, the fitting the discrete unsaturated ghost attenuation curve to obtain the final continuous unsaturated ghost attenuation curve includes:
fitting the discrete unsaturated afterimage attenuation curve to obtain an original continuous unsaturated afterimage attenuation curve;
determining a non-saturated attenuation time threshold corresponding to the original continuous non-saturated afterimage attenuation curve according to the original continuous non-saturated afterimage attenuation curve and a set threshold;
and correcting the original continuous unsaturated afterimage attenuation curve according to the unsaturated attenuation time threshold value to obtain the final continuous unsaturated afterimage attenuation curve.
In some embodiments, the modifying the original continuous non-saturated afterimage attenuation curve according to the non-saturated attenuation time threshold includes:
when the residual image attenuation time is less than or equal to the unsaturated attenuation time threshold value, keeping the original continuous unsaturated residual image attenuation curve;
and when the ghost attenuation time is greater than the unsaturated attenuation time threshold, replacing the ghost values of the points, which are greater than the attenuation time threshold, on the original continuous unsaturated ghost attenuation curve with the ghost values corresponding to the unsaturated attenuation time threshold.
In some embodiments, the determining of the saturated exposure afterimage compensation coefficient includes the following steps:
collecting a first bright field image under the condition of no-load saturated exposure;
collecting a bright field image under the condition of saturated exposure with load;
collecting a second bright field image under the condition of no-load saturated exposure again;
determining an afterimage value in the second bright field image according to the undetermined saturated exposure afterimage compensation coefficient, the bright field image under the condition of loaded saturated exposure and the continuous saturated afterimage attenuation curve;
and (3) subtracting the afterimage value in the second bright-field image from the second bright-field image to approximate the first bright-field image, and calculating the saturated exposure afterimage compensation coefficient (Kc) by reverse estimation.
In some embodiments, the determining of the unsaturated exposure afterimage compensation coefficient includes the following steps:
collecting a third bright field image under the condition of no-load unsaturated exposure;
collecting a bright field image under the condition of non-saturated exposure with load and a dark field image after exposure;
collecting a fourth bright field image under the condition of no-load unsaturated exposure again;
determining an afterimage value in the fourth bright field image according to the to-be-determined unsaturated exposure afterimage compensation coefficient, the loaded unsaturated exposed dark field image and the continuous unsaturated afterimage attenuation curve;
and (3) subtracting the residual image value in the fourth bright field image from the fourth bright field image to approximate the third bright field image, and calculating the unsaturated exposure residual image compensation coefficient (Kb) by reverse estimation.
It should be noted that, before processing, the acquired image is generally subjected to background correction, gain correction and dead pixel correction, and then the image after background correction, gain correction and dead pixel correction is subjected to subsequent processing.
Based on the same inventive concept, as shown in fig. 2, an embodiment of the present application further provides a device for correcting an afterimage of a flat panel detector, where the device includes: the image processing device comprises an image acquisition module 11, a judgment module 12, a first residual image value determination module 13, a second residual image value determination module 14 and a residual image correction module 15.
An image acquisition module 11 configured to obtain a current frame DR image obtained by scanning a subject and previous sets of consecutive DR images, each set of DR image including a bright field image and a dark field image;
a judging module 12 configured to judge, for any one of the plurality of groups of consecutive DR images, whether an exposure corresponding to the group of DR images belongs to a saturated exposure or a non-saturated exposure;
a first afterimage value determining module 13, configured to determine, if the set of DR images is a saturation exposure, an afterimage value of a bright field image remaining in the current frame DR image in the set of DR images according to the determined saturation exposure afterimage compensation coefficient, the bright field image in the set of DR images, and the determined final continuous saturation afterimage attenuation curve;
a second afterimage value determining module 14, configured to determine, if the image is an unsaturated exposure, an afterimage value of a bright field image remaining in the current frame DR image in the set of DR images according to the determined unsaturated exposure afterimage compensation coefficient, the dark field images in the set of DR images, and the determined final continuous unsaturated afterimage attenuation curve;
and the residual shadow correction module 15 is configured to subtract the sum of residual shadow values of bright-field images in each group of DR images in the current frame DR image to obtain a residual shadow corrected DR image.
In some embodiments, as shown in fig. 3, the apparatus for correcting an afterimage of a flat panel detector further includes: an afterimage attenuation curve determination module 16.
The afterimage attenuation curve determination module 16 is configured to:
collecting a dark field image before exposure;
collecting bright field images under the condition of no-load saturated exposure/unsaturated exposure, and collecting a dark field image at set time intervals in a set time period after exposure;
generating a discrete saturated/unsaturated afterimage attenuation curve according to the dark field image before exposure, the bright field image under the condition of no-load saturated exposure/unsaturated exposure and each dark field image after exposure;
and fitting the discrete saturated/unsaturated afterimage attenuation curve to obtain the final continuous saturated/unsaturated afterimage attenuation curve.
In some embodiments, the afterimage attenuation curve determination module 16 is configured to:
fitting the discrete saturated/unsaturated afterimage attenuation curve to obtain an original continuous saturated/unsaturated afterimage attenuation curve;
determining a saturation/non-saturation attenuation time threshold corresponding to the original continuous saturated/non-saturation afterimage attenuation curve according to the original continuous saturated/non-saturation afterimage attenuation curve and a set threshold;
and correcting the original continuous saturated/unsaturated afterimage attenuation curve according to the saturated/unsaturated attenuation time threshold value to obtain the final continuous saturated/unsaturated afterimage attenuation curve.
In some embodiments, the afterimage attenuation curve determination module 16 is configured to: when the ghost attenuation time is less than or equal to the saturation/non-saturation attenuation time threshold, maintaining the original continuous saturation/non-saturation ghost attenuation curve;
when the ghost attenuation time is larger than the saturation/non-saturation attenuation time threshold, replacing the ghost values of the points, which are larger than the attenuation time threshold, on the original continuous saturation/non-saturation ghost attenuation curve with the ghost values corresponding to the saturation/non-saturation attenuation time threshold.
In some embodiments, as shown in fig. 4, the apparatus for correcting an afterimage of a flat panel detector further includes: a first compensation factor determination module 17.
The first compensation factor determination module 17 is configured to:
collecting a first bright field image under the condition of no-load saturated exposure;
collecting a bright field image under the condition of saturated exposure with load;
collecting a second bright field image under the condition of no-load saturated exposure again;
determining an afterimage value in the second bright field image according to the undetermined saturated exposure afterimage compensation coefficient, the bright field image under the condition of loaded saturated exposure and the continuous saturated afterimage attenuation curve;
and subtracting the residual image value in the second bright field image from the second bright field image to approximate the first bright field image, and calculating the saturated exposure residual image compensation coefficient by reverse calculation.
In some embodiments, as shown in fig. 4, the apparatus for correcting an afterimage of a flat panel detector further includes: a second compensation factor determination module 18.
The second compensation factor determination module 18 is configured to:
collecting a third bright field image under the condition of no-load unsaturated exposure;
collecting a bright field image under the condition of non-saturated exposure with load and a dark field image after exposure;
collecting a fourth bright field image under the condition of no-load unsaturated exposure again;
determining an afterimage value in the fourth bright field image according to the to-be-determined unsaturated exposure afterimage compensation coefficient, the loaded unsaturated exposed dark field image and the continuous unsaturated afterimage attenuation curve;
and (4) subtracting the residual image value in the fourth bright field image from the fourth bright field image to approximate the third bright field image, and calculating the unsaturated exposure residual image compensation coefficient by reverse calculation.
The implementation process of the functions and actions of each unit in the above device is specifically described in the implementation process of the corresponding step in the above method, and is not described herein again.
For the device embodiments, since they substantially correspond to the method embodiments, reference may be made to the partial description of the method embodiments for relevant points. The above-described embodiments of the apparatus are merely illustrative, and the units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the scheme of the application. One of ordinary skill in the art can understand and implement it without inventive effort.
Based on the same inventive concept, the present application further provides a storage medium, on which a computer program is stored, and when the program is executed by a processor, the method for correcting the afterimage of the flat panel detector in any possible implementation manner is implemented.
Alternatively, the storage medium may be a non-transitory computer readable storage medium, which may be, for example, a ROM, a Random Access Memory (RAM), a CD-ROM, a magnetic tape, a floppy disk, an optical data storage device, and the like.
Based on the same inventive concept, referring to fig. 5, an embodiment of the present application further provides a medical apparatus, which includes a memory 71 (e.g., a non-volatile memory), a processor 72, and a computer program stored on the memory 71 and executable on the processor 72, and when the processor 72 executes the program, the steps of the method for correcting the ghost of the flat panel detector in any possible implementation manner are implemented. The medical device may be, for example, a DR imaging system.
As shown in fig. 5, the medical device may also generally include: a memory 73, a network interface 74, and an internal bus 75. In addition to these components, other hardware may be included, which is not described in detail.
It should be noted that the flat panel detector image sticking correction device can be implemented by software, which is a logical device formed by reading computer program instructions stored in a non-volatile memory into a memory 73 for operation by a processor 72 of a medical apparatus where the flat panel detector is located.
Embodiments of the subject matter and the functional operations described in this specification can be implemented in: digital electronic circuitry, tangibly embodied computer software or firmware, computer hardware including the structures disclosed in this specification and their structural equivalents, or a combination of one or more of them. Embodiments of the subject matter described in this specification can be implemented as one or more computer programs, i.e., one or more modules of computer program instructions, encoded on a tangible, non-transitory program carrier for execution by, or to control the operation of, data processing apparatus. Alternatively or additionally, the program instructions may be encoded on an artificially generated propagated signal, e.g., a machine-generated electrical, optical, or electromagnetic signal, that is generated to encode and transmit information to suitable receiver apparatus for execution by the data processing apparatus. The computer storage medium may be a machine-readable storage device, a machine-readable storage substrate, a random or serial access memory device, or a combination of one or more of them.
The processes and logic flows described in this specification can be performed by one or more programmable computers executing one or more computer programs to perform corresponding functions by operating on input data and generating output. The processes and logic flows can also be performed by, and apparatus can also be implemented as, special purpose logic circuitry, e.g., an FPGA (field programmable gate array) or an ASIC (application-specific integrated circuit).
Computers suitable for executing computer programs include, for example, general and/or special purpose microprocessors, or any other type of central processing unit. Generally, a central processing unit will receive instructions and data from a read-only memory and/or a random access memory. The basic components of a computer include a central processing unit for implementing or executing instructions and one or more memory devices for storing instructions and data. Generally, a computer will also include, or be operatively coupled to receive data from or transfer data to, or both, one or more mass storage devices for storing data, e.g., magnetic, magneto-optical disks, or optical disks. However, a computer does not necessarily have such a device. Moreover, a computer may be embedded in another device, e.g., a mobile telephone, a Personal Digital Assistant (PDA), a mobile audio or video player, a game console, a Global Positioning System (GPS) receiver, or a portable storage device such as a Universal Serial Bus (USB) flash drive, to name a few.
Computer-readable media suitable for storing computer program instructions and data include all forms of non-volatile memory, media and memory devices, including by way of example semiconductor memory devices (e.g., EPROM, EEPROM, and flash memory devices), magnetic disks (e.g., an internal hard disk or a removable disk), magneto-optical disks, and CD ROM and DVD-ROM disks. The processor and the memory can be supplemented by, or incorporated in, special purpose logic circuitry.
While this specification contains many specific implementation details, these should not be construed as limitations on the scope of any invention or of what may be claimed, but rather as descriptions of features specific to particular embodiments of particular inventions. Certain features that are described in this specification in the context of separate embodiments can also be implemented in combination in a single embodiment. In other instances, features described in connection with one embodiment may be implemented as discrete components or in any suitable subcombination. Moreover, although features may be described above as acting in certain combinations and even initially claimed as such, one or more features from a claimed combination can in some cases be excised from the combination, and the claimed combination may be directed to a subcombination or variation of a subcombination.
Similarly, while operations are depicted in the drawings in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. In some cases, multitasking and parallel processing may be advantageous. Moreover, the separation of various system modules and components in the embodiments described above should not be understood as requiring such separation in all embodiments, and it should be understood that the described program components and systems can generally be integrated together in a single software product or packaged into multiple software products.
Thus, particular embodiments of the subject matter have been described. Other embodiments are within the scope of the following claims. In some cases, the actions recited in the claims can be performed in a different order and still achieve desirable results. Further, the processes depicted in the accompanying figures do not necessarily require the particular order shown, or sequential order, to achieve desirable results. In some implementations, multitasking and parallel processing may be advantageous.
The above description is only exemplary of the present application and should not be taken as limiting the present application, as any modification, equivalent replacement, or improvement made within the spirit and principle of the present application should be included in the scope of protection of the present application.
Claims (14)
1. A method for correcting the afterimage of a flat panel detector is characterized by comprising the following steps:
obtaining a current frame digital X-ray DR image obtained by scanning a detected object and a plurality of groups of previous continuous DR images, wherein each group of DR images comprises a bright field image and a dark field image;
for any one of the plurality of groups of continuous DR images, judging whether the exposure corresponding to the group of DR images belongs to saturated exposure or unsaturated exposure;
if the image is in saturated exposure, determining a residual image value of a bright field image in the group of DR images remaining in the current frame DR image according to the determined saturated exposure residual image compensation coefficient, the bright field image in the group of DR images and the determined final continuous saturated residual image attenuation curve;
if the exposure is the unsaturated exposure, determining a residual image value of a bright field image in the group of DR images remaining in the current frame DR image according to the determined unsaturated exposure residual image compensation coefficient, the dark field image in the group of DR images and the determined final continuous unsaturated residual image attenuation curve;
and subtracting the sum of residual shadow values of bright-field images in all groups of DR images in the current frame DR image from the current frame DR image to obtain a residual shadow corrected DR image.
2. The method of claim 1, wherein the determining of the final continuous saturation/non-saturation ghost attenuation curve comprises the steps of:
collecting a dark field image before exposure;
collecting bright field images under the condition of no-load saturated exposure/unsaturated exposure, and collecting a dark field image at set time intervals in a set time period after exposure;
generating a discrete saturated/unsaturated afterimage attenuation curve according to the dark field image before exposure, the bright field image under the condition of no-load saturated exposure/unsaturated exposure and each dark field image after exposure;
and fitting the discrete saturated/unsaturated afterimage attenuation curve to obtain the final continuous saturated/unsaturated afterimage attenuation curve.
3. The method of claim 2, wherein fitting the discrete saturation/non-saturation afterimage attenuation curve to obtain the final continuous saturation/non-saturation afterimage attenuation curve comprises:
fitting the discrete saturated/unsaturated afterimage attenuation curve to obtain an original continuous saturated/unsaturated afterimage attenuation curve;
determining a saturation/non-saturation attenuation time threshold corresponding to the original continuous saturated/non-saturation afterimage attenuation curve according to the original continuous saturated/non-saturation afterimage attenuation curve and a set threshold;
and correcting the original continuous saturated/unsaturated afterimage attenuation curve according to the saturated/unsaturated attenuation time threshold value to obtain the final continuous saturated/unsaturated afterimage attenuation curve.
4. The method of claim 3, wherein the modifying the original continuous saturation/non-saturation afterimage attenuation curve according to the saturation/non-saturation attenuation time threshold comprises:
when the ghost attenuation time is less than or equal to the saturation/non-saturation attenuation time threshold, maintaining the original continuous saturation/non-saturation ghost attenuation curve;
when the ghost attenuation time is larger than the saturation/non-saturation attenuation time threshold, replacing the ghost values of the points, which are larger than the attenuation time threshold, on the original continuous saturation/non-saturation ghost attenuation curve with the ghost values corresponding to the saturation/non-saturation attenuation time threshold.
5. The method according to claim 1, wherein the determination of the saturated exposure afterimage compensation coefficient comprises the steps of:
collecting a first bright field image under the condition of no-load saturated exposure;
collecting a bright field image under the condition of saturated exposure with load;
collecting a second bright field image under the condition of no-load saturated exposure again;
determining an afterimage value in the second bright field image according to the undetermined saturated exposure afterimage compensation coefficient, the bright field image under the condition of loaded saturated exposure and the continuous saturated afterimage attenuation curve;
and subtracting the residual image value in the second bright field image from the second bright field image to approximate the first bright field image, and calculating the saturated exposure residual image compensation coefficient by reverse calculation.
6. The method according to claim 1, wherein the determination of the unsaturated exposure afterimage compensation coefficient comprises the steps of:
collecting a third bright field image under the condition of no-load unsaturated exposure;
collecting a bright field image under the condition of non-saturated exposure with load and a dark field image after exposure;
collecting a fourth bright field image under the condition of no-load unsaturated exposure again;
determining an afterimage value in the fourth bright field image according to the to-be-determined unsaturated exposure afterimage compensation coefficient, the loaded unsaturated exposed dark field image and the continuous unsaturated afterimage attenuation curve;
and (4) subtracting the residual image value in the fourth bright field image from the fourth bright field image to approximate the third bright field image, and calculating the unsaturated exposure residual image compensation coefficient by reverse calculation.
7. A flat panel detector afterimage correction apparatus, comprising:
the image acquisition module is configured to acquire a current frame digital X-ray DR image obtained by scanning an object to be detected and previous groups of continuous DR images, wherein each group of DR images comprises a bright field image and a dark field image;
the judging module is configured to judge whether the exposure corresponding to the group of DR images belongs to saturated exposure or unsaturated exposure for any one group of the plurality of groups of continuous DR images;
a first residual image value determining module configured to determine a residual image value of a bright field image in the set of DR images remaining in the current frame DR image according to the determined saturated exposure residual image compensation coefficient, the bright field image in the set of DR images, and the determined final continuous saturated residual image attenuation curve if the set of DR images is saturated exposure;
a second residual shadow value determining module configured to determine a residual shadow value of a bright field image in the group of DR images remaining in the current frame DR image according to the determined unsaturated exposure residual shadow compensation coefficient, the dark field image in the group of DR images, and the determined final continuous unsaturated residual shadow attenuation curve if the group of DR images is unsaturated exposure;
and the residual shadow correction module is configured to subtract the sum of residual shadow values of bright-field images in all groups of DR images in the current frame DR image from the current frame DR image to obtain a residual shadow corrected DR image.
8. The apparatus of claim 7, further comprising: a ghost attenuation curve determination module;
the afterimage attenuation curve determination module is configured to:
collecting a dark field image before exposure;
collecting bright field images under the condition of no-load saturated exposure/unsaturated exposure, and collecting a dark field image at set time intervals in a set time period after exposure;
generating a discrete saturated/unsaturated afterimage attenuation curve according to the dark field image before exposure, the bright field image under the condition of no-load saturated exposure/unsaturated exposure and each dark field image after exposure;
and fitting the discrete saturated/unsaturated afterimage attenuation curve to obtain the final continuous saturated/unsaturated afterimage attenuation curve.
9. The apparatus of claim 8, wherein the afterimage attenuation curve determination module is configured to:
fitting the discrete saturated/unsaturated afterimage attenuation curve to obtain an original continuous saturated/unsaturated afterimage attenuation curve;
determining a saturation/non-saturation attenuation time threshold corresponding to the original continuous saturated/non-saturation afterimage attenuation curve according to the original continuous saturated/non-saturation afterimage attenuation curve and a set threshold;
and correcting the original continuous saturated/unsaturated afterimage attenuation curve according to the saturated/unsaturated attenuation time threshold value to obtain the final continuous saturated/unsaturated afterimage attenuation curve.
10. The apparatus of claim 9, wherein the afterimage attenuation curve determination module is configured to:
when the ghost attenuation time is less than or equal to the saturation/non-saturation attenuation time threshold, maintaining the original continuous saturation/non-saturation ghost attenuation curve;
when the ghost attenuation time is larger than the saturation/non-saturation attenuation time threshold, replacing the ghost values of the points, which are larger than the attenuation time threshold, on the original continuous saturation/non-saturation ghost attenuation curve with the ghost values corresponding to the saturation/non-saturation attenuation time threshold.
11. The apparatus of claim 7, further comprising: a first compensation coefficient determination module;
the first compensation factor determination module is configured to:
collecting a first bright field image under the condition of no-load saturated exposure;
collecting a bright field image under the condition of saturated exposure with load;
collecting a second bright field image under the condition of no-load saturated exposure again;
determining an afterimage value in the second bright field image according to the undetermined saturated exposure afterimage compensation coefficient, the bright field image under the condition of loaded saturated exposure and the continuous saturated afterimage attenuation curve;
and subtracting the residual image value in the second bright field image from the second bright field image to approximate the first bright field image, and calculating the saturated exposure residual image compensation coefficient by reverse calculation.
12. The apparatus of claim 7, further comprising: a second compensation coefficient determination module;
the second compensation factor determination module is configured to:
collecting a third bright field image under the condition of no-load unsaturated exposure;
collecting a bright field image under the condition of non-saturated exposure with load and a dark field image after exposure;
collecting a fourth bright field image under the condition of no-load unsaturated exposure again;
determining an afterimage value in the fourth bright field image according to the to-be-determined unsaturated exposure afterimage compensation coefficient, the loaded unsaturated exposed dark field image and the continuous unsaturated afterimage attenuation curve;
and (4) subtracting the residual image value in the fourth bright field image from the fourth bright field image to approximate the third bright field image, and calculating the unsaturated exposure residual image compensation coefficient by reverse calculation.
13. A storage medium having a computer program stored thereon, which, when being executed by a processor, carries out the steps of the method according to any one of claims 1 to 6.
14. A medical device comprising a memory, a processor and a computer program stored on the memory and executable on the processor, wherein the steps of the method of any one of claims 1-6 are performed when the program is executed by the processor.
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