JPH06114012A - Color evaluation method of color image - Google Patents

Abstract

PURPOSE:To obtain an evaluation method which enables evaluation of color of a color image stably and efficiently without evaluation of a clinic image by any physician. CONSTITUTION:An R filter section, a G filter section and a B filter section are selected sequentially at the S14, the intensity of the light passing through the R filter section, the G filter section and the B filter section selected is detected at the S 15 and at the S 16 the Dj (J=R, G, B) is calculated based on a detection data to be displayed on a display section 30. The Dj (J=R, G, B) calculated at the S 18 is substituted to a discriminant formula of Z=1.679-9.506DR+73.808DG-60.812DB to obtain a computed value Z (0). Thus, the computed value Z(0) is compared with a specified criterion to judge the propriety thereof. Then, a shift is made to the S 19 to complete.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color evaluation method for a color image, particularly a color image for judging the quality of an endoscopic color image.

[0002]

2. Description of the Related Art Photographic density, which is the magnitude of light modulation by a certain portion on a photographic film or photographic print, is measured by JIS (eg: JIS7605, JIS7653).
It is indispensable to the photographic science, as can be seen from the provisions of. That is, to evaluate the brightness and hue of an image, to predict how the film will work during the photo printing process,
Further, determining a certain reference amount of the coloring dye in the image for the purpose of controlling the developing process is extremely important to both the user and the producer.

The color of an image is evaluated by color density, and depending on its application, according to JIS7653, the status A density is used for a film or print to be observed directly or by projection, and a color designed for printing like a negative film. Status B density is specified for evaluation of photographic materials. These are all called arbitrary three-color diffusion density, use filters with different spectral transmission characteristics,
The target color density is obtained. As specific applications thereof, the status A density is used for checking the development processing of reversal film in a developing place, the check of a reproduction system including illumination photography for an image exposed in a single color, and the status B density is It is used to check the color balance of negative film printed on photographic paper at Ragui.

[0004]

As described above, the prior arts are all aimed at knowing or obtaining an appropriate color balance, and determine whether the color of the final color image is good or bad. It is not a judgment. This is because the rating of the color of a color image differs depending on the photographer's intention and purpose of photography, and this photographer's intention and purpose of photography cannot be known to the image reproducer maker or the technician at the film development site. Also, it varies from photographer to photographer.

That is, the color evaluation of a photographic image cannot be accurately performed unless it is performed in accordance with the intention of photographing, but in the case of a general photograph, the variety of subjects and the like makes the intention of photographing significant. Can't be controlled. Therefore, under such circumstances, it is self-evident that the color evaluation of a general photograph taken cannot be uniformly regulated. For this reason, the reason is that, although the arbitrary three-color diffusion densities have been conventionally measured, they were not used for the color evaluation of the final color image.

However, in the endoscopic image, the photographing purpose is unique, and the intended purpose is to "use for diagnosis". "To be used for diagnosis."
Not only is the color of the diseased part clearly extracted, but it is a color that the doctor has been accustomed to under the direct view of the endoscope, and is a color that is empirically comfortable. More specifically, doctors will understand that subtle unevenness and color changes of living mucous membranes, white moss, redness,
Diagnosis is made based on a comprehensive subjective judgment in light of slight differences in color shades such as red print and vascular see-through image, as well as histological and pathological background, and clinical experience.

Under such circumstances, even if a manufacturer develops a new product, the color reproduction system of the developed product cannot be evaluated until the doctor's evaluation is made. Further, as described above, since the academic and clinical empirical backgrounds differ depending on individual doctors, it is necessary to conduct clinical trials and listen to their opinions under a large number of doctors, which causes a large time loss. Furthermore, since it is a subjective evaluation, it ignores the influence of the human visual characteristics such as the situation around the observation site, the color temperature of the observing equipment used, illusions, color vision constants, chromatic adaptation, and afterimages. There is also a drawback that the evaluation is not stable because it cannot be done.

The present invention has been made in view of the above circumstances, and a clinical image can be evaluated without being evaluated by a doctor.
An object of the present invention is to provide a color evaluation method for a color image, which enables stable and efficient color evaluation of a color image.

[0009]

The color evaluation method of a color image of the present invention comprises a light source for irradiating a color image to be inspected with white light and a light from the light source reflected or transmitted by the color image to be inspected. A measuring means for measuring the amount of light; and R, G, B color filters that are sequentially inserted on the optical path between the light source and the color image to be inspected or on the optical path between the color image to be inspected and the measuring means. A color evaluation method for a color image used in a light quantity inspection device, wherein the color image to be inspected is at a position where the light emitted from the light source is incident on the measuring means by being reflected or transmitted by the color image to be inspected. And a second step of measuring the amount of light based on the color image to be inspected, which is separated into R, G and B color component lights by the color filter.
And a third step of calculating a color characteristic from the light amount of each color component light measured in the second step, and comparing the color characteristic obtained in the third step with a predetermined reference value. Fourth, it has steps and.

[0010]

[Operation] The color image to be inspected is inserted at the position where the light emitted from the light source is reflected or transmitted by the color image to be inspected and is incident on the measuring means, and the R, G, and B color component lights are separated by the color filters. The light quantity based on the separated and inspected color image is measured, the color characteristic is calculated from the measured light quantity of each color component light, and the obtained color characteristic is compared with a predetermined reference value.

[0011]

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

1 to 4 relate to an embodiment of the present invention, FIG. 1 is a flow chart showing a flow of a color evaluation method of a clinical color image, and FIG. 2 is a constitution of a densitometer used for color evaluation of a clinical color image. FIG. 3 is an external view showing the external appearance of the densitometer of FIG. 2, and FIG. 4 is a flow chart showing the flow of a method of calculating a discriminant used for color evaluation of a clinical color image.

First, a method of calculating a discriminant used for color evaluation of a clinical color image by a multivariate analysis method is shown in FIG.
Will be explained.

As shown in FIG. 4, starting from step (hereinafter referred to as S) 1, a plurality of clinical film images, for example, about 500 sheets, are sampled at S2. S3
A plurality of doctors judge whether the clinical film image taken in step 2 is good or bad, and the film is classified based on the judgment in step S4.
In S5, the arbitrary three-color diffuse transmission density of the classified film is measured, and the cyan density D of status A of each film is measured.
R, magenta density DG, and yellow density DB are obtained. In step S6, the cyan density DR, magenta density DG, and yellow density DB of the status A of the individual films obtained are statistically processed, and in step S7, the variance ratio is input in the descending order, the discriminant coefficient is calculated, and the discriminant Z is calculated. Then, the process proceeds to S8 and ends.

In the case of an endoscopic image, the calculated discriminant Z was Z = 1.679-9.506DR + 73.808DG-60.812DB.

Color evaluation of a clinical color image using the discriminant thus obtained will be described.

As shown in FIG. 2, a densitometer 1 used for color evaluation of a clinical color image has a light source 2 for supplying white light.
And a mirror 4 that changes the optical path of the white light, and the illumination light whose optical path is changed by the mirror 4 is transmitted to the stage 6
The film 8 inserted on the stage 6 is irradiated with the light through an aperture 9 provided in the. The white light transmitted through the film 8 is sequentially separated by the filter 10 into the V component light for visual diffusion density measurement and the RGB component light, and the separated sequential component lights are separated by the photomultiplier tube (II) 12. More photoelectric conversion is performed, and the amount of light is measured for each color component. I. The output signal of I12 is amplified by the amplifier 14, and then the A / D converter 1
A / D conversion is carried out by 6 and transmitted to the display circuit 18. The display circuit 18 performs signal processing on the signal from the A / D converter 16 to obtain a visual diffusion transmission density (hereinafter, DV) of the status A of the film 8, an arbitrary three-color diffusion transmission density (hereinafter,
The color density or Dj (J = R, G, B)) is displayed. The filter 10 has a disk shape, and although not shown, a visual diffusion density measuring V filter portion, an R filter portion, a G filter portion, and a B filter portion are provided in the circumferential direction,
By rotating the filter 10, a desired filter section can be selected.

The appearance of the densitometer 1 is as shown in FIG.
The light source 2, the mirror 4, the amplifier 14, and the A / D converter 1 described above.
6, the stage 6 is provided on a base 22 having a built-in display circuit 18. The white light from the stage 6 passes through the condensing cylindrical portion 26 and the filter 10, I.I. I12 and the amplifier 14 are guided to the arm portion 24 having the built-in. The filter 6 can be rotated by rotating a filter turret 28 provided on the arm portion 24, and the desired filter portion can be selectively inserted in the optical path. Incidentally, DV, Dj (J = J =
R, G, B) are displayed on the display unit 30.

A color evaluation method for a clinical color image using such a densitometer will be described.

As shown in FIG. 1, starting from S11, first, in S2, the film 8 is set on the stage 6, and the center of the image in the film is aligned with the center of the aperture 9. Next, in S13, the filter turret 28 is rotated to insert the visual diffusion density measuring V filter portion of the filter 10 in the optical path, and the white light is emitted from the light source 2 to open the aperture 9, the film 8, and the filter 10. V
The light amount of the light sequentially transmitted through the filter unit is I. Measured by I12, processed by the display circuit 18 to display DV on the display unit 30, and determine whether DV <1.0. If DV <1.0, proceed to S14. It is judged that the light amount of the film 8 is insufficient, and the measurement is stopped.

Subsequently, in S14, the filter turret 28
Is rotated to sequentially select the R filter section, the G filter section, and the B filter section of the filter 10, and in S15, the intensity of light transmitted through the selected R filter section, G filter section, and B filter section is set to I.D. I12 is detected, and in S16, Dj (J = R, G, B) is calculated based on the detected data and displayed on the display unit 30. In S18, the calculated Dj (J = R, G, B) is substituted into the discriminant formula ZZ = 1.679-9.506DR + 73.808DG-60.812DB to obtain the calculated value Z (0), and this calculated value Z By comparing (0) with a predetermined determination criterion, it is determined whether the quality is good or not,
The process proceeds to S19 and ends.

The comparison between the calculated value Z (0) and the predetermined discrimination criterion in S18 is, for example, if (1) -14 <Z (0) <-3, the standard (good) (2)- If 3 ≦ Z (0) ≦ 2.6 or Z (0) <14, intermediate (allowable range) (3) If Z (0)> 2.6, it is determined as defective.

Here, the transmission characteristics of the filter 10 which greatly affects the measurement of DV and Dj (J = R, G, B) will be described. The transmission characteristic of the filter 10 does not mean that it has the characteristic by itself. That is, at the time of DV measurement, the spectral distribution of the light source 2, the spectral transmission characteristics of the filter 10 and the I.V. It is sufficient that the product of the spectral sensitivity distributions of I12 is close to the standard visual sensitivity characteristic. With respect to the other color densities, it is sufficient that each color density has a characteristic that the value obtained by multiplying the above three values is defined as the status A. The values of these details are specified in JIS7605 and JIS765.
3 are described.

As described above, according to the color evaluation method of the clinical color image of this embodiment, the evaluation of each clinical color image can be objectively judged by a doctor by using the previously determined discriminant. Therefore, the color evaluation of the color image can be performed stably and efficiently.

In the above embodiment, the transmissive object (film 10) is described, but a reflective object (printed image) may be used. In this case, not the transmission density but the reflection density is measured. Further, the density of diffused light is not limited, and the density of parallel light may be used. Furthermore, the measurement site of the film is not limited to the center, and the measurement sequence is DV, DR,
It does not have to be in the order of DG and DB, but in any order. Also,
It is not limited to DV <1.0, as long as some of the prediction accuracy is tolerated. Furthermore, the discriminant was calculated using three variables of DR, DG, and DB as parameters, but two variables, for example,
It is sufficiently effective to use DG and DB as parameters.

[0026]

As described above, according to the color image evaluation method of the present invention, the color of the color image to be inspected is incident on the measuring means when the light emitted from the light source is reflected or transmitted by the color image to be inspected. An image is inserted, separated into R, G, and B color component lights by a color filter, the amount of light based on the color image to be inspected is measured, and the color characteristics are calculated from the measured amount of light of each color component light. Since the color characteristics are compared with a predetermined reference value, there is an effect that the color image of the color image can be stably and efficiently evaluated without the evaluation of the clinical image by the doctor.

[Brief description of drawings]

FIG. 1 is a flowchart showing a flow of a color evaluation method for a clinical color image according to an embodiment.

FIG. 2 is a configuration diagram showing a configuration of a densitometer used for color evaluation of a clinical color image according to an embodiment.

FIG. 3 is an external view showing the external appearance of the densitometer of FIG. 2 according to an embodiment.

FIG. 4 is a flowchart showing a flow of a method for calculating a discriminant used in color evaluation of a clinical color image according to an embodiment.

[Explanation of symbols]

 1 ... Densitometer 2 ... Light source 6 ... Stage 8 ... Film 10 ... Filter 12 ... I. I 14 ... Amplifier 16 ... A / D converter 18 ... Display circuit

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[Procedure amendment]

[Submission date] November 6, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] 0003

[Correction method] Change

[Correction content]

The color of an image is evaluated by color density, and depending on its application, according to JIS7653, the status A density is used for a film or print to be observed directly or by projection, and a color designed for printing like a negative film. Status B density is specified for evaluation of photographic materials. These are all called arbitrary three-color diffusion density, use filters with different spectral transmission characteristics,
The target color density is obtained. As specific applications thereof, the status A density is used for checking the development processing of reversal film in a developing place, the check of a reproduction system including illumination photography for an image exposed in a single color, and the status B density is It is used to check the color balance of negative film printed on photographic paper in the laboratory .

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0018

[Correction method] Change

[Correction content]

The appearance of the densitometer 1 is as shown in FIG.
The light source 2, the mirror 4, the amplifier 14, and the A / D converter 1 described above.
6, the stage 6 is provided on a base 22 having a built-in display circuit 18. The white light from the stage 6 passes through the condensing cylindrical portion 26 and the filter 10, I.I. I12 and the amplifier 14 are guided to the arm portion 24 having the built-in. The full
The filter 10 can be rotated by rotating a filter turret 28 provided on the arm portion 24, and the desired filter portion can be selectively inserted in the optical path. Incidentally, DV and Dj processed by the display circuit 18
(J = R, G, B) is displayed on the display unit 30.

Claims (1)

[Claims] 1. A light source for irradiating a color image to be inspected with white light, measuring means for measuring the amount of light from the light source reflected or transmitted by the color image to be inspected, the light source and the color to be inspected. A color evaluation method for a color image used in a light quantity inspection device having R, G, and B color filters that are sequentially inserted on an optical path with an image or on an optical path with the inspected color image and the measuring means. Then, a first step of inserting the color image to be inspected at a position where the light emitted from the light source is reflected or transmitted by the color image to be inspected to enter the measuring means, and R by the color filter. Second, the light amount is separated into respective color component lights of G, G, and B, and the amount of light based on the color image to be inspected is measured.
And a third step of calculating a color characteristic from the light amount of each color component light measured in the second step, and comparing the color characteristic obtained in the third step with a predetermined reference value. Fourth, a color evaluation method of a color image, which comprises the step of.