JP3038428B2 - Radiation image information reader - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radiation image information reading apparatus for reading and displaying radiation image information stored and recorded on a stimulable phosphor.

[0002]

2. Description of the Related Art Conventionally, X-ray photography has been used to obtain radiographic images. This method easily obtains a fluoroscopic image inside a subject, and has been widely used as an extremely powerful method, particularly in the field of diagnosis in medical treatment.
However, this method has a small difference in the X-ray transmittance of each tissue in the human body, a low contrast of an image obtained because the X-rays are scattered in the subject, and a problem that the X-rays are harmful to the human body. However, there are drawbacks such as narrow latitude and severe shooting conditions. To compensate for these drawbacks, a high-sensitivity, wide latitude X-ray detector is used to convert X-ray images into electrical signals and perform image processing to reduce the effect on the human body and produce high-quality images. How to get it has been explored.

As an example of such a radiographic method, radiation transmitted through a subject is absorbed and stored in a certain kind of phosphor, and then this phosphor is excited with a certain kind of energy to accumulate the phosphor. A method has been considered in which the emitted radiation energy is emitted as fluorescent light, and the fluorescent light is detected and imaged. As a specific method, for example, in US Pat. No. 3,859,527 and JP-A-55-12144, a stimulable phosphor is used as a phosphor and electromagnetic radiation selected from visible light and infrared light is used as excitation energy. A radiation image conversion method to be used has been proposed.

In this method, a radiation image conversion panel having a stimulable phosphor layer formed on a support is used, and the stimulable phosphor layer of the radiation image conversion panel absorbs radiation transmitted through a subject, and By accumulating radiation energy corresponding to the intensity of the light, and then scanning the stimulable phosphor layer with stimulating excitation light, the accumulated radiation energy is extracted as a light signal, and an image is formed by the intensity of the light. What you get. This final image may be reproduced as a hard copy or on a picture tube such as a CRT.

The stimulable phosphor is a radiation (X-ray, α-ray)
Radiation, β-rays, γ-rays, ultraviolet rays, etc.), and when excited with a certain energy such as light or heat, the phosphor emits a photostimulated luminescence in accordance with the radiation energy stored in the phosphor. Fluorescent material. The radiation image conversion panel having a stimulable phosphor-containing layer here means a plate (panel), a drum or a flexible film having a stimulable phosphor layer surface. Various forms are generically referred to (hereinafter simply referred to as conversion panels).

The above method has a very practical advantage in that an image can be recorded over a very wide radiation exposure area as compared with a conventional radiographic system using silver halide photography. That is, it has been recognized that the amount of radiation exposure in the conversion panel and the intensity or the amount of stimulated emission emitted by the stimulated excitation light after accumulation of the radiation are proportional to a very wide range. Even if the exposure amount fluctuates greatly, the reading gain of the stimulated emission is set to an appropriate value, read by a photoelectric conversion unit, converted into an electric signal, and a recording material such as a photographic light-sensitive material using the electric signal. By outputting a visible image on a display device such as a CRT, it is possible to obtain a radiation image that is not affected by a change in the radiation exposure amount.

According to this method, a radiographic image stored and recorded on the conversion panel is converted into an electric signal, and then subjected to appropriate signal processing. Using this electric signal, a recording material such as a photographic photosensitive material, a CRT, or the like is used. By outputting a visible image on a display device such as the one described above, an extremely great effect that a radiation image with excellent diagnostic suitability can be obtained can be expected.

[0008]

However, in order to eliminate the influence of fluctuations in imaging conditions and the like or to obtain a radiation image with excellent diagnostic adequacy as described above, the recording of the radiation image stored and recorded on the conversion panel is required. It is indispensable to perform appropriate signal processing on the radiation image based on the display of a visible image for observation and interpretation of image information such as a state, a part of a subject, or an imaging method such as a simple contrast.

As a method for extracting image information of a radiation image stored and recorded on a conversion panel prior to displaying such a visible image, a method disclosed in Japanese Patent Application Laid-Open No. 55-50180 is known. This method is based on the finding that the light intensity or the amount of instantaneous light emitted from the conversion panel when the conversion panel is irradiated with radiation is proportional to the radiation energy stored and recorded in the conversion panel, by detecting the instantaneous light emission. The purpose is to extract image information of a radiographic image, perform appropriate signal processing based on this information, and obtain a radiographic image excellent in diagnosis. According to this method, it is possible to apply an appropriate signal processing to the radiation image, eliminate the influence of fluctuations in imaging conditions and the like, and can obtain a radiation image with excellent diagnostic adequacy,
In general, the radiation irradiating unit is divided into a plurality of member groups, and the radiation irradiating unit and the radiation image reading unit are usually distant from each other. It has to be configured, and it has the drawback that the apparatus becomes complicated and the increase in cost cannot be avoided.

Japanese Patent Application Laid-Open No. 55-116340 discloses that
A non-stimulable phosphor is provided in the vicinity of the conversion panel, and the image information of the radiation image recorded on the conversion panel is detected by detecting the light emission emitted by the non-stimulable phosphor at the time of recording a radiation image with a photodetector. A method for extracting is disclosed. However, this method has the disadvantages of the method disclosed in Japanese Patent Application Laid-Open No. 55-50180, and indirectly estimates image information since the stimulable phosphor itself is not used as an object of the extraction means. However, there is a disadvantage that the information obtained in this way has low reliability.

Further, as a method of extracting image information of a radiation image recorded on a conversion panel prior to displaying a visible image, a method disclosed in Japanese Patent Application Laid-Open No. 58-67240 is also known. In this method, prior to a reading operation for obtaining a visible image for observation reading (hereinafter referred to as main reading), the conversion panel is used by using stimulating excitation light having an energy lower than that of the stimulating excitation light used in the operation. A reading operation (hereinafter, referred to as pre-reading) for extracting image information of a radiation image recorded in the computer is performed, and appropriate signal processing is performed based on the information to obtain a radiation image excellent in diagnosis. Things.

However, in this method, the closer to 1 the stimulating excitation light energy in the pre-reading and that in the main reading are, the smaller the amount of radiation energy remaining and stored in the main reading, the lower the stimulating excitation light energy in the pre-reading. The excitation light energy needs to be lower than that in the main reading. To do so, enlarge the spot system of the stimulating excitation light in the pre-reading, reduce the intensity of the stimulating excitation light, and increase the scanning speed of the stimulating excitation light. Alternatively, it is necessary to take measures such as increasing the moving speed of the conversion panel, and there is a disadvantage that the structure of the radiation image reading apparatus becomes extremely complicated.

Further, in this method, for the above-described reason, the stimulating excitation light energy in the pre-reading needs to be significantly lower than that in the main reading, and the stimulating luminescence generated by the pre-reading is very weak. It is something.
For this reason, it is difficult to extract the image information with sufficiently high precision by pre-reading, or in order to extract the image information with sufficiently high precision, the detectability of the stimulated emission detection system in pre-reading is significantly improved. There were drawbacks such as the need to do so.

Further, in this method, even if the stimulating excitation light energy in the pre-reading is set sufficiently lower than that in the main reading, it is difficult to avoid dissipation of the stored radiation energy, and as a result, the radiation is released at the time of the main reading by the pre-reading. However, there is a serious drawback in that the stimulated emission intensity or the amount of light emitted is reduced, and the system sensitivity is reduced.

On the other hand, there is also known a method completely different from the above-mentioned method. In this method, the radiation image stored in the conversion panel is read and temporarily stored in an image storage device, and then the radiation image signal stored in the image storage device is subjected to arithmetic processing to obtain image information of the radiation image. Is extracted, and appropriate signal processing is performed based on this information to obtain a radiographic image excellent in diagnostic appropriateness. However, this method requires that the radiation image is once stored in an image storage device and further processed.
The arithmetic processing takes a long time, and it takes a long time from reading of the radiographic image to display thereof, which has a serious disadvantage that real-time performance is poor.

Also, as disclosed in Japanese Patent Application Laid-Open No. 62-97533, a method for improving the real-time performance by providing an image extracting means for grasping the state of an image from reading the image to storing the image is also known. It has been disclosed.

This method uses real image data and enables real-time processing, and is extremely accurate. However, high-speed processing is required to perform processing in synchronization with reading of image data, and image data reaches a maximum of 5 million pixels. Therefore, simple processing of creating a histogram requires only 23-bit calculation accuracy. Since it is required, a normal microcomputer cannot be used, and dedicated hardware is required.
In addition, the delay of the display processing delays the determination of the quality of the image in determining whether the state of the display image is good, and also increases the time and effort required for re-imaging in the event of a shooting error or the like.

An object of the present invention is to provide a radiation image reading apparatus capable of efficiently obtaining processing conditions for a read image after capturing a radiation image on a conversion panel and quickly obtaining an image suitable for diagnostic performance. It is in.

[0019]

To achieve the above object, the present invention provides: 1) a reading means for reading a radiation image conversion panel on which a radiation image is recorded to obtain image data comprising a plurality of pixels; Thinning means for thinning the read image data at the same thinning rate in the vertical and horizontal directions of the radiation image, and a floor corresponding to the radiation image based on a frequency distribution of the image data thinned by the thinning means. A radiation image information reading apparatus, comprising: means for obtaining tone processing conditions; and 2) the thinning means converts the read image data into one.
A radiation image information reading apparatus characterized in that it is thinned out from / 4 to 1/32. Is proposed.

[0020]

Embodiments of the present invention will be described below in detail with reference to the drawings. 1 is a block diagram of a radiographic image capturing apparatus according to the present invention, which is shown in the case of a chest radiographic apparatus. Radiation from the radiation source 21 is applied to the radiation conversion panel 23 through the chest region of the subject 22. Radiation conversion panel 23
Is mounted on the front surface of the radiation image information recording / reading unit 24, and in the radiation image information recording / reading unit 24, a light beam unit 41 using a semiconductor laser (this may be a gas laser or a solid-state laser), An optical scanner 42 for irradiating the radiation conversion panel 23 with the light beam of
A photoelectric converter 43 for detecting stimulated emission light emitted from the radiation conversion panel 23 is provided. The photoelectric converter 43 includes a light collector 43a made of an optical fiber, a filter 43b that allows only light in the stimulated emission wavelength region to pass, and a photomultiplier 43c that converts the light passing through the filter 43b into an electric signal. Next, in the radiation image information recording / reading unit 24, a current-voltage converter 44 for converting an output current from the photoelectric converter 43 into a voltage signal, and a voltage signal of the current-voltage converter 44 are logarithmically amplified. And an A / D converter 46 for converting the output of the amplifier 45 into digital data.

The A / D converter 46 is connected to the radiation conversion panel 2.
In order to convert the image having a wide dynamic range of 3 as faithfully as possible, a range of three digits of stimulated emission light is obtained as 10-bit conversion data. Further, a control circuit 47 for inputting data from the A / D converter 46 is provided in the radiation image information recording / reading section 24, and the control circuit 47
1 light beam intensity adjustment, photomultiplier gain adjustment by adjusting the power supply voltage of photomultiplier high-voltage power supply 48, gain adjustment of current-voltage converter 44 and A / D converter 46, and A / D
The input dynamic range of the converter 46 is adjusted, and the reading gain of the radiation image information is comprehensively adjusted.

Next, the control unit 25 is a computer control device, and the central processing unit (hereinafter referred to as CPU) 50 is connected to the following processing elements by a system bus SB and an image bus VB. Image display means (image monitor)
The image display means 51 includes a display control unit 51a and a system bus S
The frame memory 52 as storage means is connected to the CPU 50 via a frame bus B and a frame memory control unit 52a. The information input means 53 includes a keyboard 53a and an LCD display means 53.
b through the interface 53c.
Combined with zero. The reading synchronization unit 54 includes a reading control unit 54a coupled to the CPU 50 and the reading control unit 54a.
X-ray adapter 54b coupled to the radiation source 1
And a control circuit 47. 56
Denotes an I / O interface for an external device (not shown); 57, a magnetic disk controller for the magnetic disk device 58 (or an external optical disk device, magnetic tape device); and 59, a memory. Note that the CPU 50 can also be connected to an external terminal.

The operation of such a device is described below.
The identification information of the subject 22 to be X-rayed is input from the keyboard 53a of the control unit 25. The identification information includes an ID number, a name, a date of birth, a sex, an imaging part, an imaging date and the like. However, the shooting date and time is
The ID information may be automatically inserted by a built-in calendar clock, or if the ID information is managed by an external device, the ID information may be sent and only the collation may be performed. Alternatively, only the collation may be performed by receiving the input from the external terminal. Further, the identification information input here may be only information relating to the patient to be imaged at that time, or a series of information may be input in advance, and the imaging may be sequentially performed later. The identification information is input, and the subject 22 is set at the photographing position to perform photographing. When the shooting button is pressed, the CPU 50 sets the reading control unit 54a.
To start reading. The reading control unit 54a controls the driving circuit 10 via the X-ray adapter 54b,
1 instructs X-ray imaging. The radiation source 21 irradiates the object 22 with radiation (X-rays). This radiation passes through the subject 22, energy is accumulated in the stimulable phosphor layer of the radiation conversion panel 23 according to the radiation transmittance distribution of the subject 22, and a latent image of the subject 22 is formed there. Thus, the X-ray imaging is completed.

When the X-ray imaging is completed, the light beam unit 41 generates a light beam whose beam intensity is controlled, the light beam is changed by the light scanner 42, and the light path is changed by the reflecting mirror, and the radiation conversion panel is changed. The light is guided to 23 as excitation scanning light.
The radiation conversion panel 23 outputs stimulated emission light proportional to the latent image energy by the excitation scanning light. The photoelectric converter 43 detects the stimulated emission light and outputs a current signal corresponding to the incident light. The output current passes through a current-voltage converter 44, an amplifier 45, and an A / D converter 46, becomes digital image data, is applied to a control circuit 47, and is transferred to the control unit 25.

FIG. 4 is a block diagram showing the configuration of the reading control section 54a in the control section 25. This reading control unit 5
4a is an input switch SW which is switched in synchronization with each other
1. It is composed of output switches SW2 and line buffers A and B composed of RAM having a storage capacity of 2048 pixels.
Here, the line buffers A and B correspond to one line of the image data in the main scanning direction. When the image data of the first line from the radiation image information recording / reading unit 24 is stored in the line buffer A, the input switch SW1 and the output switch SW2 are switched, and the image data of the second line is stored in the line buffer B. . At the same time, the image data of the first line of the line buffer A is output and the image bus VB
Are sequentially stored in the frame memory 52.
The input / output switches SW1 and SW2 are switched for each line, and the roles of the line buffers A / B are changed.

FIG. 5 is a schematic diagram of the configuration of the frame memory 52. This frame memory 52 has 2048 * 256
It is composed of a RAM having a storage capacity of 0 pixels. The image data converted by the radiation image information recording / reading unit 24 and temporarily stored in the line buffers A / B is stored in the frame memory 52 line by line. At the same time, the stored image data is transferred to the display controller 51a or the magnetic disk controller 57 via the image bus VB.

From the frame memory 52 to the display controller 51a
When the image data is transferred to the display controller 51a, the image data is read out from the frame memory 52 every four pixels in both the main scanning direction and the sub-scanning direction, and is continuously written to the display memory in the display control unit 51a.
This is because the display CRT has only a display resolution of 512 pixels * 640 pixels, so that both main and sub pixels are thinned to 1/4. When transferring image data from the frame memory 52 to the magnetic disk control unit 57, the image data is continuously read from the frame memory 52 and continuously written to the FIFO memory in the magnetic disk control unit 57. In this way, the frame memory 5 is thinned out or continuously.
2, the frame memory control unit 52a has the configuration shown in FIG.

In the figure, basically, the read / write timing of the entire frame memory 52 is generated in a frame memory timing control circuit 61, and a main scanning direction address generator 62 in the X axis direction and a sub scanning in the Y axis direction are generated. The address of the frame memory 52 to be accessed by the direction address generator 63 is specified, and the data is stored in the image bus VB.
Is read or written via. The main scanning direction address generator 62 is an 11-bit sub-scanning direction address generator 6 corresponding to 2048 pixels.
3 has the same configuration except that it is composed of 12 bits corresponding to 2560 pixels.

Here, a case where reading is performed every four pixels will be described. First, the CPU 50 sets the address of the head pixel position in the latch circuits 65 and 66 through the I / F logic 64. Next, the CPU 50 sets +4, which is the address increment, in the latch circuits 67 and 68. Then, the CPU 50 sets the read flag of the command latch in the frame memory timing control circuit 61 and X
Sets the direction addition flag and instructs the start of data transfer.

In response to this command, the frame memory timing control circuit 61 first sets the head pixel position data of the latch circuits 65 and 66 to the latch circuits 71 and 72 through the multiplexers 69 and 70, and sets these latch data. Switching is performed by the multiplexer 73, and a frame memory address is generated through the buffer 74. When the head pixel data based on the frame memory address is read, the frame memory timing control circuit 61 switches the multiplexer 69 to the adder / subtractor 75 side. The adder / subtractor 75 performs addition / subtraction of the latch data of the latch circuits 67 and 71, and outputs the latch circuit 7 for each timing signal from the frame memory timing control circuit 61.
The pixel position data obtained by adding the increment of the latch circuit 67 to the current value of 1 is set in the latch circuit 71. With this control, the frame memory timing control circuit 61 performs +4 increment control of the main scanning direction address generator 62 every time one pixel data is transferred.

When the transfer of one line is completed, the sub-scanning direction address generator 63 is operated every time the transfer of one line is completed, in the same manner as the operation of the scanning direction address generator 62, to perform +4 increment control. Further, the frame memory timing control circuit 61 supplies the RAS and CAS signals to the DRAM frame memory 52 every time one pixel is read, and also controls the refresh operation. With the above-described control, it is possible to obtain image data obtained by thinning out a captured image to 1/4.

When changing the thinning rate, the latch circuit 67 is used.
And changing the set value to the latch circuit 68. For example, when the set value to the latch circuit 67 and the latch circuit 68 is +1, continuous access is performed. When the set value to the latch circuit 67 is −1 and the set value to the latch circuit 68 is +1, the left-right inverted image is displayed. Can be read.

The image data read from the frame memory 52 is transferred through the I / F logic 77 and the image bus VB. The CPU 50 manages the transfer of each line, and transfers the image data to the display control unit 51a. When the transfer to the magnetic disk control unit 57 becomes necessary, the address at that time is stored at the end of the transfer of the line, and the magnetic disk control unit 57
The transfer is performed by setting the address of the frame memory to be transferred to, the increment value, and the command. Then, the address, increment, command, and the like stored at the end of the transfer are reset, and the transfer to the display control unit 51a is restarted. Although this causes an overhead in setting to the latch and the register and lowers the effective speed, it is extremely infrequent compared to the image transfer, and apparently enables parallel operation.

During the reading operation, the control circuit 47 of the radiation image information recording / reading unit 24 sends the data to the frame memory 52.
Transfer from the frame memory 52 to the display control unit 51a or to the magnetic disk control unit 57 is performed in parallel as described above, but almost simultaneously with the completion of reading, display on the image display unit 51 and data storage in the magnetic disk device 58 Is made.

At the end of reading, the CPU 50 sets the start address in the latch circuits 65 and 66,
The value is set to +32 in the latch circuits 67 and 68, and the data is transferred to the buffer memory in the magnetic disk control unit 57. The number of pixels at this time is 64 * 64 pixels, for a total of 4096 pixels. This is a form in which pixel thinning is performed to 1/32 in both main and sub scanning, and the image is trimmed into a square.
Using this image data, the CPU 50 obtains the cumulative frequency distribution of the image, obtains the image processing conditions that are the optimal display characteristics of the image, and changes the contents of the display look-up table in the display control unit 51a. Thus, 1/3 in both main and sub scanning.
The present inventor has found that although the number of pixels is reduced to 2 (the number of pixels is 1/1024), the feature values such as the maximum value, minimum value, and median value of the image and the cumulative frequency distribution hardly change from the original image data. It has been found that the use of this phenomenon greatly simplifies the operation, so that even a 16-bit microprocessor can make a determination with almost no time delay in obtaining an optimum display characteristic of an image. FIGS. 6A to 9H illustrate the cumulative frequency distribution and frequency distribution characteristics at each thinning rate. As can be seen from this example, even when compared with the cumulative frequency distribution of the original image data (FIG. 6A), the cumulative frequency distribution thinned out every 32 pixels (FIG. 8F) has almost the same shape. There is no problem if the image state is estimated using this. Even if an image with a thinning rate higher than this is used (FIGS. 9 (G) and 9 (H)), the estimation is not so disturbed, which is effective both in hardware and processing time.

7 (D) and FIG. 8 (E), the processing time is not so long even if a 16-bit CPU is used. It is possible to perform processing comparable to that, and it is effective.

It should be noted that, in the case of an X-ray image, the information of the peripheral portion of the image has little influence on the whole, and even if the upper and lower portions are extracted as the image extraction region, the characteristics thereof are hardly impaired. In such a case, reading control of only the central portion is performed, and when the read image is considerably smaller than 2048 * 2560 pixels, the thinning rate is reduced to 31, 30,. Appropriate adjustment of the reading area and the thinning rate can be easily performed by changing the latch data.

As an example, main scan 2048 pixels, sub scan 2
When reading an image of 464 pixels, the upper and lower parts are each 2
Extraction data of 64 * 64 pixels can be obtained by thinning out an image of 2048 * 2048 pixels, which is omitted for every 08 lines, by 1/32. This is because the extraction is completed 200 lines or more before the reading is completed, then the cumulative frequency distribution is calculated, the maximum value, the minimum value, the median value, etc. are calculated, and the optimal characteristics for the image as the image processing conditions are obtained. Even if the lookup table data is created, all the calculations can be completed before the reading is completed. This means that by changing the display look-up table in the display control unit 51a, it is possible to observe a CRT image with optimal display characteristics almost simultaneously with the end of reading.

FIG. 2 is a block diagram of the display controller 51a. The image data passed through the image bus VB is sequentially written into the display memory 81 through the data buffer 80. The display memory 81 stores 10-bit data at 512 * 640.
It has a storage capacity for pixels. The data stored in the display memory 81 is sequentially transferred to a display look-up table 82 for converting 10-bit (1024-level) data to 8-bit data, converted and compressed into 8-bit data, and this data is subjected to D / A conversion. The data is converted to analog data by a device 83, further amplified by an amplifier 84, converted into a CRT video signal, and
Provided to the RT display. The display control of the display memory 81 is performed by a memory control circuit 85, and the entire display control such as data transfer control and generation of a synchronization signal is performed by a display control circuit 86. Commands for these controls are given from the CPU 50 through the system bus SB and the I / F logic 87.

The display control having such a configuration will be described below. Display lookup table 82 by CPU 50
, The display changes at that time. Therefore, the CPU 50 erases the image that has been displayed by giving an erasure command to the display control circuit 86 at the start of photographing. This can be completed in one frame display time by using a dual port RAM as the display memory 81 and writing black data from the read port side. Here, when erasing the display memory 81, linear table data is written into the display look-up table 82. This allows the entire area of the image data to be observed on the display during reading, thereby enabling a capture of a shift in a photographing position and an approximate feeling of the image data. For example, the radiation image information recording / reading unit 24 quantizes a 3-digit range of X-ray dose to 10 bits to obtain digital image data. However, the effective range is actually about 1.5 digits, and the image data is 10 bits. It is possible to observe on the CRT which of the (0 to 1023) levels exists. From this observation, it is possible to confirm whether or not the image is located near the white or black level due to a setting error of the photographing condition, and it is possible to immediately determine whether or not re-imaging is required.

By processing the extracted image data according to the image processing conditions, the display image of the CRT is changed to an image having an appropriate gradation almost at the same time when the reading is completed, and is made an image having good diagnostic performance. At this time, if the irradiation field or the photographing conditions of the photographing are largely different from those of the normal case, the image may not be sufficiently satisfied with the preset gradation characteristics. In this case, it can be dealt with by changing the gradation by scanning the gradation control function key of the keyboard 53a. That is, since the density of the X-ray image and the gamma value, which is its inclination, are important, the two parameters are changed by the display look-up table 82, which is the image processing condition, to digitally change the image processing condition. Fix it. From the above, it is possible to confirm an image immediately after photographing and to observe an image having a desired gradation.

When observing an image in detail, it is possible to enlarge and pan the image by using the enlargement of the keyboard 53a and the panning function key. The image can be enlarged by reducing the thinning rate and transferring the image from the frame memory to the display memory 81.
This is realized by shifting the read start address of “1” and transferring only images newly appearing on the CRT. To enable this control, the display memory 81 is configured to be endless in both the main scanning direction and the sub-scanning direction.

Further, when the image is inverted right and left by the photographing method, the image can be corrected by inverting the image left and right using the left and right inversion function key. In addition, when there is an input error in the subject name, the date of birth, or the like, correction using the keyboard is possible. When the above-described checking operation is completed, the process proceeds to the next photographing. At this point, all the data is determined, and the data can be transferred to an external device. Further, after a certain period of time after the operator stops performing the operation without taking the next image, the data can be automatically determined to enable automatic transfer to an external device.

The above-mentioned external device may be an upper host computer, or a film printer for recording an image, or both. When the host computer is used, the image data is divided into one block for each of a plurality of lines, read from the magnetic disk control unit 57, transferred to the buffer memory in the external device interface via the image bus VB, and transmitted to the host computer. It is realized by transferring. In the case of a film printer, the CPU 50 first sets a look-up table in the interface to resemble an image observed on a CRT. Then, the image is transferred and printed. That is, the CRT is configured to display an image corresponding to an image to be output and recorded.

The external device is a high-speed processing device whether it is a host computer or a film printer. However, if image data is transferred while reading image data from the magnetic disk device 58, the execution speed is greatly reduced. In some cases, or the transfer is too late. To solve this problem, the execution speed can be improved by additionally providing the frame memory 52 for one screen and switching between reading and transferring. In addition, the management information of the magnetic disk device 58 can be deleted for the image that has been transferred to the external device, so that the magnetic disk device 58 can be prevented from overflowing.

[0046]

As described above, the present invention thins out the read image data and obtains the image processing conditions corresponding to the radiation image based on the extraordinary amount of the thinned image data. The image processing conditions can be obtained at a very high speed as compared with the use. Therefore, there is an excellent effect that an appropriate image suitable for diagnosis or the like subjected to image processing can be promptly confirmed under the image processing conditions. In particular, a radiation image has a large effect because the amount of image data is larger than that of a general image.

[Brief description of the drawings]

FIG. 1 is a control circuit diagram of a frame memory according to the present invention.

FIG. 2 is a display control circuit diagram according to the present invention.

FIG. 3 is an apparatus configuration diagram of a radiation image information reading apparatus.

FIG. 4 is a block diagram of timing control in a control unit.

FIG. 5 is a schematic diagram of a configuration of a frame memory.

FIGS. 6A and 6B are measurement diagrams showing a change in a histogram with respect to a thinning rate of image data.

FIGS. 7 (C) and (D) are measurement diagrams showing a change in a histogram with respect to a thinning rate of image data.

8 (E) and 8 (F) are measurement diagrams showing a change in a histogram with respect to a thinning rate of image data.

FIGS. 9G and 9H are measurement diagrams showing a change in a histogram with respect to a thinning rate of image data.

[Explanation of symbols]

 Reference Signs List 21 radiation source 22 subject 23 conversion panel 24 radiation image information recording / reading unit 25 control unit 51a display control unit 52 frame memory 52a frame memory control unit 61 frame memory timing control circuit 62 main scanning direction address generator 63 sub scanning direction address generator 81 display Memory 82 Display lookup table

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) H04N 1/40-1/409 H04N 1/46 H04N 1/60

Claims (2)

(57) [Claims] A reading unit that reads a radiation image conversion panel on which a radiation image is recorded and obtains image data composed of a plurality of pixels, wherein the read image data is the same in a vertical direction and a horizontal direction of the radiation image. Thinning means for thinning out at a thinning rate; and means for obtaining a gradation processing condition corresponding to the radiographic image based on a frequency distribution of image data thinned out by the thinning means. Reader. 2. The radiation image information reading apparatus according to claim 1, wherein said thinning means thins the read image data from 1/4 to 1/32.