JP5294967B2 - Image processing apparatus and image processing method - Google Patents

Description

  The present invention relates to an image processing apparatus and an image processing method for processing an original image of a photographed subject, a program for causing a computer to execute each step of the image processing method, and a computer-readable storage storing the program It relates to the medium.

  In recent years, for example, in medical X-ray imaging apparatuses, digital X-ray imaging apparatuses capable of outputting digital X-ray image data have become widespread. In such digital X-ray imaging apparatuses, an X-ray that is an original image is used. Image processing of image data is indispensable. Various image processing is applied to the X-ray image data. Among them, tone conversion processing for converting the X-ray image data into a density (luminance) and contrast that are easy to diagnose is an important image processing. One.

FIG. 10 is a schematic diagram illustrating an example of a function used for general gradation conversion processing.
Specifically, FIG. 10 shows an S-shaped shape similar to the characteristic curve of the silver halide film as the shape of the function used for the gradation conversion processing. Creation of this S-shaped characteristic curve About the method, it is shown by the following patent document 1, for example.

  Further, in the X-ray image data, the entire image is not necessarily required for diagnosis, and only a part of the information may be required. For this reason, an S-shaped curve is set to the pixel value of the X-ray image data obtained so that an area obtained by deleting unnecessary areas from the entire image (hereinafter referred to as “region of interest”) has an optimal density (luminance) and contrast. It is common to associate.

As a specific method, for example, there is a method as shown in FIGS.
FIG. 11 is a schematic diagram for explaining gradation conversion processing by a general one-point method.
In FIG. 11, a pixel value representative of the region of interest in the subject (for example, the maximum pixel value in the lung field of the chest front image) becomes a predetermined output value (for example, a pixel value corresponding to a density of 1.8D). Shows a method of performing gradation conversion processing (hereinafter referred to as “one-point method”).

FIG. 12 is a schematic diagram for explaining gradation conversion processing by a general two-point method.
In FIG. 12, the pixel value distribution (for example, the minimum value to the maximum value) of the region of interest included in the image becomes an output value (for example, the minimum density 0.2D to the maximum density 3.2D) within a certain range. Shows a method of performing gradation conversion processing (hereinafter referred to as “two-point method”).

  As described above, as a specific method of associating the S-shaped curve as shown in FIG. 10 with the pixel value of the X-ray image data, there are various methods such as the one-point method and the two-point method described above.

  Further, various methods for automatically analyzing representative values of regions of interest used in the above-described one-point method and two-point method have been proposed. For example, Patent Document 2 below proposes a method of analyzing a two-dimensional structure of an image and calculating it as a representative value of a region of interest, and Patent Document 3 below describes the shape of the histogram of the image. A method for calculating a representative value of a region of interest has been proposed.

Japanese Patent Laid-Open No. 11-88688 JP 2000-163562 A JP-A-8-331385 JP 2002-245453 A JP 2000-276605 A Japanese Patent No. 3631095

  Incidentally, the X-ray image data acquired by the X-ray imaging apparatus is a very high-resolution image (for example, pixel pitch: 160 μm, number of pixels: 7.2 million pixels). While high-precision analysis can be performed, there is a problem that processing time is required. As means for solving such a problem, Patent Document 3 discloses that processing time is shortened by using image data with reduced resolution (thinned image data) when performing analysis.

  However, in Patent Document 3, since image data is thinned out without considering the size of the target structure to be analyzed, sufficient analysis accuracy may not be obtained depending on the imaging region. For example, when a lung field that is a region of interest is analyzed from a profile in the horizontal axis direction with respect to a chest front image as shown in FIG. 13A, the lung field that is a target structure is a relatively large structure. Here, FIG.13 (b) and FIG.13 (c) have shown the pixel value in the position of II 'of the chest front image shown to Fig.13 (a). When analyzing the global structure shown in FIG. 13 (a), it is not necessary to analyze the profile of the high-resolution image data as shown in FIG. 13 (b), and the sampling is roughened as shown in FIG. 13 (c). Even if the profile of low-resolution image data is analyzed, sufficient analysis accuracy can be obtained.

  On the other hand, for example, when analyzing a finger that is a region of interest from a profile in the horizontal axis direction with respect to a finger image as shown in FIG. 14A, the finger that is the target structure has a relatively small structure. Here, FIG. 14B and FIG. 14C show pixel values at the position II-II ′ of the chest front image shown in FIG. When the local structure shown in FIG. 14A is analyzed, the shape of the finger that is the target structure cannot be expressed with the profile of the low-resolution image data with rough sampling as shown in FIG. It becomes difficult to analyze the finger structure well.

  The present invention has been made in view of such problems, and when performing processing for analyzing an image, a mechanism for realizing a reduction in processing time required for the analysis processing without reducing the analysis accuracy is applied. The purpose is to do.

  The image processing apparatus of the present invention is an image processing apparatus that processes an original image of a photographed subject, and includes a predetermined area setting unit that sets a predetermined area including a region of interest in the original image, and the predetermined area setting unit. Resolution conversion means for converting the resolution of the original image based on the set size of the predetermined area, and at least one representative value indicating the distribution tendency of the region of interest from the resolution conversion image converted by the resolution conversion means. Analyzing means for analyzing.

  The present invention also includes an image processing method by the above-described image processing apparatus, a program for causing a computer to execute the image processing method, and a computer-readable storage medium that stores the program.

  According to the present invention, when processing for analyzing an image, the processing time required for the analysis processing can be shortened without reducing the analysis accuracy.

1 is a schematic diagram illustrating an example of a schematic configuration of an X-ray imaging apparatus (image processing apparatus) according to a first embodiment of the present invention. 3 is a flowchart illustrating an example of a processing procedure of an image processing method performed by the X-ray imaging apparatus (image processing apparatus) according to the first embodiment of the present invention. It is a schematic diagram which shows an example of the setting method of the predetermined area | region in step S101 of FIG. It is a schematic diagram which shows an example of the setting method of the predetermined area | region in step S101 of FIG. It is a schematic diagram which shows an example of the setting method of the predetermined area | region in step S101 of FIG. It is a schematic diagram which shows the 1st Embodiment of this invention and shows an example of the function used for a gradation conversion process. It is a schematic diagram which shows an example of schematic structure of the X-ray imaging apparatus (image processing apparatus) which concerns on the 2nd Embodiment of this invention. It is a flowchart which shows an example of the process sequence of the image processing method by the X-ray imaging apparatus (image processing apparatus) which concerns on the 2nd Embodiment of this invention. It is a schematic diagram which shows an example of the setting method of the predetermined area | region in step S202 of FIG. It is a schematic diagram which shows an example of the function used for a general gradation conversion process. It is a schematic diagram for demonstrating the gradation conversion process by the general one point method. It is a schematic diagram for demonstrating the gradation conversion process by a general two-point method. It is a schematic diagram for demonstrating the subject of a prior art. It is a schematic diagram for demonstrating the subject of a prior art.

  Hereinafter, embodiments (embodiments) for carrying out the present invention will be described with reference to the drawings. In the following embodiments of the present invention, an example in which an X-ray imaging apparatus that captures an object using an X-ray that is a kind of radiation is applied as an image processing apparatus according to the present invention will be described. In each embodiment of the present invention, an example in which an X-ray imaging apparatus is applied as an image processing apparatus according to the present invention will be described. For example, other radiation (for example, α rays, β rays, γ rays, etc.) It is also possible to apply a radiation imaging apparatus that captures a subject using

(First embodiment)
First, the first embodiment of the present invention will be described.

  FIG. 1 is a schematic diagram illustrating an example of a schematic configuration of an X-ray imaging apparatus (image processing apparatus) according to the first embodiment of the present invention. An X-ray imaging apparatus 100 shown in FIG. 1 is an apparatus having a function of performing effective image processing when outputting X-ray image data (radiation image data) of a photographed subject on a film or a monitor.

  An X-ray imaging apparatus 100 shown in FIG. 1 includes an X-ray generation circuit 110, a two-dimensional X-ray sensor 120, a data acquisition circuit 130, a preprocessing circuit 140, a CPU 150, a main memory 160, an operation panel 170, an image display 180, an image. It has a processing circuit 190 and a bus.

  In the X-ray imaging apparatus 100 shown in FIG. 1, the preprocessing circuit 140, the CPU 150, the main memory 160, the operation panel 170, the image display 180, and the image processing circuit 190 are connected to a bus (CPU bus). In the X-ray imaging apparatus 100, the preprocessing circuit 140 is connected to the data acquisition circuit 130, and the data acquisition circuit 130 is connected to the X-ray generation circuit 110 and the two-dimensional X-ray sensor 120.

  The X-ray generation circuit 110 emits beam-shaped X-rays (radiation) 111 a to the subject H based on, for example, control of the CPU 150 via the data acquisition circuit 130 and the preprocessing circuit 140.

  The two-dimensional X-ray sensor 120 receives the X-ray 111b transmitted through the subject H, and outputs an X-ray image signal based on the X-ray 111b. In the two-dimensional X-ray sensor 120, for example, pixels corresponding to each pixel of an X-ray image to be photographed are formed in a two-dimensional matrix.

  The data acquisition circuit 130 converts the X-ray image signal output from the two-dimensional X-ray sensor 120 into a predetermined digital signal, and outputs this to the preprocessing circuit 140 as X-ray image data (radiation image data).

  The preprocessing circuit 140 performs preprocessing such as offset correction processing and gain correction processing on the X-ray image data output from the data collection circuit 130. Based on the control of the CPU 150, the preprocessing circuit 140 temporarily stores the preprocessed X-ray image data as original image data in the main memory 160 via the bus and outputs it to the image processing circuit 190. To do.

  The CPU 150 controls each component of the X-ray imaging apparatus 100 as necessary, and comprehensively controls the operation of the X-ray imaging apparatus 100.

  The main memory 160 stores programs necessary for processing by the CPU 150, various data, various information, and the like, and functions as a working memory for the CPU 150.

  The operation panel 170 is operated when a user (operator) gives various instructions to the X-ray imaging apparatus 100.

  The image display 180 displays various images and various information based on the control of the CPU 150, for example.

  The image processing circuit 190 performs image processing of captured X-ray image data based on, for example, control of the CPU 150. The image processing circuit 190 includes a predetermined area setting circuit 191, a resolution conversion circuit 192, an analysis circuit 193, and a gradation conversion circuit 194.

  The predetermined area setting circuit 191 performs a process of setting a predetermined area on the X-ray image (original image) based on the X-ray image data.

  The resolution conversion circuit 192 performs processing for converting the resolution of the X-ray image (original image) based on the size of the predetermined area set by the predetermined area setting circuit 191. Here, the resolution conversion circuit 192 converts the resolution so that the total number of pixels in the predetermined area in the X-ray image (resolution conversion image) after resolution conversion becomes a constant value.

  The analysis circuit 193 performs processing for analyzing at least one representative value indicating the distribution tendency of the region of interest from the X-ray image (resolution conversion image or the like) whose resolution is converted by the resolution conversion circuit 192.

  The gradation conversion circuit 194 performs gradation conversion processing of an X-ray image (resolution conversion image or the like) based on the representative value analyzed by the analysis circuit 193.

  The bus (CPU bus) of the X-ray imaging apparatus 100 is used to connect the preprocessing circuit 140, the CPU 150, the main memory 160, the operation panel 170, the image display 180, and the image processing circuit 190 so that they can communicate with each other. is there.

  In the X-ray imaging apparatus 100 configured as described above, the CPU 150 uses the program stored in the main memory 160, various information, and the like to operate the entire X-ray imaging apparatus 100 according to an operation instruction from the operation panel 170. Control and so on. Thereby, the X-ray imaging apparatus 100 operates as follows.

  First, when a shooting instruction is input from the user via the operation panel 170, the CPU 150 detects this and transmits the shooting instruction to the data collection circuit 130 via the preprocessing circuit 140. When receiving an imaging instruction, the data acquisition circuit 130 controls the X-ray generation circuit 110 and the two-dimensional X-ray sensor 120 to execute X-ray imaging.

  In X-ray imaging, first, the X-ray generation circuit 110 emits X-rays 111a to the subject H, and the two-dimensional X-ray sensor 120 inputs the X-rays 111b that pass through the subject H while being attenuated. An X-ray image signal based on the X-ray 111 b is output to the data acquisition circuit 130. Here, in the present embodiment, the subject H is a human body. That is, the X-ray image signal output from the two-dimensional X-ray sensor 120 is a signal related to a human body image.

  In the data acquisition circuit 130, the X-ray image signal output from the two-dimensional X-ray sensor 120 is converted into a predetermined digital signal and output to the preprocessing circuit 140 as X-ray image data. The preprocessing circuit 140 performs preprocessing such as the above-described offset correction processing and gain correction processing on the X-ray image data from the data acquisition circuit 130, and converts the preprocessed X-ray image data into the original image. The data is output to the main memory 160 and the image processing circuit 190. Then, the image processing circuit 190 performs predetermined image processing on the original image data.

Next, an image processing method by the image processing circuit 190 of the X-ray imaging apparatus 100 configured as described above will be described.
FIG. 2 is a flowchart showing an example of a processing procedure of an image processing method by the X-ray imaging apparatus (image processing apparatus) according to the first embodiment of the present invention. Specifically, FIG. 2 shows an example of a processing procedure of an image processing method in the image processing circuit 190 of the X-ray imaging apparatus 100.

First, before starting the processing of FIG. 2, the image processing circuit 190 receives pre-processed X-ray image data (original image data) from the pre-processing circuit 140, for example.
When the original image data is received, in step S101, the predetermined region setting circuit 191 determines a region including a substantially region of interest on the original image based on the original image data based on, for example, imaging part information from the operation panel 170. Set as area. Here, the process of step S101 will be specifically described below.

  3, 4, and 5 are schematic diagrams illustrating an example of a predetermined area setting method in step S <b> 101 of FIG. 2.

  Here, it is possible to roughly grasp the position of the region of interest on the original image (on the two-dimensional X-ray sensor 120) according to the imaging region of the subject H. Therefore, in the process of step S101, the predetermined area setting circuit 191 acquires the imaging region information input from the operation panel 170 in advance when the user gives an imaging instruction from the main memory 160, and determines the predetermined area according to the imaging region information. Is set as appropriate.

  For example, in the chest front image shown in FIG. 3 (FIG. 3A), a wide rectangular area from the center on the two-dimensional X-ray sensor 120 (on the original image), that is, an area substantially including the lung field that is the area of interest. Is set as a predetermined area 301 (FIG. 3B). In addition, for example, in the thoracic vertebra front imaging shown in FIG. 4 (FIG. 4A), a region in a rectangular range that is long in the vertical direction from the center on the two-dimensional X-ray sensor 120 (on the original image), that is, a thoracic vertebra that is a region of interest Is set as a predetermined area 401 (FIG. 4B). Further, for example, in the finger photographing shown in FIG. 5 (FIG. 5A), a narrow rectangular area near the center on the two-dimensional X-ray sensor 120 (on the original image), that is, a finger that is a region of interest is substantially included. The area is set as a predetermined area 501 (FIG. 5B).

  In this embodiment, the example in which the predetermined area is automatically set according to the imaging region information has been described. However, for example, the predetermined area preset by the user for each imaging region is stored in the main memory 160 and the imaging is performed. Sometimes, the predetermined area may be set using the predetermined area information.

Here, it returns to description of FIG. 2 again.
When the process of step S101 ends, the process proceeds to step S102.
The processing in steps S102 to S104 is processing for converting the resolution of the original image based on the original image data based on the size of the predetermined area in the resolution conversion circuit 192. This will be specifically described below.

First, in step S102, the resolution conversion circuit 192 sets the enlargement / reduction ratio (magnification) R of the original image based on the original image data based on the size of the predetermined area set by the predetermined area setting circuit 191 as follows. It calculates with Formula (1).
R = (Rows × Columns × Pitch) / Tar (1)

  In Equation (1), Rows is the number of pixels in the row direction of the predetermined area (pixel), Columns is the number of pixels in the predetermined direction of the predetermined area (pixel), and Pitch is the pixel pitch (μm). Tar is a constant for defining the resolution of the converted image. Further, when the enlargement / reduction ratio R is smaller than 1.0, it means reduction of the image, and when it is larger than 1.0, it means enlargement of the image. Note that Tar is determined empirically in consideration of, for example, the resolution necessary for the analysis. In this embodiment, Tar = 4500, for example.

  Here, the enlargement / reduction ratio R in the equation (1) decreases as the predetermined area increases. As described above, the predetermined region is a region that includes a substantially region of interest, and the larger the predetermined region, the larger the target structure to be analyzed. That is, as the predetermined area becomes larger, sufficient analysis accuracy can be obtained even if the resolution is reduced and the resolution is lowered. By using the equation (1), enlargement / reduction corresponding to the size of the target structure to be analyzed is achieved. The reduction ratio can be set.

The method for calculating the enlargement / reduction ratio R is not limited to the expression (1), and any method may be used as long as the predetermined area becomes larger, the enlargement / reduction ratio R becomes smaller. For example, it is also possible to calculate the enlargement / reduction ratio R using the following equation (2), where minL is the number of images in the short side direction of a predetermined region (pixel).
R = (minL × Pitch) / Tar (2)
In this case, the enlargement / reduction ratio R decreases as the short side of the predetermined region increases.

  Subsequently, in step S103, the resolution conversion circuit 192 determines whether or not the enlargement / reduction ratio R calculated in step S102 is a reduction smaller than 1.0.

As a result of the determination in step S103, if the enlargement / reduction ratio R calculated in step S102 is reduction smaller than 1.0, the process proceeds to step S104.
In step S104, the resolution conversion circuit 192 performs a process of reducing the original image based on the original image data by R times to convert the resolution of the original image. Here, the method for reducing the original image is not particularly limited, and for example, interpolation reduction can be performed using nearest neighbor interpolation, linear interpolation, cubic spline interpolation, or the like. Note that details regarding the interpolation reduction are already known, and the description thereof is omitted here.

  When the process of step S104 is completed, or when it is determined that the image is not reduced in step S103, the process proceeds to step S105.

  In step S105, the analysis circuit 193 obtains at least one representative value indicating the distribution tendency of the region of interest from the resolution-converted image data converted by the resolution conversion circuit 192 (or the original image data that has not been reduced). Calculate and analyze it.

  Here, the analysis method in step S105 is not particularly limited, but various methods such as a method of recognizing from a histogram of image data and a method of recognizing a region of interest from a two-dimensional structure of image data. Can be used. Note that since the region of interest differs for each imaging region, analysis processing may be performed by a different method based on the imaging region set on the operation panel 170, for example. Specifically, for example, in the case of the cervical spine, the method described in Patent Document 4 already proposed by the present applicant can be used. In this method, the representative value of the cervical spine that is the region of interest can be analyzed by extracting the contour line of the neck region in the subject region. For example, in the case of the chest, the method described in Patent Document 5 already proposed by the present applicant can be used. In this method, the representative value of the lung field, which is the region of interest, can be analyzed by limiting the region based on the spatial positional relationship of the images.

  Subsequently, in step S106, the gradation conversion circuit 194 performs image gradation conversion processing based on the image data for which the representative value is calculated in step S105, based on the representative value analyzed by the analysis circuit 193. Here, the process of step S106 will be specifically described below.

FIG. 6 is a schematic diagram illustrating an example of a function used in the gradation conversion process according to the first embodiment of this invention.
Specifically, in step S106, for example, using the S-curve described in Patent Document 1 already proposed by the present applicant, the representative value of the region of interest is displayed on the operation panel 170 as shown in FIG. Gradation conversion processing is performed so that the desired density and contrast set via the above are obtained. Note that the gradation conversion processing in step S106 is not limited to the one using an S-order curve as shown in FIG. 6, and for example, a straight line or the like may be used.

As described above, in the X-ray imaging apparatus 100 according to the first embodiment, the resolution conversion image obtained by converting (reducing) the resolution of the original image based on the size of the predetermined area including the substantially interested area and converting the resolution. The representative value indicating the distribution tendency of the region of interest is analyzed.
According to such a configuration, the analysis process can be executed with a resolution that takes into account the size of the region of interest (the size of the target structure), and therefore the processing time required for the analysis process is reduced without reducing the analysis accuracy. be able to.

(Second Embodiment)
Next, a second embodiment of the present invention will be described.

  FIG. 7 is a schematic diagram illustrating an example of a schematic configuration of an X-ray imaging apparatus (image processing apparatus) according to the second embodiment of the present invention. Here, in the X-ray imaging apparatus 200 shown in FIG. 7, the same components as those in the X-ray imaging apparatus 100 according to the first embodiment shown in FIG. To do.

  Specifically, the X-ray imaging apparatus 200 shown in FIG. 7 is configured by adding an irradiation field recognition circuit 291 in addition to the configuration of the X-ray imaging apparatus 100 shown in FIG. Therefore, in FIG. 7, the image processing circuit including the irradiation field recognition circuit 291 is described as “image processing circuit 290”.

  The irradiation field recognition circuit 291 irradiates only the area necessary for diagnosis with respect to the original image in order to prevent the irradiation field area (the X-ray exposure to the area unnecessary for diagnosis and the decrease in contrast due to scattering). A process of recognizing a so-called “irradiation field stop” is performed. That is, the irradiation field recognition circuit 291 performs processing for recognizing an X-ray (radiation) irradiation field region in the original image.

An image processing method by the image processing circuit 290 of the X-ray imaging apparatus 200 will be described.
FIG. 8 is a flowchart illustrating an example of a processing procedure of an image processing method performed by an X-ray imaging apparatus (image processing apparatus) according to the second embodiment of the present invention. Specifically, FIG. 8 shows an example of a processing procedure of an image processing method in the image processing circuit 290 of the X-ray imaging apparatus 200. Moreover, in each step of the flowchart shown in FIG. 8, the same step number is attached | subjected about the step similar to the step of the flowchart shown in FIG. 2, The description is abbreviate | omitted.

First, before starting the processing of FIG. 8, the image processing circuit 190 receives pre-processed X-ray image data (original image data) from the pre-processing circuit 140, for example.
When the original image data is received, in step S201, the irradiation field recognition circuit 291 performs processing for recognizing the irradiation field region on the original image based on the original image data. Here, as a method for recognizing the irradiation field region, for example, the method described in Patent Document 6 that has already been proposed by the present applicant can be used. In this method, the irradiation field edge likelihood is scored based on the pixel value pattern of the target pixel and its surrounding pixels to recognize the irradiation field region.

  Subsequently, in step S202, the predetermined region setting circuit 191 sets, as a predetermined region, a region including a substantially region of interest on the original image based on the original image data based on the irradiation field region recognized by the irradiation field recognition circuit 291. Set. Here, the process of step S202 will be specifically described below.

  FIG. 9 is a schematic diagram showing an example of a predetermined area setting method in step S202 of FIG. Here, FIG. 9A shows an irradiation field region 901 in thoracic vertebra front imaging, and FIG. 9B shows an irradiation field region 902 in finger imaging.

  Here, as shown in FIGS. 9A and 9B, the irradiation field regions 901 and 902 include a range (including a region of substantial interest) in order to prevent X-ray exposure to a region unnecessary for diagnosis. Region). Therefore, in the process of step S202, the irradiation field areas (901 and 902) recognized by the irradiation field recognition circuit 291 are set as predetermined areas. In this example, the irradiation field region and the predetermined region are made to coincide with each other. However, in the present invention, it is not necessary to completely match the irradiation field region and the predetermined region. Alternatively, an area that is made smaller may be set as the predetermined area. That is, a mode in which a predetermined area is set from a range included in the irradiation field area can be applied.

  In the process of step S202 of the present embodiment, since the predetermined area is set based on the irradiation field area, there is an effect of saving the trouble of setting the predetermined area in advance. In addition, since the irradiation field area is set according to the positional relationship between the two-dimensional X-ray sensor 120 and the subject H and the physique of the subject H, it is possible to set the predetermined area robustly against such a variable element. Is possible.

When the process of step S202 ends, the process proceeds to step S102.
Thereafter, the processing of the flowchart shown in FIG. 8 is completed through the processing of steps S102 to S106 shown in FIG.

As described above, in the X-ray imaging apparatus 200 of the second embodiment, an irradiation field region recognition process of the original image is performed, and a predetermined region including a substantially region of interest on the original image is determined based on the irradiation field region. I am trying to set it.
According to such a configuration, in addition to the effects of the first embodiment, it is possible to save time and labor for setting a predetermined area in advance and to set an optimal predetermined area.

(Other embodiments of the present invention)
Each step of FIGS. 2 and 8 showing the image processing method by the X-ray imaging apparatus (image processing apparatus) according to each embodiment of the present invention described above is stored in the storage medium (160) by the CPU (150) of the computer. It can be realized by executing the program. This program and a computer-readable recording medium storing the program are included in the present invention.

  In addition, the present invention can be implemented as, for example, a system, apparatus, method, program, storage medium, or the like. Specifically, the present invention may be applied to a system including a plurality of devices. You may apply to the apparatus which consists of one apparatus.

  In the present invention, a software program (in the embodiment, a program corresponding to the flowcharts shown in FIGS. 2 and 8) for realizing the functions of the above-described embodiments is directly or remotely supplied to a system or apparatus. including. The present invention also includes a case where the system or the computer of the apparatus is achieved by reading and executing the supplied program code.

  Accordingly, since the functions of the present invention are implemented by computer, the program code installed in the computer also implements the present invention. In other words, the present invention includes a computer program itself for realizing the functional processing of the present invention.

  In that case, as long as it has the function of a program, it may be in the form of object code, a program executed by an interpreter, script data supplied to the OS, and the like.

  Examples of the recording medium for supplying the program include a flexible disk, hard disk, optical disk, magneto-optical disk, MO, CD-ROM, CD-R, and CD-RW. There are also magnetic tape, nonvolatile memory card, ROM, DVD (DVD-ROM, DVD-R) and the like.

  As another program supply method, a browser on a client computer is used to connect to an Internet home page. The computer program itself of the present invention or a compressed file including an automatic installation function can be downloaded from the homepage by downloading it to a recording medium such as a hard disk.

  It can also be realized by dividing the program code constituting the program of the present invention into a plurality of files and downloading each file from a different homepage. That is, a WWW server that allows a plurality of users to download a program file for realizing the functional processing of the present invention on a computer is also included in the present invention.

  In addition, the program of the present invention is encrypted, stored in a storage medium such as a CD-ROM, distributed to users, and key information for decryption is downloaded from a homepage via the Internet to users who have cleared predetermined conditions. Let me. It is also possible to execute the encrypted program by using the downloaded key information and install the program on a computer.

  Further, the functions of the respective embodiments described above are realized by the computer executing the read program. In addition, based on the instructions of the program, the OS running on the computer performs part or all of the actual processing, and the functions of the above-described embodiments can also be realized by the processing.

  Further, the program read from the recording medium is written in a memory provided in a function expansion board inserted into the computer or a function expansion unit connected to the computer. Thereafter, based on the instructions of the program, the CPU provided in the function expansion board or function expansion unit performs part or all of the actual processing, and the functions of the above-described embodiments are also realized by the processing.

  Note that each of the above-described embodiments is merely a specific example for carrying out the present invention, and the technical scope of the present invention should not be construed as being limited thereto. . That is, the present invention can be implemented in various forms without departing from the technical idea or the main features thereof.

100: X-ray imaging apparatus (image processing apparatus), 110: X-ray generation circuit, 111a, 111b: X-ray, 120: two-dimensional X-ray sensor, 130: data collection circuit, 140: preprocessing circuit, 150: CPU, 160: main memory, 170: operation panel, 180: image display, 190: image processing circuit 190, 191: predetermined area setting circuit, 192: resolution conversion circuit, 193: analysis circuit, 194: gradation conversion circuit

Claims (14)

An image processing apparatus that processes an original image of a photographed subject,
Predetermined area setting means for setting a predetermined area including a region of interest in the original image;
Resolution conversion means for converting the resolution of the original image based on the size of the predetermined area set by the predetermined area setting means;
An image processing apparatus comprising: an analysis unit that analyzes at least one representative value indicating a distribution tendency of the region of interest from the resolution-converted image converted by the resolution conversion unit.   The image processing apparatus according to claim 1, wherein the resolution conversion unit converts the resolution so that a total number of pixels in the predetermined area in the resolution-converted image after resolution conversion becomes a constant value.   The image processing apparatus according to claim 1, wherein the predetermined area setting unit sets the predetermined area based on a photographing part of the original image in the subject. An irradiation field recognition means for recognizing an irradiation field area of the radiation in the original image;
The image processing apparatus according to claim 1, wherein the predetermined area setting unit sets the predetermined area based on an irradiation field area recognized by the irradiation field recognition unit.   The image processing apparatus according to claim 4, wherein the predetermined area setting unit sets the predetermined area from a range included in the irradiation field area.   6. The image processing according to claim 1, further comprising a gradation conversion unit configured to convert a gradation of the resolution-converted image based on the representative value analyzed by the analysis unit. apparatus. An image processing method for processing an original image of a photographed subject,
A predetermined region setting step for setting a predetermined region including a region of interest in the original image;
A resolution conversion step of converting the resolution of the original image based on the size of the predetermined area set in the predetermined area setting step;
An analysis step of analyzing at least one representative value indicating a distribution tendency of the region of interest from the resolution-converted image converted in the resolution conversion step.   8. The image processing method according to claim 7, wherein, in the resolution conversion step, the resolution is converted so that the total number of pixels in the predetermined area in the resolution-converted image after resolution conversion becomes a constant value.   The image processing method according to claim 7 or 8, wherein, in the predetermined area setting step, the predetermined area is set based on a photographing part of the subject in the original image. A radiation field recognition step for recognizing a radiation field area of the radiation in the original image;
The image processing method according to claim 7 or 8, wherein, in the predetermined area setting step, the predetermined area is set based on the irradiation field area recognized in the irradiation field recognition step.   The image processing method according to claim 10, wherein in the predetermined area setting step, the predetermined area is set from a range included in the irradiation field area.   12. The image processing according to claim 7, further comprising a gradation conversion step of converting a gradation of the resolution-converted image based on the representative value analyzed in the analysis step. Method.   The program for making a computer perform each step of the image processing method of any one of Claims 7 thru | or 12.   A computer-readable storage medium storing the program according to claim 13.

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