JPS60182434A - Reproducing device for radiation image - Google Patents

Abstract

PURPOSE:To make corrections so that the quantity of light emission is proportional to recording density by converting the detected quantity of accelerated phosphorescence according to a conversion table when an image is recorded on a silver salt film, etc., on the basis of the detected quantity of accelerated phosphorescence. CONSTITUTION:A phosphorescent body 3 is exposed to a subject 2 by using an X-ray source 1. The phosphorescent body 3 when irradiated with readout light 4 causes accelerated phosphorescence in proportion to the quantity of said exposure, so the readout light 4 is cut off by a filter 5 and only the accelerated phosphorescence is detected by a photoelectric tube 6. Its detected value is converted into a digital value, which is converted according to the conversion table in a storage means 7. An image recording means 9 forms a record on a film, etc., on the basis of the converted value. When there is some deviation between the detected value and recording density owing to the gamma value, development condition, etc., of the film, an image generating means 10 generates a reference signal to be recorded directly without the intervention of the conversion table, and its density is read to rewrite the conversion table and correct the deviation so that a proportional relation is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a radiation image reproducing device used for medical diagnosis and the like.

(Prior Art) Conventionally, an X-ray photography device has been used as a device for non-destructively observing the inside of a substance. According to this device, it is possible to easily capture a perspective image of the inside of a subject (mainly a human body) by 1q.
Therefore, it has been frequently used as an extremely powerful support especially in the field of medical diagnosis. However, with this type of X-ray photography apparatus, the difference in X-ray transmittance of each tissue is small, and the X-rays are scattered within the subject, so the contrast of the obtained image is low, and the X-rays are Harmful to the human body and radiation
This method had drawbacks such as a narrow ude and difficult photographing conditions.

To compensate for these shortcomings, we convert X-ray images into electrical signals using an X-ray detector with high sensitivity and a wide radius node.
A method of producing high-quality images with less impact on the human body by using image information processing has been explored.As an example of a radiographic reduction device using such a method, is absorbed and accumulated in a phosphor, then this phosphor is excited with a certain kind of energy, the radiation energy accumulated in the phosphor is emitted as fluorescence, and this fluorescence is detected. As a specific method for realizing such a device, for example, US Pat. A radiation image conversion method using a photostimulable phosphor and using electromagnetic radiation selected from visible light and infrared rays as excitation energy has been proposed.

This conversion method uses a panel in which a stimulable phosphor layer is formed on a support, and the stimulable phosphor layer of the panel absorbs the radiation that has passed through the subject, allowing it to respond to the intensity of the radiation. By accumulating radiation energy and then scanning and exposing this photostimulable phosphor layer with photostimulable excitation light, the accumulated radiation energy is extracted as a light intensity signal, and an image is created by the intensity of the extracted light. This is what you get. This final image is an image record! It may be reproduced as a hard copy on a machine, or it may be reproduced as a soft copy on an image display device such as a CRT.

However, the characteristics of the device and recording medium for reproducing and recording images are not linear even if the conventional device falls over.
Also, it usually shows changes over time. Therefore, when the image information captured by C is reproduced and recorded as an electric signal,
The reproduced image is different from the original recorded image, and moreover, reproducibility cannot be obtained. For example, as a recording device,
・If you use photographic film as a printer or recording medium,
The recording characteristics are Is-shaped characteristics, and the photo printer.

This characteristic changes due to variations in the light source and development conditions. When such a recording apparatus is used, image information as an electrical signal is recorded with changing gradation characteristics, and the recording characteristics change due to development conditions or changes over time, resulting in C.

(Objective of the Invention) The present invention has been made in view of the above points.
An object of the present invention is to provide a J-line image reproducing device.

(Structure of the Invention) The present invention achieves the above-mentioned object4 by irradiating a radiation image onto a radiation image recording medium having a stimulable phosphor layer, thereby accumulating the radiation image in an imagewise manner on the radiation image recording medium. In a radiation image reproducing device that excites the energy of the irradiated radiation with excitation light to produce stimulated luminescence, converts this stimulated luminescence into an electrical signal according to the intensity of the light, and reproduces an image. , a storage means for storing a changeable reproduction information conversion table, a first image reproduction and recording means for reproducing and recording an image using the reproduction information conversion table in the storage means, and generating a standardized image as appropriate. , a second image reproduction and recording means for reproducing and recording the standardized image without going through the storage means; The invention is characterized by comprising means.

Here, the reproduction information conversion table is a table used to correct and cover the characteristics of the reproduction/recording device and the characteristics of the recording medium (hereinafter referred to as recording characteristics). ) is usually recorded via this reproduction information conversion table. Further, this reproduction information conversion table must be able to be changed successively based on the recorded standardized image once without going through the reproduction information conversion table. Standardized images are used to find out what density of image will be reproduced and recorded based on the value of a certain image signal, and all image signals within a valid range are reproduced and recorded.
There is C after measuring the 'a degree.

In reality, several to several dozen binary values are selected from the valid range, and the image of each value is made to have the area of a certain fI! play.

(Example) Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a basic diagram showing one embodiment of the present invention. In the figure, 1 is a radiation generating device, 2 is a subject, and 3 is a 1lisf that records a radiation image transmitted through the subject 2.
4 is an excitation light source for emitting the radiation latent image recorded on the radiation image recording medium 3 as stimulated luminescence; 5 is an excitation light source for emitting reflected light of the excitation light; This is a filter that only transmits stimulated luminescence emitted from the recording medium 3.

6 is a photoelectric conversion device that receives stimulated luminescence emitted from the radiation image recording medium 3 and converts it into an electric signal; 7 is a storage device that stores an information conversion table for reproduction; 8 is a photoelectric conversion device @ 6 that detects An image converting device converts the converted image signal using a reproduction information conversion table in the storage device 7, and an image recording device 9 records the converted image.

Reference numeral 10 denotes a standardized image generating device, which normally records the image directly in the image recording device 9 without converting it by the converting device 8 based on the reproduction information conversion table. Reference numeral 11 denotes a changing device that obtains the density information of this standardized image and changes the reproduction information conversion table in the storage means 7. After the standardized image generated by the standardized image generator 10 is converted into an image by the image converting device w8 using the reproduction information conversion table, it is recorded by the image recording device 9, and when the 81 degrees are checked, it is recorded in the ffi device 7. You can know whether the reproduction information conversion table is appropriate. Note that if the photoelectric conversion device 6 does not generate a signal that becomes noise due to the reflected light from the excitation light source 4, the filter 5 is not necessary and the excitation light source 4
In order to cut the reflected light from the filter 5, it is also possible to use a method of separating each light by utilizing the delay in light emission, as disclosed in Japanese Patent Application No. 57-124744.

The operation of the device configured as described above will be explained as follows.

When the object 2 is placed between the radiation transmittance @ 1 and the radiation image recording medium 3 and radiation is irradiated, the radiation passes through the object 2 according to the radiation transmittance of each part of the object 2, and the transmitted image (depending on the intensity of the radiation) image) is incident on the radiation image recording medium 3. The incident transmitted image is absorbed by the phosphor layer of the radiation image recording medium 3, and a number of electrons or holes corresponding to the amount of radiation absorbed in the phosphor layer are generated, and these are absorbed by the phosphor layer. is accumulated at the trap level. In other words, an accumulated image (latent image) of radiation transmittance is formed.

Once the latent image has been formed, this latent image is then scanned and excited with excitation light emitted from the excitation light source 4 and radiated as stimulated luminescence, which is converted into an electrical signal (image signal) by the photoelectric conversion device 6. ). The image signal may be output as an analog signal or may be converted into a digital value using an A/D converter and output. FIG. 2 is a diagram showing an example of a reproduction information conversion table included in the storage device 7. As shown in FIG. Here, the image signal is represented as a digital quantity.

The image conversion device 8 uses this reproduction information conversion table stored in the storage device 7 to search for the value of the input signal from the left column of the table, and outputs the value in the corresponding right column of the table. Also, the third
If you use a table with a structure in which the input signal value corresponds to the address of the storage area as shown in the figure, you can simply call up the contents of the storage device, eliminating the need for searching and making conversion easier. .

In addition, when handling the image signal as an analog signal, use a numerical generator such as a polygonal approximation circuit as shown in Figure 4 (a) or a high-order polynomial generation circuit as shown in Figure 4 (b). Use.

In this case, the distinction between a storage device and a conversion device is not clear, but
Each constant of the circuit element corresponds to the contents of the reproduction information conversion table.

FIG. 5 is a diagram showing an example of an image generated by the standardized image generation device 10. 81 in the figure is the lowest level of the signal, all
is the highest level, and the signal level is between a2 to an- and icl. If the image signal is a digital signal, it may be a device that generates a signal whose value changes in stages, or it may be a device that creates such a signal in advance and stores it in a storage device so that it can be recalled and used. It's okay.

When the main scanning is in the direction shown by arrow A in Fig. 5, the signal value changes as shown in Fig. 6 (a), and in the direction shown by arrow B in Fig. 5.
In the case of the j direction indicated by , the change is made as shown in FIG. 6 (b). If the image signal is an analog (cog signal), a similar signal may be created as an analog signal, or a method may be used in which the digital image signal is D/A converted to an analog signal.

By the way, the number n of signal levels in an image shown in FIG. 5 is the number of all signal FJs in the case of a digital signal, and the number of signal levels n that can be processed by the device to distinguish them as signals of different magnitudes in the case of an analog signal. The number of all signals is sufficient. However, in practice, the number may be smaller than that. If the value is too small, the error caused by correction of the recording characteristics using the reproduction information conversion table becomes large. The required number n differs depending on the recording device and recording medium, and when using a recording device and recording medium with good linearity, two signals, the minimum signal and the maximum signal, are sufficient. When using a recording device or a recording medium with poor linearity, it is desirable to have 10 or more.

The image generated by the standardized image generator @10 is recorded by the image recorder @9.

Corresponding to a and ~a11 in Fig. 5 of the recorded normalized image 4
The smallpox in the area is measured with a densitometer (V in the figure). A new reproduction information conversion table is created from this density measurement value and is input to the reproduction information conversion table changing device 11. The reproduction information conversion table changing device 11 changes the contents of the reproduction information conversion table in the storage device 7 based on this. Here, changing the reproduction information conversion table means changing the contents of this table in the case illustrated in Fig. 2, and changing the contents of the storage device in the case illustrated in Fig. 3. In the case illustrated in FIGS. 4(a) and 4(b), the resistance value of each resistor is changed.

Next, how to create the above-mentioned reproduction information conversion table will be explained in detail. Now, the magnitude of the signal at each level of the normalized image and ′
It is assumed that the relationship of fA leakage is the relationship expressed by the song Filf+ in FIG. In the figure, the horizontal axis shows the signal magnitude of each level of the normalized image, the vertical axis shows the density of each level of the normalized image, point A on each axis shows the maximum value, and point B shows the minimum value. Show value. As is clear from the figure, even if the signal is minimized, the lowest density level is often not zero due to the initial W1 resistance of the recording medium. Now, if 8
Think about how to convert a level 1 signal. a
Is the signal at level l a? However, it is desired that this image be recorded as a density of A3. However, the image is at the level FJ IU + of a3 and lLa 4, and if the signal level of a4 is output, it will be recorded at the desired density. That is, it is sufficient to change 11 so that a1→a5. The result is as shown in FIG. In the figure, the horizontal axis indicates the magnitude of the input signal of the reproduction information conversion table, and the vertical axis indicates the magnitude of the output signal of the reproduction information conversion table. This diagram is equivalent to the inverse transformation of the conversion from the abscissa to the ordinate, where the lowest 11 degrees of the vertical axis in FIG. 7 is the lowest signal level, and the highest density is the highest signal level. If the normalized image does not include all image signal levels, interpolation is used between each point. The interpolation method is
Number of points n and recording device.

Although it differs depending on the characteristics of the recording medium, the most suitable method is selected from among a linear interpolation method, a high-order function interpolation method, and the like.

After updating the reproduction information conversion table in the recording device 7 in this way, this update can be done by converting the standardized image using the updated reproduction information conversion table and then recording it with the image recording device @9. I can confirm it. If the reproduction information conversion table is created to correct recording characteristics without error, then the normalized image recorded after image conversion using this reproduction information conversion table will have the lowest level of the image signal as the lowest density. In other words, the highest level should be recorded at the highest density, and the intermediate levels should be recorded so that the signal level and density are proportional. Calculations for creating a new conversion table from the concentration information are performed externally and the reproduction information conversion table changing device 1
1, but the reproduction information conversion table changing device 1
1 preferably has a function of automatically performing the above-mentioned calculation, and is capable of updating the reproduction information conversion table simply by changing the density. Furthermore, if a densitometer is built into the reproduction information conversion table changing device 11, and the reproduction information conversion table is fully automatically updated when a standardized image is input 4. ,convenient. In this case, if post-processing is required, such as at the image output section of the image recording device 9 or at the beginning of development of photographic film, it is convenient to provide the densitometer 11 at the output section of the post-processing device.

The image recording device 9 may be, for example, a photo printer that scans and records a photographic film, an inkjet printer, a thermal printer, or a camera that directly records an image displayed on a CRT.

A recording device capable of producing 1 q of hard copies, such as an electrophotographic printer or an electric discharge printer, is used.

Here, the photostimulable phosphor used in the present invention will be explained. As mentioned above, a stimulable phosphor is a phosphor that emits photostimulable light when it is irradiated with radiation and then irradiated with stimulable excitation light, but from a practical point of view, Desirably, it is a phosphor whose stimulated luminescence is covered by stimulated excitation light with a wavelength of 500 to 800 nm. As such a photostimulable phosphor, for example, Mason described in JP-A-48-8'0488M
: Δ× (where A is either Ho or Dy, 0.001≦X≦1 mol%), Sr 804 described in JP-A-48-80489
:Ax (where A is at least one of Dy, Tb and Tla, and x is o, ooi≦X≦1 mol%), the general formula is BaO-X A/
203: Barium aluminate body expressed by ELI (0.-8≦×≦10), the general formula is MO・
X5iOz:A<However, M is M(1, Ca, Sr, Z
n, Cd or Ba, and A is Ce, Tb, Eu, T
'm, Pb, l'/, at least one of Bi and Mn, where x is 0°5≦×≦2.5), JP-A-Sho 55-12
The general formula described in Publication No. 144 is n OX :
X A (however, in is at least one of La, Y, Cd and ln, X i, t C/ and or Br, A
f, t Ce and/or X, x satisfies Q<x<0.1), or the general formula is n
Re X2 ・m AX2' :X EU or n l:
l! e X3-m AX2' : x Eu -y
Sm (wherein, Re is at least one of La, Cd, Y, l-n, and A is an alkaline earth metal: Ba, Sr.

At least one of Ca, X and X' are F.

Represents at least one of CIl and Br. Also, ×
and y is 1x1Q-4<x<3X10', lX10
It satisfies the condition ``4x1x10-1'': TJ number, and 07m is 1x10-''<07m <7x10-'
Examples include fluorophores represented by ``Chashaku''.

The phosphor used in the radiation image reproduction device of the present invention is not limited to the above 1i1B phosphor. Needless to say, any fluorescent substance may be used as long as it shows the above.

The average particle diameter of the photostimulable phosphor used is usually 0, taking into consideration the sensitivity and granularity of the radiation image recording medium 3.
．． The thickness is appropriately selected within the range of 1 to 100 μm. More preferably, those having an average particle diameter of 1 to 30 μm are used.

In the radiation image recording medium 3 of the present invention, generally,
The above-mentioned stimulable phosphor is dispersed in a suitable binder and applied to a support. As a binder, for example, Zeradin J
: eel protein, polycoccalides such as dextran or gum arabic, polyvinyl butyral, polyvinyl acetate, nitroelulose, ethyl cellulose, vinylidene chloride-vinyl chloride copolymer, polymethyl methacrylate-1.

Binders commonly used for layer formation are used, such as vinyl chloride-vinyl acetate copolymers, polyurethanes, cellulose acetate butyrate, polyvinyl alcohol, and the like.

Generally, the binder is 0.00% to 1 part of the stimulable phosphor.
It is used in a range of 0.01 to 1 part by weight. However, in terms of sensitivity and sharpness of the obtained tlj radiation image recording medium, it is preferable that the amount of the binder is small, and from the viewpoint of ease of coating, it is more preferably in the range of 0.03 to 0.2 parts by weight. Furthermore, there are no particular limitations on the material of the support.

Furthermore, in the radiation image recording medium 3 of the present invention, the phosphor layer is generally exposed to the outside (the surface that is not hidden by the bottom of the phosphor layer substrate) by physically or chemically treating the phosphor layer. A protective layer is provided for protection. This protective layer is
The protective layer coating solution may be directly applied onto the phosphor layer to form the protective layer, or a separately formed protective layer may be adhered onto the phosphor layer.

As the material for the protective layer, conventional materials for the protective layer such as nitrocellulose, ethylcellulose, hirulose acetate-1-, polynisder, polyethylene terephthalate, etc. can be used.

Note that this protective layer transmits stimulated luminescence light, and when irradiation with excitation light is performed from the protective layer side, it transmits excitation light.
n are selected.

Next, an example of a method for manufacturing the radiation image recording medium 3 will be described below. First, the phosphor is mixed with a binder solvent solution such as polyvinyl butyral, 21-rocellulose, etc. (the solvent is cyclohexane,
a mixture of ethyl acetate, ethyl acetate, and butyl acetate, etc.) to prepare a coating solution with a viscoelasticity of approximately 50 centistokes. Next, this solution was uniformly applied onto a horizontally placed poly]nidylene terephthalate film (support), left to stand day and night, and air-dried to form a phosphor layer. Let's call it body panel 3. The thickness of the stimulable phosphor layer formed by drying the above coating solution depends on the characteristics of the radiation image recording medium, the type of stimulable phosphor, the binder and the stimulable phosphor. Generally, the appropriate range is 10 μm to 1000 μm, preferably 80 μm to 600 μm, although it varies depending on the mixing ratio of the body.

As the support, in addition to a plastic film, for example, a transparent glass plate, a metal plate such as Aluminum 11, etc. may be used.

Furthermore, in order to improve the sharpness of the image formed on the radiation image recording medium, white powder may be dispersed in the stimulable phosphor layer as described in, for example, JP-A-55-146447. You can also use JP-A-55-1
As described in Japanese Patent No. 63500, the sharpness of the image of the stimulable phosphor layer is increased by dispersing a coloring agent that absorbs the stimulable excitation light in the stimulable phosphor layer. Stiff,
It may be appropriately colored in order to absorb the stimulated excitation light.

Furthermore, in order to improve the sharpness and sensitivity of this radiation image recording medium, a light reflecting layer is provided between the support and the stimulable phosphor layer as disclosed in Japanese Patent Application Laid-open No. 11393/1983. It may also be provided.

As the photostimulative excitation light source 4, a light source that includes an exhaustive excitation wavelength of the photostimulable phosphor used in the radiation image recording medium 3 is used. In particular, when a laser beam is used, the optical system becomes simple and the intensity of the excitation light can be increased, so that the stimulated luminescence efficiency can be increased and more favorable results can be obtained. Lasers include He-Ne laser, He'-Cd laser, Ar ion laser, ) (r ion laser, N2 laser, YAG laser and their second harmonic, ruby laser, semiconductor laser, various dye lasers, copper There are metal vapor lasers such as vapor lasers.Usually, He-Ne lasers and A
Although a continuous wave laser such as an r-ion laser is desirable, a pulsed laser can also be used if the pulse is synchronized with the scanning time of one pixel on the panel. Also, without using the filter 5, the molecule 11'! When using the method described above, it is preferable to use a pulsed laser rather than modulate using a continuous wave laser.

The filter 5 is a filter that transmits the stimulated luminescence emitted from the radiation image recording medium 3 and cuts out the stimulated excitation light. It is determined by the combination of the emission wavelength and the wavelength of the photostimulation excitation light source 4.

For example, in the case of a practically preferable combination in which the stimulated excitation wavelength is between 500 and 800 nm and the stimulated emission wavelength is between 300 and 500 nm, the filter should be, for example, Toshiba C-39, (, -40 nm). ,V-40,V-42,V-44
, Corning Co.'#7-5・$, 7-59, Spect 0 Film Co., Ltd. BG 1. BG 3゜BG-25,8G
A purple to stomach-colored glass filter such as -37 can be used. Furthermore, by using an interference filter, it is possible to select and use a filter with arbitrary characteristics to some extent. The photoelectric conversion device 6 may be any device capable of converting a change in the amount of light into a change in an electrical signal, such as a phototube, a photomultiplier tube, a photodiode, a phototransistor, a solar cell, or a photoconductive element.

When there are multiple image recording devices 9, or when there are multiple recording media 3 to be used, multiple reproduction information conversion tables are stored in the storage device 7, and the image conversion device 8 performs recording from among them. It is preferable to be able to select and convert the format corresponding to the device or medium to be used.For example, when using a photo printer as the Ii!i image recording device 9, there are differences in the type of photographic film used and the processing method. Since the recording characteristics differ depending on the type of photographic film, when using multiple layers of photographic film or different developing processes, it is necessary to record standardized images for each film, read the mI!1, and create an exchange table. .

In addition, this playback information conversion table records a standardized image when the recording characteristics change due to aging of the recording device or change of the recording medium, and converts the information (which must be changed) based on the IA degree information. .For example, image recording)! i@9 ni fu 11-
When using a printer, the recording characteristics change due to the deterioration of the light source of the photo printer and the deterioration of the developer, as well as changes in the photographic film or development method, so the recording characteristics may change depending on the number of sheets recorded or for a certain period of time, for example, every 100 sheets. Alternatively, it is preferable to change the reproduction information conversion table periodically, such as every day.

The above devices are devices in which the image recording device 9 displays not a hard copy record but a soft copy, such as a CRT display device, a liquid crystal display, an electrochromic display, an electroluminescent display, a fluorescent display tube, a plasma display, and a laser display. It can also be applied to cases where In this case, the displayed image is generally represented by the intensity of light output from the display device. Therefore, the standardized image is displayed, and the reproduction information conversion table is changed based on the luminance information. That is, in the method of creating the reproduction information conversion table described above, the density of the recorded standardized image may be used as the brightness of the displayed standardized image, and a similar method may be used.

Hereinafter, the apparatus of the present invention has been described in detail.The apparatus of the present invention has an image signal converter provided between the photoelectric converter 6 and the image signal converter 8 based on the reproduction information conversion table, and is configured to perform image processing. can be done.

Another application of the present invention is to equally print images recorded by two or more types of image recording devices.

In this case, if the present invention is applied to each recording device, the same image will naturally be obtained, but the difference due to the difference in recording characteristics between the image signal and the recorded image will not be a problem, and the difference in recording characteristics between the recorded images will be corrected. If it is desired, one of the image recording devices reproduces and records the reproduction information without going through the reproduction information conversion table according to the present invention, and the other image recording device reproduces the reproduction information so that it has the same conversion characteristics as that of the recording device. This can be recorded using a conversion table.

(Effects of the Invention) As described above in detail, according to the present invention, captured image information is corrected based on a changeable reproduction information conversion table, and the reproduction information conversion table By specifying changes based on the density information of the normalized image,
It is possible to realize a radiation image reproducing device whose recording characteristics do not change due to changes over time or the like.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram showing an embodiment of the present invention, FIG. 2 is a diagram showing an example of a reproduction information conversion table included in a storage device, and FIG.
Figure 4 shows another example. Figure 4 shows an example of the configuration of a function generator. Figure 5 shows an example of an image generated by the normalized image generator. Figure 6 shows a signal generator. Diagram 7 showing how to change
The figure shows the relationship between the magnitude of the level signal and the density of the normalized image, and FIG. 8 shows the conversion result. 1... Radiation generating device @ 2... Subject 3... Radiation image recording device 4... Excitation light source 5... Filter 6... Photoelectric conversion device 7... Storage device 8... Image Conversion device 9...Image recording device 10...Standardized image generation device 11...Changing device Patent applicant Konishi Roku Photo Industry Co., Ltd. - Company X Representative Patent attorney Fuji Ijima 1 figure 'j Figure A2 Figure Leather 3 Left Column Right A11 Address Data Figure Leather 5 Figure Leather 6 (A) Equivalent to 11th Yo ni Hanase Figure 7 Figure 8

Claims (1)

[Claims] Radiation with a photostimulable phosphor layer! )jI! By irradiating an active line image onto an i1 image recording medium, the image is emitted! ) The energy of the irradiated radiation imagewise accumulated in the one-line image recording medium is stimulated with excitation light to produce stimulated luminescence, and - this stimulated luminescence is converted into an electrical signal according to the strength of the light. A radio DAF that plays images! In the image reproducing device, a storage means for storing a changeable reproduction information conversion table; a first image reproduction recording means for reproducing and recording an image according to the reproduction information conversion table in the storage means; a second image reproducing and recording means for appropriately generating a standardized image and reproducing and recording the mRakuhoku image without going through the storage means; and reproduction in the storage means based on the density information of the reproduced Iζ standardized image. 1. A radiation image reproducing apparatus, comprising: means for changing an information conversion table.