JPH02272529A - Method and device for reading radiograph information - Google Patents

Abstract

PURPOSE:To set the best read conditions and image processing conditions by determining the read conditions or image processing conditions according to the characteristic value of a condition setting image signal which constitutes the remaining histogram area after a 1st area between the signal maximum value of a histogram and a threshold value which is a specific quantity less than the maximum value and a 2nd area between the signal minimum value and a threshold value which is a specific quantity larger than the minimum value are removed from the histogram. CONSTITUTION:An image signal which is extracted from a preread image signal Sp is sent to a histogram generation part to generate a cumulative histogram. In this case, the area between the signal maximum value and the threshold value which is the specific quantity less than it and the area between the signal minimum value and the threshold value which is the specific quantity larger than the minimum value are removed from the histogram and the read conditions and image processing conditions are determined according to the characteristic value of the image signal which constitutes the remaining histogram area. Consequently, the best read conditions and image processing conditions can be set.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a method for reading image information from a radiation image information recording medium such as a stimulable phosphor sheet as an electrical image signal, and more particularly, to Before subjecting the image to visible image reproduction, the outline of the radiation image information recorded on the recording medium is read, and based on this outline information, the radiation image information reading conditions and/or image processing conditions for the above-mentioned visible image reproduction are determined. The present invention relates to a method for reading radiation image information that determines the amount of radiation image information, and an apparatus for implementing the method.

(Prior art) When a certain type of phosphor is irradiated with radiation (X-rays, α-rays, β-rays, γ-rays, electron beams, ultraviolet rays, etc.), a part of this radiation energy is accumulated in the phosphor, and this It is known that when a phosphor is irradiated with excitation light such as visible light, the phosphor exhibits stimulated luminescence depending on the accumulated energy, and phosphors that exhibit this property are called stimulable phosphors. .

Using this stimulable phosphor, radiation image information of the human body, etc. is temporarily recorded on a stimulable phosphor sheet, and this stimulable phosphor sheet is scanned with excitation light such as a laser beam to generate stimulated luminescence light. The resulting stimulated luminescent light is read photoelectrically to obtain an image signal, and based on this image signal, a radiation image is output as a visible image to a recording material such as a photographic light-sensitive material or a display device such as a CRT. An image information recording and reproducing system has already been proposed by the present applicant (Japanese Patent Application Laid-Open No. 1249/1989).
No. 2, No. 5G-11395, etc.).

This method has the practical advantage that images can be recorded over a much wider range of radiation exposure compared to conventional radiographic systems using silver halide photography. In other words, in stimulable phosphors, it is recognized that the amount of emitted light that is stimulated and emitted by excitation after accumulation is proportional to the amount of radiation exposure over an extremely wide range, and therefore the amount of radiation exposure varies depending on various imaging conditions. Even if the value varies considerably, the amount of stimulated luminescent light emitted from the stimulable phosphor sheet is read by the photoelectric converting means by setting the reading gain to an appropriate value and converted into an electrical signal. By using a signal to output a radiation image as a visible image to a recording material such as a photographic light-sensitive material or a display device such as a CRT,
A radiation image that is not affected by variations in radiation exposure can be obtained.

In addition, according to this system, radiation image information stored and recorded on a stimulable phosphor sheet is converted into an electrical signal, then subjected to appropriate signal processing, and this electrical signal is used to produce recording materials such as photographic light-sensitive materials, CRTs, etc. By outputting radiographic images as possible Nfm on the display device, observation interpretation aptitude (
The extremely large effect of being able to obtain radiographic images with excellent diagnostic suitability can also be obtained.

In this way, in a radiation imaging system using a stimulable phosphor sheet, the reading gain can be set to an appropriate value to photoelectrically convert the stimulated luminescence light and output it as a visible image, so it is possible to Fluctuations in radiation exposure amount due to fluctuations in tube voltage or MAS value, fluctuations in sensitivity of stimulable phosphor sheets, fluctuations in sensitivity of photodetectors, changes in exposure amount due to subject conditions, or differences in radiation transmittance depending on the subject, etc. Even if the stored energy stored in the stimulable phosphor differs due to the causes of these factors, and furthermore, even if the amount of radiation exposure is reduced, it is possible to obtain a radiation image that is not affected by fluctuations in these factors.

However, in order to eliminate the influence of fluctuations in imaging conditions or obtain radiographic images with excellent observation and interpretation properties, it is necessary to change the recording state of the radiographic image information accumulated and recorded on the stimulable phosphor sheet, as well as the chest and abdomen. Visual images for observation and interpretation of recorded patterns (hereinafter collectively referred to as "accumulated recorded information") determined by the body part of the subject, the imaging method such as plain radiography, contrast radiography, etc. The system determines the recording scale factor so that the resolution is optimized according to the contrast of the recording pattern, and the reading gain is adjusted to an appropriate value based on the acquired accumulated recording information. It is necessary.

As a method for grasping the accumulated record information of radiation images before outputting visible images, Japanese Patent Application Laid-Open No. 58-87240
The method disclosed in No. This method uses excitation light of a lower level than the excitation light that should be irradiated during the reading operation (hereinafter referred to as "main reading") to obtain a visible image for observation and interpretation. Perform a reading operation (hereinafter referred to as "pre-reading") to understand the accumulated record information of the radiation image stored and recorded on the stimulable phosphor sheet, grasp the outline of the accumulated record of the radiation image, and perform the main reading. At this time, the reading gain is appropriately adjusted, the recording scale factor is determined, or the signal processing conditions are determined based on this pre-read information.

According to the above method, the recording state and recording pattern of the radiation image information accumulated and recorded on the stimulable phosphor sheet can be known in advance before the actual reading, so the reading gain can be adjusted appropriately based on this recorded information. By adjusting the recording pattern, determining the recording scale factor, and applying signal processing to the electrical signals after reading according to this recording pattern, it becomes possible to obtain a radiographic image with excellent suitability for observation and interpretation.

Various methods have been considered for grasping the accumulated record information of a stimulable phosphor sheet from the pre-read image signals obtained by the above-mentioned pre-reading. There are known methods for determining the value. In other words, this average value indicates the overall level of the pre-read image signal, so for example, if the reading gain for main reading is set according to this average value, the level of the main reading image signal can always be kept within an appropriate range. becomes possible.

However, when grasping the accumulated record information of the stimulable phosphor sheet as described above, as shown in FIG. If the shaded area in the figure) B, the protector C shown in Figure 4B (which protects the subject from radiation), or the part where Ba contrast agent is injected in contrast imaging of the digestive tract, etc. are recorded, the accumulated record of the subject A problem arises in that information is misunderstood. In other words, in the stimulable phosphor sheet, the accumulated radiation energy is either particularly high or particularly low in the areas where the radiation is directly incident, the protector, or the Ba contrast agent injection area, and therefore the average value of the pre-read image signal is small. However, since such an area is unrelated to the subject, the average value that increases or decreases as described above does not accurately reflect the accumulated recorded information of the subject.

We have described above the problems that occur when determining the reading conditions and image processing conditions based on the average value of the pre-read image signal, but it is not limited to this average value, but it is greatly influenced by the radiation direct incidence area and the part of the protective body. Similar problems arise when determining reading conditions and image processing conditions based on pre-read image signal characteristic values (for example, other median values, etc.).

Therefore, the present applicant has previously proposed a radiation image information reading method that can correctly grasp accumulated recorded information regarding a subject by pre-reading without causing the above-mentioned problems (Japanese Patent Laid-Open No. 131-287380).

This radiation image information reading method calculates a histogram of a pre-read image signal in a radiation image information reading method that performs pre-reading to determine the reading conditions and/or image processing conditions in the main reading as described above, and the maximum signal of this histogram is and/or find characteristic values (average value, median value, etc.) of the pre-read image signal in a region excluding at least the sharp peak region near the signal minimum value,
The present invention is characterized in that reading conditions and image processing conditions are determined according to this characteristic value.

The sharp peak region that occurs near the signal maximum value in the histogram is due to the direct incidence region of the radiation.

On the other hand, the sharp peak region that occurs near the signal minimum value of the histogram is due to a portion where radiation is significantly absorbed by the protector, contrast agent, or the like. Therefore, the characteristic values of the image signal in the area excluding at least the sharp peak area will correctly reflect the accumulated recorded information regarding the subject, excluding the influence of the direct radiation incidence area, the protector, etc.

(Problems to be Solved by the Invention) As mentioned above, the method of Japanese Patent Application Laid-open No. 11-287380 is extremely effective in practice, but subsequent research by the present inventors has shown that If the high radiation absorption material being used is gold teeth, artificial bones, etc., the sharp peak region mentioned above (in this case, near the signal minimum value) may not clearly appear in the histogram of the pre-read image signal. I understand that. Similarly, even when a radiation spot is recorded in a radiation image, the sharp peak region (in this case, near the signal maximum value) may not appear clearly depending on the recording state.

Above, we have explained the case where pre-reading is performed separately before main reading, but the present applicant has, for example,
No. 1, etc., the above-mentioned pre-reading is omitted and the outline of the accumulated recorded information is grasped from the image signal obtained in one reading process,
We have proposed a method for determining conditions for image processing to be applied to the image signal during visible image reproduction, or for conversion processing equivalent to changing reading conditions, based on the accumulated recorded information ascertained as described above. Problems can occur in this case as well. In addition, when obtaining electrical image signals by reading radiographic image information from conventionally used silver halide photographic film for X-ray photography using a microphotometer, etc., the conditions for image processing, etc. for this image signal are set as described above. In this case, the above-mentioned problems may occur as well.

Therefore, the present invention eliminates the above-mentioned unnecessary sharp peak region even if it does not clearly appear in the histogram of the image signal, and improves the reading conditions for a recording medium such as a stimulable phosphor sheet and/or the image processing (the above-mentioned reading The object of the present invention is to provide a radiation image information reading method that can optimally set conditions (including conversion processing equivalent to changing conditions), and an apparatus suitable for implementing the method.

(Means and Effects for Solving the Problems) As described above, the radiation image information reading method according to the present invention reads radiation image information from a recording medium on which radiation image information is recorded to obtain an image signal. When reproducing a radiation image as a visible image based on this image signal, a reading process is performed to read the outline of the radiation image information to obtain a condition setting image signal, and the outline indicated by this condition setting image signal is In a radiation image information reading method, the radiation image information reading conditions and/or image processing conditions for obtaining the visible image are determined based on the information,
A histogram of the above-mentioned image signal for condition setting is obtained, and the first region in this histogram is between the signal maximum value and a threshold value smaller than that by a predetermined amount, and/or the first region between the signal minimum value and a threshold value larger than that by a predetermined amount. The second region between the threshold and the histogram is removed from the histogram, and the reading conditions and/or the image are determined based on the characteristic values (average value, median value, etc.) of the image signal for condition setting that constitutes the remaining histogram region. This method is characterized by determining processing conditions.

Note that the above-mentioned "reading process for reading the outline of radiation image information" may be "pre-reading", or as described above, it may also be used as a reading process for obtaining an image signal for visible image reproduction. Good too.

The above-mentioned first and second regions are divided into different parts of the total signal width, for example, from the maximum signal value (minimum value) to the minimum value (maximum value) side, depending on the subject in the radiographic image to be read, the imaged region, etc. It can be specified as a percentage, etc. If the first or second region is set appropriately, the radiation extraction described above will be performed based on the reading conditions and the histogram from which the portion of the image signal that carries parts, gold teeth, artificial bones, etc. is removed. Image processing conditions are now determined,
They are adapted to the accumulated record information regarding the subject.

The appropriate widths of the first region and the second region can be determined based on experiments and experience for each subject and region to be imaged, but they can also be determined for each radiographic image. . The present invention also provides a radiation image information reading device that can define the first or second region in this manner.

The radiation image information reading device according to the present invention includes a reading means for reading radiation image information from a recording medium on which the radiation image information is recorded and obtaining an image signal for reproducing the radiation image as a visible image; A radiographic image comprising: condition determining means for determining radiographic image information reading conditions and/or image processing conditions when obtaining the visible image, based on general information indicated by a condition setting image signal obtained from a recording medium. In the information reading device, the condition determination means includes a cumulative histogram creation section that creates a cumulative histogram of the image signal for condition setting, and a cumulative frequency of H% in each of the cumulative histograms.
, a threshold calculation unit that calculates a first threshold α and a second threshold β such that L% (H>L); The present invention is characterized by comprising a condition determining section that determines the reading conditions and/or image processing conditions based on signal characteristic values (average value, median value, etc.).

(Example) Hereinafter, the present invention will be described in detail based on an example shown in the drawings.

FIG. 1 shows a radiation image information recording and reproducing system equipped with a radiation image information reading device according to an embodiment of the present invention. This radiation image information recording and reproducing system basically includes a radiation image capturing section 20, a pre-reading reading section 30, a main reading reading section 40, and an image reproducing section 50. In the radiographic image capturing unit 20, radiation 102 is emitted from a radiation source 100 such as an X-ray tube toward a subject (subject) 101, for example. This subject 101
As described above, the stimulable phosphor sheet 103 that accumulates radiation energy is placed at the position where the radiation 102 that has passed through the stimulable phosphor sheet 103 is irradiated.
The transmitted radiation image information of the subject 101 is accumulated and recorded.

The stimulable phosphor sheet 103 on which the radiation image information of the subject 101 has been recorded in this manner is sent to the pre-reading reading section 30 by sheet transport means 110 such as a transport roller. In the pre-reading reading section 30, the pre-reading laser beam [2
The laser beam 202 emitted from the laser beam 2
A filter 2 that cuts the wavelength range of stimulated luminescence light emitted from the stimulable phosphor sheet 103 by excitation of 02
03, the light is linearly deflected by a light deflector 204 such as a galvanometer mirror, and is incident on the stimulable phosphor sheet 103 via a flat reflecting mirror 205. Here, the laser light source 201 is selected so that the wavelength range of the laser light 202 as excitation light does not overlap with the wavelength range of the stimulated luminescence light emitted by the stimulable phosphor sheet 103. On the other hand, the phosphor sheet 103 is moved by a sheet transport means 21 such as a transport roller.
0, the phosphor sheet 103 is moved in the direction of the arrow 20B for sub-scanning, and as a result, the entire surface of the phosphor sheet 103 is irradiated with the laser light 202. Here, the emission intensity of the laser light source 201, the beam diameter of the laser light 202, the laser light 202
The scanning speed of the stimulable phosphor sheet 103 and the transport speed of the stimulable phosphor sheet 103 are as follows.
The energy of the excitation light (laser light 202) for pre-reading is selected to be smaller than that for main reading performed in the main reading reading unit 40, which will be described later.

When irradiated with the laser beam 202 as described above, the stimulable phosphor sheet 103 emits stimulated luminescent light with an amount corresponding to the radiation energy stored and recorded therein, and this luminescent light is transmitted to the pre-reading light guide 207. incident on . The stimulated luminescence light is guided through the light guide 207, exits from the exit surface, and is received by a photodetector 208 such as a photomultiplier. A filter is attached to the light receiving surface of the photodetector 208, which transmits only light in the wavelength range of stimulated luminescence light and cuts light in the wavelength range of excitation light, and detects only stimulated luminescence light. It is now possible to do so. The detected stimulated luminescence light is converted into an electrical signal carrying accumulated recording information, and is sent to an amplifier 2.
09. The signal output from the amplifier 209 is digitized by the A/D converter 211 and inputted to the condition determining section 314 of the main reading reading section 40 as a pre-read image signal (condition setting image signal) Sp. The condition determining unit 314 determines the reading gain setting value Sk, the recording scale factor setting value cp, and the reproduction image processing condition setting value C based on the accumulated recording information indicated by the prefetch image signal Sp.

Note that the determination of these set values 5kSGp and C will be described later.

The stimulable phosphor sheet 103 whose pre-reading has been completed as described above is transferred to the reading section 40 for main reading.

In the main reading reading section 40, the main reading laser light source 301
The laser beam 302 emitted from this laser beam 302
A filter 303 that cuts the wavelength range of stimulated luminescent light emitted from the stimulable phosphor sheet 103 by excitation of the stimulable phosphor sheet 103.
After passing through the stimulable phosphor sheet 103, the beam diameter is strictly adjusted by a beam expander 304, linearly deflected by an optical deflector 305 such as a galvanometer mirror, and passed through a flat reflecting mirror 306 to the stimulable phosphor sheet 103. incident on the top. There is a distance f between the optical deflector 305 and the plane reflecting mirror 306.
A θ lens 307 is arranged so that the beam diameter of the laser beam 302 scanning the stimulable phosphor sheet 103 is made uniform. On the other hand, the stimulable phosphor sheet 103 is transported in the direction of the arrow 308 by a sheet transport means 320 such as a transport roller to perform sub-scanning, and as a result, the entire surface of the stimulable phosphor sheet 103 is irradiated with laser light. When irradiated with the laser beam 302 in this manner, the stimulable phosphor sheet 103 emits stimulated luminescence light with an amount corresponding to the radiation energy stored and recorded therein, and this luminescent light enters the main reading light guide 309. do. Stimulated luminescent light guided through the main reading light guide 309 while undergoing repeated total reflection is emitted from its exit surface and is received by a photodetector 31O such as a photomultiplier. Photodetector 3
A filter that selectively transmits only the wavelength range of the stimulated luminescent light is attached to the light receiving surface of the photodetector 310 so that the photodetector 310 detects only the stimulated luminescent light.

The output of the photodetector 310 that photoelectrically detects the stimulated luminescent light representing the radiation image recorded on the stimulable phosphor sheet 103 is read based on the reading gain setting value Sk determined by the condition determining section 314. Amplifier 31 with set gain
1, the electrical signal is amplified to an appropriate level. The amplified electrical signal is input to the A/D converter 312, and based on the recording scale factor setting value cp, it is converted into a digital signal with a recording scale factor suitable for the signal fluctuation width, and the digital signal is input to the signal processing circuit 313. . The digital signal is subjected to signal processing (image processing) in the signal processing circuit 313 based on the reproduction image processing condition setting value C so as to obtain a radiation image excellent in suitability for observation and interpretation, and is output.

The read image signal (actual read image signal) So output from the signal processing circuit 313 is transmitted to the optical modulator 401 of the image reproducing unit 50.
is man-powered. In this image reproducing unit 50, a laser beam 403 from a recording laser light source 402 is transmitted to an optical modulator 40.
1, it is modulated based on the main reading image signal So manually inputted from the signal processing circuit 313, and is transmitted to the scanning mirror 404.
The light beam is deflected by the light beam and scans over a photosensitive material 405 such as photographic film. The photosensitive material 405 is then transported in a direction perpendicular to the scanning direction (arrow 406 direction) in synchronization with the scanning, and a radiation image based on the actual reading image signal So is output onto the photosensitive material 405. In addition to this method, various other methods can be used to reproduce the radiographic image, such as the above-mentioned CRT display.

Next, with reference to FIG. 2 which shows the condition determination unit 314 in detail,
Determination of the reading gain setting value Sk, the recording scale factor setting value Gp, and the image processing condition setting value C will be explained. The pre-read image signal Sp is stored in the storage unit 350 of the condition determination unit 314, and is also stored in the table converter 351.
The signal is sent to a D/A converter 352, where it is converted into an analog signal and sent to an image display means 353 such as a CRT. In this image display means 353, a radiation image of the subject 101 carried by the pre-read image signal Sp is displayed. After observing the displayed radiation image, the operator uses input means 354, such as a keyboard, to
It is possible to determine an image region A (see FIGS. 4A and 4B) on which the histogram analysis is to be performed, and manually input information S1 indicating the region A to the signal extraction unit 355.

The signal extraction section 355 calculates the coordinates of the area A based on this manually inputted information S1, and sends a signal S2 indicating the coordinates to the storage section 350. In the storage unit 350, a pre-read image signal Sp' of the area indicated by the signal S2 is extracted from the above-mentioned pre-read image signal Sp, and this extracted image signal Sp'
is sent to the cumulative histogram creation section 356. The cumulative histogram creation section 35G creates a cumulative histogram of this image signal Sp'.

If a histogram of the above extracted pre-read image signal Sp' is created, it will be as shown by the solid line in FIG. That is, if the stimulable phosphor sheet 10
When a highly radiation-absorbing material such as a gold tooth or an artificial bone is imprinted in the image area A of 3, a region R consisting of a low-level signal that carries it appears in the above histogram near the signal minimum value S1in. . As described above, this region R is often not a clearly sharp peak region.

On the other hand, if a radiation spot is recorded in the image area A of the stimulable phosphor sheet 103, the above histogram includes an area Q consisting of a high level signal carrying it near the signal maximum value S maw. Appear.

As described above, this region Q may not be a clear sharp peak region.

A signal S3 indicating the cumulative histogram created by the cumulative histogram creation section 356 is sent to the threshold calculation section 357. The threshold calculation section 357 includes the input means 354.
, a signal SH indicating the upper limit cumulative frequency H% and a signal SL indicating the lower limit cumulative frequency L% are input. The above-mentioned cumulative histogram is, for example, as shown by the virtual line in FIG.
% etc. The threshold calculation unit 357 calculates a first threshold α for which the cumulative frequency is H%, and a second threshold β such that the cumulative frequency is L%, from the cumulative histogram indicated by the signal S3. (See Figure 3). The signals indicating the first and second threshold values α and β thus obtained are input to the signal extraction section 355, and are also input to the table converter 3.
51 will be man-powered. The signal extraction unit 355 receives the input α,
Based on the value of β, only signals in the range β to α are extracted from the pre-read image signal Sp stored in the storage unit 350, and the extracted pre-read image signal Sp” is input to the average value calculation unit 358. The average value calculation section 358 calculates the average value of this pre-read image signal Sp'' and sends a signal S4 indicating the calculated value to the storage section 359. This storage section 359
, the optimum reading gain setting value S for each of the above average values is determined.
k, recording scale factor setting value cp, and image processing condition setting value C are stored in advance, and from these stored values, optimal setting values Sk, Gp, and C corresponding to the average value indicated by the above signal S4 are read out. It will be done. These reading gain setting value Sk, recording scale factor setting value Gp, and image processing condition setting value C are respectively input to the amplifier 311, A/D converter 312, and signal processing circuit 313 as described above.

As mentioned above, the reading gain setting value Sk, the recording scale factor setting value cp, and the image processing condition setting value C are
These set values Sk, Gp, and C are determined based on the pre-read image signal Sp'' for areas other than the first area Q and second area R shown in the figure, so these set values Sk, Gp, and C are determined based on the radiation extraction area, gold tooth, Excluding the influence of artificial bones, etc., it becomes optimal for the accumulated recorded information of the subject lot.

On the other hand, when the table converter 351 receives the values α and β, all the pre-read image signals Sp with the values α to S wax are uniformly set to α, and all the pre-read image signals Sp with the values Sm1n to β are uniformly set to α. Set the internal conversion table to convert to β. Thereby, the image display means 353 displays a radiation image based on the image signals in the signal range used for determining the reading gain setting value Sk, the recording scale factor setting value Gp, and the image processing condition setting value C.

Therefore, the operator can set the upper limit cumulative frequency H26 and the lower limit cumulative frequency L% to optimal values by performing interactive processing while observing this display image.

In the embodiment described above, both the first region Q and the second region R in the histogram are removed, but depending on the radiographic image to be read,
Only one of these regions Q and R may be removed. In order to do so when using the apparatus shown in FIG.
It is sufficient to input 0% or the lower limit cumulative frequency L-0%.

Furthermore, in the above embodiment, the range of the image signal Sp used to determine the reading conditions and image processing conditions is determined based on the cumulative histogram. The threshold values α and β may be input directly from an input means. In that case, the threshold values α, β are each set, for example, in the signal range S ll1i
Maximum signal value 5IIax by 10% width of n-S max
A smaller value, a value larger than the signal minimum value S +lin by a similar width, etc. may be determined.

Further, the above embodiment is applied to a case where a stimulable phosphor sheet is used as a recording medium and pre-reading is performed. In the case where the outline of the accumulated record information is grasped from the image signal and the conditions for image processing to be applied to the image signal are determined based on the accumulated record information grasped as described above, it is also possible to use The same applies to the case of using silver salt photographic film.

(Effects of the Invention) As described above in detail, in the present invention, a histogram of the image signal for condition setting is obtained, and a first region between the signal maximum value in this histogram and a predetermined threshold value two times smaller than the histogram, and/or a second region between the signal minimum value and a threshold value larger than the minimum value by a predetermined amount is removed from the histogram, and reading conditions and Since the image processing conditions are determined, the optimum reading conditions and/or image processing conditions corresponding to the accumulated record information of the subject can be determined, excluding the effects of radiation extraction and special high radiation absorption materials. Can be set. Therefore, according to the present invention, it is possible to always obtain radiographic images with excellent suitability for observation and interpretation.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram of an apparatus for reading radiation image information according to the method of the present invention, FIG. 2 is a block diagram showing the main parts of the apparatus of FIG. 1, and FIG. 3 is an explanatory diagram explaining the present invention in detail. , FIG. 4 is an explanatory diagram showing a state of recording radiation image information on a stimulable phosphor sheet according to the present invention. 20...Radiation image capturing unit 30...Reading unit for pre-reading 40...Reading unit for main reading 100...
Radiation source lot...Subject 102...
- Radiation 103...Stormative phosphor sheet 201...Laser light source for pre-reading 202...Laser light for pre-reading 204...Light deflector for pre-reading 208...Photodetector for pre-reading 210...Pre-reading Sheet transport means 301...Laser light source for main reading 302...Laser light for main reading 305...Light deflector for main reading 310...Photodetector for main reading 311...Amplifier 312...A/D Converter 313...Signal processing circuit 314...Condition determining unit 320...Book reading sheet transport means 350.359...Storage unit 351...Table converter 352...D/A Converter 353...
・Image display means 354...Input means 355・
...Signal extraction section 35G...Cumulative histogram creation section 357...Threshold value calculation section 358...Average value calculation section A...Image area B for determining conditions...Radiation irradiation field Sk...・Reading gain setting value Gp...Recording scale factor setting value C...Reproduction image processing condition setting value So...Actual reading image signal Sp...Pre-reading image signal Sp...Extracted pre-reading image signal"

Claims (2)

[Claims] (1) When reading radiation image information from a recording medium on which radiation image information is recorded to obtain an image signal, and reproducing the radiation image as a visible image based on this image signal, an outline of the radiation image information. A reading process is performed to read the image signal for condition setting, and based on the general information indicated by the image signal for condition setting, radiation image information reading conditions and/or image processing conditions for obtaining the visible image are determined. In the radiation image information reading method, a histogram of the condition setting image signal is determined, and a first region between a signal maximum value in this histogram and a threshold value smaller than the maximum signal value by a predetermined amount; or a second region between the minimum signal value and a threshold value larger than the minimum value by a predetermined amount is removed from the histogram, and the second region is determined based on the characteristic value of the condition setting image signal constituting the remaining histogram region. A radiation image information reading method characterized by determining reading conditions and/or image processing conditions. (2) reading means for reading radiation image information from a recording medium on which the radiation image information is recorded and obtaining an image signal for reproducing the radiation image as a visible image; and condition settings obtained from the recording medium. a radiation image information reading device comprising: condition determining means for determining radiation image information reading conditions and/or image processing conditions when obtaining the visible image based on the general information indicated by the image signal for the purpose of obtaining the visible image; The means includes a cumulative histogram creation unit that creates a cumulative histogram of the condition setting image signal, and a cumulative frequency of H% in each of the cumulative histograms.
, a threshold calculation unit that calculates a first threshold value α and a second threshold value β such that L% (H>L); A radiation image information reading device comprising: a condition determining unit that determines the reading conditions and/or image processing conditions based on characteristic values of signals.