JP2003288590A - Image processor, image recording device, image display device, image processing method, image recording method, image display method and program, and recording medium where the program is recorded - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To output an image with proper gradation characteristics that an observer views without feeling the glare nor darkness. <P>SOLUTION: A medical image recording device 100 which outputs medical images by recording them on an image recording medium α makes gradation corrections of a medical image inputted from outside by an image processing part 110 under the control of a control part 120 so that the mean optical physical quantity of its specified area or specified signal value matches an ideal specified range suitable for an image observation by the observer and sends a recording head control signal, a recording medium conveyance signal, and a head conveyance signal corresponding to the gradation-corrected image signal to a recording head unit 130, a transport roller 140, and a recording head conveyance part 150 to record the gradation-corrected image on the image recording medium α. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image processing apparatus for processing an image, an image recording apparatus for recording an image, an image display apparatus for displaying an image, an image processing method, an image recording method, an image display method, a program and a program. The present invention relates to a recording medium on which is recorded.

[0002]

2. Description of the Related Art Recently, a method for obtaining medical radiation image information without using a radiographic film made of a silver salt photosensitive material has been devised. For example, using an imaging plate mainly composed of a stimulable phosphor, after once accumulating a radiation image, it is taken out as a stimulable luminescent light by using excitation light,
A radiation image reading device (Computed Radiography, hereinafter abbreviated as CR) that obtains an image signal by photoelectrically converting this light has become widespread.

Recently, a device (Flat Panel) for reading radiation image information by combining a radiation phosphor or radiation photoconductor with a two-dimensional semiconductor detector such as a TFT switching element.
Detector, hereinafter abbreviated as FPD) has also been proposed.

Further, radiation image input devices other than simple X-ray imaging, such as X-ray computed tomography apparatus (X-ray CT apparatus) and magnetic resonance image forming apparatus (MRI apparatus), are also widespread. These medical image input devices often provide image information in the form of digital signals.

In diagnosing these medical images, a method of recording image information on a transmissive recording medium and / or a reflective recording medium and observing it in the form of a hard copy is often used.

As a medical image recording apparatus for recording medical image information on a recording medium, a method of recording an image by laser exposure on a transmission recording medium using a silver salt recording material is often used. According to this method, a monochrome multi-gradation image can be drawn with excellent gradation, and high diagnostic ability can be obtained by recording on a transparent medium and observing it with transmitted light.

In recent years, the image quality of ink jet recording has been improved with the improvement of miniaturization of ink droplets and improvement of resolution, and paper,
Even when an image is recorded on a reflective recording medium having a support such as PET (Poly Ethylene Terephthalate resin), it is possible to obtain a certain image quality. For this reason, recently, the possibility of recording a medical image using an inkjet recording apparatus has been expected.

Further, in recent years, while the conventional form using a radiographic film still exists, an image display device (so-called,
It is conceivable that the number of diagnostic forms in which diagnosis is performed using a medical image displayed by a display device) and that image is printed (so-called soft copy) using a small printer or the like if necessary.

[0009]

Even if the image output form is changed like a film or a display, when a medical image is diagnosed under a certain condition, the image is output so as to have the same gradation characteristic. Is desirable. For example, Japanese Patent Application Laid-Open No. 6-261252 describes a medical image system which is effective with respect to variations in photographing and is supposed to observe images under the same conditions.

However, along with the diversification of the image output form and the image photographing method, the diversification of the image use is also progressing. For example, the image may be used not only for diagnosis but also as a reference image, a reduced image may be attached to a medical record, or a comment may be written on the recorded image itself. In particular, the inkjet image recording device, which is characterized by low cost, is used with various modalities such as CR, FPD, X-ray CT, and MRI imaging device, as well as L such as HIS (hospital network) and RIS (radiology network).
There is a case where the printer is connected to an AN and used as a POD (Print On Demand) printer.

Therefore, it is considered that images are observed more frequently under various observation conditions than when images are observed under certain conditions. Furthermore, depending on the selection of transmission / reflection image, selection of monochrome / color, or selection of the purpose of use,
The gradation characteristics required by the observer cause a large individual difference depending on the observation conditions and the preference of the observer.

In the image recording apparatus, the image must be recorded after adjusting the gradation characteristics one by one according to the observation environment and the application. In the image display device, display settings (contrast, brightness) must be adjusted one by one according to the observation environment and application.

An object of the present invention, which has been made in view of the above problems, is to perform image processing in advance and output an image having a good image quality, particularly an image having appropriate gradation characteristics without causing glare or darkness for an observer. It is to be.

[0014]

In order to solve the above-mentioned problems, the invention according to claim 1 is an image processing apparatus for processing an image based on an image signal representing the image. Approximation means for approximating the average optical physical quantity in the predetermined area set by the area setting means based on the recording gradation characteristics in the area setting means for setting the predetermined area and the image recording means for recording the image on the image recording medium. And a gradation correction unit that corrects the gradation characteristics of the image signal so that the average optical physical quantity estimated by the estimation unit falls within a predetermined range.

According to a second aspect of the present invention, there is provided an image processing device for image-processing an image based on an image signal representing the image, the signal-value range setting means for setting a predetermined signal value range of the image signal, and the image. Approximate means for approximating an average optical physical quantity in the predetermined signal value range set by the signal value range setting means, based on the recording gradation characteristic in the image recording means for recording on the recording medium, and the average estimated by the approximating means. Gradation correction means for correcting the gradation characteristic of the image signal so that the optical physical quantity falls within a predetermined range.

According to a third aspect of the present invention, there is provided an image processing device for image-processing an image based on an image signal representing the image, wherein an area setting means for setting a predetermined area of the image signal and an image recording medium for the image. An approximation means for approximating an average optical physical quantity in the predetermined area set by the area setting means, based on the recording gradation characteristics in the image recording means for recording the image and the light source information when observing the image; An image processing apparatus, comprising: a gradation correction unit that corrects the gradation characteristic of the image signal so that the average optical physical quantity estimated by the unit falls within a predetermined range.

According to a fourth aspect of the present invention, there is provided an image processing device for image-processing an image based on an image signal representing the image, the signal-value range setting means for setting a predetermined signal value range of the image signal, and the image. Approximation means for approximating an average optical physical quantity in the predetermined signal value range set by the signal value range setting means based on recording gradation characteristics in the image recording means for recording on a recording medium and light source information when observing the image. And a gradation correction unit that corrects the gradation characteristics of the image signal so that the average optical physical quantity estimated by the estimation unit falls within a predetermined range.

According to a fifth aspect of the present invention, in the image processing apparatus according to the first or third aspect, the predetermined area and the predetermined range are set according to at least one of a subject and an image recording magnification related to the image signal. Characterized in that at least one of the predetermined area and the predetermined range changed by the changing means is used to make an approximation.

According to a sixth aspect of the present invention, in the image processing apparatus according to the second or fourth aspect, the predetermined signal value range and the predetermined signal value range are set in accordance with at least one of the feature of the histogram relating to the image signal and the image recording magnification. A changing means for changing at least one of the predetermined ranges, wherein the estimating means makes an approximation using at least one of the predetermined signal range and the predetermined range changed by the changing means. Characterize.

The invention according to claim 7 is the invention as defined in claims 1, 2 and
5. The image processing device according to any one of 5 and 6, wherein the optical physical quantity related to the average optical physical quantity is any one of transmission density, reflection density, light transmittance, light reflectance, or lightness. And

The invention according to claim 8 is the image processing apparatus according to any one of claims 3 to 6, characterized in that the optical physical quantity relating to the average optical physical quantity is an optical physical quantity of either luminance or illuminance. And

According to a ninth aspect of the present invention, in the image processing apparatus according to the eighth aspect, the optical physical quantity related to the average optical physical quantity is luminance, and the maximum luminance of the image at the time of observation is Lmax and the minimum luminance is Lmin. The predetermined range of the average luminance L when the entire image is set to the predetermined region or the predetermined signal value range is 0.05 <(L-Lmin) / (Lmax-Lmin) <0.2. And

According to a tenth aspect of the present invention, in the image processing apparatus according to the eighth aspect, the optical physical quantity relating to the average optical physical quantity is luminance, and the maximum luminance of the image at the time of observation is Lmax and the minimum luminance is Lmin. The predetermined range of the average luminance L when the subject area is the predetermined area or the predetermined signal value range is 0.1 <(L-Lmin) / (Lmax-Lmin) <0.3. To do.

The invention according to claim 11 is the image processing apparatus according to claim 8, wherein the optical physical quantity relating to the average optical physical quantity is illuminance, and the maximum illuminance of the image during observation is Emax and the minimum illuminance is Emin. The predetermined range of the average illuminance E when the entire image is set to the predetermined region or the predetermined signal value range is 0.05 <(E-Emin) / (Emax-Emin) <0.2. And

According to a twelfth aspect of the present invention, in the image processing apparatus according to the eighth aspect, the optical physical quantity related to the average optical physical quantity is illuminance, and the maximum illuminance of the image during observation is Emax and the minimum illuminance is Emin. The predetermined range of the average illuminance E when the subject area is the predetermined area or the predetermined signal value range is 0.1 <(E-Emin) / (Emax-Emin) <0.3. To do.

The invention according to claim 13 is the invention according to claims 3 to 12.
In the image processing device according to any one of the items 1 to 3, a light source information input unit for inputting the light source information is provided, and the estimation unit is
It is characterized in that the light source information is inputted into the light source information inputting means to make an approximate calculation.

The invention according to claim 14 is the invention according to claim 1,
The image processing apparatus according to any one of 5 to 7, further comprising a background area changing unit that changes a background area of the image signal based on a recording gradation characteristic in the image recording unit, At least one of them uses the image signal whose background area has been changed by the background area changing means.

The invention of claim 15 relates to claims 3 to 6,
In the image processing device according to any one of 8 to 13, a background area changing unit that changes a background area of the image signal based on recording gradation characteristics in the image recording apparatus and light source information when observing the image. At least one of the respective units of the image processing apparatus uses the image signal whose background area has been changed by the background area changing unit.

The invention according to claim 16 is defined by claims 1 to 15.
In the image processing device according to any of 1,
It is characterized by being a medical image.

The invention according to claim 17 is the invention according to claims 1 to 16.
The image processing apparatus according to any one of the above 1 to 3 is an image recording apparatus including an image recording unit that records an image signal whose gradation characteristic is corrected by the gradation correction unit on the image recording medium. To do.

According to the eighteenth aspect of the present invention, there is provided an image processing device for image-processing an image based on an image signal representing the image, wherein an area setting means for setting a predetermined area of the image signal and an image display surface are provided. Approximating means for approximating an average optical physical quantity in the predetermined area set by the area setting means, based on display gradation characteristics in the image display means for displaying and light source information when observing the image, and the approximating means. Gradation correction means for correcting the gradation characteristics of the image signal such that the average optical physical quantity estimated by the above is included in a predetermined range.

According to a nineteenth aspect of the present invention, there is provided an image processing device for image-processing an image based on an image signal representing the image, wherein a signal range setting means for setting a predetermined signal range of the image signal and an image display surface. Based on display gradation characteristics in the image display means displayed above and light source information when observing the image, an estimating means for approximating an average optical physical quantity in the predetermined signal value range set by the signal value range setting means, Gradation correction means for correcting the gradation characteristics of the image signal so that the average optical physical quantity estimated by the estimation means falls within a predetermined range.

According to a twentieth aspect of the present invention, in the image processing apparatus according to the eighteenth aspect, one of the predetermined area and the predetermined range is selected according to at least one of a subject and an image display magnification related to the image signal. It is characterized in that it comprises a changing means for changing at least one, and the estimating means makes an approximation using at least one of the predetermined region and the predetermined range changed by the changing means.

According to a twentieth aspect of the present invention, in the image processing apparatus according to the nineteenth aspect, the predetermined signal range and the predetermined range are determined in accordance with at least one of a feature of a histogram relating to the image signal and an image display magnification. Changing means for changing at least one of the predetermined signal value range and the predetermined range changed by the changing means. .

The invention described in claim 22 is,
1. The image processing apparatus according to any one of 1 above, wherein the optical physical quantity relating to the average optical physical quantity is an optical physical quantity of either luminance or illuminance.

According to a twenty-third aspect of the present invention, in the image processing apparatus according to the twenty-second aspect, the optical physical quantity related to the average optical physical quantity is luminance, and the maximum luminance of the image at the time of observation is Lmax and the minimum luminance is Lmin. The predetermined range of the average luminance L when the entire image is set to the predetermined region or the predetermined signal value range is 0.05 <(L-Lmin) / (Lmax-Lmin) <0.2. And

According to a twenty-fourth aspect of the present invention, in the image processing apparatus according to the twenty-second aspect, the optical physical quantity relating to the average optical physical quantity is luminance, and the maximum luminance of the image at the time of observation is Lmax and the minimum luminance is Lmin. The predetermined range of the average luminance L when the subject area is the predetermined area or the predetermined signal value range is 0.1 <(L-Lmin) / (Lmax-Lmin) <0.3. To do.

According to a twenty-fifth aspect of the present invention, in the image processing apparatus according to the twenty-second aspect, the optical physical quantity relating to the average optical physical quantity is illuminance, and the maximum illuminance of the image during observation is Emax and the minimum illuminance is Emin. The predetermined range of the average illuminance E when the entire image is set to the predetermined region or the predetermined signal value range is 0.05 <(E-Emin) / (Emax-Emin) <0.2. And

According to a twenty-sixth aspect of the present invention, in the image processing apparatus according to the twenty-second aspect, the optical physical quantity related to the average optical physical quantity is the illuminance, and the maximum illuminance of the image at the time of observation is Emax and the minimum illuminance is Emin. The predetermined range of the average illuminance E when the subject area is the predetermined area or the predetermined signal value range is 0.1 <(E-Emin) / (Emax-Emin) <0.3. To do.

The invention of claim 27 is the same as claims 18 to 2.
6. The image processing device according to any one of 6 above, further comprising light source information input means for inputting the light source information, wherein the estimating means makes an approximation using the light source information input by the light source information input means. .

The invention according to claim 28 is the invention according to claims 18 to 2.
7. The image processing device according to claim 7, further comprising a background area changing unit that changes a background area of the image signal based on recording gradation characteristics in the image recording apparatus and light source information when observing the image. At least one of the respective units of the image processing apparatus uses the image signal whose background area has been changed by the background area changing unit.

The invention according to claim 29 is the invention according to claims 18 to 2.
8. The image processing device according to any one of 8 to 8, wherein the image is a medical image.

The invention according to claim 30 is the invention according to claims 18 to 2.
9. The image display device according to any one of 9 above, further comprising image display means for displaying an image signal whose gradation characteristic is corrected by the gradation correction means on the image display surface. And

According to a thirty-first aspect of the present invention, there is provided an image processing method for image-processing an image based on an image signal representing the image, wherein a predetermined area of the image signal is set and the image is recorded on an image recording medium. On the basis of the recording gradation characteristic in, the average optical physical quantity in the set predetermined region is roughly estimated, and the gradation characteristic of the image signal is corrected so that the estimated average optical physical quantity is included in a predetermined range. , Is characterized.

According to a thirty-second aspect of the present invention, there is provided an image processing method for image-processing an image based on an image signal representing the image, wherein a predetermined signal range of the image signal is set, and the image is recorded on an image recording medium. Based on the recording gradation characteristic in recording, the average optical physical quantity in the set predetermined signal value range is roughly estimated, and the gradation characteristic of the image signal is set so that the estimated average optical physical quantity is included in a predetermined range. It is characterized in that it is corrected.

According to a thirty-third aspect of the present invention, there is provided an image processing method for image-processing an image based on an image signal representing the image, wherein a predetermined area of the image signal is set and the image is recorded on an image recording medium. Based on the recording gradation characteristics and the light source information when observing the image, the average optical physical quantity in the set predetermined area is roughly estimated, and the estimated average optical physical quantity is included in a predetermined range. In addition, the gradation characteristic of the image signal is corrected.

According to a thirty-fourth aspect of the present invention, there is provided an image processing method for image-processing an image based on an image signal representing the image, wherein a predetermined signal value range of the image signal is set, and the image is recorded on an image recording medium. Based on recording gradation characteristics in recording and light source information when observing the image, an average optical physical quantity in the set predetermined signal value range is roughly estimated, and the estimated average optical physical quantity is included in a predetermined range. The gradation characteristic of the image signal is corrected as described above.

The invention described in Item 35 is defined by Items 31-3.
4. The image processing method according to any one of 4 above, which is an image recording method for recording the image signal whose gradation characteristic has been corrected on the image recording medium.

A thirty-sixth aspect of the present invention is an image processing method for image-processing an image based on an image signal representing the image, wherein a predetermined area of the image signal is set and the image is displayed on the image display surface. On the basis of the display gradation characteristics and the light source information at the time of observing the image, the average optical physical quantity in the set predetermined area is roughly estimated, and the estimated average optical physical quantity is included in a predetermined range. In addition, the gradation characteristic of the image signal is corrected.

The thirty-seventh aspect of the present invention is an image processing method for image-processing an image based on an image signal representing the image, wherein a predetermined signal value range of the image signal is set, and the image is displayed on the image display surface. Based on display gradation characteristics in display and light source information when observing the image, an average optical physical quantity in the set predetermined signal value range is roughly estimated, and the estimated average optical physical quantity is included in a predetermined range. The gradation characteristic of the image signal is corrected as described above.

According to a thirty-eighth aspect of the present invention, in the image processing method according to any one of the thirty-sixth and thirty-seventh aspects, the image display method displays the image signal whose gradation characteristic is corrected on the image display surface. Is characterized by.

According to a thirty-ninth aspect of the invention, a function of setting a predetermined region of an image signal representing an image in a computer,
Based on recording gradation characteristics in image recording of an image on an image recording medium, a function of roughly estimating an average optical physical quantity in the set predetermined area, and the estimated average optical physical quantity being included in a predetermined range. And a function for correcting the gradation characteristic of the image signal, and a program for realizing the function.

According to a 40th aspect of the present invention, the setting is made on the basis of a function of setting a predetermined signal value range of an image signal representing an image in a computer and a recording gradation characteristic in recording an image on an image recording medium. And a function for approximating an average optical physical quantity in the predetermined signal value range, and a function for correcting the gradation characteristic of the image signal so that the estimated average optical physical quantity is included in a predetermined range. Is characterized in that.

According to a forty-first aspect of the invention, a function of setting a predetermined area of an image signal representing an image in a computer,
A function of estimating an average optical physical quantity in the set predetermined region based on recording gradation characteristics in image recording of an image on an image recording medium and light source information when observing the image; It is a program for realizing a function of correcting the gradation characteristic of the image signal so that the average optical physical quantity falls within a predetermined range.

According to a forty-second aspect of the present invention, a function of setting a predetermined signal value range of an image signal representing an image in a computer, a recording gradation characteristic in recording an image on an image recording medium, and observing the image Based on the light source information of
A function of approximating an average optical physical quantity in the set predetermined signal value range and a function of correcting the gradation characteristic of the image signal so that the approximated average optical physical quantity is included in a predetermined range are realized. It is a program for

The invention described in claim 43 is, in accordance with claims 39 to 4,
The program according to any one of 2 above is a program for causing the computer to realize a function of recording an image signal of which the gradation characteristic is corrected on the image recording medium.

According to a forty-fourth aspect of the invention, a function of setting a predetermined area of an image signal representing an image on a computer is provided.
Based on the display gradation characteristics in the display of the image on the image display surface and the light source information when observing the image, a function of estimating an average optical physical quantity in the set predetermined region, and the estimated It is a program for realizing a function of correcting the gradation characteristic of the image signal so that the average optical physical quantity falls within a predetermined range.

According to a forty-fifth aspect of the invention, a function of setting a predetermined signal value range of an image signal representing an image in a computer, a display gradation characteristic in displaying the image on the image display surface, and observing the image Based on the light source information, a function of approximating an average optical physical quantity in the set predetermined signal value range, and a gradation characteristic of the image signal so that the estimated average optical physical quantity is included in a predetermined range. It is a program for realizing the correction function and.

According to a forty-sixth aspect of the present invention, in the program according to the forty-fourth aspect or the forty-fifth aspect, the computer is made to realize a function of displaying the image signal whose gradation characteristic is corrected on the image display surface. It is a program for

According to a forty-seventh aspect of the present invention, the function of setting a predetermined area of an image signal representing an image in a computer is provided.
Based on recording gradation characteristics in image recording of an image on an image recording medium, a function of roughly estimating an average optical physical quantity in the set predetermined area, and the estimated average optical physical quantity being included in a predetermined range. And a computer-readable recording medium in which a program for realizing the function of correcting the gradation characteristic of the image signal is recorded.

According to the invention described in claim 1, 31, 39 or 47, when the image is observed under a constant environment, the glare or darkness for the observer is prevented in the gradation region corresponding to the predetermined region. It is possible to obtain a recorded image having proper gradation characteristics that is not felt.

According to a forty-eighth aspect of the present invention, the setting is made on the basis of a function of setting a predetermined signal value range of an image signal representing an image in a computer and a recording gradation characteristic in recording an image on an image recording medium. And a function for approximating an average optical physical quantity in the predetermined signal value range, and a function for correcting the gradation characteristic of the image signal so that the estimated average optical physical quantity is included in a predetermined range. Is a computer-readable recording medium on which is recorded.

According to the invention described in claims 2, 32, 40 or 48, when observing an image under a constant environment, in the gradation area corresponding to a predetermined signal value range, glare or darkness is observed for the observer. It is possible to obtain a recorded image having proper gradation characteristics without feeling a sharpness.

According to a forty-ninth aspect of the invention, a function of setting a predetermined area of an image signal representing an image in a computer,
A function of estimating an average optical physical quantity in the set predetermined region based on recording gradation characteristics in image recording of an image on an image recording medium and light source information when observing the image; A computer-readable recording medium recording a program for realizing the function of correcting the gradation characteristic of the image signal so that the average optical physical quantity falls within a predetermined range.

According to the invention described in claim 3, 33, 41 or 49, it is appropriate that the observer does not feel glare or darkness in the gradation region corresponding to the predetermined region regardless of the change of the observation environment. A recorded image having various gradation characteristics can be obtained.

According to a fiftieth aspect of the present invention, a function of setting a predetermined signal value range of an image signal representing an image in a computer, a recording gradation characteristic in recording an image on an image recording medium, and observing the image Based on the light source information of
A function of approximating an average optical physical quantity in the set predetermined signal value range and a function of correcting the gradation characteristic of the image signal so that the approximated average optical physical quantity is included in a predetermined range are realized. It is a computer-readable recording medium in which a program for recording is recorded.

According to the invention described in claim 4, 34, 42 or 50, the observer feels glare or darkness in the gradation region corresponding to the predetermined signal value range regardless of the change of the observation environment. It is possible to obtain a recorded image having appropriate gradation characteristics.

The invention described in claim 51 is, in accordance with claims 47 to 5,
0. A recording medium according to any one of 0, which is a computer-readable recording medium recording a program for causing the computer to realize a function of recording an image signal of which the gradation characteristic is corrected on the image recording medium. It is characterized by being.

According to the seventeenth, thirty-fifth, thirty-third, or fifty-first aspect of the invention, it is possible to record a recorded image having appropriate gradation characteristics without causing the observer to feel glare or darkness.

According to a fifty-second aspect of the present invention, a function of setting a predetermined area of an image signal representing an image in a computer,
Based on the display gradation characteristics in the display of the image on the image display surface and the light source information when observing the image, a function of estimating an average optical physical quantity in the set predetermined region, and the estimated A computer-readable recording medium recording a program for realizing the function of correcting the gradation characteristic of the image signal so that the average optical physical quantity falls within a predetermined range.

According to the eighteenth, thirty-sixth, forty-fourth and twenty-fifth aspects of the present invention, it is appropriate that the observer does not feel glare or darkness in the gradation region corresponding to the predetermined region regardless of the change of the observation environment. A display image having various gradation characteristics can be obtained.

According to a fifty-third aspect of the present invention, a function of setting a predetermined signal value range of an image signal representing an image in a computer, a display gradation characteristic in displaying the image on an image display surface, and observing the image Based on the light source information, a function of approximating an average optical physical quantity in the set predetermined signal value range, and a gradation characteristic of the image signal so that the estimated average optical physical quantity is included in a predetermined range. It is a computer-readable recording medium in which a program for realizing the correcting function and a program for realizing the correcting function are recorded.

According to the invention as set forth in claim 19, 37, 45 or 53, it is possible to prevent the observer from feeling glare or darkness in the gradation region corresponding to the predetermined signal value range regardless of the change of the observation environment. It is possible to obtain a display image having proper gradation characteristics.

According to a 54th aspect of the invention, in the recording medium according to the 52nd or 53th aspect, the computer is provided with a function of displaying an image signal whose gradation characteristic is corrected on the image display surface. It is a computer-readable recording medium in which a program for causing the program is recorded.

According to the invention as set forth in claim 30, 38, 46 or 54, it is possible to display a display image having proper gradation characteristics without causing the observer to feel glare or darkness.

According to the fifth aspect of the present invention, when the predetermined range is changed according to the subject of the image signal, the tendency of the histogram can be easily analogized to easily perform the gradation correction. When changing the predetermined range according to the magnification,
It is possible to obtain a recorded image having proper gradation characteristics in which the characteristics of human eyes are taken into consideration, without causing the observer to feel glare or darkness by roughly estimating the visual field range during observation.

According to the sixth aspect of the invention, when the predetermined range is changed according to the characteristics of the histogram of the image signal,
Even with the same subject, gradation correction can be performed according to variations due to differences in subjects, and when changing the predetermined range according to the image recording magnification, the visual field range at the time of observation is roughly estimated to reduce glare to the observer. Without feeling the darkness,
It is possible to obtain a recorded image having proper gradation characteristics in which the characteristics of human eyes are taken into consideration.

According to the seventh aspect of the invention, as the optical physical quantity, a universal physical value such as transmission density, reflection density, light transmittance, light reflectance, or lightness is used to obtain a gradation with high reproducibility. It is possible to perform correction, and it is possible to obtain a recorded image that always has appropriate gradation characteristics without causing the observer to feel glare or darkness.

According to the eighth aspect of the present invention, by using a universal physical value of luminance or illuminance as the optical physical quantity, gradation correction with high reproducibility can be performed, and glare or darkness can be achieved for the observer. It is possible to always obtain a recorded image having proper gradation characteristics without feeling a sharpness.

According to the ninth aspect of the present invention, by setting the average luminance L which makes the entire image a predetermined region or a predetermined signal value range within a predetermined range, the observer does not feel glare or darkness. Thus, it is possible to obtain a recorded image having appropriate gradation characteristics.

According to the tenth aspect of the present invention, by setting the average luminance L that sets the subject region as the predetermined region or the predetermined signal value range within the predetermined range, the observer does not feel glare or darkness. Thus, it is possible to obtain a recorded image having appropriate gradation characteristics.

According to the eleventh aspect of the present invention, the average illuminance E which sets the entire image as the predetermined region or the predetermined signal value range is set within the predetermined range, so that the observer does not feel glare or darkness. Thus, it is possible to obtain a recorded image having appropriate gradation characteristics.

According to the twelfth aspect of the present invention, by setting the average illuminance E that sets the subject region as the predetermined region or the predetermined signal value range within the predetermined range, the observer does not feel glare or darkness. Thus, it is possible to obtain a recorded image having appropriate gradation characteristics.

According to the thirteenth aspect of the present invention, since the light source information according to the observation environment can be input, the gradation characteristic according to the observation environment does not cause the observer to feel glare or darkness. A recorded image can be obtained.

According to the invention of claim 14 or 15,
Based on the changed and adjusted background area, it is possible to obtain a recorded image having an appropriate gradation characteristic without causing the observer to feel glare or darkness.

According to the sixteenth aspect of the present invention, it is possible to obtain a recorded medical image having appropriate gradation characteristics without causing the observer to feel glare or darkness.

According to the twentieth aspect of the invention, when the predetermined range is changed according to the subject of the image signal, the tendency of the histogram can be easily analogized to easily perform the gradation correction. When the predetermined range is changed according to the magnification, the visual field range at the time of observation is roughly estimated, and the display has proper gradation characteristics that does not cause the observer to feel glare or darkness and takes into account the characteristics of human eyes. Images can be obtained.

According to the twenty-first aspect of the invention, when the predetermined range is changed according to the characteristics of the histogram of the image signal, gradation correction can be performed according to variations due to differences between subjects even for the same subject. Yes, when changing the predetermined range according to the image display magnification, the visual field range at the time of observation is roughly estimated, and the appropriate gradation that does not feel glare or darkness for the observer, taking into account the characteristics of human eyes A display image having characteristics can be obtained.

According to the twenty-second aspect of the invention, by using a universal physical value of luminance or illuminance as the optical physical quantity, it is possible to perform gradation correction with high reproducibility, and the glare and the darkness to the observer. It is possible to obtain a display image having an appropriate gradation characteristic without feeling a sharpness.

According to the twenty-third aspect of the present invention, by setting the average luminance L that makes the entire image a predetermined region or a predetermined signal value range within a predetermined range, the observer does not feel glare or darkness. As a result, a display image having appropriate gradation characteristics can be obtained.

According to the twenty-fourth aspect of the present invention, by setting the average luminance L that sets the subject region as the predetermined region or the predetermined signal value range within the predetermined range, the observer does not feel glare or darkness. As a result, a display image having appropriate gradation characteristics can be obtained.

According to the twenty-fifth aspect of the present invention, by setting the average illuminance E which makes the entire image a predetermined region or a predetermined signal value range within a predetermined range, the observer does not feel glare or darkness. As a result, a display image having appropriate gradation characteristics can be obtained.

According to the twenty-sixth aspect of the present invention, by setting the average illuminance E which makes the subject region a predetermined region or a predetermined signal value range within a predetermined range, the observer does not feel glare or darkness. As a result, a display image having appropriate gradation characteristics can be obtained.

According to the twenty-seventh aspect of the present invention, since the light source information according to the observation environment can be input, the gradation characteristic according to the observation environment does not cause glare or darkness to the observer. A display image can be obtained.

According to the twenty-eighth aspect of the present invention, it is possible to obtain a display image having a proper gradation characteristic without causing the observer to feel glare or darkness based on the changed and adjusted background area.

According to the twenty-ninth aspect of the present invention, it is possible to obtain a display medical image having proper gradation characteristics without causing the observer to feel glare or darkness.

[0097]

BEST MODE FOR CARRYING OUT THE INVENTION The first embodiment and the second embodiment of the present invention will be described below in order with reference to the accompanying drawings.

(First Embodiment) FIG. 1 shows the present embodiment.
~ It demonstrates with reference to FIG. The present embodiment has a configuration in which an image recording device is used as an example of a device to which the gradation converting means is applied. First, the device features of the present embodiment will be described with reference to FIGS. FIG. 1 shows an image recording apparatus 10
FIG. 2 is a block diagram showing a functional block relating to image recording of 0, and FIG. 2 is a diagram showing an internal configuration of the image processing unit 110 of FIG. 1.

As shown in FIG. 1, a medical image recording apparatus 100 for recording and outputting a medical image on an image recording medium α includes an image processing section 110, a control section 120, a recording head unit 130, and a conveying roller 140. And the recording head transport unit 1
And 50.

The image processing section 110 receives an original image signal from an external medical imaging device or storage device and executes necessary image processing. As the image processing, a gradation correction processing for correcting the gradation characteristics of the recorded image to be optimal depending on the state of the image recording apparatus 100, the state of the image recording medium α, or the observation environment of the observer is performed. To do. Further, the input of the original image signal from the outside may be via various networks. The image signal processed by the image processing unit 110 is transmitted to the control unit 120. The image processing unit 110 has the functions of an area setting unit, an approximate setting unit, a gradation correction unit, a signal range setting unit, and a changing unit described in the claims.

The control section 120 controls each section of the image recording apparatus 100, controls the gradation correction processing under the control of the image processing section 110, and controls the recording head unit 130, the recording head conveying section 140 and the conveying roller 150. By control
Recording of the image after gradation correction on the image recording medium α is controlled.

The recording head unit 130 records an image by ejecting ink. The recording head unit 130 includes four types of black inks K1 to K4 having different densities.
The print heads 131 to 134 respectively corresponding to the above are provided in a line, and ink is ejected based on the print head control signal corresponding to the image signal received from the control unit 120. The recording heads 131 to 134 may be integrated or may be individually provided.

As described above, by forming an image using the four different kinds of black ink in the recording head unit 130, an image of higher image quality and multiple gradations is obtained as an image for medical diagnosis or reference. Can be obtained.
In order to create a medical image that requires multiple tones, it is desirable to use at least 3 to 4 types of black ink having different densities. In order to eliminate the streak unevenness peculiar to the image recording apparatus, it is necessary to uniformly eject the ink from the recording heads 131 to 134 onto the recording surface of the image recording medium α, which results in an increase in the ink absorption amount. Accordingly, the ink image receiving layer of the image recording medium α must be thickened. If the ink image receiving layer is thick, the surface of the recording surface is likely to be scratched, and the image recording medium α must be handled more carefully.

The ink ejecting mechanism of the recording head unit 130 may use a piezo effect or an ink jet system using the force of bubble formation that occurs when ink is instantly heated. About 64 to 512 nozzle holes are suitable for an inkjet used for medical images.
The flight speed of the ink droplet is preferably 2 to 20 [m / s],
The amount of ink ejected from one drop is preferably 1 to 50 [picoliter].

The carrying roller 140 carries the image recording medium α in the main scanning direction based on the recording medium carrying signal received from the control unit 120. The recording head transport unit 150, based on the head transport signal received from the control unit 120, in the sub-scanning direction orthogonal to the main scanning direction of the image recording medium α,
The recording head unit 130 is moved.

Therefore, the conveying roller 140 conveys the image recording medium α in the main operating direction based on the recording medium conveying signal, and the recording head conveying section 150 moves the recording head unit 130 in the sub-scanning direction based on the head conveying signal. Move
The recording heads 131 to 134 form and record an image on the image recording medium α based on the recording head control signal.

As shown in FIG. 2, inside the image processing unit 110, an average optical physical quantity estimating unit 1 for estimating the average optical physical quantity from the input image signal and the data of the current gradation characteristics thereof.
11 and a γ-LUT (look-up table) of the average optical physical quantity estimated by the average optical physical quantity estimating unit 111 and the original gradation characteristic (gradation characteristic suitable for a certain observation environment).
And a gradation correction unit 112 that outputs a γ-LUT having a corrected gradation characteristic for performing gradation correction on the image signal using.

The gradation correction unit 112 stores in the gradation information storage unit 112a that stores the average optical physical quantity that is an ideal value, and the average optical physical quantity and gradation information storage unit 112a that is estimated by the average optical physical quantity estimation unit 111. And a gradation correction calculation unit 112b that calculates the corrected γ-LUT of the gradation characteristics by using the difference between the average optical physical quantities of the ideal values and the γ-LUT of the original gradation characteristics.

Here, the γ-LUT will be described. γ-L
UT is an input / output characteristic obtained via an image output device (image recording device, image display device). In particular,
The input object is an “image signal value”, and the output object is an input / output characteristic that is a “physical quantity (psychological physical quantity)”. Generally, the output matter in the transmission image is transmission density, and the output matter in the reflection image is lightness.

A mode of holding information about input / output characteristics (γ-
The LUT holding form) may be software or hardware, and the holding form may be a table or a function. When the image signal processing (image processing) is performed a plurality of times, the image signal value input first corresponds to the input object in the image output device.

For example, when the image output apparatus has only one fixed LUT (hereinafter referred to as the first LUT), another LUT (hereinafter, referred to as the first LUT) is operated before the first LUT is operated.
By performing image signal processing in advance using a second LUT) and then acting on the first LUT, gradation characteristic conversion can be substantially performed.

In the case where the image output device includes a signal value converting means that operates the second LUT, the γ-LUT in this image output device is the second LUT for the original image signal, It is an input / output characteristic obtained as a result of sequentially operating the first LUT.

On the other hand, when the image output device does not include the signal value converting means for operating the second LUT, the γ-LUT in the image output device is the same as the original image signal. It is an input / output characteristic obtained as a result of applying the LUT of 1.

Here, the optical density as the image density will be described. The optical density D is defined as D _T = −log ₁₀ T or D _R = −log ₁₀ R with respect to the optical density D _T of a transmission image and the optical density D _R of a reflection image. T and R are light transmittance and light reflectance, respectively. D _T and D _R are the transmission density,
It is called the reflection density.

In each of the embodiments of the present invention, the optical density can be applied to both the transmission density and the reflection density. Therefore, unless otherwise specified, the density represents either the transmission density or the reflection density. And The density of the image is the density of the entire image including the density of the recording material attached to the image recording medium α and the density of the image recording medium α itself. Further, for example, in the embodiment of the present invention, the concentration is measured using PDA-65 (manufactured by Konica Corporation).

The lightness in the embodiment of the present invention is the lightness in the CIE-LAB color system recommended by CIE1976 and is a kind of psychophysical quantity that well expresses the degree of light and shade. The brightness can be obtained from the above-mentioned light transmittance and light reflectance.

The brightness in the embodiments of the present invention is the brightness intensity per unit area projected in a given direction, and the unit is [cd / m ² ]. The luminance meter used in the measurement of the present invention was BM-9 (manufactured by Topcon Corporation), and the measurement angle was 1 °.

Further, the illuminance in the embodiment of the present invention is an incident light flux per unit area, and the unit is [l
x]. For example, the illuminometer used for measurement is IM
-5M (manufactured by Topcon Corporation).

The image recording medium α is characterized in that a substantially monochrome image is drawn with the liquid ink, and is practically 1
A sheet-like shape having an area of 5 × 10 [cm ² ] or more, square-shaped notches in the square shape, and a void-type ink absorption on at least one surface made of a colorless or blue-colored resin having a thickness of 75 to 250 μm A recording medium having at least one layer is preferable.

If the thickness of the image recording medium α is less than 75 μm, the sheet hangs down and is difficult to handle.
If it is thicker than μm, it has a drawback that it is considerably heavy when carrying it in a stack. Further, since the X-ray film used conventionally is colorless and transparent or colored blue, it is preferable to use a support made of a colorless or blue colored resin as the image recording medium α so that the user does not feel uncomfortable. preferable. This blue coloring is for preventing the eyes from being dazzled by excessive transmitted light from the non-image portion, and also has an effect of making a black image look more preferable.

The image recording medium α has at least one void type ink absorbing layer on at least one side, and the surface not having the ink absorbing layer has mechanical transportability of the printer and the films do not stick to each other when stacked. It is a preferred embodiment to have a matte layer to prevent them from sticking to each other. Further, the image recording medium α can be obtained by increasing the porosity of the ink absorbing layer as much as possible, and matting the surface of the ink absorbing layer to generate irregularities.

Further, in the image recording medium α, a white metal oxide such as titanium oxide or lead oxide can be added to the ink absorbing layer or a layer thereunder. Further, the image recording medium α is provided with a layer on the side opposite to the side having the ink absorbing layer of the support, and a metal oxide such as titanium oxide or lead oxide is dispersed therein, and the ink absorbing layer is supported. It can also be provided on both sides of the body.

As the material of the sheet-shaped support of the image recording medium α, polyesters such as polyethylene terephthalate, cellulose esters such as nitrocellulose and cellulose acetate, and polysulfone, polyimide, polycarbonate and the like can be used. Also,
It is preferable that the sheet-shaped support is also colored blue. Further, since the ink absorption layer is provided on at least one surface of the sheet-shaped support, the sheet-shaped support is subjected to corona discharge treatment, flame treatment, ultraviolet irradiation treatment, etc. to improve the adhesiveness of the ink absorption layer. I need to keep it.

The ink absorbing layer has a porosity of 40 to 9
It is preferably a layer of three-dimensional network with 0%. This three-dimensional network structure is formed from silica fine particles or organic fine particles having an average particle diameter of 20 nm or less and a water-soluble resin, and the mass ratio of silica fine particles or organic fine particles to the water-soluble resin is 1.2: 1 to 12 It is preferably in the range of 0.1. In this case, the pores forming the voids of the three-dimensional network structure have an average diameter of 5 to 40 nm, and the pores forming the voids have a pore volume of 0.3 to 1 [ml / g].

The silica particles are inorganic silicic acid, and have 2 to 3 silalol groups per surface 1 [nm ² ] thereof,
Three-dimensional network structure of silica particles aggregated 10-100
It preferably consists of chains formed by the linkage of secondary particles having a particle size of nm. As the fine particles, colloidal silica, calcium silicate, zeolite, kaolinite, halosite, muscovite, talc, calcium carbonate, calcium sulfate, aluminum oxide and the like can be used.

Polyvinyl alcohol is preferably used as the water-soluble resin, but examples of other water-soluble resins include gelatin and others disclosed in JP-A-7-276789. Further, the ink absorption layer preferably has a specific surface area of 50 to 500 [m ² / g]. Further, in order to prevent the sheets from sticking to each other when the sheet-shaped image recording media α are superposed, it is preferable to disperse matte particles having an average particle diameter of 5 to 100 μm on the surface. Further, a surfactant can be added as an antistatic agent for the surface.

On the surface without the ink absorbing layer, gelatin or a water-soluble resin can be applied to prevent curling. In addition, antistatic processing, mat processing for preventing sticking, coloring with blue, and metal oxide particles such as titanium oxide particles and zinc oxide particles can be added to this surface.

When an observer interprets a recorded image recorded on the image recording medium α, many films are often handled in a short time. At this time, since the front and back of the image can be seen at a glance, it is preferable that the front and back can be easily distinguished by, for example, providing a notch on the right shoulder of the image recording medium α.

The recording head unit 130 can form an image by ejecting a plurality of inks having different color tones by using ink jet recording heads 131 to 134 which are means for ejecting a plurality of inks independently. Further, it is possible to form an image by ejecting a plurality of single color inks having different densities by using the ink jet recording heads 131 to 134 which are means for ejecting a plurality of inks independently.

That is, the recording heads 131 to 134 are
The above inks may be used alone or in combination, and different ink jet heads may be used for each ink density of a single color ink having a plurality of density levels, for example, two, three, and four levels. For example, in the case of monochrome image formation, K1, K2, K3,
K4 ink can be used. If a color image is to be formed, the inkjet head is used for each ink of yellow (Y), magenta (M), cyan (C) and black (K).

As the color material of the ink dissolved or dispersed in water, any of pigments, water-soluble dyes and disperse dyes may be used. Conventionally known organic and inorganic pigments can be used as the pigment. For example, azo pigments such as azo lakes, insoluble azo pigments, condensed azo pigments, chelate azo pigments, phthalocyanine pigments, perylene and perylene pigments,
Anthraquinone pigments, quinacridone pigments, dioxazine pigments, thioindigo pigments, isoindolinone pigments, polycyclic pigments such as quinophthaloni pigments, basic dye type lakes, dye lakes such as acid dye type lakes, nitro pigments,
Examples include nitroso pigments, aniline black, organic pigments such as daylight fluorescent pigments, and inorganic pigments such as carbon black.

As the method for dispersing the pigment, various types such as a ball mill, a sand mill, an attritor, a roll mill, an agitator, a Henschel mixer, a colloid mill, an ultrasonic homogenizer, a pearl mill, a wet jet mill and a paint shaker can be used. It is also possible to add a dispersant when dispersing the pigment. As the dispersant, an anionic surfactant, a nonionic surfactant,
Alternatively, a polymer dispersant or the like may be used.

As the ink, a black ink can be prepared by selecting an appropriate pigment or using a known combination of dyes or a single kind of dye. Examples of the water-soluble dyes include acid dyes and basic dyes reactive dyes, and examples of the water-soluble black dyes include CI (color index) direct black 9, 17, 19, 2
2, 32, 51, 56, 62, 69, 77, 80, 9
1, 94, 97, 108, 112, 113, 114, 1
17, 118, 121, 122, 125, 132, 14
6, 154, 166, 168, 173, 199 and the like.

In addition, when a pigment is used, for example, carbon black is used as the pigment, ethylene glycols,
When a surfactant or an antiseptic agent is mixed, a water-soluble black ink that is liquid at room temperature can be obtained. Similarly, when using a dye, Direct Black 19 (DirectBlac)
k19), Direct Black 159, Surfer Black 1 (Surfer Black 1), Acid Black 2 (Acid Black 2), CI Food Black 2 and the like are prepared by adding a solution such as ethylene glycol, glycerin, a surfactant and a preservative. A water-soluble black ink that is liquid at room temperature is obtained. The direct black 19 (blue ink) is used for adjusting the color tone by mixing an appropriate amount.

The inks used for the recording heads 131 to 134 cover a wide density area while combining the inks having different densities and color tones and subtly changing the color tones according to the density changes of the image. Is preferable as the image forming method.

When inks of different color tones are used, Acid Blue 9 (Acid Blue) is used as a coloring material.
9), Acid Red 52 and 94, Acid Yellow 23 (Acid Yellow)
23), Direct Yellow 86 (Direct Ye)
low 86) and 142 are used. In addition, it is preferable to use the ink disclosed in, for example, JP-A 2000-129182.

Examples of the water-soluble organic solvent used in the ink include alcohols (eg, methanol, ethanol, propanol, isopropanol, butanol, isobutanol, secondary butanol, tertiary butanol, pentanol, hexanol, cyclohexanol). , Benzyl alcohol, etc.), polyhydric alcohols (eg, ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, polypropylene glycol, butylene glycol,
Hexanediol, pentanediol, glycerin, hexanetriol, thiodiglycol, etc.), polyhydric alcohol ethers (eg, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether,
Ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monobutyl ether, ethylene glycol monomethyl ether acetate, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, triethylene glycol Monobutyl ether, ethylene glycol monophenyl ether, propylene glycol monophenyl ether, etc.),
Amines (for example, ethanolamine, diethanolamine, triethanolamine, N-methyldiethanolamine, N-ethyldiethanolamine, morpholine,
N-ethylmorpholine, ethylenediamine, diethylenediamine, triethylenetetramine, tetraethylenepentamine, polyethyleneimine, pentamethyldiethylenetriamine, tetramethylpropylenediamine, etc.),
Amides (eg, formamide, N, N-dimethylformamide, N, N-dimethylacetamide, etc.), heterocycles (eg, 2-pyrrolidone, N-methyl-2-pyrrolidone, cyclohexylpyrrolidone, 2-oxazolidone, 1 , 3-dimethyl-2-imidazolidinone, etc., sulfoxides (eg, dimethyl sulfoxide etc.), sulfones (eg, sulfolane etc.), urea, acetonitrile, acetone and the like.

If desired, a surfactant may be added to the ink. As the surfactant preferably used in the ink, dialkyl sulfosuccinates,
Anionic surfactants such as alkylnaphthalene sulfonates and fatty acid salts, polyoxyethylene alkyl ethers, polyoxyethylene alkyl allyl ethers, acetylene glycols, nonionic interfaces such as polyoxyethylene / polyoxypropylene block copolymers Examples of the surfactant include cationic surfactants such as alkylamine salts and quaternary ammonium salts.

In addition to the above, the ink includes an antiseptic agent, an antifungal agent, and
It is also possible to add a pH adjusting agent, a viscosity adjusting agent and the like, if necessary.

Now, referring to FIG. 3, the image recording medium α
The relationship between the illumination condition and the brightness near the image surface in the observation of the image by the observer will be described. FIG. 3 is a diagram showing the relationship between the illumination condition and the brightness near the image surface.
FIG. 4 is a diagram showing a main observation mode when observing a transmission image α1, and FIG. 9B shows the same observation mode as that in FIG. It is a figure which shows a low observation form, (c) is a figure which shows the same observation form as FIG.
(D) is a figure which shows the main observation forms at the time of observing a reflection image (alpha) 4.

First, as shown in FIG. 3A, in the case of the main observation mode in observing the transmission image α1, the transmission image α1 is arranged on the diffusion plate 3 on the light box 2 which is the light source, and the observation is performed. The person 4 observes the transmitted image α1 while maintaining an appropriate observation distance. When light is incident on the retina of the eye of the observer 4, the observer 4 perceives a contrast difference in the amount of transmitted or reflected light in the transmitted image α1, so that the observer 4 can obtain information regarding the transmitted image α1 (specifically, shape / brightness). You can get

In observing the transmitted image α1, two kinds of light, that is, auxiliary light from the light box 2 and ambient light such as illumination and natural light have a great influence on the image observation. It is preferable that the light source of the light box 2 is strong in order to improve the diagnostic ability of the image, and 1000 [cd / m ² ] in a typical light box ² .
It has a degree of brightness. On the other hand, ambient light turns off the illumination and
As it is reported that it is suitable for diagnosis when observing an image at [lx] or less, the illuminance (luminance) is normally lowered and the contribution is small.

Next, as shown in FIG.
Although the observation form is the same as in (a), the transmitted image α
In the case of the observation mode in which the image density in 2 is low overall, the image density in the transmission image α2 is low, so the amount of light transmitted from the light box 2 increases and the amount of light reaching the retina of the eyes of the observer 4 increases. The observer 4 feels glare when observing the transmission image α2.

Next, as shown in FIG.
Although the observation form is the same as in (a), the transmitted image α
In the case of an observation mode in which the image density in 3 is high overall, the image density in the transmission image α3 is high, so the amount of light transmitted from the light box 2 decreases and the amount of light reaching the retina of the eye of the observer 4 decreases. The observer 4 feels darkness when observing the transmission image α3.

Next, as shown in FIG. 3D, in the case of the main observation mode in observing the reflection image α4, as shown in FIG.
Unlike the transmission images α1 to α3 in (a) to (c), there is no auxiliary light source from the back of the image, and the observer 4 observes the reflection image α4 only with ambient light such as illumination light or natural light.

Similar to the case of observing the transmission images α1 to α3, when the image density in the reflection image α4 is higher than the appropriate density, the observer 4 feels bright when observing the reflection image α4, and the image density is lower than the appropriate density. When it is low, the observer 4 may feel dark when observing the reflection image α4. As described above, although there are various variations depending on the transmission images α1 to α3, the reflection image α4, the observer 4, and the like, it can be said that there is a gradation characteristic suitable for the observation environment during image observation.

For the transmitted image, the relationship between the luminance L and the optical density D is expressed by the equation L = La + Lo · 10 ^−D using the simplest model equation. Here, Lo is the luminance of the light box without the presented recording medium, and La is the luminance contributing factor due to the ambient illuminance reflected from the recording medium. Typical values of the parameters are Lo = 2000 [cd / m ² ] and La = 10 [cd / m ² ].

For the reflection image, the relationship between the luminance L and the optical density D is represented by the equation L = Lo · 10 ^−D using the simplest model equation. Where Lo is the maximum brightness obtained from the diffuse reflection of the existing illumination. Typical values for parameters are
Lo = 150 [cd / m ² ].

Here, with reference to FIG. 4, the relationship between the observation distance and the luminance in the vicinity of the observer in observing the image of the observer will be described. FIG. 4 is a diagram showing the relationship between the observation distance and the brightness in the vicinity of the observer, and FIG. 4A is a diagram showing a case where the image observation distance is d1 and the radius of the visible range is r1 when observing a transmission image. , (B) are diagrams showing a case where the observation distance is d2 and the radius of the visible range is r2 when observing the transmission image,
(C) is a diagram showing a case where an observation distance is d1 and a radius of a visible range is r1 when observing a reflection image.

When observing the transmitted image α5 in FIG. 4A, the image observation distance is d1 and the radius of the visible range is r1. The observation distance when observing the transmission image α5 in FIG.
2. The radius of the visible range is r2. Since the visible range of the observer 4 depends on the viewing angle, d1 / r1 = d2 / r
2 = constant.

In the case of FIG. 4A, the output size of the image to be observed is small and the observation distance is short, and the amount of light incident on the retina of the eye of the observer 4 from the transmitted light increases. May feel dazzling. Also, FIG.
In the case of (a), since the output size of the image to be observed is large and the observation distance is long, and the amount of light incident on the retina of the observer 4 from the transmitted light increases, the observer 4 may feel dark. Since the amount of light from the transmissive light source 2 is substantially inversely proportional to the distance from the light source 2, assuming that the brightness near the viewer 4 is I / (d0 + d1) in the case of FIG.
In the case of (b), the brightness near the viewer 4 is approximately I /
It is represented by (d0 + d2).

Further, the above-mentioned relationship of the luminance holds in the reflection image α6 shown in FIG. 4C. However, since the main light source 2A in the reflected image α6 is the illumination light, the distance between the illumination light source 2A and the surface of the image α6 is shown in FIG.
This corresponds to d0 in (a). However, the transparent image α5
In contrast, d is 0 to 10 cm, and d is 0 to several meters in the reflection image α6. Therefore, when observing the reflection image α6, the brightness in the vicinity of the observer 4 is hardly influenced by the observation distance.

From the above, in order to obtain a gradation characteristic suitable for an observer when observing an image, it is preferable to set the brightness in the vicinity of the observer within a predetermined range. However, since it is difficult to constantly measure and manage the brightness near the observer, it is more practical to correct the gradation so that the optical physical quantity that may be related to the brightness near the observer falls within a predetermined range. . Note that the optical physical quantity refers to all physical quantities that can be optically measured, such as transmission density, reflection density, light transmittance, light reflectance, brightness, or illuminance, which is strictly different from the physical quantity, but psychological. The lightness called physical quantity is also included.

Next, the operation of the image recording apparatus 100 will be described with reference to FIGS. First, the flow of operations of the image recording apparatus 100 will be described with reference to FIG. FIG. 5 is a diagram showing the gradation correction processing, (a) is a flowchart showing the first gradation correction processing, and (b) is a flowchart showing the second gradation correction processing. In this embodiment mode, FIG. 5A is used.

First, with reference to FIG. 5A, the first gradation correction processing for gradation-processing a photographed medical image will be described. First, the control unit 120 of the image recording apparatus 100 reads and executes a first gradation correction processing program stored in advance in a storage unit (not shown), triggered by input of an original image signal of a captured image from the outside. By doing so, the first gradation correction processing is started.

The flowchart of FIG. 5 shows the image recording apparatus 1
This is for explaining the processing for causing the computer configuring 00 to realize each function. This processing will be described by taking an example in which the control unit 120 as a computer stores in the storage unit in the form of a readable program code, but it is not necessary to store all the functions in the storage unit, and if necessary, It may be realized by receiving a part or all of it via a network.

The operation is performed by operating the various devices so as to realize the respective functions of the present embodiment, with respect to the computer (for example, CPU or MPU) in the apparatus or system connected to the various devices. This is a case where it is implemented by supplying a program code for realizing each function and operating the various devices according to a program stored in a computer in the apparatus or system, which is included in the present embodiment. There is no end.

In this case, the program code itself of the software realizes the function of the present embodiment, and the program code itself and means for supplying the program, for example, such program code The recorded recording medium constitutes the present embodiment. As the recording medium on which the program code is recorded, for example, a flexible disk, a hard disk, an optical disk, a magneto-optical disk, a CD-ROM, a DVD, a magnetic tape non-volatile memory card, a ROM, or the like can be used.

Moreover, not only the functions of the present embodiment are realized by executing the supplied program code by the computer, but also the OS (operating system) or other OS in which the program code is operating in the computer. Needless to say, the program code is included in this embodiment even when the functions such as application software are jointly realized.

Further, after the supplied program code is stored in the memory provided in the function expansion board of the computer or the function expansion unit connected to the computer, the function expansion board or function expansion unit is instructed based on the program code instruction. It goes without saying that the present embodiment also includes a case where the CPU or the like included in the above performs some or all of the actual processing and each function is realized by the performed processing. The above description of the program and the recording medium recording the program is the same in the second to sixth embodiments.

First, the control unit 120 of the image recording apparatus 100.
Causes the image processing unit 110 to extract a predetermined region of the input image signal (step S1). Here, step S
1 will be specifically described with reference to FIGS. 6 (a) and 6 (b).
6A and 6B are diagrams showing a predetermined area and a predetermined signal value range in a medical image, FIG. 6A is a view showing input image data, and FIG. 6B is image data in which the predetermined area is extracted. It is a figure and (c) is a histogram which shows the pixel number with respect to the image signal value of the input image data.

FIG. 6A is a schematic diagram of an abdominal tomographic image in an X-ray CT image, and shows a subject region E1 and a subject region E1 corresponding to the abdomen of the subject with respect to the entire image region of the image data α7. The area other than the above area and the back surface area E2 having a high output density can be roughly classified.

In step S1, for example, as shown in FIG.
As shown in (b), the predetermined area E3 in the medical image of FIG. 6 (a) is extracted. The predetermined area represents a spatial area such as ROI (Region of Interest) in the medical image. For example, the predetermined area E3 can be extracted by being designated and input by the operator via an input unit (not shown) of the image recording apparatus 100 or by applying some extraction algorithm. The extraction algorithm is, for example, a method such as threshold value discrimination, average signal value in the vicinity, edge detection, and feature amount extraction, and can extract only a predetermined area.

Then, as shown in FIG. 5A, the control section 120 of the image recording apparatus 100 uses the image signal of the predetermined area extracted in step S1 to process the information image processing section 110.
The average optical physical quantity approximating unit 111 is calculated to calculate the average optical physical quantity (step S2). As a method of improving the diagnostic ability (diagnostic reproducibility) of the observer, since the image is usually observed in the same environment of the observer, the amount of light passing through the image may be made constant. Therefore, for example, assuming a case where an image is actually recorded, a method of estimating an average transmission density which is an average optical physical quantity is used.

Step S2 will be described in detail with reference to FIG. FIG. 7 is a diagram showing an approximate average transmission density in a predetermined region, FIG. 7A is a diagram showing an example of a predetermined region in an original image signal having a two-dimensional array, and FIG.
4C is a graph showing a transmission density characteristic with respect to an image signal value relating to the image recording apparatus 100, and FIG. 6C is a graph showing a light transmittance characteristic corresponding to the image signal value.

First, for the sake of explanation, the average optical physical quantity approximating unit 111 shows an example of the predetermined area in the original image signal having a two-dimensional array for explanation, as shown in FIG. 7A. As an example, it is assumed that the predetermined area in the original image signal is set to an area having a size of 5 pixels × 5 pixels. The numerical value written on each grid represents the image signal value at each pixel, and the pixel (i,
j) The image signal value at (i, j = 1, 2, 3, 4, 5) is Sij. For example, the image signal value of the pixel (3, 4) is S34 = 146.

Then, the average optical physical quantity estimating unit 111
A graph of the transmission density characteristic DT with respect to the image signal value S relating to the image recording apparatus 100 as shown in FIG. 7B is stored in a storage unit (not shown) from the original gradation characteristic γ-LUT (image signal value (X-axis ), And the recording density (characteristic of the Y axis)). The graph of FIG. 7B is designed so that the transmission density linearly increases with respect to the image signal value.

When there are a plurality of γ-LUTs built in the storage section (not shown) of the image recording apparatus 100, one of them, which is suitable for recording the original image signal, is the "original gradation characteristic" ( 2 is a straight line). When there is only one γ-LUT built in the storage unit (not shown) of the image recording apparatus 100, that γ-LUT is the “original gradation characteristic”.

As the first average transmission density estimation processing for estimating the average transmission density most simply, the average optical physical quantity estimation unit 1 is used.
Reference numeral 11 denotes a design transmission density (design transmission density should be obtained when an image is output) based on the image signal value of each pixel in the predetermined area shown in FIG. 7A based on the LUT of FIG. 7B. (Transmission density), and the average of the design transmission densities of the 25 pixels is calculated by the following formula.

[Equation 1] In this example, N = 5. The estimated value Dave1 is set as the average transmission density.

FIG. 7C shows the image signal value S of FIG. 7B.
Is a modification of the description of the transmission density D _T characteristic with respect to, and shows the relationship of the light transmittance T with respect to the image signal value S. The relationship between the light transmittance T and the transmission density D _T is T = 10 ^−DT
According to the equation of, the light transmittance T for the image signal value S
It is possible to obtain the characteristic that the exponentially decreases.

As another process for estimating the average transmission density most rigorously, as the second average transmission density estimation process, the average optical physical quantity estimation unit 111 uses the graph shown in FIG.
Used as T, the image signal value of each pixel in the predetermined area shown in FIG. 7A is converted into the design light transmittance based on the LUT of FIG. 7C, and the design light transmittance of the 25 pixels is converted. The average value of is calculated by the following formula.

[Equation 2] In this example, N = 5. The estimated average light transmittance T
From ave, the average transmission density is further estimated by the following equation.

[Equation 3] The estimated Dave2 is the average transmission density. The second average transmission density approximating process is a process for obtaining the average transmission density based on the definition of the transmission density.

As another process for estimating the average transmission density relatively rigorously and simply, as the third average transmission density estimation process, the average optical physical quantity estimation unit 111 uses the average optical physical quantity estimation unit 111 for each pixel in the predetermined area shown in FIG. 7A. The average value of the image signal values at is calculated by the following equation.

[Equation 4] In this example, N = 5. From the estimated average image signal value Save, the average transmission density is estimated by the following equation, which is a predetermined approximation equation.

[Equation 5] The estimated Dave3 is taken as the average transmission density.

Compared with the first and second average transmission density estimation processing, the third average transmission density estimation processing does not require conversion processing from an image signal value to another physical quantity, and the histogram distribution in a predetermined area If the transmission density characteristic corresponding to the tendency or the image signal value is known in advance, it may be slightly strict, but it can be easily obtained. Note that [Equation 5]
The approximate expression of may be any function as long as it is a function that can uniquely obtain the average transmission density from the average image signal value, and does not need to be exactly the same.

Although the above is the description of step S2 in the case of outputting a transparent image, in the reflective image, the set reflective density may be used instead of the set transparent density, and the transparent image As in the case, the average reflection density can be calculated.

Then, as shown in FIG. 5A, the control unit 120 of the image recording apparatus 100 uses the average optical physical quantity estimated in step S2 to cause the gradation correction unit 112 of the information image processing unit 110 to The gradation correction characteristic is calculated, the original image signal is gradation-corrected using the calculated corrected gradation correction characteristic (step S3), and the first gradation correction processing is ended. After the first gradation correction processing, the control unit 120 supplies the recording head control signal, the recording medium conveyance signal, and the head conveyance signal based on the original image signal whose gradation has been corrected, to the recording head unit 130 and the conveyance roller 140, respectively. And the image is transmitted to the recording head transport unit 150, and the gradation-corrected image is recorded on the image recording medium α.

The predetermined range is an ideal value of the optical physical quantity having a predetermined width. In step S3,
Gradation correction is performed so that the estimated average optical physical quantity falls within a predetermined value.

When there are a plurality of γ-LUTs built in the storage section (not shown) of the image recording apparatus 100, a plurality of γ-Ls are used.
Of the UT, obtained by considering the observation environment,
A .gamma.-LUT that is more suitable than the "original tone characteristic" is selected as the "corrected tone characteristic" (curve in FIG. 2).

When only one γ-LUT is built in the storage unit (not shown) of the image recording apparatus 100, the "original image signal"
(X-axis) and the recording density (Y-axis) when the image is recorded according to the "original gradation characteristic" after converting the "original image signal" into the "corrected image signal" are the "corrected gradation". "Characteristic". In this case, since the gradation characteristics are changed without changing the γ-LUT of the image recording apparatus 100, the γ-LU is practically used.
Equivalent to generating T (achieved exclusively in software, for example).

Specifically, the gradation correction in step S3 is performed by the gradation correction section 112 by calculating the average optical physical quantity estimated in step S2 and the average optical physical quantity which is the ideal value stored in the gradation information holding section 112a. And the difference value and the original gradation characteristic are used to calculate and output the corrected gradation characteristic in the gradation correction calculation unit 112b. The post-correction gradation characteristics include, as described above, a configuration of selecting from a plurality of γ-LUTs and a configuration of creating using one γ-LUT, but the present invention is not limited to this and the post-correction gradation characteristics are not limited to this. A configuration in which selection and creation of characteristics are combined may be used. Further, in the present embodiment, the difference ΔA in average transmission density, which is one optical physical quantity, is calculated and used.

Next, an example of gradation correction processing will be described with reference to FIG. FIG. 8 is a diagram showing a comparison between the original gradation characteristic and the corrected gradation characteristic, (a) is a first graph showing the transmission density with respect to the original image signal, and (b) is the original image signal. 2C is a second graph showing the transmission density with respect to FIG.
It is a 1st graph which shows the image signal after correction with respect to an original image signal, (d) is a 2nd graph which shows the image signal after correction with respect to an original image signal, (e) is after correction with respect to an original image signal It is a 3rd graph which shows an image signal.

Here, as an example, the image recording characteristic is that the transmission density becomes a straight line with respect to the image signal value, and gradation correction is performed by the gradient of the straight line. As shown in FIG. 8A, the average transmission density Dcalc in a predetermined area of the original image signal on the original gradation characteristic is lowered to reduce the transmission within the predetermined density range on the corrected gradation characteristic. The density is corrected to Do. The predetermined density range is a range of transmission density suitable for observation by an observer, as calculated in FIG. Similarly, FIG.
As shown in, the average transmission density Dcalc in the predetermined area of the original image signal on the original gradation characteristic is raised to be corrected to the transmission density Do within the predetermined density range on the corrected gradation characteristic. ing.

Corresponding to FIG. 8 (a), as shown in FIG. 8 (c), the image signal values of all points of the original image signal on the original gradation characteristic are lowered and corrected. All the points of the post-correction image signal on the gradation characteristic are corrected. Similarly, FIG.
Corresponding to (b), as shown in FIG. 8 (d), the image signal values of all the points of the original image signal on the original gradation characteristic are raised upward to show on the corrected gradation characteristic. , All points of the post-correction image signal are corrected. In addition, as shown in FIG.
Although it is similar to FIG. 8C, it is also possible to adopt a configuration in which correction processing is performed in order to smooth the high signal range.

Therefore, according to the present embodiment, when observing an image under a constant environment, it is possible to properly observe the gradation area corresponding to the predetermined area without causing the observer to feel glare or darkness. A recorded image having gradation characteristics can be obtained.

Incidentally, at least one of the predetermined region and the predetermined range may be changed according to the imaged region which is the subject of the image signal. In that case, since the subject includes the characteristics of the histogram, the image is easily imaged. Gradation correction can be easily performed by analogy with the tendency of the signal histogram.

(Second Embodiment) This embodiment will be described with reference to FIGS. The first embodiment has a configuration in which a predetermined area in the original image signal is extracted and the average transmission density of the predetermined area is roughly estimated to perform gradation correction. Instead, a predetermined signal value is extracted, the average transmission density of the predetermined signal area is roughly estimated, and gradation correction is performed. This embodiment is similar to the first embodiment in terms of the device features of the present embodiment, so description thereof will be omitted.

With reference to FIG. 5B, the second gradation correction processing for gradation processing of the photographed medical image will be described. First, the control unit 120 of the image recording apparatus 100 uses the input of the original image signal of the captured image as a trigger, and
The second gradation correction processing is started by reading and executing a program of the second gradation correction processing stored in advance in a storage unit (not shown).

First, the control unit 120 of the image recording apparatus 100.
Causes the image processing unit 110 to extract a predetermined signal range of the input image signal (step T1). Here, step T1 will be specifically described with reference to FIG. Figure 6
(C) is a figure which shows the image signal value histogram of the input image data.

At step T1, for example, as shown in FIG.
As shown in (c), the predetermined signal value E4 in the medical image of FIG. 6 (a) is extracted. The predetermined signal value range is a pixel in a certain image signal value range in the histogram of the image signal of the medical image. For example, the signal value range before and after the sub-peak (the number of pixels P) existing in the lowest signal value range and 50% or more (the number of pixels P / 2) of the frequency of the sub-peak is set as the predetermined signal value range. A method can be considered, but the setting method is not limited to this. For example, the predetermined signal value range E4 can be specified by the operator through an input unit (not shown) of the image recording apparatus 100 and extracted.

Strictly speaking, FIG. 5 of the first embodiment is used.
The predetermined area E3 in (b) and FIG. 5 of the present embodiment.
Although it does not match the predetermined signal value range E4 in (c), it can be used as one method of analogizing the predetermined region.

Then, as shown in FIG. 5B, the control unit 120 of the image recording apparatus 100 uses the image signal in the predetermined signal range extracted in step T1 to process the information image processing unit 1
The average optical physical quantity approximating unit 111 of 10 is caused to calculate the average optical physical quantity (step T2).

Step T2 will be described in detail with reference to FIG. FIG. 9 is a diagram showing an approximate average luminance in a predetermined signal value range, (a) is a graph showing a transmission density characteristic corresponding to an image signal value related to the image recording apparatus 100, and (b) is an image signal. It is a graph which shows the brightness characteristic with respect to a value, (c) is a histogram which shows the number of optical pixels with respect to an image signal value, (d) is a graph which shows the cumulative brightness with respect to an image signal value.

Here, the case where the average brightness is obtained as the average optical physical quantity will be described. As shown in FIG. 9A, the transmission density characteristic with respect to the image signal value is designed so that the transmission density linearly increases with respect to the image signal value. FIG. 9B is a diagram in which the transmission density characteristic with respect to the image signal value of FIG. 9A is changed, and shows the relationship of the luminance with respect to the image signal value. Note that the brightness here means the brightness on the surface of the transmission image. Since the relationship between the luminance L and the transmission density Dt follows the equation of L = La + Lo · 10 ^−Dt , the characteristic that the luminance L exponentially decreases with respect to the image signal value is obtained.

FIG. 9C is a histogram of the number of pixels with respect to the image signal value in the medical image shown in FIG. 9A and the predetermined signal value range E5 set in step T1.
Indicates. FIG. 9D shows a result obtained by integrating the brightness obtained in FIG. 9B for each pixel number in FIG. 7C, the horizontal axis represents the image signal value, and the vertical axis represents the cumulative brightness. That is, the number of pixels (frequency) in the image signal value i is Ni,
The brightness at the image signal value i is Li, and the predetermined signal value range is M
Image signal values i = So, So + 1, So + 2, ..., So +
When M−1, (ΣLi · Ni) / M (i = So,
So + 1, So + 2, ..., So + M-1) can be used to approximate the average luminance. In FIG. 9D, the average brightness corresponds to the area of the shaded area.

Then, as shown in FIG. 5B, the control section 120 of the image recording apparatus 100 uses the average optical physical quantity estimated in step T2 in the gradation correction section 112 of the information image processing section 110 to The gradation correction characteristics are calculated, the original image signal is gradation-corrected using the calculated corrected gradation correction characteristics (step T3), and the second gradation correction processing is ended. After the second tone correction processing, the control unit 120
A recording head control signal, a recording medium conveyance signal, and a head conveyance signal are generated based on the gradation-corrected original image signal, and the recording head unit 130 and the conveyance roller 140 are respectively generated.
And the image recording medium α transmitted to the recording head transport unit 150.
The gradation-corrected image is recorded on.

The gradation correction in step T3 is specifically, the gradation correction unit 112 compares the average optical physical quantity estimated in step T2 with the average optical physical quantity stored in the gradation information holding unit 112a. The gradation correction calculation unit 112b calculates and outputs the corrected gradation characteristic using the difference value and the original gradation characteristic. The post-correction gradation characteristic has a configuration of selecting from a plurality of γ-LUTs, a configuration of using one γ-LUT, and a configuration of combining these.
The predetermined range is an ideal value of the optical physical quantity having a predetermined width. In step T3, gradation correction is performed so that the estimated average optical physical quantity falls within the predetermined range.

Next, an example of gradation correction processing will be described with reference to FIG. FIG. 10 is a diagram showing a comparison between the original gradation characteristic and the corrected gradation characteristic, (a) is a graph of the transmission density corresponding to the image signal value, showing the original gradation characteristic, and (b).
FIG. 4A is a graph of accumulated luminance corresponding to image signal values showing original gradation characteristics, and FIG. 9C is a graph of transmission density corresponding to image signal values showing original gradation characteristics and corrected gradation characteristics. Is.

Original gradation characteristics as shown in FIG. 10A are obtained, and as shown in FIG.
Suppose that the luminance is smaller than the ideal value in the signal value range E6 and the luminance is higher than the ideal value in the signal value range E7. And FIG.
As shown in (c), the gradation G is smoothly corrected so that the average brightness of the signal value ranges E6 and E7 approaches the ideal value while fixing the point G at the boundary of the predetermined signal value ranges E6 and E7.

In the recording head unit 130 of the 100-image recording apparatus 100, when the transmission density at the point G2 lower than the point G1 in FIG. 10C is the maximum transmission density,
Considering this, the curve is smoothly moved so as to pass through the point G2.

For example, in step T2, the average transmission density of the area E6 shown in FIG. 10A shown in FIG. 2 is set as the average optical physical quantity A, and the average transmission density of the area E7 is set as the average optical physical quantity B. An approximate calculation can be made in step 111, and in step T3, the gradation correction unit 112 can be configured to output the corrected gradation characteristics using the two optical physical quantities A and B.

Therefore, according to the present embodiment, when observing an image under a constant environment, it is appropriate that the observer does not feel glare or darkness in the gradation region corresponding to the predetermined signal value range. A recorded image having various gradation characteristics can be obtained.

Note that it is possible to adopt a configuration in which at least one of the predetermined signal range and the predetermined range is changed in accordance with the characteristics of the histogram of the image signal, and in that case, even if the same subject, there are variations due to differences between the subjects. It is possible to perform gradation correction according to the above.

(Third Embodiment) This embodiment is shown in FIG.
This will be described with reference to FIG. This embodiment is the same as the second embodiment, and only different parts will be described. The device configuration of the present embodiment uses the configurations of FIGS. 1 and 2.

In this embodiment, in the second tone correction processing shown in FIG. 5B of the second embodiment, the control unit 120 causes the image interpolation processing before the predetermined signal range in step T1. The predetermined range changing process and the predetermined range changing process are sequentially executed. However, the present invention is not limited to this. For example, the image interpolation process and the predetermined range changing process may be executed between steps T1 and T2.

When an image is recorded on the image recording medium α using the image recording apparatus 100 based on the image signal obtained by the X-ray CT apparatus, an image interpolation process is usually required. The image interpolation processing means resampling the original image signal at a predetermined image interpolation magnification. For example, if the original image signal is
In the case of two-dimensional array data, when the image size in the original image signal is 1, the image signal data of δ ² times is obtained when the image interpolation processing with the image interpolation magnification δ is performed. When δ> 1, it is called expansion interpolation, and when δ <1, it is called reduction interpolation. As the image interpolation method, various image interpolation methods such as simple interpolation (in the case of integer multiple image interpolation), pi linear interpolation, spline interpolation, bicubic interpolation, etc. are known, but not limited to this.

For example, it is assumed that an object is photographed by using an X-ray CT apparatus and an original image signal of sampling size ΔX1 is obtained. Based on this original image signal, when an image recording apparatus having a minimum recording size of ΔX2 is used for the image recording apparatus 100 and an image is recorded in a question of the size of the subject,
The image may be recorded after the image interpolation processing is performed on the original image with the image interpolation magnification δ = ΔX2 / ΔX1.

In order to obtain an image larger than the image size of the subject, δ> ΔX2 / ΔX1, and to obtain an image smaller than the image size of the subject, δ <ΔX2 / ΔX1. The image may be recorded after performing. Therefore, the image output size can be arbitrarily changed by changing the image interpolation magnification inside the image recording apparatus 100.

As described with reference to FIG. 4 in the first embodiment, the original image signal is subjected to the gradation correction processing so that the luminance is suitable for the observer's observation. When a medical image is recorded by changing the, the observer often observes the image by appropriately changing the observation distance according to the size. Since the contrast resolution in human vision is a bandpass type that has a peak at a low spatial frequency, when an observer observes a predetermined structure important for diagnosis, it is possible to perform image diagnosis while maintaining an optimum observation distance. Is.

Particularly in a transmission image having a small image output size, when the observer attempts to reduce the observation distance, the amount of light incident on the retina of the observer increases, and glare may be felt. Therefore, it is preferable to keep the brightness near the observer within a predetermined range regardless of the image output size, but it is practically difficult to measure and manage the brightness near the observer for each observation. Therefore, it is preferable to keep the brightness near the image surface within a predetermined range while paying attention to the observation environment.

As the image interpolation processing, the image recording apparatus 100
The control unit 120 causes the image processing unit 110 to input the image signal of the captured image input from the outside to the observer, for example, via an input unit (not shown), and inputs the image interpolation magnification, and based on the image interpolation magnification, Image interpolation is performed on the captured image data.

Then, the control unit 120 controls the image processing unit 11
0 in step T of FIG. 5 (b) according to the image magnification.
A predetermined range changing process for changing the predetermined range (luminance in the present embodiment) used in the gradation correction process of No. 3 is performed.

A predetermined range changing process for changing the predetermined range according to the image interpolation magnification will be described with reference to FIG. Figure 1
FIG. 1 is a diagram for explaining a predetermined range change or a background ratio change according to the image size, (a) is a graph showing an ideal average luminance characteristic with respect to the image magnification of a transparent image, (b)
Is a graph showing an ideal average luminance characteristic with respect to the image magnification of a reflection image, (c) is a graph showing a background ratio with respect to the image magnification of a transmission image, and (d) is a background ratio with respect to the image magnification of a reflection image. It is a graph which shows. In this embodiment mode, FIGS. 11A and 11B are used.

FIGS. 11A and 11B show average density characteristics as ideal average optical physical quantities in the signal value range E6 with respect to image magnification (image interpolation magnification) in a transmission image and a reflection image, respectively. The image magnification represents a ratio with the image output size based on the actual size of the subject, and the image interpolation magnification represents a unit of image interpolation. For example, when the image magnification is 1, the image interpolation magnification is 2.19. And work together. The sampling size is ΔX
It is assumed that 1 = 87.5 μm and ΔX2 = 40.0 μm.

Here, on the vertical axis of FIGS. 11 (a) and 11 (b),
The "ideal average brightness in the signal range E6" is as shown in FIG.
This corresponds to the ideal value of the average luminance in the signal range E6 of 0 (b). FIG. 11A is a diagram showing an example of a transmission image. When the observer observes the image even when the observer's observation distance is short, the ideal average luminance is reduced as the image magnification is reduced. There is no glare. The predetermined range is changed by setting the predetermined range based on the changed ideal average brightness. Figure 11
FIG. 1B is a diagram showing an example of a reflection image, and FIG.
The tendency is almost the same as that of 1 (a).

The controller 120 sets the predetermined range by
The changed ideal optical physical quantity is newly written in the gradation correction holding unit 112b or the existing value is rewritten.

After the predetermined range changing process, steps T1 to T
3 is executed, and in step T3, gradation correction is performed on the image signal of the photographed image using the predetermined range changed in the predetermined range changing process (the ideal optical physical quantity having a width).

Therefore, since the change is made in accordance with the image recording magnification, the visual field range at the time of observation is roughly estimated, and the proper floor in which the human eyes' characteristics are taken into consideration without causing the observer to feel glare or darkness. It is possible to obtain a recorded image having tonality characteristics.

(Fourth Embodiment) This embodiment is shown in FIG.
1 and FIG. 12 will be described. FIG. 12 is a diagram for explaining the background area changing process in the image recording apparatus 100. This embodiment is the same as the third embodiment, but in the second gradation correction processing shown in FIG. 5B of the second embodiment, before the predetermined signal range extraction in step T1. In addition, although the control unit 120 is configured to sequentially execute the image interpolation process and the background region changing process, the present invention is not limited to this. For example, the image interpolation process and the background region changing process may be performed between steps T1 and T2. It may be configured to execute.

The back area changing process may be performed before the image interpolation process or after the image interpolation process. However, it is preferable to add / cut the background area in advance before the image interpolation processing because the calculation amount of the image interpolation processing can be omitted.
Further, in the present embodiment, a case will be described in which the back area change processing is performed after the image interpolation processing.

As image interpolation processing, the image recording apparatus 100
The control unit 120 causes the image processing unit 110 to input the image signal of the captured image input from the outside to the observer, for example, via an input unit (not shown), and inputs the image interpolation magnification, and based on the image interpolation magnification, Image interpolation is performed on the captured image data.

Then, as shown in FIG. 12, the control unit 120 of the image recording apparatus 100 executes the background area changing process according to the image interpolation magnification. FIG. 12 shows the image recording apparatus 10.
It is a figure explaining the background area change process in 0. Figure 1
2, the background area changing unit 113 is provided in the image processing unit 110, and the image recording process includes steps T1 to T1.
T3 + means the image recording process. The image processing unit 110 has the function of the background area changing unit described in the claims.

As the image interpolation processing, first, the control unit 120
Causes the background area changing unit 113 of the image processing unit 110 to calculate an appropriate background ratio based on the image magnification obtained in the image interpolation processing.

FIGS. 11C and 11D show background ratio characteristics with respect to the image magnification (image interpolation magnification) in the transmission image and the reflection image, respectively. The background ratio represents the area ratio of the background portion, that is, (the area of the background area) / (the area of the entire area). In the original image signal, the background ratio is already determined according to the image signal, but in the present embodiment, when the image is recorded on the image recording medium α, the rear area is added / cut to change.

FIG. 11C is a diagram showing an example of a transparent image. In the transparent image, since the light box has a large light-shielding effect, image output is performed so as to reduce the transmitted light from a portion other than the subject region. Size (image interpolation method)
The background ratio is changed according to. FIG. 11D is a diagram showing an example of the reflection image. In the reflection image, since there is no light source of high brightness such as a light box in the extension of observation, there is almost no need to shield the light. Therefore, it is not necessary to change the background ratio according to the image output size (image interpolation method).

On the contrary, when the image recording apparatus 100 is an ink jet image recording apparatus, the recording medium and the recording material (ink) are independent, and the image density is increased by increasing the amount of the recording material used. However, it is not preferable to excessively increase the background ratio in order to save recording materials.

Then, the control unit 120 controls the image processing unit 11
Based on the obtained background ratio, the background region changing unit 113 of 0 performs the background region changing process in which the image signal of the photographed image subjected to the image interpolation process is not subjected to the background region cutting, the process is not performed, or the background region is added. After the background area changing process, the image signal changed in the background area changing process is processed as shown in FIG.
The processes of steps T1 to T3 of (b) are performed, and then the image is recorded on the image recording medium α.

Therefore, according to the present embodiment, it is possible to obtain a recorded image having an appropriate gradation characteristic without causing the observer to feel glare or darkness based on the changed and adjusted background area.

In FIG. 12, adjustment is made so that the data is recorded in the same size including the background area, but the present invention is not limited to this. In addition, the background area is evenly cut in four directions, up, down, left, and right.
It is preferable to make additions. Also, if the background area can be cut off like a limb, the background area is cut off,
When the background region cannot be cut off like the front of the chest, the area occupied by the background region can be made constant and the transmission density in the background region can be increased.

(Fifth Embodiment) FIG. 13 shows the present embodiment.
Will be described with reference to. 13A and 13B are diagrams for explaining information input regarding the observation environment, FIG. 13A is a diagram showing an input screen, and FIG. 13B is a diagram showing an ideal optical physical quantity setting process.

This embodiment has a configuration in which, in addition to the configurations of the first to fourth embodiments, a configuration for allowing an observer to input observation information regarding the observation environment including light source information such as illumination of the observation environment is added. Yes, the additional part will be described.

In this embodiment, the image input device 100 shown in FIG. 1 is provided with an observation information input section 160 for inputting observation information concerning an observation environment from an observer, and an observation information input section 160.
Further, an optical physical quantity setting unit 170 for setting an ideal value of the optical physical quantity based on the observation information input in (3) is further provided.

The observation information input section 160 is described as a touch panel for inputting information by pressing the display on the screen, but the present invention is not limited to this. Other than that, various forms such as a push button, a DIP switch, and an input keyboard are conceivable. However, the present invention is not limited to this, and any configuration may be applied as long as the light source information can be easily input. For example, the observation information input section 160 may be arranged on the operation panel installed in the image recording apparatus 100 and provided with an LED display or the like.
It may be arranged together with an externally connected display such as a CRT, LCD, or organic EL.

"BALLANCE" in FIG. 13A is a gradation balance, which may be, for example, a predetermined range of the optical physical quantity, or the position of a fixed point such as the fixed point G shown in FIG. The input can be set based on a factor important for gradation correction. "ROOM LIGHT" represents the outside light level,
It can be input and set based on information such as the illuminance of room light and the type of fluorescent lamp.

The "LIGHT BOX" means the presence or absence of a light box as auxiliary light, the brightness or illuminance when the light box is used, or the type of the light box.
Input and set information such as light sources such as fluorescent lamps. “LUT NO” is the γ-LUT of the original gradation characteristic to be selected, for example, FIG.
The maximum density such as the maximum density G2 shown in (c), for example, the slope of the straight line of the characteristic shown in FIG.

Therefore, since the gradation correction is performed by using the input information of the observation environment, the observer can be dazzled or dark in the gradation region corresponding to the predetermined region or the predetermined signal value range regardless of the change of the observation environment. It is possible to obtain a recorded image having proper gradation characteristics without feeling a sharpness.

(Sensory Evaluation Example) Here, FIG. 14 and FIG.
With reference to, an example of results of sensory evaluation of a medical image will be sequentially described from sample preparation to evaluation results. FIG. 14 is a diagram showing an example of the relationship between the measured luminance value and the subjective evaluation result.
FIG. 5 is a diagram showing an example of the relationship between the measured value of illuminance and the subjective evaluation result. This sensory evaluation is performed when the gradation correction in the predetermined area corresponding to the first embodiment is combined with the structure for performing the gradation correction processing on the image using the light source information of the observation environment in the fifth embodiment. Is a sensory evaluation example.

First, as an image used as a sample for sensory evaluation, a human body was photographed from the front of the chest using Regius 350 (manufactured by Konica Corporation), the obtained 12-bit image signal was converted into an 8-bit image signal, and a predetermined image signal was obtained. An image was recorded on an image recording medium by PM-950C (manufactured by Epson Corporation) based on the gradation characteristics. The image recording medium is a special OHP sheet (manufactured by Seiko Epson Corp.) when recording a transparent image, and an inkjet special paper when recording a reflective image.
Photolike QP (manufactured by Konica Corporation) was used.

Next, the gradation characteristics of the image will be described.
The γ-LUT is set so that the output density D has linearity with respect to the image signal value of the image, that is, D = Dmin + S · (Dmax−Dmin) / Smax, and the γ-LUT is set. The image subjected to the gradation correction processing based on the image was recorded on the image recording medium. Dmin is the minimum output density, Dmax is the maximum output density, S is the image signal value, and Smax is
Is the maximum value of the image signal value.

Next, the observation environment in sensory evaluation will be described. The observation environment has different illumination conditions for the transmission image and the reflection image. In order to maintain the diagnostic ability of the observer, the indoor illuminance was set low when observing the transmission image, and the indoor illuminance was set high when observing the reflection image.

In the transmitted image, the lightness in the room was kept substantially constant (average value 24 [cd / m ² ]), and the luminance of the light box was changed in three ways to observe the transmitted image. In the reflection image, a light box was not used, and the brightness of the room was changed in three ways to observe the reflection image.

The "conventional example" in FIGS. 14 and 15 is an example of an image recorded on an image recording medium without performing the above-described gradation correction process, and is optimum under a predetermined observation environment. I chose an image with the expected gradation characteristics. Similarly, "Example" is an example of an image recorded on an image recording medium by performing gradation correction processing of gradation characteristics in consideration of each observation condition. Specifically, the above-mentioned Dmin was made constant, and only the gradient of the straight line was changed to perform gradation correction. Further, “gradient γ” in FIGS. 14 and 15 represents a straight line gradient of the above-mentioned gradation characteristic, and the gradient in the gradation characteristic in the conventional example is γ =
It means the gradient ratio when it is set to 1.0.

The "luminance (illuminance) when the light is ON" in FIGS. 14 and 15 is the luminance (illuminance) near the light box surface when the power of the light box is turned on with the indoor lighting turned on. Refers to the measured value. In addition, “luminance (illuminance) when the light is off” in FIGS. 14 and 15 is the luminance (illuminance) in the vicinity of the light box surface when the power of the light box is turned off with the indoor lighting turned on.
Is the measured value of.

In the reflection image, since the image is not observed using the light box, it is described as "-" in FIGS. 14 and 15. By the way, all the measured values are measured by arranging the film at substantially the same position on the light box, and are the measured values of the brightness (illuminance) in the non-printed portion where the ink does not adhere.

Next, the evaluation method of sensory evaluation will be described. The subject of sensory evaluation performed the sensory evaluation by observing the transmission image and the reflection image of the front of the chest described above under the observation environment described above. In addition, as shown in FIG. 14 and FIG.
L ”,“ L ”,“ G ”,“ D ”,“ DD ”(LL: dazzling, L: dazzling, G: proper, D: slightly dark, DD:
The evaluation method using the (dark) evaluation standard was adopted. The test subjects are three principal researchers who are engaged in medical device development belonging to the applicant company, and the evaluation results of this sensory evaluation are the average of the three.

Next, the evaluation results of the sensory evaluation will be described. First, the relationship between gradation correction and average luminance will be described with reference to FIG. To check the relationship between proper gradation characteristics and average brightness L in a predetermined area, when the brightness (maximum brightness) of the non-printed portion when the light box is ON is Lmax and the brightness of the background area (minimum brightness) is Lmin. The average luminance balance B1 = (L-Lmin) / (Lmax-Lmin) was calculated. The luminance meter used for the measurement was BM-9 (manufactured by Topcon Corporation), the measurement angle was 1 °, and the observability was 5
The average luminance balance B1 was obtained for the images that were evaluated as “G” in the graded evaluation.

[0245] The "subject average brightness" in FIG.
Is the average brightness when the subject area is a predetermined area, and is the average value of the brightness estimated from the histogram of the image signal. Further, the "average image brightness" in FIG. 14 means
The average luminance is shown when the entire image is in a predetermined area, and is the average value of the luminance estimated from the histogram of the image signal.
The entire image refers to the entire image area including the subject area and the background area.

Regarding the subject average luminance balance B1 on the front of the chest, 0.10 <B1 <0.20, and similar results were obtained with the transmission image and the reflection image.
Further, in addition to the front of the chest shown in FIG. 14, the same evaluation was performed on the lumbar side surface and the limb bones. As a result, 0.20 <B1 <0.30 was found for the lumbar side surface and 0.15
<B1 <0.25, and 0.1 <B1 <0.
It has been found that a range of 3 is preferred.

Image average brightness balance B in front of chest
Regarding No. 1, 0.05 <B1 <0.15, and similar results were obtained with the transmission image and the reflection image.
Further, in addition to the front of the chest shown in FIG. 14, the same evaluation was performed on the lumbar side surface and the limb bones.
<B1 <0.20 and both are 0.05 <B1 <
It has been found that a range of 0.2 is preferred.

From the above evaluation results, with respect to the average subject brightness in the medical image, the average subject brightness balance B1
Is preferably 0.1 <B1 <0.3, and the image average brightness balance B2 is 0.0
It is preferable that 5 <B1 <0.2. The configuration in which the subject average brightness falls within the above range is particularly effective when observing a reflection image, and the configuration in which the image average brightness falls within the above range is particularly effective when observing a transmission image.

Next, the relationship between gradation correction and average illuminance will be described with reference to FIG. In order to investigate the relationship between the proper gradation characteristics and the average illuminance E in a predetermined area, the illuminance (maximum illuminance) of the non-printed portion when the light box is turned on is Ema.
x, the average illuminance balance B2 = (E-Emin) / (Emax-Emin) where Emin is the illuminance (minimum illuminance) of the background area was determined. The illuminance meter used for the measurement was IM-5M (manufactured by Topcon Corporation), the measurement angle was 1 °, and the average illuminance balance B2 for the image having the “G” rating out of the five-level observability evaluation I asked.

[0250] Incidentally, "subject average illuminance" in FIG.
Is the average illuminance when the subject area is a predetermined area, and is the average value of the illuminance estimated from the histogram of the image signal. Further, the “image average illuminance” in FIG. 15 means
The average illuminance when the entire image is in a predetermined area is shown, and is the average value of the illuminance estimated from the histogram of the image signal.

Regarding the subject average illuminance balance B2 on the front of the chest, 0.10 <B2 <0.20, and similar results were obtained with the transmission image and the reflection image.
Further, in addition to the front of the chest shown in FIG. 15, the same evaluation was performed on the lumbar side surface and the limb bone.
<B2 <0.25, and 0.1 <B2 <0.
It has been found that a range of 3 is preferred.

Image average illuminance balance B in front of chest
With respect to 2, 0.05 <B2 <0.15, and similar results were obtained with the transmission image and the reflection image.
Further, in addition to the front of the chest shown in FIG. 15, the same evaluation was performed on the lumbar side surface and the limb bone. As a result, the lumbar side surface was 0.10 <B2 <0.20, and the limb bone was 0.05.
<B2 <0.20 and both are 0.05 <B2 <
It has been found that a range of 0.2 is preferred.

From the above evaluation results, and regarding the average illuminance of the subject in the medical image, the average illuminance balance B2 of the subject is preferably 0.1 <B2 <0.3,
Regarding the image average illuminance, the image average illuminance balance B2 is preferably 0.05 <B2 <0.2. The configuration in which the subject average brightness falls within the above range is particularly effective when observing a reflection image, and the configuration in which the image average brightness falls within the above range is particularly effective when observing a transmission image.

Therefore, according to the evaluation result of this sensory evaluation,
It has been confirmed that it is preferable to correct the gradation characteristics of the transmitted image in accordance with the brightness of the light box, and it is preferable that the reflected image be corrected of the gradation characteristics in accordance with the brightness of the illumination light.
By applying the gradation characteristic correction method described in this sensory evaluation example, it becomes possible to correct the gradation characteristic to an appropriate one according to the observation environment.

By applying the gradation correction processing described in this sensory evaluation, it has been proved that a recorded image having more appropriate gradation characteristics without causing the observer to feel glare or darkness can be obtained. It was

In this sensory evaluation, the sensory evaluation is performed with the entire image or the subject region as the predetermined region, but the evaluation result in the case where the sensory evaluation is performed with the entire image or the subject region as the predetermined signal range is also the same. It was in this case,
The entire image is a signal value range corresponding to the entire image, and the subject region is a signal value range corresponding to the subject region.

(Sixth Embodiment) This embodiment is shown in FIG.
Will be described with reference to. FIG. 16 is a block diagram showing functional blocks related to image display of the image display device 200 of this embodiment. The image display device 200 receives an image signal of a captured image from the outside, and an image processing unit 210 that performs image processing on the received image signal, a control unit 220 that controls each unit of the image display device 200, and an LCD (Liquid Crystal Dispersion).
play), a liquid crystal panel 230 for displaying an image on the liquid crystal
An address driver 240 for controlling pixel display in the horizontal axis direction of the liquid crystal unit 230, and a data driver 250 for controlling pixel display in the vertical axis direction of the liquid crystal unit 230.

The image signal image-processed by gradation correction in the image processing unit 210 is converted into an address driver control signal and a data driver control signal in the control unit 220, and the address driver control signal and the data driver control signal are respectively addressed. The image signal transmitted to the driver 240 and the data driver 250 and subjected to image processing is displayed on the liquid crystal panel 230.

The image processing section 210 and the control section 220 are similar to those shown in FIG.
Corresponding to the image processing unit 110 and the control unit 120 shown in FIG.
0 and the data driver 250 correspond to the recording head unit 130, the conveyance roller 140, and the recording head conveyance unit 150 for recording on the image recording medium α shown in FIG.

The image processing is the same as the image processing by the gradation correction in the first to fifth embodiments, and the description thereof will be omitted. However, various optical physical quantities are calculated on the liquid crystal panel 230.
Is a value corresponding to the liquid crystal display on the screen, and is, for example, the brightness or illuminance of the liquid crystal panel 230.

Therefore, according to the present embodiment, the observer feels glare and darkness in the gradation region corresponding to the predetermined region or the predetermined signal value range under a constant environment or regardless of the change of the observation environment. It is possible to obtain a display image having proper gradation characteristics.

In the present embodiment, the liquid crystal panel 230 is used as the means for displaying an image, but the present invention is not limited to this, and a digital micromirror device (DMD) display, an electrochromic display (ECD), an electric display. Electrophoretic display (EPI
D), CRT (Cathode Ray Tube), plasma display (PDP), fluorescent display tube (VFD), light emitting diode (LED) display, electroluminescence (EL) display, field emission display (FED), organic EL display, etc. All known display devices can be used regardless of the light emitting type and the light emitting type.

Further, when the fifth embodiment is combined with the present embodiment, if the image display device (the liquid crystal panel 230) and the observation information input section are integrated into the image display device 200, the observation including the light source information is performed. It is preferable because the input of information is easy to set.

Further, also in the present embodiment, the same sensory evaluation as the above (sensory evaluation) was performed, and almost the same evaluation result as in the case of image recording was obtained. That is,
In medical image display, the subject average brightness B1 is preferably 0.1 <B1 <0.3 for the subject average brightness, and the image average brightness B1 is 0.05 <B1 <for the image average brightness. The average subject illuminance balance B2 is preferably 0.1 <B2 <0.3, and the average image illuminance balance B2 is 0. It was confirmed that it was preferable that 05 <B2 <0.2.

Incidentally, in the first to fifth embodiments,
An example of an image recording apparatus using an inkjet recording method as the recording means has been described, but the recording method is not limited to the inkjet recording method, and other methods such as a wet type
A dry silver salt laser recording method, a thermal transfer recording method, an impact recording method such as a wire dot recording method, or any other recording method can be applied. Further, it is not necessary to limit to the serial recording method, and a so-called line recording method may be used.

In addition, in the first to sixth embodiments,
Although the X-ray X-ray CT apparatus (X-ray computed tomography apparatus) has been described as the image input apparatus (imaging apparatus), the image input apparatus (imaging apparatus) is not limited to this. For example, an X-ray imaging apparatus or a magnetic resonance image forming apparatus (MRI apparatus). ), An ultrasonic image capturing / diagnosing apparatus, an electronic endoscope, a fundus camera, or the like may be used.

Further, in the gradation correction according to the first to sixth embodiments, the average optical physical quantity in the predetermined area or the predetermined signal value area is only roughly estimated, and if the accuracy of the estimation is acceptable. The method does not matter. For example,
It is also possible to downsize the original image signal in advance by trimming or the like, set a predetermined region and a predetermined signal region for the image signal, or roughly estimate the average optical physical quantity. Unlike the image interpolation processing, the downsizing is used only for the calculation of the average optical physical quantity approximation and the like. At this time, the amount of calculation is reduced, which is preferable. Further, a method of obtaining the average optical physical quantity in the estimation of the average optical physical quantity includes a statistical average and a median value, but the method is not limited to this.

In addition, in the first to sixth embodiments,
It is preferable to have a notifying unit for notifying the observer of the recommended observation distance for informing the observer of the recommended observation condition. In the image recording apparatus 100, a mode is conceivable in which display means for displaying an image together with recording of a medical image on the image recording medium α is provided to display recommended observation conditions. Further, it is preferable that the image display device 200 according to the sixth embodiment displays the image together with the medical image.

Further, in the medical images in the first to sixth embodiments, especially in the case of a monochrome multi-gradation medical image obtained by simple X-ray photography, which requires extremely high image quality, its gradation correction is performed. It is effective because the effect of is prominent. In addition, in the first to sixth embodiments, the configuration for recording or displaying a medical image has been described, but the present invention is not limited to this, and can be applied to images in a wide range of fields used for digital recording and display. . Also, as an image,
The present invention can be applied not only to monochrome images, but also to color images in which primary colors of YMCK or RGB are combined.

In addition, in the first to fifth embodiments,
Although the image recording apparatus 100 has been described, the image recording apparatus 100
May be divided into an image processing device for image-processing an image and an image recording unit for recording the image-processed image,
In that case, the image processing apparatus is an embodiment of the present invention. In addition, in the sixth embodiment, the image display device 20
Although 0 has been described, the image display device 200 may be configured to be divided into an image processing device that performs image processing on an image and an image processing unit that displays an image that has undergone image processing. It becomes the embodiment of.

Although the embodiments of the present invention have been described above, the present invention is not necessarily limited to the above-described means and techniques, and the objects referred to in the present invention can be achieved and the effects referred to in the present invention can be achieved. Modifications can be appropriately made within the range.

[0272]

According to the invention described in claims 1, 31, 39, or 47, when an image is observed in a constant environment, in the gradation area corresponding to a predetermined area, the observer is dazzled or dark. It is possible to obtain a recorded image having proper gradation characteristics without feeling a sharpness.

According to the invention as set forth in claim 2, 32, 40 or 48, when an image is observed under a constant environment, the observer is dazzled or dark in a gradation region corresponding to a predetermined signal value range. It is possible to obtain a recorded image having proper gradation characteristics without feeling a sharpness.

According to the invention described in claim 3, 33, 41 or 49, it is appropriate that the observer does not feel glare or darkness in the gradation region corresponding to the predetermined region regardless of the change of the observation environment. A recorded image having various gradation characteristics can be obtained.

According to the invention as set forth in claim 4, 34, 42 or 50, it is possible to prevent the observer from feeling glare or darkness in the gradation region corresponding to a predetermined signal value range irrespective of changes in the observation environment. It is possible to obtain a recorded image having appropriate gradation characteristics.

According to the invention described in claim 5, when the predetermined range is changed according to the subject of the image signal, the tendency of the histogram can be easily analogized to easily perform the gradation correction. When changing the predetermined range according to the magnification,
It is possible to obtain a recorded image having proper gradation characteristics in which the characteristics of human eyes are taken into consideration, without causing the observer to feel glare or darkness by roughly estimating the visual field range during observation.

According to the invention described in claim 6, when the predetermined range is changed according to the characteristics of the histogram of the image signal,
Even with the same subject, gradation correction can be performed according to variations due to differences in subjects, and when changing the predetermined range according to the image recording magnification, the visual field range at the time of observation is roughly estimated to reduce glare to the observer. Without feeling the darkness,
It is possible to obtain a recorded image having proper gradation characteristics in which the characteristics of human eyes are taken into consideration.

According to the seventh aspect of the present invention, by using a universal physical value of transmission density, reflection density, light transmittance, light reflectance, or lightness as the optical physical quantity, a gradation with high reproducibility can be obtained. It is possible to perform correction, and it is possible to obtain a recorded image that always has appropriate gradation characteristics without causing the observer to feel glare or darkness.

According to the eighth aspect of the present invention, by using a universal physical value of luminance or illuminance as the optical physical quantity, it is possible to perform gradation correction with high reproducibility, and the glare or darkness is observed for the observer. It is possible to always obtain a recorded image having proper gradation characteristics without feeling a sharpness.

According to the ninth aspect of the invention, the average luminance L that sets the entire image as the predetermined region or the predetermined signal value range is set within the predetermined range, so that the observer does not feel glare or darkness. Thus, it is possible to obtain a recorded image having appropriate gradation characteristics.

According to the tenth aspect of the present invention, by setting the average luminance L that sets the subject region as the predetermined region or the predetermined signal value range within the predetermined range, the observer does not feel glare or darkness. Thus, it is possible to obtain a recorded image having appropriate gradation characteristics.

According to the eleventh aspect of the present invention, by setting the average illuminance E which makes the entire image a predetermined region or a predetermined signal value range within a predetermined range, the observer does not feel glare or darkness. Thus, it is possible to obtain a recorded image having appropriate gradation characteristics.

According to the twelfth aspect of the present invention, by setting the average illuminance E which makes the subject region a predetermined region or a predetermined signal value range within a predetermined range, the observer does not feel glare or darkness. Thus, it is possible to obtain a recorded image having appropriate gradation characteristics.

According to the thirteenth aspect of the present invention, since the light source information according to the observation environment can be input, the gradation characteristic according to the observation environment does not cause the observer to feel glare or darkness. A recorded image can be obtained.

According to the invention of claim 14 or 15,
Based on the changed and adjusted background area, it is possible to obtain a recorded image having an appropriate gradation characteristic without causing the observer to feel glare or darkness.

According to the sixteenth aspect of the present invention, it is possible to obtain a recorded medical image having proper gradation characteristics without causing the observer to feel glare or darkness.

According to the seventeenth, thirty-fifth, thirty-third, or fifty-first aspect of the invention, it is possible to record a recorded image having proper gradation characteristics without causing the observer to feel glare or darkness.

According to the eighteenth, thirty-sixth, forty-fourth and twenty-fifth aspects of the present invention, it is appropriate that the observer does not feel glare or darkness in the gradation region corresponding to the predetermined region regardless of the change of the observation environment. A display image having various gradation characteristics can be obtained.

According to the invention as set forth in claim 19, 37, 45 or 53, it is possible for an observer to feel glare and darkness in a gradation region corresponding to a predetermined signal value range regardless of changes in the observation environment. It is possible to obtain a display image having proper gradation characteristics.

According to the twentieth aspect of the invention, when the predetermined range is changed according to the subject of the image signal, the tendency of the histogram can be easily analogized, and the gradation correction can be easily performed. When the predetermined range is changed according to the magnification, the visual field range at the time of observation is roughly estimated, and the display has proper gradation characteristics that does not cause the observer to feel glare or darkness and takes into account the characteristics of human eyes. Images can be obtained.

According to the twenty-first aspect of the invention, when the predetermined range is changed according to the characteristics of the histogram of the image signal, even the same subject can be subjected to gradation correction according to variations due to differences in subjects. Yes, when changing the predetermined range according to the image display magnification, the visual field range at the time of observation is roughly estimated, and the appropriate gradation that does not feel glare or darkness for the observer, taking into account the characteristics of human eyes A display image having characteristics can be obtained.

According to the twenty-second aspect of the invention, by using a universal physical value of luminance or illuminance as the optical physical quantity, it is possible to perform gradation correction with high reproducibility, and the glare and the darkness to the observer. It is possible to obtain a display image having an appropriate gradation characteristic without feeling a sharpness.

According to the twenty-third aspect of the present invention, by setting the average luminance L that sets the entire image as the predetermined region or the predetermined signal value range within the predetermined range, the observer does not feel glare or darkness. As a result, a display image having appropriate gradation characteristics can be obtained.

According to the twenty-fourth aspect of the present invention, by setting the average luminance L which makes the subject region a predetermined region or a predetermined signal value range within a predetermined range, the observer does not feel glare or darkness. As a result, a display image having appropriate gradation characteristics can be obtained.

According to the twenty-fifth aspect of the present invention, by setting the average illuminance E which makes the entire image a predetermined region or a predetermined signal value range within a predetermined range, the observer does not feel glare or darkness. As a result, a display image having appropriate gradation characteristics can be obtained.

According to the twenty-sixth aspect of the present invention, the average illuminance E which sets the subject area as the predetermined area or the predetermined signal value range is set within the predetermined range, so that the observer does not feel glare or darkness. As a result, a display image having appropriate gradation characteristics can be obtained.

According to the twenty-seventh aspect of the present invention, since the light source information according to the observation environment can be input, the gradation characteristic according to the observation environment does not cause the observer to feel glare or darkness. A display image can be obtained.

According to the twenty-eighth aspect of the invention, it is possible to obtain a display image having an appropriate gradation characteristic without causing the observer to feel glare or darkness based on the changed and adjusted background area.

According to the twenty-ninth aspect of the present invention, it is possible to obtain a display medical image having appropriate gradation characteristics without causing the observer to feel glare or darkness.

According to the invention as set forth in claim 30, 38, 46 or 54, it is possible to display a display image having proper gradation characteristics without causing the observer to feel glare or darkness.

[Brief description of drawings]

FIG. 1 is a block diagram showing functional blocks related to image recording of an image recording device 100 according to a first embodiment of the present invention.

2 is a diagram showing an internal configuration of an image processing unit 110 in FIG.

3A and 3B are diagrams showing a relationship between an illumination condition and a luminance near the image surface, FIG. 3A is a diagram showing a main observation mode in observing a transmission image α1, and FIG. FIG. 11 is a diagram showing an observation mode in which the observation image is the same as that in a), but the image density in the transmission image α2 is low overall
Although the observation form of (c) is the same as that of (a),
It is a figure which shows the observation form in which the image density in the transmission image (alpha) 3 is generally high, and (d) is a figure which shows the main observation forms in the case of observing a reflection image (alpha) 4.

FIG. 4 is a diagram showing a relationship between an observation distance and brightness near an observer, and FIG. 4A is a diagram showing a case where an image observation distance is d1 and a radius of a visible range is r1 during observation of a transmission image. , (B) has an observation distance d when observing a transmission image.
2 is a diagram showing a case where the radius of the visible range is r2,
(C) is a diagram showing a case where an observation distance is d1 and a radius of a visible range is r1 when observing a reflection image.

FIG. 5 is a diagram showing gradation correction processing, in which FIG.
6B is a flowchart showing the gradation correction processing of FIG.
6 is a flowchart showing a second gradation correction process.

6A and 6B are diagrams showing a predetermined area and a predetermined signal value range in a medical image, FIG. 6A is a view showing input image data, and FIG. 6B is image data in which the predetermined area is extracted. It is a figure and (c) is a histogram which shows the pixel number with respect to the image signal value of the input image data.

7A and 7B are diagrams showing an average transmission density estimation in a predetermined area, FIG. 7A is a diagram showing an example of a predetermined area in an original image signal having a two-dimensional array, and FIG. 7B is an image recording apparatus 100. 3C is a graph showing the transmission density characteristic with respect to the image signal value according to FIG.

8A and 8B are diagrams showing a comparison between original gradation characteristics and post-correction gradation characteristics, FIG. 8A is a first graph showing a transmission density with respect to an original image signal, and FIG. 8B is an original image signal. 2C is a second graph showing the transmission density with respect to, and FIG. 6C is a first graph showing the corrected image signal with respect to the original image signal,
(D) is a second graph showing the corrected image signal for the original image signal, and (e) is a third graph showing the corrected image signal for the original image signal.

FIG. 9 is a diagram showing an approximate average luminance in a predetermined signal value range, FIG. 9A is a graph showing a transmission density characteristic corresponding to an image signal value related to the image recording apparatus 100, and FIG.
Is a graph showing luminance characteristics with respect to image signal values,
(C) is a histogram showing the number of light pixels with respect to the image signal value, and (d) is a graph showing the cumulative luminance with respect to the image signal value.

FIG. 10 is a diagram showing a comparison between original gradation characteristics and post-correction gradation characteristics; (a) is a graph of transmission density corresponding to image signal values, showing original gradation characteristics; Is a graph of cumulative luminance corresponding to an image signal value, showing original gradation characteristics, and (c) shows original gradation characteristics and post-correction gradation characteristics,
It is a graph of the transmission density corresponding to an image signal value.

FIG. 11 is a diagram illustrating a predetermined range change or a background ratio change according to the image size, and FIG. 11A is a graph showing an ideal average luminance characteristic with respect to the image magnification of a transparent image,
(B) is a graph showing the ideal average luminance characteristic with respect to the image magnification of the reflection image, (c) is a graph showing the background ratio with respect to the image magnification of the transmission image, and (d) is the image magnification of the reflection image. 5 is a graph showing a background ratio with respect to.

FIG. 12 is a diagram illustrating a background area changing process in the image recording apparatus 100.

13A and 13B are diagrams for explaining information input regarding an observation environment, FIG. 13A is a diagram showing an input screen, and FIG. 13B is a diagram showing an ideal optical physical quantity setting process.

FIG. 14 is a diagram showing an example of a relationship between a measured value of luminance and a subjective evaluation result.

FIG. 15 is a diagram showing an example of a relationship between a measured value of illuminance and a subjective evaluation result.

FIG. 16 is a block diagram showing functional blocks related to image display of an image display device 200 according to a sixth embodiment of the present invention.

[Explanation of symbols]

100 ... Image recording device 110 ... Image processing unit 111 ... Average optical physical quantity estimation unit 112 ... Gradation correction unit 112a ... Gradation information holding unit 112b ... Gradation correction calculation unit 113 ... Background area change unit 120 ... Control unit 130 ... Recording head unit 131, 132, 133, 134 ... Recording head 140 ... Recording head transport unit 150 ... Conveyor roller α ... Image recording medium 160 ... Observation information input section 170 ... Optical physical quantity setting unit 200 ... Image display device 110 ... Image processing unit 120 ... Control unit 200 ... Image display device 210 ... Image processing unit 220 ... Control unit 230 ... Liquid crystal panel 240 ... Address driver 250 ... Data driver

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) H04N 5/57 H04N 1/40 101E 5C077 5/91 B41J 3/00 AF term (reference) 2C262 AA02 AA24 AB13 BB36 BC07 BC10 BC17 GA19 4C093 AA01 AA26 CA04 EE09 FA35 FD03 FD07 FF08 FF13 FF15 FF19 FF27 FF30 FG02 5B057 AA08 BA03 CA02 CA08 CA12 CA16 CB02 LA15 CA01 LA3 CA01 LA03 5C04 DB01 DB01 DB01 DB02 DB05 DB0 DB0 DB05 DB09 DB02 DB05 DB0 DB05 DB0 DB0 PP46 PQ12 PQ19 SS06

Claims (54)

[Claims] 1. An image processing apparatus for image-processing an image based on an image signal representing the image, the area setting means setting a predetermined area of the image signal, and the image recording means recording the image on an image recording medium. On the basis of the recording gradation characteristics in, the approximate means for approximating the average optical physical quantity in the predetermined area set by the area setting means, and the average optical physical quantity estimated by the approximating means are included in a predetermined range. An image processing apparatus, comprising: a gradation correction unit that corrects gradation characteristics of the image signal. 2. An image processing apparatus for image-processing an image based on an image signal representing the image, the signal-value range setting means setting a predetermined signal value range of the image signal, and the image recording the image on an image recording medium. Based on the recording gradation characteristics in the recording means, an estimating means for approximating an average optical physical quantity in the predetermined signal value range set by the signal value range setting means, and the average optical physical quantity estimated by the approximating means within a predetermined range. An image processing apparatus comprising: a gradation correction unit that corrects the gradation characteristic of the image signal so as to be included. 3. An image processing apparatus for performing image processing on an image based on an image signal representing the image, the area setting means for setting a predetermined area of the image signal, and the image recording means for recording the image on an image recording medium. Based on the recording gradation characteristics in and the light source information at the time of observing the image, an approximate means for approximating an average optical physical quantity in the predetermined area set by the area setting means, and the approximating means estimated by the approximating means. An image processing apparatus, comprising: a gradation correction unit that corrects gradation characteristics of the image signal so that the average optical physical quantity falls within a predetermined range. 4. An image processing apparatus for image-processing an image based on an image signal representing the image, the signal-value range setting means setting a predetermined signal value range of the image signal, and the image recording the image on an image recording medium. Based on the recording gradation characteristics in the recording means and the light source information when observing the image, an approximation means for estimating an average optical physical quantity in the predetermined signal value range set by the signal value range setting means, and the approximation means An image processing apparatus comprising: a gradation correction unit that corrects gradation characteristics of the image signal so that the estimated average optical physical quantity falls within a predetermined range. 5. A changing means for changing at least one of the predetermined area and the predetermined range according to at least one of a subject and an image recording magnification relating to the image signal, and the rough calculating means. The image processing apparatus according to claim 1 or 3, wherein an approximation is performed using at least one of the predetermined area and the predetermined range changed by the changing unit. 6. A change means for changing at least one of the predetermined signal range and the predetermined range according to at least one of a characteristic of a histogram and an image recording magnification relating to the image signal, The image processing apparatus according to claim 2 or 4, wherein the approximating means makes an approximation using at least one of the predetermined signal value range and the predetermined range changed by the changing means. 7. The optical physical quantity related to the average optical physical quantity is
7. The image processing apparatus according to claim 1, wherein the image processing apparatus is an optical physical quantity of any one of transmission density, reflection density, light transmittance, light reflectance, and lightness. 8. The optical physical quantity related to the average optical physical quantity is
7. The image processing apparatus according to claim 3, wherein the image processing apparatus is an optical physical quantity of either brightness or illuminance. 9. The optical physical quantity related to the average optical physical quantity is brightness, and the maximum brightness of an image at the time of observation is Lmax and the minimum brightness is Lm.
and the predetermined range of the average luminance L when the whole image is set to the predetermined area or the predetermined signal value range is 0.05 <(L-Lmin) / (Lmax-Lmin) <0.2. 9. The image processing apparatus according to claim 8, wherein: 10. The optical physical quantity related to the average optical physical quantity is brightness, and the maximum brightness of an image at the time of observation is Lmax and the minimum brightness is Lm.
In, the predetermined range of the average brightness L when the subject area is the predetermined area or the predetermined signal value range is 0.1 <(L-Lmin) / (Lmax-Lmin) <0.3. The image processing apparatus according to claim 8, which is characterized in that. 11. The optical physical quantity related to the average optical physical quantity is illuminance, and the maximum illuminance of the image at the time of observation is Emax and the minimum illuminance is Em.
In, the predetermined range of the average illuminance E when the entire image is set to the predetermined region or the predetermined signal value range is 0.05 <(E-Emin) / (Emax-Emin) <0.2. 9. The image processing apparatus according to claim 8, wherein: 12. The optical physical quantity related to the average optical physical quantity is illuminance, and the maximum illuminance of an image at the time of observation is Emax and the minimum illuminance is Em.
In, the predetermined range of the average illuminance E when the subject area is the predetermined area or the predetermined signal value range is 0.1 <(E-Emin) / (Emax-Emin) <0.3. The image processing apparatus according to claim 8, which is characterized in that. 13. A light source information input means for inputting the light source information, wherein the estimating means makes an approximation using the light source information inputted by the light source information input means. The image processing device according to any one of the above. 14. A background area changing means for changing a background area of the image signal based on a recording gradation characteristic in the image recording means, wherein at least one of the respective means of the image processing apparatus is
The image processing apparatus according to claim 1, wherein the background area changing unit uses the image signal whose background area has been changed. 15. A background area changing unit that changes a background area of the image signal based on recording gradation characteristics in the image recording apparatus and light source information when observing the image is provided. At least one of the means is
The image signal whose background area has been changed by the background area changing means is used.
The image processing device according to any one of 1. 16. The image processing apparatus according to claim 1, wherein the image is a medical image. 17. The image processing apparatus according to claim 1, further comprising image recording means for recording the image signal whose gradation characteristic is corrected by said gradation correction means on said image recording medium. An image recording device characterized by the following. 18. An image processing apparatus for image-processing an image based on an image signal representing the image, comprising: an area setting means for setting a predetermined area of the image signal; and an image display means for displaying on an image display surface. Based on display gradation characteristics and light source information when observing the image,
Approximating means for approximating an average optical physical quantity in the predetermined region set by the area setting means, and correcting the gradation characteristic of the image signal so that the average optical physical quantity estimated by the approximating means is included in a predetermined range. An image processing apparatus, comprising: 19. An image processing apparatus for image-processing an image based on an image signal representing the image, comprising signal value range setting means for setting a predetermined signal value range of the image signal, and image display for displaying on an image display surface. Based on the display gradation characteristics in the means and the light source information when observing the image,
Approximating means for approximating an average optical physical quantity in the predetermined signal value range set by the signal value range setting means, and gradation characteristics of the image signal so that the average optical physical quantity estimated by the approximating means is included in a predetermined range. An image processing apparatus comprising: a gradation correction unit that corrects 20. Change means for changing at least one of the predetermined region and the predetermined range in accordance with at least one of a subject and an image display magnification related to the image signal, 19. The image processing apparatus according to claim 18, wherein an approximation is performed using at least one of the predetermined area and the predetermined range changed by the changing unit. 21. Change means for changing at least one of the predetermined signal value range and the predetermined range in accordance with at least one of a characteristic of a histogram relating to the image signal and an image display magnification, 20. The image processing apparatus according to claim 19, wherein the means makes an approximation using at least one of the predetermined signal range and the predetermined range changed by the changing means. 22. The image processing apparatus according to claim 18, wherein the optical physical quantity related to the average optical physical quantity is an optical physical quantity of either luminance or illuminance. 23. The optical physical quantity related to the average optical physical quantity is brightness, and the maximum brightness of an image at the time of observation is Lmax and the minimum brightness is Lm.
and the predetermined range of the average luminance L when the whole image is set to the predetermined area or the predetermined signal value range is 0.05 <(L-Lmin) / (Lmax-Lmin) <0.2. The image processing apparatus according to claim 22, wherein 24. The optical physical quantity relating to the average optical physical quantity is luminance, and the maximum luminance of the image at the time of observation is Lmax and the minimum luminance is Lm.
In, the predetermined range of the average brightness L when the subject area is the predetermined area or the predetermined signal value range is 0.1 <(L-Lmin) / (Lmax-Lmin) <0.3. The image processing apparatus according to claim 22, which is characterized in that 25. The optical physical quantity relating to the average optical physical quantity is illuminance, and the maximum illuminance of an image at the time of observation is Emax and the minimum illuminance is Em.
In, the predetermined range of the average illuminance E when the entire image is set to the predetermined region or the predetermined signal value range is 0.05 <(E-Emin) / (Emax-Emin) <0.2. The image processing apparatus according to claim 22, wherein 26. The optical physical quantity related to the average optical physical quantity is illuminance, and the maximum illuminance of the image at the time of observation is Emax and the minimum illuminance is Em.
In, the predetermined range of the average illuminance E when the subject area is the predetermined area or the predetermined signal value range is 0.1 <(E-Emin) / (Emax-Emin) <0.3. The image processing apparatus according to claim 22, which is characterized in that 27. The light source information inputting means for inputting the light source information is provided, and the estimating means makes an approximation using the light source information inputted in the light source information inputting means. The image processing device according to any one of the above. 28. A background area changing unit for changing a background area of the image signal based on recording gradation characteristics in the image recording apparatus and light source information when observing the image is provided. At least one of the means is
The image processing apparatus according to any one of claims 18 to 27, wherein the image signal whose background area has been changed by the background area changing means is used. 29. The image processing apparatus according to claim 18, wherein the image is a medical image. 30. The image processing apparatus according to claim 18, further comprising image display means for displaying on the image display surface an image signal whose gradation characteristic has been corrected by the gradation correction means. An image display device characterized by the following. 31. An image processing method for image-processing an image based on an image signal representing the image, wherein a predetermined area of the image signal is set, and a recording gradation characteristic in image recording on an image recording medium is set. On the basis of the above, the average optical physical quantity in the set predetermined area is roughly estimated, and the gradation characteristic of the image signal is corrected so that the estimated average optical physical quantity is included in a predetermined range. Image processing method. 32. An image processing method for image-processing an image based on an image signal representing the image, wherein a predetermined signal value range of the image signal is set, and a recording gradation characteristic in image recording of the image on an image recording medium. Based on, the average optical physical quantity in the set predetermined signal value range is roughly estimated, and the gradation characteristic of the image signal is corrected so that the estimated average optical physical quantity is included in a predetermined range. Image processing method. 33. An image processing method for image-processing an image based on an image signal representing the image, wherein a predetermined area of the image signal is set, and recording gradation characteristics in image recording of the image on an image recording medium are provided. Based on the light source information at the time of observing the image, an average optical physical quantity in the set predetermined area is roughly estimated, and the estimated average optical physical quantity is included in a predetermined range. An image processing method characterized by correcting tonality characteristics. 34. An image processing method for image-processing an image based on an image signal representing the image, wherein a predetermined signal value range of the image signal is set, and a recording gradation characteristic in image recording of the image on an image recording medium. Based on the light source information when observing the image, the average optical physical quantity in the set predetermined signal value range is roughly estimated, and the image signal so that the estimated average optical physical quantity is included in a predetermined range. An image processing method characterized by correcting the gradation characteristics of. 35. An image recording method according to any one of claims 31 to 34, characterized in that the image signal whose gradation characteristic has been corrected is recorded on said image recording medium. 36. An image processing method for image-processing an image based on an image signal representing the image, wherein a predetermined region of the image signal is set, and a display gradation characteristic in displaying the image on an image display surface is provided. Based on the light source information at the time of observing the image, an average optical physical quantity in the set predetermined area is roughly estimated, and the estimated average optical physical quantity is included in a predetermined range. An image processing method characterized by correcting tonality characteristics. 37. An image processing method for image-processing an image based on an image signal representing the image, wherein a predetermined signal value range of the image signal is set, and display gradation characteristics in displaying the image on the image display surface. Based on the light source information when observing the image, the average optical physical quantity in the set predetermined signal value range is roughly estimated, and the image signal so that the estimated average optical physical quantity is included in a predetermined range. An image processing method characterized by correcting the gradation characteristics of. 38. The image processing method according to claim 36 or 37, wherein the image signal whose gradation characteristic has been corrected is displayed on the image display surface. 39. A function of setting a predetermined area of an image signal representing an image in a computer, and an average optics in the set predetermined area based on a recording gradation characteristic in image recording of an image on an image recording medium. A program for realizing a function of estimating a physical quantity, and a function of correcting gradation characteristics of the image signal so that the estimated average optical physical quantity falls within a predetermined range. 40. Based on a function of setting a predetermined signal value range of an image signal representing an image on a computer and recording gradation characteristics in image recording of an image on an image recording medium, the set predetermined signal value range A program for realizing a function of approximating an average optical physical quantity and a function of correcting gradation characteristics of the image signal so that the approximated average optical physical quantity falls within a predetermined range. 41. Based on a function of setting a predetermined area of an image signal representing an image on a computer, a recording gradation characteristic in recording an image on an image recording medium, and light source information when observing the image. A function of approximating an average optical physical quantity in the set predetermined area, and a function of correcting the gradation characteristic of the image signal so that the approximated average optical physical quantity is included in a predetermined range. Program for. 42. Based on a function of setting a predetermined signal value range of an image signal representing an image in a computer, a recording gradation characteristic in recording an image on an image recording medium, and light source information when observing the image. A function of approximating an average optical physical quantity in the set predetermined signal value range, and a function of correcting the gradation characteristic of the image signal so that the approximated average optical physical quantity is included in a predetermined range, Program to realize. 43. The program according to any one of claims 39 to 42, wherein the computer is caused to realize a function of recording an image signal of which the gradation characteristic is corrected on the image recording medium. program. 44. Based on a function of setting a predetermined area of an image signal representing an image on a computer, display gradation characteristics in displaying the image on an image display surface, and light source information when observing the image. A function of approximating an average optical physical quantity in the set predetermined area, and a function of correcting the gradation characteristic of the image signal so that the approximated average optical physical quantity is included in a predetermined range. Program for. 45. Based on a function of setting a predetermined signal value range of an image signal representing an image on a computer, display gradation characteristics in displaying the image on an image display surface, and light source information when observing the image. A function of approximating an average optical physical quantity in the set predetermined signal value range, and a function of correcting the gradation characteristic of the image signal so that the approximated average optical physical quantity is included in a predetermined range, Program to realize. 46. The program according to claim 44, wherein the computer is caused to realize a function of displaying the image signal whose gradation characteristic has been corrected on the image display surface. . 47. A function of setting a predetermined area of an image signal representing an image in a computer, and an average optics in the set predetermined area based on a recording gradation characteristic in image recording of an image on an image recording medium. A computer-readable recording recording a program for realizing a function of approximating a physical quantity and a function of correcting gradation characteristics of the image signal so that the approximated average optical physical quantity falls within a predetermined range. Medium. 48. A function of setting a predetermined signal value range of an image signal representing an image in a computer, and based on a recording gradation characteristic in image recording of an image on an image recording medium, the set predetermined signal value range A computer-readable program storing a program for realizing the function of approximating the average optical physical quantity and the function of correcting the gradation characteristic of the image signal so that the approximated average optical physical quantity falls within a predetermined range. Recording medium. 49. Based on a function of setting a predetermined area of an image signal representing an image in a computer, a recording gradation characteristic in recording an image on an image recording medium, and light source information when observing the image. A function of approximating an average optical physical quantity in the set predetermined area, and a function of correcting the gradation characteristic of the image signal so that the approximated average optical physical quantity is included in a predetermined range. A computer-readable recording medium in which a program for recording is recorded. 50. Based on a function of setting a predetermined signal value range of an image signal representing an image on a computer, a recording gradation characteristic in recording an image on an image recording medium, and light source information when observing the image. A function of approximating an average optical physical quantity in the set predetermined signal value range, and a function of correcting the gradation characteristic of the image signal so that the approximated average optical physical quantity is included in a predetermined range, A computer-readable recording medium recording a program to be realized. 51. The recording medium according to any one of claims 47 to 50, wherein the computer is made to realize a function of recording an image signal whose gradation characteristic has been corrected on the image recording medium. A computer-readable recording medium on which a program for recording is recorded. 52. Based on a function of setting a predetermined area of an image signal representing an image in a computer, display gradation characteristics in displaying the image on an image display surface, and light source information when observing the image. A function of approximating an average optical physical quantity in the set predetermined area, and a function of correcting the gradation characteristic of the image signal so that the approximated average optical physical quantity is included in a predetermined range. A computer-readable recording medium in which a program for recording is recorded. 53. Based on a function of setting a predetermined signal value range of an image signal representing an image on a computer, display gradation characteristics in displaying the image on an image display surface, and light source information when observing the image. A function of approximating an average optical physical quantity in the set predetermined signal value range, and a function of correcting the gradation characteristic of the image signal so that the approximated average optical physical quantity is included in a predetermined range, A computer-readable recording medium recording a program to be realized. 54. The recording medium according to claim 52, wherein the computer is made to realize a function of displaying the image signal whose gradation characteristic has been corrected on the image display surface. A computer-readable recording medium recording a program.