JP2001100337A - Method and device for processing radiation image and information recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the throughput of an image reading process and to shorten the wait time required for a user in image reading with a method and device for reading radiation image information by shortening the time required after the image information is read before the image information is outputted as image data or images of two kinds of characteristics varying from each other. SOLUTION: When a digital image signal Si based on the image information detected from a front surface side is inputted to an Si sampling section 41, the sampling section obtains a signal S1' by executing sampling at every prescribed sampling period from the S1. When the signal S1' is inputted to a front surface image data forming section 43, the data forming section subjects the signals S' to prescribed image data processing and data conversion and forms and outputs the surface image data having such density analyzability and data system which allow the display and output of the image of the fine fineness suitable for ordinary use so as to be applied to the inspection of an internal organ disease part, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radiographic image processing method and apparatus, and an information recording medium, and more particularly to a radiographic image information reading method for reading radiographic image information of a subject recorded on a stimulable phosphor sheet to obtain image data. And an information recording medium.

[0002]

2. Description of the Related Art Conventionally, a radiation image of a subject recorded on a stimulable phosphor sheet is read to obtain an image signal, and the image signal is subjected to predetermined image processing. Displaying an image on an image display device such as a CRT display and outputting the image to a film by a printer such as an LP (laser printer) have been put to practical use in the medical field and other various fields. In general, as a device for reading a radiation image from a stimulable phosphor sheet, for example, a CR (Computed) using digital image processing technology, which is a combination of a reading device such as a radiation image reading scanner and a general-purpose computer, is used.
Radiography) device is used.

[0003] Here, the CR device means that when radiation is irradiated, a part of the radiation energy is accumulated, and when irradiated with excitation light such as visible light or infrared light, the CR energy is used in accordance with the accumulated radiation energy. This is an apparatus that obtains radiation image information of a subject such as the inside of a human body using the characteristic of a stimulable phosphor (stimulable phosphor) that emits stimulable light. That is, after projecting radiation onto a subject and recording the radiation transmission image on a sheet-shaped stimulable phosphor (accumulative phosphor sheet),
The stimulable phosphor sheet is scanned with excitation light to generate stimulated emission light, and the stimulated emission light is photoelectrically read by using a photoelectric reading unit such as a photomultiplier (photomultiplier tube), thereby obtaining the aforementioned light. An apparatus that performs a series of processes of reading radiation image information, that is, obtaining an image signal of a subject, is referred to as a CR apparatus. Such CR devices have been widely used in recent years and have been put into practical use (for example, Japanese Patent Application Laid-Open Nos. 55-12429, 56-11395, 55-163472, and 56 by the present applicant).
-104645 and 55-116340).

As a method of photoelectrically reading the stimulated emission light, the applicant of the present application scans both surfaces of the stimulable phosphor sheet with excitation light and emits the stimulated emission light as described above. A double-sided condensing type reading method for reading photoelectrically by photoelectric reading means has been proposed (for example, Japanese Patent Application Laid-Open No. 55-87970).
No. JP-A-8-116435). In such a two-sided condensing reading method (two-sided condensing reading method and an apparatus used therein), a radiation image of a subject is stored on a stimulable phosphor sheet in which a stimulable phosphor is laminated on one surface of a transparent support. After the recording, the stimulable phosphor sheet is irradiated with excitation light, and the stimulated emission light on each of the front and back sides is read by photoelectric reading means arranged on each of the front and back sides.

[0005] The front side image signal and the back side image signal read from the front and back surfaces of the stimulable phosphor sheet in this way are added (superimposed synthesis) for each pixel corresponding to the front and back phases in one sheet. . By performing such an addition operation over all the pixels in one sheet, added image data (superimposed composite image data) based on the image information carried on the one sheet is obtained.

The image visualized based on the superimposed and added image data is output (displayed) on a display screen of an image display device such as a CRT image output device or a liquid crystal display device. Alternatively, the image is output as an image printed (printed and recorded) on a film or printing paper by an image print output device such as a film printer device. Alternatively, the added image data may be recorded in an image data recording device provided with a RAM for recording image data, a magnetic recording medium, or the like. According to such a double-sided reading method and apparatus, high-frequency noise, which has been randomly generated in the image signals on the front and back sides, is smoothed by an addition operation, and stimulated emission light is emitted from both sides of the stimulable phosphor sheet. Since light is collected, the light collection efficiency is also improved, the relative adverse effect of noise on image data can be reduced, and the S / N ratio in image data can be significantly improved.

As described above, in the conventional radiation image reading method and apparatus, the surface image signal read from one surface (front surface) of one stimulable phosphor sheet, or the image signal read from the back surface in addition thereto. Image signals are superimposed and synthesized to obtain image data corresponding to image information carried in one sheet. Then, the one type of image data thus generated is further converted into a data format or image density that satisfies characteristics suitable for recording, display output, print output, and the like desired by the user, and converted into image data. The image visualized on the basis is displayed and output or recorded.

[0008]

However, in the conventional method and apparatus as described above, basically, at the time of radiation exposure, an image signal read from a surface (otenmen) closer to a light source or a double-sided image signal is read. In the optical reading system, characteristics such as a data format or image density that can be subjected to image processing or recorded in a magnetic storage device from one type of image signal obtained by adding image signals read from the front and back. The image data having characteristics according to a desired output device was obtained by generating image data having the following, and further performing image density conversion or data format conversion on the one image data as original data. Above, it was displayed on a desired output device or printed out. As a result, it takes a long processing time from reading the image information recorded on the stimulable phosphor sheet to performing data processing on the image information and displaying or printing the image information.
The output process throughput tended to be low.

When the throughput of such a series of image reading to output processes is low, the time required for the process tends to be a waiting time for the user.

[0010] The present invention has been made in view of the above points, and a radiation image information reading method and apparatus have the following advantages.
The time required for reading image information from the stimulable phosphor sheet and outputting an image or image data generated based on the information is shortened, thereby improving the throughput of the image reading process, and as a result, time efficiency is improved. It is an object of the present invention to achieve high radiation image information reading and to minimize the waiting time required for image reading for a user.

[0011]

A radiation image processing method according to the present invention comprises irradiating excitation light to a stimulable phosphor sheet on which radiation image information is stored and recorded from both sides of the stimulable phosphor sheet. The emitted stimulating light is detected, an image signal carrying the radiation image information is generated based on the stimulating light, and the image signal is processed to form image data corresponding to the radiation image information. In the radiation image processing method described above, stimulated emission light emitted from both sides of the stimulable phosphor sheet is read under different reading conditions, and two types of image data having different characteristics carrying the radiation image information are obtained. It is characterized by the following.

Here, the reading condition may be a reading sampling period.

The reading condition may be a density resolution.

The radiation image processing apparatus according to the present invention irradiates the stimulable phosphor sheet, on which the radiation image information is stored and recorded, with excitation light, thereby stimulating light emitted from both sides of the stimulable phosphor sheet. A radiation image processing apparatus that detects light, generates an image signal carrying the radiation image information based on the stimulated emission light, and processes the image signal to form image data corresponding to the radiation image information. Stimulating light emitted from both sides of the stimulable phosphor sheet are read under different reading conditions to obtain two sets of image data having different characteristics carrying the radiation image information. It is.

Here, a reading sampling period may be used as the reading condition.

The reading condition may be a density resolution. Alternatively, the density resolution may be used together with the reading sampling period.

Further, the information recording medium according to the present invention is characterized in that the stimulable phosphor sheet, on which the radiation image information is stored and recorded, is irradiated with excitation light to emit stimulus emitted from both sides of the stimulable phosphor sheet. Detecting the emitted light, generating an image signal carrying the radiation image information based on the stimulated emission light, and processing the image signal to form image data corresponding to the radiation image information. And causing the computer to execute a procedure of reading stimulated emission light emitted from both sides of the stimulable phosphor sheet under different reading conditions and obtaining two sets of image data having different characteristics carrying the radiation image information. It is characterized by storing software.

[0018]

According to the present invention, the front / back image information is detected from the stimulable phosphor sheet, and the front / back image information is treated as signals of different systems, respectively, and the signals are sampled at the sampling period and The image data is processed as image data of different systems having different data characteristics such as density resolution, and the image data of each of these two systems is output as a different data format. Further, based on the image data, different output states and Display output or print output as an output format image.

As described above, the two types of image signals of the front and back sides are separately processed in parallel to obtain two types of image data having different characteristics. A series of processing time required for outputting the image data or the visualized image through the signal processing and the data processing can be reduced as compared with the related art. As a result, it is possible to improve the throughput of the image reading process, achieve radiation image information reading with high time efficiency, and reduce the waiting time required for the user to read the image.

More specifically, such two different reading conditions and data characteristics include, for example, thinning out the number of sub-scanning lines when reading image information (in other words, reducing the number of sub-scanning lines). ) Or by changing the concentration resolution. In addition, such a method uses conventional general hardware for reading image information from the stimulable phosphor sheet,
If the signal processing procedure or the data processing procedure is executed by mounting software on a general-purpose computer such as a personal computer, the above-described method and apparatus according to the present invention can be easily realized.

[0021]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a schematic diagram of an optical reading portion in a dual-side focusing type radiation image information reading apparatus according to an embodiment of the present invention, and FIG. 2 focuses on signal processing of the entire radiation image information reading apparatus. FIG.

As shown in FIG. 1, in a radiation image information reading apparatus 1 including a radiation image information output apparatus, a stimulable phosphor sheet (hereinafter simply referred to as a sheet) 1 is rotated by driving a motor (not shown). It is arranged on endless belts 9a and 9b. In a state where the sheet 1 is disposed on the endless belts 9a and 9b, a laser light source 10 that emits a light beam 11 as excitation light, and the light beam 11 is reflected and deflected above the sheet 1, and is not shown. A rotating polygon mirror 12 driven by a motor to scan the sheet 1 in the main direction and a scanning lens 19 for converging the reflected and deflected light beam 11 on the sheet 1 and scanning at a constant speed are arranged. Further, above the position where the light beam 11 is scanned in the drawing, a condensing guide 24a for condensing the photostimulated light 13a emitted by the scanning of the light beam 11 from above is arranged in close proximity. A light-collecting guide 24b for collecting the stimulated emission light 13b from below is disposed vertically below the sheet 1 at the position. The stimulating light 13a, 1
Photomultiplier (photomultiplier tube) that detects 3ab photoelectrically
25a and 25b are provided so as to correspond to each other.
These condensing guides 24a, 24b and photomultiplier 25
a, 25b, the stimulated emission light 13a, 13b emitted from the front and back of the stimulable phosphor sheet 1 is detected, respectively.
The image signals SA and SB are obtained.

As shown in FIG. 2, the output of the photomultiplier 25a is connected to a log amplifier (logarithmic amplifier) 26a.
The output of the og amplifier 26a is connected to a filter 27a,
The output of the filter 27a is connected to an A / D converter 28a. Similarly, the output of the photomultiplier 25b is connected to a log amplifier 26b, the output of the log amplifier 26b is connected to a filter 27b, and the output of the filter 27b is A / D.
It is connected to a converter 28b. A / D converter 28a,
Each output from 28b is connected to an image data generation circuit 40, and the output of the image data generation circuit 40 is connected to an image display device or the like not shown in FIG.

As shown in FIG. 3, the image data generation circuit 40 receives a digital image signal S1 based on image information detected from the front side, and performs sampling at a predetermined sampling period from S1. Signal S1 '
And a signal S1 '
Is input, a front side image data generation unit 43 that outputs front side image data S3 by performing predetermined image data processing, and a digital image signal S2 based on image information detected from the back side are input. A S2 sampling section 42 for outputting a signal S2 'obtained by performing sampling at a predetermined sampling cycle from the S2, and receiving the signal S2', performing predetermined image data processing on the signal S2 ', etc. And a back-side image data generator 44 for outputting the image data S4.

Using this radiation image information reading apparatus,
When reading the image signal carrying the radiation image information, first, the sheet 1 on which the radiation image of the subject is accumulated and recorded is set on the endless belt 9a, conveyed (sub-scan) in the direction of arrow Y, and the endless belt is moved. Move to 9b side. On the other hand, a light beam 11 emitted from a laser light source 10 is reflected and deflected by a rotating polygon mirror 12 which is driven by a motor (not shown) and rotates at a high speed in the direction of the arrow, enters the sheet 1 and travels in the sub-scanning direction (Y direction of the arrow). Main scanning in the direction of arrow X, which is substantially perpendicular to When the light beam 11 irradiates the sheet 1, the stimulating light 13 a is emitted from the upper side of the sheet 1 and the lower side of the sheet 1 is emitted in accordance with the radiation image information stored and recorded in the irradiated area. , The stimulating light 13b is emitted.

The stimulated emission light 13a emitted from the upper side of the sheet 1 is incident on the incident end face of the condensing guide 24a, and travels through the inside of the condensing guide 24a by repeating total reflection.
The light is emitted from the emission end face and received by the photomultiplier 25a. The photomultiplier 25a converts the stimulating light 13a representing the radiation image into an analog electric signal SA corresponding to the light amount. Similarly, the stimulated emission light 13b emitted from the lower side of the sheet 1 is collected by the condensing guide 24b.
Is led to the photomultiplier 25b, and the photomultiplier 2
5b, which is photoelectrically detected by an analog electric signal S
B. The electric signal SA output from the photomultiplier 25a is supplied to a log amplifier 26a, a filter 27a,
The data is sequentially input to the / D converter 28a, is digitally converted by the A / D converter 28a, and is input to the image data generation circuit 40 as a digital image signal S1. Similarly, the electric signal SB output from the photomultiplier 25b
Are sequentially input to a log amplifier 26b, a filter 27b, and an A / D converter 28b, are digitally converted by the A / D converter 28b, and are input to the image data generation circuit 40 as a digital image signal S2. Here, the digital image signal S1 based on the stimulated emission light 13a emitted from the upper side of the sheet 1, that is, the surface closer to the radiation source when a radiation image of the subject is formed, is called a surface image signal S1, That is, the digital image signal S2 based on the stimulated emission light 13b emitted from the lower side of the back sheet 1 is referred to as a back image signal S2 (the same applies hereinafter).

In the image data generation circuit 40, when the digital image signal S1 based on the image information detected from the front side is input, the S1 sampling section 41 performs sampling from the S1 at a predetermined sampling cycle. A signal S1 'is obtained. Then, the surface image data generation unit 43
Receives a signal S1 ', performs predetermined image data processing and data conversion on the signal S1', and displays and outputs an image having a definition suitable for normal use such as a transmission image inspection of a diseased part. Surface image data S3 having a density resolution and data format capable of being generated is generated and output.
On the other hand, when the digital image signal S2 based on the image information detected from the back side is input, the S2 sampling unit 42 receives the digital image signal S2 from the S1 sampling unit 41 in parallel with the time. Also, sampling is performed at a coarse sampling density (that is, a long sampling cycle) to obtain a signal S2 '. Then, when the signal S2 ′ is input, the back side image data generation unit 44
′ Is subjected to predetermined image data processing or data conversion to output an image such as a sub-nail image (heading reference image), which may have a lower definition than the normal definition. The corresponding back surface image data S4 with relatively coarse pixel density and density resolution is generated and output.

Next, an example of a case where the above-described double-sided condensing type radiation image information reading apparatus or method according to the present invention is executed using a general-purpose computer such as a personal computer (hereinafter abbreviated as a personal computer). Will be described.

In this example, a case where the procedure performed by the image data generation circuit 40 among the above-described steps is executed using a personal computer will be described. FIG. 4 is a diagram showing an example of the main part of the overall system configuration when the radiation image information reading apparatus according to the present invention is constructed using such a personal computer as the main part.

This system includes an image capturing device 300 of a standing image capturing stand type, an image processing terminal device 100 using a personal computer connected thereto via a data transmission system 400,
The main part is constituted by an image display device 200 provided with a CRT screen or the like for displaying an image to be processed.

In such a system, the upright image capturing table type image reading device 300 is provided with
4b, photomultipliers 25a, 25b, log amplifier 26
a, 26b, filters 27a, 27b, A / D converter 2
8a and 28b for reading a radiation image of a subject and outputting a digitized front surface image signal S1 and a back surface image signal S2 thereof.

The image processing terminal device 100 is a personal computer on which software indicating the operation procedure of the image data generation circuit 40 is already loaded. The operation procedure of the image data generation circuit 40 as described above is performed by the personal computer. Is executed. Loading of such an operation procedure of the image data generation circuit 40 is performed using an information recording medium 110 such as a magnetic recording medium or an optical recording disk storing software indicating such an operation procedure according to the present invention. Will be That is, the image processing terminal device 100 includes the S1 sampling unit 4 described above.
1, S2 sampling unit 42, surface image data generation unit 4
3. The back side image data generation unit 44 is formed in a so-called software implementation.

The image display device 200 is a high-definition CRT image display device attached to the image processing terminal device 100 which is a personal computer. The image display device 200 is connected to a VGA output terminal of the image processing terminal device 100 and is connected to the image processing terminal device. The image processed at 100 or the processed image is displayed on the display screen.

As shown in FIG. 5, the main operation of this system is as follows. First, the standing image capturing table type image reading device 300 reads a radiation image of a subject (Step 1; S1, the same applies hereinafter), and outputs the surface image signal. S1 and back side image signal S2
Is transmitted to the image processing terminal device 100 via the transmission system 400 (S2).

Subsequently, the image processing terminal apparatus 100 converts the transmitted front side image signal S1 and back side image signal S2 into
Separate systems are applied to each. That is, when the image signal S1 is input to the S1 sampling unit 41, the image signal S1 is sampled every predetermined sampling period to obtain a signal S1 '(S3). When the signal S1 'is input to the surface image data generation unit 43, the signal S1' is subjected to predetermined image data processing and data conversion to obtain a surface image corresponding to an image having a definition suitable for normal use. The image data S3 is generated and output to the image display device 200 (S4).

On the other hand, the S2 sampling unit 42
When the image signal S2 is input to the
Sampling is performed at a coarse density from 2 to obtain a signal S2 '(S5). When the signal S2 'is input to the back side image data generation unit 44, the signal S2' is subjected to predetermined image data processing and data conversion to obtain a relatively coarse definition such as an 8-bit sub nail image. The back surface image data S4 having a density resolution and a data format that can be determined by the degree or display quality is generated, and is output to the image display device 200 (S6).

Subsequently, when the user selects the display of the full image for normal diseased part diagnosis, the image display device 200 (S7).
F), an image for normal disease diagnosis is displayed on almost the entire display screen 201 based on the surface image data S3 (S8). Alternatively, when the user selects the display of the sub nail image (B in S7), an 8-bit sub nail image is displayed on the display screen 20 based on the back side image data S4.
1 is displayed at a predetermined position on the upper left, for example (S
9).

Alternatively, if the user selects to perform image processing such as mask processing on the image while observing the image displayed and output as described above (C in S7), such an image is displayed. (S
10). Needless to say, other image processing such as the mask processing may be performed using a general image processing technique such as a conventional mask processing.

By executing the procedures from S3 (step 3) to S10 in the series of procedures described above using the image processing terminal device 100 and the image display device 200, that is, a so-called personal computer, the above-described procedures are performed. This is preferable because the radiation image information reading method or apparatus according to the present invention can be easily realized without newly preparing a new apparatus for executing.

In a conventional general radiation image information reading apparatus, the front side image signal S1 and the back side image signal S2 are superimposed and synthesized for each corresponding pixel on the front and back, and the image signals S1, Although the process of obtaining one image data from S2 can be executed, such a conventional process does not alienate the method according to the present invention when applied to the radiation image information reading apparatus. It goes without saying that it may be possible to function separately. That is, for example, if the user desires to obtain two types (two systems) of image data in a short time, the above-described processes from S1 to S10 are executed. If it is desired to obtain one image data from S2, one image data may be obtained from both front and back image signals S1 and S2 as in the conventional process. Needless to say, such switching of the function may be realized by, for example, selectively clicking and switching an icon switch implemented in software on the screen.

In the above embodiment, image data corresponding to an image having a definition suitable for normal use is generated as the front image data S3, and a display output of an image such as a sub nail image is generated as the back image data S4. Although the case of generating image data having a relatively coarse pixel density, density resolution and data format corresponding to the above has been described, it goes without saying that image data of two systems having different characteristics is not limited thereto. No. In addition to this, for a radiation image used, for example, when performing an examination of a diseased part where strict gradation expression is not required, a relatively coarse density resolution obtained from the back surface image data S4 is used in the same manner as described above. It is also possible to use image data.

Also, in the system shown in FIG.
An example is shown in which the upright stand type image reading apparatus 300 is used as a means for reading the image signals S1 and S2 carrying the radiation image information accumulated and recorded on the sheet 1, that is, a scanner. Needless to say, such a device is not limited to this. Any device may be used as long as it functions as a scanner that reads the image signals S1 and S2 as described above.

The front side image data generating section 43 and the back side image data generating section 44 may further have a function of normalizing the signals S1 'and S2' in addition to the above functions. Good. It goes without saying that a conventional general method may be used for such a normalization method itself.

As described above in detail, according to the method and apparatus of the embodiment of the present invention, the two types of image signals S1 and S2 are processed in parallel processing separately from each other to obtain different characteristics. Since two sets of image data S3 and S4 are obtained,
From the image reading of one sheet 1, the image signals S1,
Through signal processing and data processing for S2, a series of processing time required for outputting the image data S3 and S4 or displaying and outputting an image obtained by visualizing the image data S3 and S4 can be shortened as compared with the related art. as a result,
By improving the throughput of the image reading process, it is possible to achieve time-efficient radiation image information reading, and to reduce the waiting time required for the user to perform image reading.

In such a method, the hardware itself for reading image information from the sheet 1 is a conventional general hardware, and its signal processing procedure or further data processing procedure is performed by a so-called personal computer. If the processing terminal device 100 and the image display device 200 are implemented by software and executed, it is possible to realize the procedure very simply without specially preparing a device dedicated to such a procedure.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an optical reading portion in a dual-side focusing type radiation image information reading apparatus according to an embodiment of the present invention.

FIG. 2 is a circuit block diagram focusing on signal processing of the entire radiation image information reading apparatus.

FIG. 3 is a diagram showing a main configuration of an image data generation circuit 40;

FIG. 4 is a diagram showing a main part of an overall system configuration when a radiation image information reading apparatus according to the present invention is constructed using a personal computer.

FIG. 5 is a diagram showing an example of an operation (procedure) when a main part of the method and apparatus according to the present invention is executed using a personal computer.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Laser light source 12 Rotating polygon mirror 19 Scanning lens 24a Focusing guide 24b Focusing guide 25a Photomultiplier 25b Photomultiplier 40 Image data generation circuit 41 S1 sampling part 42 S2 sampling part 43 Surface image data generation part 44 Backside image data generation part

Claims (7)

[Claims] 1. A stimulable phosphor sheet on which radiation image information is stored and recorded is irradiated with excitation light to detect photostimulated light emitted from both sides of the stimulable phosphor sheet, and A radiation image processing method for generating an image signal carrying the radiation image information based on the exhaust light and processing the image signal to form image data corresponding to the radiation image information; A radiation image processing method comprising: reading out stimulated emission light emitted from both sides under different reading conditions to obtain two types of image data having different characteristics carrying the radiation image information. 2. The radiation image processing method according to claim 1, wherein the reading condition is a reading sampling period. 3. The radiation image processing method according to claim 1, wherein the reading condition is a density resolution. 4. A stimulable phosphor sheet on which radiation image information is stored and recorded is irradiated with excitation light to detect photostimulated light emitted from both sides of the stimulable phosphor sheet, and A radiation image processing apparatus that generates an image signal carrying the radiation image information based on the exhausted light and processes the image signal to form image data corresponding to the radiation image information, wherein the stimulable phosphor sheet A radiation image processing apparatus which reads stimulable light emitted from both sides under different reading conditions to obtain two types of image data having different characteristics and carrying the radiation image information. 5. The radiation image processing apparatus according to claim 4, wherein a reading sampling period is used as the reading condition. 6. The radiation image processing apparatus according to claim 4, wherein a density resolution is used as the reading condition. 7. A stimulable phosphor sheet on which radiographic image information is stored and recorded is irradiated with excitation light to detect stimulated emission light emitted from both sides of the stimulable phosphor sheet, and the stimulable phosphor sheet is irradiated with the excitation light. Generating an image signal carrying the radiation image information based on the exhausted light, and processing the image signal to form image data corresponding to the radiation image information; and Software for causing a computer to execute a procedure of reading stimulable light emitted from both sides under different reading conditions and obtaining two types of image data having different characteristics carrying the radiation image information is stored. Characteristic information recording medium.