JP2001245140A - Image processing apparatus and image processing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To process or output a radiographic image in optimum size. SOLUTION: An image processing apparatus for processing a radiographic image, formed in correspondence with the amount of radiation dose which passed through a subject, having diagnostic region recognizing means 262 for recognizing a region required for diagnosing a formed radiographic image output size determining means 263 for determining the number of pixels corresponding to the region recognized by the diagnosis region recognition means, and output image generating means 264 for generating output images from the radiographic images corresponding to the number of pixels determined by the output size determining means.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an image processing method and an image processing apparatus for processing a radiation image, and more particularly, to an image processing method and an image processing apparatus capable of outputting a radiation image at an optimum size.

[0002]

2. Description of the Related Art In recent years, devices capable of directly taking a radiation image as a digital image have been developed. For example, as a device that detects the amount of radiation applied to a subject and obtains a radiation image formed in accordance with the detected amount as an electric signal, a method using a detector using a stimulable phosphor is disclosed in Japanese Unexamined Patent Application Publication No. 2005-110,026. 55-12429 gazette, JP-A-63-189853 gazette,
Many have been disclosed.

In such an apparatus, a stimulable phosphor is applied to a sheet-like substrate, or is fixed by vapor deposition or the like. To absorb.

Thereafter, the stimulable phosphor is excited by light or heat energy to emit the radiation energy accumulated by the stimulable phosphor as a result of the above-mentioned absorption, and the fluorescence is converted to a photoelectric energy. Conversion is performed to obtain an image signal.

On the other hand, an electric charge corresponding to the intensity of the irradiated radiation is generated in the photoconductive layer, the generated electric charge is accumulated in a plurality of two-dimensionally arranged capacitors, and the accumulated electric charge is taken out. Has been proposed.

[0006] Such a radiation image detecting apparatus uses what is called a flat panel detector (FPD). As described in Japanese Patent Application Laid-Open No. 9-90048, this type of FPD can detect fluorescence with a photodiode or a CCD or C-MOS sensor. A similar FPD is described in Japanese Patent Application Laid-Open No. 6-342098.

[0007]

By the way, in radiation imaging, radiation is usually irradiated using a radiation shield called an irradiation field stop to remove scattered radiation in order to avoid unnecessary exposure to the human body. In general, imaging is performed with a limited area (irradiation field).

As a result, the radiographic image obtained by the above-described apparatus includes an area unnecessary for diagnosis, such as outside the irradiation field. Then, when such a radiation image is output as a film, the film is used including unnecessary regions, so that the film and the developing solution are wasted.

When a radiation image including an area such as an irradiation field is displayed on a CRT display,
Since the image data includes unnecessary areas,
Unnecessary areas may be displayed with high brightness,
Dazzling and adversely affects diagnosis.

Also, the size of the image data increases,
The storage area and processing time are wasted. Further, since the size of the image data is increased, the transfer time on the network is also increased.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to realize an image processing method and an image processing apparatus capable of processing or outputting a radiation image at an optimum size. I do.

[0012]

That is, the present invention for solving the above-mentioned problems is as follows.

(1) The invention according to claim 1 is an image processing method for processing a radiation image according to a radiation amount transmitted through a subject, and recognizes an area required for diagnosis in the formed radiation image. Diagnostic area recognition step to perform, an output size determination step to determine the number of pixels of the output image according to the recognized area, and an output image generation step to generate an output image from the radiation image according to the determined number of pixels, An image processing method comprising:

According to a ninth aspect of the present invention, there is provided an image processing apparatus for processing a radiation image corresponding to a radiation dose transmitted through a subject, and recognizes an area required for diagnosis of the formed radiation image. Diagnostic area recognition means, output size determination means for determining the number of pixels of the output image according to the area recognized by the diagnosis area recognition means, and a radiographic image according to the number of pixels determined by the output size determination means And an output image generating means for generating an output image.

According to these inventions, an area required for diagnosis is recognized in the formed radiation image, the number of pixels of the output image is determined according to the recognized area, and the radiation is determined according to the determined number of pixels. An output image is generated from the image.

As a result, areas unnecessary for diagnosis are not included in the output image, and it becomes possible to process or output a radiation image at an optimum size.

(2) In the invention described in claim 2, the area required for the diagnosis is an area in an irradiation field, and the irradiation field is recognized in the diagnosis area recognition step. 1. The image processing method according to item 1.

In the invention according to claim 10, the area required for diagnosis to be recognized by the diagnosis area recognition means is an area in an irradiation field, and the diagnosis area recognition means recognizes the irradiation field. An image processing apparatus according to claim 9, wherein:

In these inventions, in the above (1), the area required for diagnosis is an area inside the irradiation field, so that the outside of the irradiation field unnecessary for diagnosis is not included in the output image, and the radiation image is It is possible to process or output with the optimal size.

(3) The invention described in claim 3 is characterized in that the area required for the diagnosis is an area in a region of interest of a radiographic image, and the diagnostic region recognition step recognizes the region of interest. The image processing method according to claim 1, wherein

According to the eleventh aspect of the present invention, the area required for the diagnosis to be recognized by the diagnostic area recognition means is an area within a region of interest of a radiographic image, and the diagnostic area recognition means has a region of interest. The image processing apparatus according to claim 9, wherein the image processing apparatus recognizes an area.

In these inventions, in the above (1), the region required for diagnosis is set to a region within the region of interest, so that the outside of the region of interest unnecessary for diagnosis is not included in the output image, and radiation It is possible to process or output an image at an optimal size.

(4) The invention according to claim 4, wherein in the output image generating step, a plurality of output images are output side by side. This is an image processing method.

According to a twelfth aspect of the present invention, the output image generating means outputs a plurality of output images side by side.
An image processing apparatus according to any one of claims 9 to 11, wherein:

In these inventions, the above (1) to (3)
In, since multiple output images can be output side by side,
An output medium that does not include a region unnecessary for diagnosis can effectively use an output medium.

(5) The invention according to claim 5, further comprising an output size correcting step of correcting the determined number of pixels, generating and outputting an output image from a radiation image according to the corrected number of pixels. The image processing method according to any one of claims 1 to 4, characterized in that:

The invention according to claim 13 further comprises an output size correcting means for correcting the determined number of pixels, wherein the output image generating means is adapted to adjust the radiation according to the number of pixels corrected by the output size correcting means. The image processing apparatus according to claim 9, wherein an output image is generated from the image and output.

In these inventions, the above (1) to (4)
In, the determined number of pixels can be corrected, so that an output image modified in accordance with various factors can be generated and output.

(6) The invention according to claim 6 has an output size correcting step of correcting the determined number of pixels, and a display step of displaying an image of the corrected number of pixels. An image processing method according to any one of claims 1 to 5.

The invention according to claim 14 has output size correcting means for correcting the determined number of pixels, and display means for displaying an image of the corrected number of pixels. An image processing apparatus according to any one of claims 9 to 13.

In these inventions, the above (1) to (4)
In, the determined number of pixels can be corrected and an image having the corrected number of pixels can be displayed, so that an output image corrected in accordance with various factors can be output after confirmation.

(7) The invention according to claim 8, wherein in the output size determining step, the number of pixels of the output image is determined according to the size of the subject.
An image processing method according to claim 6.

According to a fifteenth aspect of the present invention, in the output size determining means, the number of pixels of the output image is determined according to the size of the subject. An image processing apparatus according to any one of the first to third aspects.

In these inventions, the above (1) to (6)
In determining the output size, the number of pixels of the output image is determined according to the size of the subject.
It is possible to generate an output image at a predetermined ratio (enlargement, equal magnification, reduction) with respect to the original subject.

(8) In the invention described in claim 7, in the output image generating step, a plurality of output images are juxtaposed and output, and any one of the images is rotated as necessary at the time of juxtaposition. An image processing method according to any one of claims 1 to 3, characterized in that:

Further, the invention according to claim 16 is characterized in that the output image generating means outputs a plurality of output images side by side, and rotates any one of the images as necessary at the time of side by side. An image processing apparatus according to any one of claims 9 to 11.

In these inventions, the above (1) to (3)
In the above, a plurality of output images can be juxtaposed and rotated and output as necessary, so that an output medium that does not include a region unnecessary for diagnosis can effectively use an output medium.

[0038]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, an embodiment of the present invention will be described in detail with reference to the drawings. First, the configuration of the radiation image processing apparatus according to the present embodiment will be described, and thereafter, the operation of the radiation image processing apparatus will be described, and further, the image processing will be described in detail.

<Configuration of Radiation Image Processing Apparatus> FIG. 2 is a system configuration diagram showing the overall configuration of the radiation image processing apparatus. The radiation generator 30 is controlled by the controller 10, and the radiation emitted from the radiation generator 30 is applied to the imaging panel mounted on the front of the radiation image reader 40 through the subject 5.

FIG. 3 shows the configuration of a radiation image reader 40 using an FPD (Flat Panel Display). The imaging panel 41 has a substrate having a thickness enough to obtain a predetermined rigidity, and a detection element 412- (1, 1) that outputs an electric signal in accordance with the dose of the irradiated radiation is provided on the substrate.
1) to 412- (m, n) are two-dimensionally arranged in a matrix. Further, the scanning lines 415-1 to 415-m and the signal lines 416-1
416-n are arranged, for example, orthogonally.

The scanning lines 415-1 to 415 of the imaging panel 41
-m is connected to the scanning drive unit 44. Scan driver 4
4 to one of the scanning lines 415-1 to 415-m.
When the readout signal RS is supplied to 15-p (p is any value of 1 to m), the electric signal SV corresponding to the dose of the radiation emitted from the detection element connected to the scanning line 415-p. -1 to
SV-n is output and supplied to the image data generation circuit 46 via the signal lines 416-1 to 416-n.

The detecting element 412 may be any element that outputs an electric signal corresponding to the dose of the irradiated radiation.
For example, when a detection element is formed using a photoconductive layer in which an electron-hole pair is generated upon irradiation with radiation and the resistance value changes, the amount of radiation generated in the photoconductive layer depends on the amount of radiation generated in the photoconductive layer. Amount of charge is stored in the charge storage capacitor,
The charge stored in the charge storage capacitor is supplied to the image data generation circuit 46 as an electric signal. It is preferable that the photoconductive layer has a high dark resistance value, such as amorphous selenium, lead oxide, cadmium sulfide, mercuric iodide, or a photoconductive organic material (a photoconductive layer to which an X-ray absorbing compound is added). And the like, and amorphous selenium is particularly desirable.

When the detection element 412 is formed using, for example, a scintillator or the like that generates fluorescence when irradiated with radiation, a photodiode generates an electric signal based on the intensity of the fluorescence generated by the scintillator. It may be supplied to the image data generation circuit 46.

As disclosed in Japanese Patent Application Laid-Open No. 9-90048, the image pickup panel 41 using such a structure generates fluorescent light by absorbing X-rays into a phosphor layer such as an intensifying screen. Some types detect the intensity of fluorescence with a photodetector such as a photodiode provided for each pixel. As another method for detecting fluorescence, there is a method using a CCD or a C-MOS sensor.

In particular, in the imaging panel (FPD) of the type disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 6-342098, since the X-ray dose is directly converted into the electric charge amount for each pixel, the sharpness of the FPD is hardly deteriorated and the sharpness is reduced. Therefore, the effects of the X-ray image recording system and the X-ray image recording method are large and suitable.

Further, the image pickup panel 41 can be configured as shown in FIGS. FIG. 4 is a front view of a radiation image detector that can be used as the imaging panel 41, and shows an example in which the radiation image detector is configured by a plurality of units. The dotted line in FIG. 4 is a line of the grid 50 of the radiation image detector, but is actually hidden by the protective member and the X-ray scintillator and cannot be seen from the front. FIG. 4 shows an example in which the number of units is 6 × 6 = 36, but the number is not limited to this.

FIG. 5 is a schematic diagram of a longitudinal section of the radiation image detector. The radiation image detector includes an X-ray scintillator 51,
A lens array 52 and an area sensor 54 corresponding to each lens 53 of the lens array 52 are arranged in this order. The X-ray scintillator 51 is protected by a protection member 55. Each lens 53 of the lens array 52 is supported by a lens support member 58, and a transparent member 5 is provided between the X-ray scintillator 51 and the lens array 52.
6 are arranged. The area sensor 54 is supported by an area sensor support member 57.

The shapes, thicknesses, ray paths, etc. of the components of the radiation image detector are not accurate. The grating 50 does not directly touch the X-ray scintillator 51, but abuts on the transparent member 56, thereby preventing the grating 50 from hitting the X-ray scintillator 51 and damaging it. Prevents missing parts.

Each lens 5 of the lens array 52
3 are arranged in this order, the spatial resolution is high, the image quality is high, the thickness is small, the size is small, and the weight is low.

The X-ray scintillator 51 emits visible light by exposure to X-rays such as gadolinium oxysulfide and cesium iodide, and the X-ray scintillator 51 emits visible light by exposure to X-rays to increase the spatial resolution. High image quality.

The lens array 52 is made up of a lens group composed of a combination of two or more different lenses 53, and has a high spatial resolution, high image quality, and a small thickness. If the imaging magnification of the lens 53 is from 1 / 1.5 to 1/20, and if the imaging magnification is more than 1 / 1.5, the area sensor becomes too large and the arrangement becomes difficult.
If it is smaller than 20, the distance from the X-ray scintillator 51 to the lens becomes longer, and the thickness of the radiation image detector increases.

Further, as the area sensor 54, a CCD or C
-A clear image can be obtained by using a solid-state imaging device such as a MOS sensor.

The image data generating circuit 46 sequentially selects the supplied electric signals SV based on an output control signal SC from a reading control circuit 48 described later and converts them into digital image data DT. The image data DT is supplied to the reading control circuit 48.

The reading control circuit 48 is connected to the controller 10, and based on the control signal CTD supplied from the controller 10, the scanning control signal RC and the output control signal S
Generate C. The scanning control signal RC is used as the scanning driving unit 44.
And the scanning line 415 based on the scanning control signal RC.
The read signal RS is supplied to -1 to 415-m.

The output control signal SC is supplied to the image data generation circuit 46. For example, when the imaging panel 41 is composed of (m × n) detection elements 412 as described above by the scanning control signal RC and the output control signal SC from the reading control circuit 48, the detection elements 412- (1,
If data based on the electric signal SV from (1) to 412- (m, n) are data DP (1,1) to DP (m, n), data DP (1,
1), DP (1,2),... DP (1, n), DP (2,1),.
Image data DT is generated in the order of P (m, n), and the image data DT is supplied from the image data generation circuit 46 to the reading control circuit 48. In the read control circuit 48,
A process of transmitting the image data DT to the controller 10 is also performed.

The image data DT obtained by the radiation image reader 40 is sent to the controller 10 via the read control circuit 48.
Supplied to When the image data obtained by the radiation image reader 40 is supplied to the controller 10 and the image data subjected to the logarithmic conversion process is supplied, the controller 1
0 can simplify the processing of the image data.

The radiation image reader is not limited to the one using the FPD, but may be one using a stimulable phosphor. FIG. 6 shows a configuration in which a radiation image reader 60 using a stimulable phosphor is used. In a conversion panel 61 irradiated with radiation, a stimulable phosphor layer is formed on a support on a support. It is provided by vapor deposition of a stimulable phosphor or application of a stimulable phosphor paint. This stimulable phosphor layer is shielded or covered by a protective member in order to block adverse effects and damage due to the environment.

The light beam generator (gas laser, solid-state laser, semiconductor laser, etc.) 62 generates a light beam whose emission intensity is controlled. This light beam reaches the scanning unit 63 via various optical systems, is deflected by the scanning unit 63, is further deflected by the reflecting mirror 64, and is guided to the conversion panel 61 as stimulating excitation scanning light. .

The light-collecting end of the light-collecting body 65 formed of an optical fiber or a sheet-shaped light guide member is disposed close to the conversion panel 61 on which the stimulating excitation light is scanned, and the light from the light beam generator 62 is emitted. The stimulated emission having an emission intensity proportional to the latent image energy generated in the conversion panel 61 by the beam scanning is received.

The filter 66 allows only light in the stimulating light emission wavelength range from the light introduced from the light collector 65 to pass therethrough. The light passing through the filter 66 is incident on the photomultiplier 67.

The photomultiplier 67 generates a current signal corresponding to the incident light by photoelectric conversion. This current signal is supplied to the current / voltage converter 70 and converted into a voltage signal. Further, after the voltage signal is amplified by the amplification unit 71, the image data D of the digital signal is converted by the A / D conversion unit 72.
Converted to T. Here, a logarithmic conversion amplifier (log amplifier) is used as the amplifier 71.

The output image data DT is sequentially image-processed in the image processing device 26, and the image data DTC after the image processing is transmitted to the external device 100 such as a printer via the interface 18.

CPU (Central Processing Unit) 11
Is for controlling image processing in the image processing device 26, and the image data DT
For various image processing (for example, spatial frequency processing, dynamic range compression, gradation processing, enlargement / reduction processing,
(Movement, rotation, statistical processing, etc.) to generate image data DTC in a form suitable for diagnosis.

The image data DTC is supplied to an external device 100 such as a printer, and a hard copy of a radiation image of each part of the human body can be obtained. Note that a monitor such as a CRT may be connected to the interface 18.
Further, a storage device (filing system) capable of storing image data of a plurality of radiation images may be connected.

The reading controller 75 adjusts the light beam intensity of the light beam generator 62, adjusts the gain of the photomultiplier 67 by adjusting the power supply voltage of the high-voltage power supply 76 for the photomultiplier, and amplifies the current / voltage converter 70. Part 71
Is adjusted, and the input dynamic range of the A / D converter 72 is adjusted, so that the reading gain is comprehensively adjusted.

The image data DT obtained from the A / D converter 72 is supplied to the controller 10 and is read by the reading controller 7 according to a control signal CTD from the controller 10.
5 is controlled.

The radiation image reader irradiates a silver halide film on which a radiation image is recorded with light from a light source such as a laser or a fluorescent lamp, and photoelectrically converts the transmitted light of the silver halide film to generate image data. May be. Further, a configuration may be employed in which radiation energy is directly converted into an electric signal using a radiation quantum counting type detector to generate image data.

Next, FIG. 7 shows the configuration of the controller 10 in FIG. The CPU 11 for controlling the operation of the controller 10 includes a system bus 12 and an image bus 13.
Are connected and the input interface 17 is connected. CP for controlling the operation of the controller 10
The operation of U11 is controlled based on a control program stored in the memory 14.

A display control unit 15, a frame memory control unit 16, an output interface 18, a photographing control unit 19, a disk control unit 20, and the like are connected to the system bus 12 and the image bus 13, and the system bus 12 is used. CPU1
The operation of each unit is controlled by the image bus 1 and the image bus 1
The transfer of image data between the respective units is performed via the interface 3.

The frame memory 21 is connected to the frame memory 21, and the image data obtained by the radiation image reader 40 is stored through the imaging controller 19 and the frame memory controller 16. The image data stored in the frame memory 21 is read and supplied to the display control unit 15 and the disk control unit 20. The frame memory 21 may store the image data supplied from the radiation image reader 40 after the CPU 11 processes the image data.

An image display device 22 is connected to the display control unit 15, and a radiographic image based on the image data supplied to the display control unit 15 is displayed on the screen of the image display device 22. Here, when the number of display pixels of the image display device 22 is smaller than the number of pixels of the radiation image reader 40,
By thinning out and reading out the image data, the entire captured image can be displayed on the screen. In addition, if the image data of the area corresponding to the number of display pixels of the image display device 22 is read out, the captured image at the desired position can be displayed in detail.

From the frame memory 21 to the disk controller 2
When the image data is supplied to the disk controller 20, for example, the image data is read continuously and the FI
The data is written to the FO memory and then sequentially stored in the disk drive 23
Will be recorded.

Further, the image data read from the frame memory 21 and the image data read from the disk device 23 are transmitted to the external device 1 via the output interface 18.
00 can also be supplied.

In the image processing section 26, the radiation image reader 4
0 to the image data D supplied via the photographing control unit 19
T irradiation field recognition processing, region of interest setting, normalization processing and gradation processing, pixel number change processing, and the like are performed. Further, frequency emphasis processing, dynamic range compression processing, and the like may be performed. Note that the image processing unit 26 is a CPU
Image processing or the like can also be performed as a configuration that 11 also serves as.

Therefore, the image processing unit 26 constitutes a diagnosis area (irradiation field area, area of interest) recognition means, output size determination means, output image generation means, and output size correction means in the claims.

The input interface 17 is connected to an input device 27 such as a keyboard. By operating the input device 27, management information such as information for identifying image data obtained by shooting and information on shooting is input.

As the external device 100 connected to the output interface 18, a scanning laser exposure device also called a laser imager is used. In this scanning laser exposure apparatus, the intensity of a laser beam is modulated by image data, exposed to a conventional silver halide photographic material or a thermal phenomenon silver halide photographic material, and then subjected to an appropriate development process to thereby obtain a radiation image. A hard copy is obtained. In addition, a material that can form a medical image having a halftone by attaching ink to a recording medium by an inkjet method may be used.

Although the frame memory 21 stores the image data supplied from the radiation image reader 40, the supplied image data may be processed by the CPU 11 and then stored. Further, the disk device 23 stores image data stored in the frame memory 21, that is, image data supplied from the radiation image reader 40 and image data obtained by processing the image data by the CPU 11 together with management information and the like. be able to.

<Operation of Radiation Image Processing Apparatus> Next, the operation of the above radiation image processing apparatus will be described. When obtaining a radiation image of the subject 5, it is assumed that the subject 5 is located between the radiation generator 30 and the imaging panel 41 of the radiation image reader 40, and the radiation emitted from the radiation generator 30 is And the radiation transmitted through the subject 5 is incident on the imaging panel 41. Note that the same applies to the case where the radiation image reader 60 is used instead of the radiation image reader 40. In the following description, the case where the radiation image reader 60 is used and the case where the radiation image reader 60 is used will be omitted. I do.

The controller 10 is input with management information indicating the identification of the subject 5 to be photographed and information relating to the photographing using the input device 27. The input of the management information using the input device 27 is performed by operating a keyboard, using a magnetic card, a bar code, an HIS (In-Hospital Information System: information management by network), and the like.

The management information includes, for example, an ID number, a name, a date of birth, a sex, a photographing date and time, a photographing site and a photographing position (for example, which part of the human body was irradiated with radiation from which direction), a photographing method (simple It consists of information such as imaging, contrast imaging, tomography, magnified imaging, etc., imaging conditions (tube voltage, tube current, irradiation time, use of scattered radiation removal grid, etc.).

The date and time of photographing can be obtained automatically from the CPU 11 by using a clock function built in the CPU 11. The management information to be input may be only information relating to the subject to be photographed at that time. A series of management information may be input in advance, and the subject may be photographed in the input order, or the management information may be input as needed. The information may be read and used.

When the power switch of the radiation image reader 40 is turned on, the control signal C
Read control circuit 4 of radiation image reader 40 based on TD
The scan panel 44 initializes the imaging panel 41. This initialization is for obtaining a correct electric signal corresponding to the radiation dose emitted from the imaging panel 41.

Image pickup panel 41 in radiation image reader 40
Is completed, irradiation of radiation from the radiation generator 30 is enabled. Here, when a switch for irradiating radiation is provided in the radiation generator 30,
When this switch is operated, radiation is irradiated from the radiation generator 30 toward the subject 5 for a predetermined time, and a signal DFS indicating the start of irradiation and a signal DFE indicating the end of irradiation are supplied to the controller 10. .

At this time, the radiation dose of the radiation applied to the imaging panel 41 of the radiation image reader 40 is modulated by the subject 5 because the degree of radiation absorption by the subject 5 differs. Detection element 412- (1,1) of imaging panel 41
In 412- (m, n), an electric signal based on the radiation modulated by the subject 5 is generated.

Next, in the controller 10, the signal DFS
Is supplied for a predetermined time, for example, when the irradiation time of the radiation is about 0.1 second, a time longer than the irradiation time (for example, about 1 second) or the signal DF
Immediately after the supply of E, the control signal CTD is supplied to the reading control circuit 48 of the radiation image reader 40 so that the radiation image reader 40 starts generating the image data DT.

On the other hand, when a switch for irradiating radiation is provided in the controller 10, when this switch is operated, an irradiation start signal CST for starting irradiation of radiation is transmitted via the imaging control unit 19. The radiation is supplied to the radiation generator 30, and the radiation is emitted from the radiation generator 30 toward the subject 5 for a predetermined time. This irradiation time is set based on, for example, management information.

Next, the controller 10 outputs a control signal CT for starting the generation of image data in the radiation image reader 40 a predetermined time after outputting the irradiation start signal CST.
D is supplied to the reading control circuit 48 of the radiation image reader 40. Note that the controller 10 detects the end of radiation irradiation by the radiation generator 30 and then controls the radiation image reader 40 to start the generation of image data by the control signal CT.
D may be supplied to the radiation image reader 40. In this case, generation of image data during irradiation of radiation can be prevented.

The reading control circuit 48 of the radiation image reader 40
In, the scanning control signal RC and the output control signal SC are generated based on the control signal CTD for starting the generation of the image data supplied from the controller 10. The scan control signal RC is supplied to the scan driver 44, and the output control signal SC is supplied to the image data generation circuit 46. The image data DT obtained from the image data generation circuit 46 is supplied to the read control circuit 48. You. This image data DT is
It is sent to the controller 10 by the reading control circuit 48.

The image data DT supplied to the controller 10 is stored in the frame memory 21 via the photographing control unit 19, the frame memory control unit 16 and the like. Using the image data stored in the frame memory 21, a radiographic image can be displayed on the image display device 22. Further, the image data stored in the frame memory 21 is processed by the image processing unit 26 and supplied to the display control unit 15, and the image data on which the image processing has been performed is stored in the frame memory 21. By supplying the image data stored in the display control unit 15 to the display control unit 15, the brightness, contrast, sharpness, and the like are adjusted, and a radiation image suitable for diagnosis or the like can be displayed. In addition, by supplying the image data subjected to the image processing to the external device 100, a hard copy of a radiation image suitable for diagnosis or the like can be obtained.

[0091] The image processing unit 26 is configured to always obtain a stable radiation image even when the level distribution of the image data output from the imaging panel 41 fluctuates due to the difference in radiation dose. DT normalization processing is performed. Further, even if the level distribution of the image data fluctuates, the gradation processing is performed on the normalized image data DTreg which is the image data after the normalization processing in order to obtain a radiation image having a density and contrast suitable for diagnosis and the like. Done.
Further, in the image processing unit 26, the normalized image data DTreg
Frequency enhancement processing to control the sharpness of the normalized radiographic image, and dynamic range to fit the entire radiographic image with a wide dynamic range within a concentration range that is easy to see without reducing the contrast of the fine structure of the subject A compression process may be performed.

<Contents of Image Processing> The details of the image processing of the image processing apparatus will be described below according to rough blocks.
Each unit of the image processing apparatus according to the present embodiment can be configured by hardware, firmware, or software. For this reason, a functional block diagram similar to a flowchart in accordance with the processing procedure of each means is shown. This functional block diagram can also be used as a flowchart for understanding the embodiment of the image processing method.

That is, the image processing of this embodiment is
Unlike conventional image processing, as shown in FIG.
It is characterized by including a change in the number of pixels. That is, in order to change the number of pixels, the processing according to the present embodiment includes (1) generation of a radiation image, generation of a reduced image, generation of a reduced image, (2) diagnosis area recognition, irradiation field recognition, interest area recognition, and (3) pixel number change. Change Pixel number correction (4) Output image generation Image output (single output, juxtaposed output) Image display (single output, juxtaposed output) Database output Hereinafter, the processing procedure of the present embodiment will be described with reference to FIG.

(1) Radiation image generation: As shown in FIG. 1, a radiation image having a signal value proportional to the logarithm of the irradiated radiation amount is obtained by a radiation image generating means 400 comprising a radiation image reader 40 and the like. Is generated.

As the radiation image generating means 400,
A sensor using sensors such as the above-described FPD or CCD, or a known device that reads a stimulable phosphor plate and generates a radiation image can be used. In each case, a signal value proportional to the logarithm of the radiation dose is obtained, and the larger the dose, the higher the signal value. The generated radiation image is sent to the image processing means 260.

Further, in order to reduce the time required for the subsequent processing of each part, the reduced image generation means 261 creates a thinned radiation image in which the number of pixels is reduced by sampling from the original radiation image. The thinned radiation image is transferred to the diagnosis area recognition means 262 at the subsequent stage. In addition, when the processing of the image processing apparatus is sufficiently fast, or when there is no problem even if the processing time is long, a radiation image without thinning may be transferred.

In the description of this embodiment, it is assumed that the subsequent processing is performed using a thinned-out radiation image.

It is desirable that the number of pixels of the thinned radiation image be as small as possible because the calculation time of various processes is reduced.
However, in the present embodiment, it is necessary to provide a sufficient amount of information to determine the characteristics of the subject. For this reason, when a 1: 1 radiographic image is obtained for each part of the human body, it is desirable to set the pixel size to about 1 mm square to 5 mm square.

(2) Diagnosis Area Recognition Processing: (2-) Irradiation Field Recognition Processing In normal radiation imaging, radiation is irradiated using a radiation shield called a radiation field stop in order to avoid unnecessary exposure to the human body. In general, imaging is performed with a limited area (irradiation field). The resulting radiation image contains
Areas unnecessary for diagnosis, such as outside the irradiation field, are also included.

Therefore, in order to reduce the waste of displaying and storing data, it is necessary to recognize only an area (diagnosis area) necessary for diagnosis, excluding unnecessary areas such as outside the irradiation field, in the radiographic image. For this reason, in the diagnostic area recognition means 262, as one of the diagnostic area recognition processing, an irradiation field recognition processing for determining an inner area of the irradiation field and an outer area of the irradiation field is performed.

In the irradiation field recognition processing, for example, Japanese Patent Application Laid-Open
The method disclosed in Japanese Patent Application Publication No. 259538 is used, for example, by using image data on a line segment from a predetermined position P on the imaging surface toward the end of the imaging surface as shown in FIG. Processing is performed. Since the signal level of the differentiated signal Sd obtained by this differentiation process increases at the irradiation field edge as shown in FIG. 8B, the signal level of the differential signal Sd is determined and one irradiation field edge candidate point is determined. EP1 is required. A plurality of irradiation field edge candidate points EP1 to EPk are obtained by radially performing the process of obtaining the irradiation field edge candidate points around a predetermined position on the imaging surface. The irradiation field edge portion is obtained by connecting the edge candidate points adjacent to the plurality of irradiation field edge candidate points EP1 to EPk thus obtained by a straight line or a curve.

Further, a method disclosed in JP-A-5-7579 can be used. According to this method, when the imaging surface is divided into a plurality of small regions, in a small region outside the irradiation field where the irradiation of the radiation is blocked by the irradiation field diaphragm, the radiation dose of the radiation becomes substantially uniform, and the variance of the image data is reduced. Becomes smaller. Also, in a small area inside the irradiation field, the radiation amount is modulated by the subject, so that the variance value is higher than in the outside of the irradiation field. Further, in a small region including the irradiation field edge portion, the portion having the smallest radiation dose and the portion of the radiation dose modulated by the subject are mixed, so that the variance value is the highest. From this, the small area including the irradiation field edge is determined based on the variance value.

Further, a method described in JP-A-7-181609 can be used. In this method, the image data is rotated and moved with respect to a predetermined center of rotation, and rotated by the parallel state detection means until the boundary line of the irradiation field is parallel to the coordinate axis of the rectangular coordinates set on the image. When the state is detected, the straight-line equation calculating means calculates the straight-line equation of the boundary before rotation based on the rotation angle and the distance from the rotation center to the boundary. After that, the area of the irradiation field can be determined by determining the area surrounded by the plurality of boundary lines from the linear equation. If the irradiation field edge is a curve, the boundary point extracting means extracts, for example, one boundary point based on the image data, and extracts the next boundary point from a group of boundary candidate points around the boundary point.
Similarly, by sequentially extracting the boundary points from the boundary candidate point group around the boundary point, it is possible to determine even if the irradiation field edge portion is a curve.

(2) Region of Interest Recognition Processing When the image processing unit 26 converts the distribution of the image data DT from the radiation image reader into a distribution of a desired level, the image data DT from the radiation image reader is converted. (Region of interest) for determining the level distribution is set. By determining a representative value from the image data in the region of interest set here and converting the representative value to a desired level, image data having a desired level of distribution can be obtained.

In this case, this region of interest can be used for recognition of the diagnostic region. That is, the diagnosis area recognition unit 262 can set an important area set as a region of interest in a radiation image as a diagnosis area.

For example, the setting of the region of interest in the rib cage in the chest front processing is performed according to the following procedure. First, the left and right lines are determined by the following S1 to S3.

S1: Obtain a vertical projection (one-way cumulative value of data) of a portion of the image data excluding the upper and lower portions of the image and the outside of the irradiation field, which have little influence on the whole (FIG. 9A). FIG. 9 (b)).

S2: From the obtained vertical projection, the range of 1/3 of the center (from 1/3 * x to
A point at which the signal value has a minimum value (Pc) at 2/3 * x) is defined as a midline column (Xc).

S3: Projection in the vertical direction obtained from one-third of the entire image (2/3 * x, 1/3 * x in FIG. 9) toward the outside of the image (left / right direction). A point whose value is equal to or smaller than the threshold value (Tl, Tr) is searched, and the first point is defined as the left end / right end (Xl, Xr) of the lung field. As the threshold value, the maximum value (Plx, Pr) of the projection value from the Pc and the column of 1/3 of the entire image is used.
x) is updated toward the outside (left-right direction) of the image, and Tl = ((k1-1) * Plx + Pc) / k1 Tr = ((k2-1) * Prx + Pc) / k2. Here, k1 and k2 are constants.

Next, upper and lower lines are determined by S4 and S5.

S4: A horizontal projection is performed in the section determined in the above step (FIG. 9 (c)).

S5: 1/4, 1 of the entire image, upper and lower, respectively
From the / 2 line (1/4 * y, 1/2 * y in FIG. 9) to the outside of the image (vertical direction), search for a point where the obtained horizontal projection value is equal to or smaller than the threshold value. , The first point is the upper end / lower end (Yt, Yb) of the right lung field. The threshold values are １ ／ * y to の of the entire image, respectively.
* Y, the maximum value (Ptx, Pbx) of the projection value in the range of 1/2 * y to 4/5 * y, and the minimum value of the projection value in the range outside the image (up and down direction) from the line of the maximum value (Ptx, Pbx) Tt = ((k3-1) * Ptx + Ptn) / k3 Tb = ((k4-1) * Pbx + Pbn) / k4 using Ptn and Pbn). Here, k3 and k4 are constants.

The parameters k1 to k4 used for obtaining the threshold value in the above equation can be obtained empirically.

The setting of the region of interest is not limited to the case where the profile is analyzed and set as described above. For example, as shown in JP-A-5-7578, the image data of each pixel is set. And a threshold determined by a discriminant analysis method, etc., and an identification code is added for each pixel based on the comparison result, and labeling is performed for each pixel group having an identification code that is equal to or greater than the threshold. Is performed to extract a lung field region, and a region of interest can be set to include the lung field and the subdiaphragm region based on the extracted lung field region.

As disclosed in Japanese Patent Application Laid-Open No. 62-26047, a lung field area is recognized by detecting a lung field contour using a boundary point tracking method, and the lung field is determined based on the recognized lung field area. Alternatively, the region of interest may be set to include the sub-diaphragm region.

Further, since it is common practice to perform imaging with the most important part in making a diagnosis being the center of the irradiation field, a circular or rectangular area is set at the center of the irradiation field area. Can be used as a region of interest.

(3) Pixel Number Change Process: (3-) Pixel Number Change The irradiation field region or the region of interest has been recognized as a diagnostic region by the above (2) diagnostic region recognition process, and this diagnostic region is referred to. The number-of-pixels changing unit 263 executes a process of changing the number of pixels of the radiation image by removing a portion other than the diagnostic region in the radiation image generated by the radiation image generating unit 400.

The pixel number changing means 263 constitutes an output size determining means in the claims.

In this case, image processing for extracting only the diagnostic area of the original radiation image and removing the remaining part (FIG. 10)
(A) → FIG. 10 (b)) or image processing for enlarging the diagnostic area to the same size as the entire original radiation image (FIG. 10).
(C) → FIG. 10 (d)). It is also possible to enlarge or reduce to another predetermined magnification. Further, it is also possible to set the magnification so that the radiation image after changing the number of pixels becomes the original size of the subject.

As described above, the area necessary for the diagnosis is recognized.
By determining the number of output pixels, it is possible to save memory required for an output image and to speed up various types of image processing.

(3-) Correction of Number of Pixels Note that the number of pixels determined based on the diagnostic area as described above can be corrected according to the operation from the input device 27 in FIG. In this case, the CPU 11 receives an operation from the input device 27 to generate pixel number correction information, and based on the pixel number correction information, the pixel number changing unit 263 executes a process of changing the number of pixels of the radiation image. By doing so, corrections can be made in accordance with various factors. In this case, by correcting the number of pixels while displaying an image on an image display unit 102, which will be described later, it is possible to check and output an output image modified in accordance with various factors.

(4) Output image generation (4-) Image output (single output, juxtaposed output) For the radiation image for which the number of pixels has been determined to be changed as described above, the output image generating means 264 changes the number of pixels. Then, the image data is output to an image output unit (printer) 101 included in the external device 100.

As described above, the position of the subject and the region of interest in the image are recognized, and the output film size,
By determining the paper size, extra film and paper are not output, so film, paper, developer,
Cost reduction of ink etc. can be expected.

(4-) Image display (single output, juxtaposed output) The radiation image whose number of pixels has been changed as described above is output to the image display means (display) 102 constituting the external device 100. .

As described above, by recognizing the position of the subject and the region of interest in the image and determining the region to be output to the display based on the information, an extra high-brightness region is not displayed. Leads to improved performance. In other words, by outputting only the area necessary for diagnosis, a low-density, (high-brightness) area outside the irradiation field is not displayed, so that it is possible to reduce misdiagnosis due to a dazzling area during display. In addition, by determining a region important for diagnosis as a region of interest, only a region necessary for diagnosis can be output, and unnecessary information can be cut, so that erroneous diagnosis can be reduced.

In the image display, information on the number of pixels (information before and after the change, such as the position, size, and number of pixels of the diagnostic area) may be displayed together with the information instead of displaying only the radiation image.

Further, in the case of 4- and 4-, it is possible to create and output one radiation image by combining a plurality of related radiation images with the number of pixels changed. is there.

For example, as shown in FIG. 11A, one radiation image is formed by combining only the diagnostic areas on the front and the side of the chest with the changed number of pixels. Similarly,
As shown in FIG. 11 (b), one radiation image is combined by combining only the diagnostic areas on the front and side of the cervical vertebra with the number of pixels changed. Similarly, as shown in FIG. 12A, one radiographic image is formed by combining the images of which the number of pixels has been changed only in the diagnostic region of the front of the knee joint and the side of the knee joint. In this case, since the number of pixels is changed only in the diagnostic area and is smaller than the original image, it is possible to reduce the two images to one.

It is also possible to combine an image of the diagnostic area with the changed number of pixels and a typical image of the diagnostic area into one image.

As described above, by displaying a plurality of related images side by side, diagnostic performance is improved. Also,
It is also useful for saving film. For example, if the front and side surfaces of the chest are output at the same time, two related parts are close to each other, so that it is easier to read the image. Further, for example, when a region of interest is set and only the region of interest is displayed, a typical normal case and the image to be read can be displayed close to each other, so that improvement in image reading performance can be expected.

When the images are displayed side by side or output as a film, the images may be arbitrarily rotated so as to facilitate comparison and interpretation. Further, images of a plurality of diagnostic regions may be joined together without gaps and output as one image. That is, conventionally, in the long imaging, the foot, the spine, and the like are output with a plurality of films, and are manually cut into the diagnostic region and connected. However, in the present embodiment, the diagnostic region is recognized and is juxtaposed without gaps. Accordingly, it is possible to display or output the image as a single image.

(4-) Output to Database In addition, the radiation image of which the number of pixels has been changed as described above is output to the database 10 constituting the external device 100.
3 and stored as data constituting a database. In this case, the database 103 may be a database file in the apparatus or a database file in any server connected to the network.

<Other Embodiments> In the above description, an image processing apparatus for handling a radiation image has been described as an example, but the present invention is not limited to handling of a radiation image. For example, C
The present invention can be applied to an image obtained by T or MRI.

[0134]

As described above, according to the present invention, the following effects can be obtained.

(1) By recognizing an area required for diagnosis and determining the number of output pixels, it is possible to save memory required for an output image and to speed up processing.

(2) Recognizing the irradiation field as a diagnostic area,
By determining the number of pixels for image output, it is possible to output only an area necessary for diagnosis. Further, since a low-density, (high-brightness) area outside the irradiation field is not displayed, it is expected that misdiagnosis due to the presence of a dazzling area can be reduced.

(3) By recognizing a region of interest as a diagnostic region, it is possible to output a region required for diagnosis. Since extra information can be cut, misdiagnosis can be reduced.

(4) Diagnostic performance is improved by displaying a plurality of related images side by side. It also helps save film. For example, if you output the front and side of the chest at the same time, two related parts are near,
Easy to read compared. Further, for example, when a region of interest is set and only the region of interest is displayed, a typical normal example and an image to be interpreted can be displayed close to each other, so that improvement in image interpretation performance can be expected.

(5) By recognizing the diagnostic area and changing the number of pixels, and further correcting the number of pixels, it is possible to output in accordance with the output film size and the paper size, and extra film and Since paper is not output, it is possible to reduce costs for films, paper, developer, ink, and the like.

(6) By changing the number of pixels while displaying the area determined as the diagnostic area, an output image modified according to various factors can be confirmed and then output. become.

(7) When the number of pixels of a radiographic image is changed by recognizing the diagnostic area, an image with a predetermined magnification can be output, so that the diagnostic area is reduced in size to the size of the entire original radiographic image. It is possible to perform image processing that enlarges the image in the same manner as described above, and image processing in which the output image becomes the original size of the subject.

(8) A plurality of output images are juxtaposed,
Since the image can be rotated and output as needed, the output medium can be effectively used by an output image that does not include a region unnecessary for diagnosis. In addition, by displaying a plurality of related images side by side, diagnostic performance is improved and film is saved.

[Brief description of the drawings]

FIG. 1 is a functional block diagram showing image processing contents of a radiation image processing apparatus according to the present invention by function.

FIG. 2 is a configuration diagram illustrating a configuration of a radiation image processing apparatus according to the exemplary embodiment;

FIG. 3 is a configuration diagram illustrating a configuration of a radiation image reader according to the exemplary embodiment;

FIG. 4 is an explanatory diagram for explaining a reading unit used in the embodiment.

FIG. 5 is an explanatory diagram for explaining a reading unit used in the embodiment.

FIG. 6 is a configuration diagram showing a configuration using another radiation image reader according to the embodiment.

FIG. 7 is a configuration diagram illustrating a configuration of a controller according to the present embodiment.

FIG. 8 is an explanatory diagram illustrating an irradiation field recognition process according to the present embodiment.

FIG. 9 is an explanatory diagram for describing recognition of a region of interest in the embodiment.

FIG. 10 is an explanatory diagram for explaining how the number of pixels is changed in the embodiment.

FIG. 11 is an explanatory diagram for explaining a state of juxtaposition output of image outputs in the embodiment.

FIG. 12 is an explanatory diagram for explaining a state of juxtaposed image output in the present embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Controller 26 Image processing part 30 Radiation generator 40, 60 Radiation image reader 41 Imaging panel 44 Scan drive part 46 Image data generation circuit 48 Reading control circuit 61 Conversion panel 62 Light beam generation part 63 Scanning part 64 Reflecting mirror 65 Condenser Body 66 Filter 67 Photomultiplier 70 Current / voltage conversion unit 75 Reading control unit 101 Image output unit 102 Image display unit 103 Database 260 Image processing unit 261 Reduced image generation unit 262 Diagnosis area recognition unit 263 Pixel number change unit 264 Output image generation Means 400 Radiation image generating means

Claims (16)

[Claims] 1. An image processing method for processing a radiation image according to a radiation dose transmitted through a subject, comprising: a diagnostic region recognition step of recognizing a region required for diagnosis of a formed radiation image; Image processing, comprising: an output size determining step of determining the number of pixels of the output image according to the determined region; and an output image generating step of generating an output image from the radiation image according to the determined number of pixels. Method. 2. The image processing method according to claim 1, wherein the region required for the diagnosis is a region in an irradiation field, and the irradiation field is recognized in the diagnosis region recognition step. 3. The image processing according to claim 1, wherein the region required for the diagnosis is a region in a region of interest of a radiation image, and the region of interest is recognized in the diagnosis region recognition step. Method. 4. The image processing method according to claim 1, wherein in the output image generating step, a plurality of output images are output side by side. 5. An output size correcting step for correcting the determined number of pixels, wherein an output image is generated from a radiation image according to the corrected number of pixels and output. Item 6. The image processing method according to any one of Items 4. 6. An output size correcting step for correcting the determined number of pixels, and a displaying step for displaying an image having the corrected number of pixels. An image processing method according to any one of the above. 7. The output image generating step, wherein a plurality of output images are juxtaposed and output, and any one of the images is rotated as required at the time of juxtaposition. Item 4. The image processing method according to any one of Items 3. 8. In the output size determination step,
Determine the number of pixels of the output image according to the size of the subject,
The image processing method according to claim 1, wherein: 9. An image processing apparatus for processing a radiation image according to a radiation dose transmitted through a subject, comprising: a diagnosis area recognizing unit for recognizing an area required for diagnosis of the formed radiation image; Output size determination means for determining the number of pixels of the output image according to the area recognized by the area recognition means; and output image generation for generating an output image from the radiation image according to the number of pixels determined by the output size determination means Means,
An image processing apparatus comprising: 10. An area required for a diagnosis to be recognized by the diagnosis area recognition means is an area in an irradiation field,
The image processing apparatus according to claim 9, wherein the diagnostic area recognition unit recognizes an irradiation field. 11. A region required for a diagnosis to be recognized by the diagnosis region recognition means is a region in a region of interest of a radiographic image, and the diagnosis region recognition device recognizes the region of interest. The image processing apparatus according to claim 9. 12. The image processing apparatus according to claim 9, wherein said output image generating means outputs a plurality of output images side by side. 13. An output size correcting unit for correcting the determined number of pixels, wherein the output image generating unit generates an output image from a radiation image according to the number of pixels corrected by the output size correcting unit. 9. The method according to claim 9, wherein the output is performed.
3. The image processing apparatus according to any one of 2. 14. The apparatus according to claim 9, further comprising: output size correcting means for correcting the determined number of pixels; and display means for displaying an image having the corrected number of pixels. An image processing device according to any one of the above. 15. The image processing apparatus according to claim 9, wherein said output size determination means determines the number of pixels of an output image according to the size of a subject. 16. The output image generating means according to claim 9, wherein a plurality of output images are juxtaposed and output, and any one of the images is rotated as necessary at the time of juxtaposition. 12. The image processing device according to any one of items 11.