JP2010088559A - Color chart - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a color chart used for performing an examination of gradation characteristics. <P>SOLUTION: The color chart includes first through third color chip groups respectively having a plurality of color chips arranged on an arc, and the color chips constituting the first through third color chip groups are arranged on one circle. The color chips constituting the first color chip group show a gradation of colors changing from black to red from one end toward the other end. The color chips constituting the second color chip group show a gradation of colors changing from black to green from one end toward the other end. The color chips constituting the third color chip group show a gradation of colors changing from black to blue from one end toward the other end. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a color chart, and more particularly to a color chart used for performing a gradation characteristic inspection in image processing of an endoscope system.

  In an endoscope system having a scope equipped with an image sensor, an image processing characteristic of the endoscope system such as white balance is inspected at the time of development or the like. In such an inspection, a chart (for example, a white balance chart) suitable for the inspection is imaged, and a value necessary for the inspection is measured from the obtained image signal or the like.

Patent Document 1 discloses an inspection device (measuring container) for inspecting image processing characteristics by imaging a color chart or the like provided inside with a scope.
Japanese Patent Laid-Open No. 05-137693

  However, in the apparatus of Patent Document 1 and the like, since a color chart for inspecting the gradation characteristics for each color is not prepared, the gradation characteristics inspection cannot be performed appropriately.

  Accordingly, an object of the present invention is to provide a color chart that can perform gradation characteristic inspection for each color in image processing of an endoscope system.

  The color chart according to the present invention includes first to third color chart groups each having a plurality of color charts arranged on an arc, and the color charts constituting the first to third color chart groups are one circle. The color charts that constitute the first color chart group are arranged on top of each other and exhibit a gradation that changes from black to red from one end to the other end, and the color chart that constitutes the second color chart group Indicates a gradation that changes from black to green from one end to the other end, and the color charts constituting the third color chart group change from black to blue from one end to the other end. Shows changing gradation.

  Since the color charts constituting the color chart (the first to third color chart groups) are arranged on one circle, the color chart is arranged so that the center point of the circle faces the objective optical system. By doing so, it is possible to obtain an image including all the color charts arranged on the circle under the same imaging conditions such as peripheral dimming by a single imaging operation.

  An image obtained by capturing all of the color charts constituting each color chart group at a time is displayed on a monitor or the like, and the light of each color (for each wavelength of light) in the portion corresponding to each color chart of the displayed image is displayed. By measuring the intensity with a spectral radiance meter, the characteristics of the portion corresponding to each color chart of the image subjected to the image processing of the endoscope system can be digitized. The information corresponding to each digitized color chart was measured for the intensity of light for each color (for each wavelength of light) corresponding to each color chart in an image processed in a normal endoscope system. It is possible to know the gradation characteristics for each color in the image processing by comparing with the numerical value assumed in the case. The digitization of the characteristics of an image that has undergone image processing is not only to measure the light intensity in the image displayed on the monitor with a spectroradiometer, but also to capture the image signal output from the processor into a video board. It is also conceivable to calculate a luminance value or the like from the obtained image. In addition, since the color chart is arranged so as to show gradation, the color chart measures the light intensity for each color (for each wavelength of light) in an image subjected to image processing in a normal endoscope system. The numerical value assumed in this case shows a change with a specific law for each adjacent color chart, and can easily compare with an actual measurement result to know the gradation characteristic. The first color chart group is used for inspecting the gradation characteristic between red, which is one of the primary colors of black and additive color mixture, and the second color chart group is one of the primary colors of black and additive color mixture. The third color chart group is used to inspect the tone characteristics between black and blue, which is one of the primary colors of additive color mixture. The

  Preferably, the color chart is formed of a matte material on the surface imaged by the scope of the endoscope apparatus.

  Thereby, it becomes possible to prevent whiteout due to reflection of light emitted from the light source unit of the endoscope system and applied to the imaging surface of the color chart via the light guide of the scope.

  Preferably, the image forming apparatus further includes a fourth color chart group having a plurality of color charts arranged on an arc, and the color charts constituting the first to fourth color chart groups are arranged on a circle. The color charts constituting the color chart group show a gradation that changes from black to yellow from one end to the other end.

  The fourth color chart group is used to inspect a gradation characteristic between black and yellow, which is the main color in the endoscopic image.

  Preferably, the image forming apparatus further includes a fifth color chart group having a plurality of color charts arranged on an arc, and the color charts constituting the first to third color chart groups and the fifth color chart group are circles. The color charts arranged on the top and constituting the fifth color chart group show gradations that change from black to white from one end to the other end.

  The fifth color chart group is used to inspect a gradation characteristic between black and white.

  Preferably, the color chart further includes a sixth color chart group having a plurality of color charts arranged on an arc, and the color charts constituting the first to third color chart groups and the sixth color chart group are circles. The color charts arranged on the top and constituting the sixth color chart group show a gradation that changes from blue to magenta from one end to the other end.

  The sixth color chart group is used for inspecting gradation characteristics between blue and magenta, which are main colors of the endoscopic image at the time of indigo staining.

  Preferably, the image forming apparatus further includes a seventh color chart group having a plurality of color charts arranged on an arc, and the color charts constituting the first to third color chart groups and the seventh color chart group are circles. The color charts arranged on the top and constituting the seventh color chart group show a gradation that changes from magenta to red from one end to the other end.

  The seventh color chart group is used to inspect gradation characteristics between magenta and red, which are main colors in an endoscopic image at the time of an upper digestive tract inspection such as a stomach.

  Preferably, the image forming apparatus further includes an eighth color chart group having a plurality of color charts arranged on an arc, and the color charts constituting the first to third color chart groups and the eighth color chart group are circles. The color charts arranged on the top and constituting the eighth color chart group show a gradation that changes from red to yellow from one end to the other end.

  The eighth color chart group is used for inspecting gradation characteristics between red and yellow, which are main colors in an endoscopic image at the time of a lower digestive tract examination such as a large intestine.

  Preferably, the image forming apparatus further includes fourth to eighth color chart groups each having a plurality of color charts arranged on an arc, and the color charts constituting the first to eighth color chart groups are arranged on a circle. The color chart constituting the fourth color chart group shows a gradation that changes from black to yellow from one end to the other end, and the color chart constituting the fifth color chart group Shows a gradation that changes from black to white from one end to the other, and the color charts constituting the sixth color chart group change from blue to magenta from one end to the other end. Color charts showing gradation and constituting the seventh color chart group show gradations that change from magenta to red from one end to the other end, and the color charts constituting the eighth color chart group are Change from red to yellow from one end to the other Show a gradient.

  More preferably, the first to eighth color chart groups are the second color chart group, the fifth color chart group, the fourth color chart group, the eighth color from the first color chart group 71a clockwise or counterclockwise. The vote group, the seventh color chart group, the sixth color chart group, and the third color chart group are arranged in this order.

  More preferably, the black color chart arranged at one end of the first color chart group and the black color chart arranged at one end of the third color chart group are shared, and the other of the third color chart group A blue color chart arranged at one end of the color chart and a blue color chart arranged at one end of the sixth color chart group, a magenta color chart arranged at the other end of the sixth color chart group, and Shared with the magenta color chart arranged at one end of the seventh color chart group, arranged at one end of the red color chart and the eighth color chart group arranged at the other end of the seventh color chart group The red color chart, the yellow color chart arranged at the other end of the eighth color chart group, and the yellow color chart arranged at the other end of the fourth color chart group, and The color charts are arranged so that at least one of the black color chart arranged at one end of the fourth color chart group and the black color chart arranged at one end of the fifth color chart group is shared. Is done.

  By sharing the color chart at the end of the adjacent color chart group, it is possible to efficiently arrange the color chart on the color chart, and one color chart is enlarged or the color chart that the color chart group has The measurement accuracy can be increased by increasing the number.

  As described above, according to the present invention, it is possible to provide a color chart capable of performing gradation characteristic inspection for each color in image processing of an endoscope system.

  Hereinafter, the configuration of the endoscope system according to the present embodiment will be described with reference to the drawings. The endoscope system 1 according to the present embodiment includes a scope 10, a processor 30, and a monitor 50 (during normal observation, refer to FIG. 1). Further, as will be described later, in order to inspect the gradation characteristics for each color in the image processing of the endoscope system 1 when the scope 10 or the processor 30 is developed or manufactured, the gradation inspection apparatus 70 and the spectral radiation A luminance meter 90 is also used.

  The scope 10 includes a light guide 11 such as an optical fiber cable, an objective optical system 13 including an objective lens and a visibility correction filter, an imaging unit 14 including an imaging element such as a CCD, and a video signal processing unit 15.

  The processor 30 includes a light source unit 31, a video signal processing unit 33, and a control unit 35 that controls each unit of the processor 30. In the processor 30, subsequent image processing for generating an image (video signal) that can be displayed on the monitor 50 is performed on the image signal acquired by the scope 10 and subjected to the previous image processing in the video signal processing unit 15.

  A monitor 50 is connected to the processor 30. The monitor 50 is a display unit that displays an image that has been subjected to image processing by the processor 30 and that conforms to a predetermined video signal standard. In addition to the monitor 50, the processor 30 may be connected to an external storage device that records image data processed by the processor 30, a printer that outputs (prints out) an image, and the like.

  During normal observation, the light emitted from the light source unit 31 is irradiated from the distal end portion of the scope 10 toward the object to be observed through the light guide 11. The light source unit 31 includes a light source 31a that emits light and a diaphragm 31b. The amount of light emitted from the light source 31a to the object to be observed through the light guide 11 is adjusted by the opening of the diaphragm 31b.

  Reflected light from the object to be observed enters the image sensor of the image capturing unit 14 via the objective optical system 13. The image sensor photoelectrically converts the incident light and outputs an image signal. The image signal output from the imaging unit 14 is subjected to the preceding image processing such as YC separation, white balance adjustment, and color correction in the video signal processing unit 15, and is output to the video signal processing unit 33 of the processor 30. In the processor 30, the video signal processing unit 33 performs subsequent image processing to obtain a video signal that can be output by the monitor 50.

  In this embodiment, at the time of development or manufacture of the scope 10 or the processor 30, the gradation inspection apparatus 70 and the spectral radiance meter 90 are used to inspect gradation characteristics for each color in the image processing of the endoscope system 1. Is done. The gradation inspection device 70 and the spectral radiance meter 90 are not used during normal observation of the endoscope system 1. The gradation inspection apparatus 70 includes a color chart 71, a fixing base 73 that fixes the color chart 71 at a position facing the objective optical system 13, and a holding unit 75 that holds the distal end portion of the scope 10 in a fixed state.

  The color chart 71 includes first to eighth color chart groups 71a to 71h. The first to eighth color chart groups 71a to 71h each have a plurality of color charts of the same shape arranged at equal intervals on the arc, and colors constituting the first to eighth color chart groups 71a to 71h. The votes are arranged on one circle C (see FIG. 2). The circle C (see the broken lines in FIGS. 2 to 4) is for explaining the arrangement state of the color chart, and is not shown on the actual color chart 71. FIG. 2 shows an embodiment in which the same color fan-shaped color chart extending radially from the center point CP of the circle C is arranged on the circle C at equal intervals to form the color chart 71. It is not limited to. For example, a configuration in which the center point CP is shared and the inner region of the small circle SC smaller than the circle C does not form a color chart (see FIG. 3), and a circular arc portion that forms a fan shape is not a curve but a straight line ( (See FIG. 4).

  In the present embodiment, the color charts constituting the first to eighth color chart groups 71a to 71h are described as having the same shape. However, the color charts obtained by imaging each color chart are displayed on the monitor 50. As long as the portion corresponding to the color chart in the color chart image has a size that can be measured by the spectral radiance meter 90, it may have a different shape. Further, the arrangement of color charts is not limited to equal intervals.

  The color chart groups are arranged in the clockwise order from the first color chart group 71a, the second color chart group 71b, the fifth color chart group 71e, the fourth color chart group 71d, the eighth color chart group 71h, and the seventh color. The vote group 71g, the sixth color chart group 71f, and the third color chart group 71c are arranged, but the arrangement order is not limited to this, and may be arranged counterclockwise, for example. However, when the arrangement order of the color chart groups is set so that the color charts arranged at the ends of the adjacent color chart groups have the same color as in this embodiment, the adjacent color chart groups will be described later. It becomes possible to share color charts of the same color.

  In the color chart 71, in order to prevent whiteout due to reflection of light emitted from the light source unit 31 and irradiated through the light guide 11, it is desirable that the surface to be imaged be made of a matte material.

  The first to eighth color charts 71a to 71h each have M color charts arranged in a line on an arc. M is an integer of 3 or more, and FIG. 2 shows a color chart 71 in the case of M = 4. In the present embodiment, the first to eighth color chart groups 71a to 71h are described as being composed of M (= 4) color charts. The number may be different.

As shown in FIG. 2, the color chart 71 has the sixth and seventh color chart groups 71f and 71g on the upper side, the second and fifth color chart groups 71b and 71e on the lower side, and the first and third color charts. With the groups 71a and 71c arranged on the right side and the fourth and eighth color chart groups 71d and 71h arranged on the left side, the color chart positions constituting the first to eighth color chart groups 71a to 71h are defined as follows: To do. The first color chart position is located at the top end of the first color chart group 71a and _{A 11,} in the downward direction (clockwise) from the _{A 11,} the the second color chart position _{A 12,} m-th color chart positions A _1m , the M-th color chart position, that is, the color chart position located at the lower end of the first color chart group 71a is defined as A _1M . m is an integer of 1 or more and M or less. The first color chart positions located at the left end of the second color chart group 71b and _{A 21,} in the right direction (counterclockwise) from the _{A 21,} the second color chart position _{A 22,} m-th color chart positions A _2m , the M-th color chart position, that is, the color chart position located at the right end of the second color chart group 71 b is A _2M . The first color chart position located at the lower end of the third color chart group 71c and _{A 31,} upward (counterclockwise) from the _{A 31,} the second color chart position _{A 32,} m-th color chart positions A _3m , and the M-th color chart position, that is, the color chart position located at the upper end of the third color chart group 71c is A _3M . The first color chart position located at the lower end of the fourth color chart group 71d and _{A 41,} in the upward direction (clockwise) from the _{A 41,} the the second color chart position _{A 42,} m-th color chart positions A _4m , the M-th color chart position, that is, the color chart position located at the upper end of the fourth color chart group 71d is A _4M . The first color chart positions located at the left end of the fifth color chart group 71e and _{A 51,} in the right direction (counterclockwise) from the _{A 51,} the second color chart position _{A 52,} m-th color chart positions A _5m , and the M-th color chart position, that is, the color chart position located at the right end of the fifth color chart group 71e is A _5M . The first color chart position located at the right end of the sixth color chart group 71f and _{A 61,} from _{A 61} to the left (counterclockwise), the second color chart position _{A 62,} m-th color chart positions A _6m , and the M-th color chart position, that is, the color chart position located at the left end of the sixth color chart group 71 f is A _6M . The first color chart position located at the right end of the seventh color chart group 71g and _{A 71,} from _{A 71} to the left (counterclockwise), the second color chart position _{A 72,} m-th color chart positions A _7m , the M-th color chart position, that is, the color chart position located at the left end of the seventh color chart group 71g is A _7M . The first color chart position is located at the top end of the eighth color chart group 71h and _{A 81,} in the downward direction (counterclockwise) from the _{A 81,} the second color chart position _{A 82,} m-th color chart positions A _8m , and the M-th color chart position, that is, the color chart position located at the lower end of the eighth color chart group 71h is A _8M .

The color charts constituting the first color chart group 71a have G and B color tones with the minimum intensity (0%), and R colors from one end (upper end) to the other end (lower end) of the array. Shows a gradation in which the color tone increases monotonously (at a constant rate) from the minimum strength (0%) to the maximum strength (100%) for each color chart, that is, changes from black to red in a clockwise direction. . Specifically, at the position A _1m in the first color chart group 71a, the strength of the color tone of R is {100 × (m−1) ÷ (M−1)}%, and the strength of the color tone of G and B is strong. A color chart having a length of 0% is arranged. 2, the position A ₁₁ of the upper end of the first color chart group 71a R, G, the intensity of the color of B are disposed color chips of black is 0% both in the position A _1M of the lower end A red color chart having a color tone strength of R of 100% and a color tone strength of G and B of 0% is arranged. The first color chart group 71a is used to inspect the gradation characteristics between black and red, which is one of the primary colors of additive color mixture.

The color charts constituting the second color chart group 71b have the minimum intensity (0%) of the colors of R and B, and G colors from one end (left end) to the other end (right end) of the array. A gradation in which the color tone increases monotonously (at a constant rate) from the minimum strength (0%) to the maximum strength (100%) for each color chart, that is, changes from black to green counterclockwise. Show. Specifically, at the position A _2m in the second color chart group 71b, the strength of the color tone of G is {100 × (m−1) ÷ (M−1)}%, and the strength of the color tone of R and B is strong. A color chart having a length of 0% is arranged. 2, the left end position _{A 21} in the second color chart group 71b is arranged color chips of the same black as the position _{A 11,} with 100% intensity of the color of G is the right end position _{A 2M,} R A green color chart having a color tone strength of 0% and B is disposed. The second color chart group 71b is used to inspect the gradation characteristics between black and green, which is one of the primary colors of additive color mixture.

The color charts constituting the third color chart group 71c have the minimum intensity (0%) of the colors of R and G, and B colors from one end (lower end) to the other end (upper end) of the array. A gradation in which the color tone increases monotonously (at a constant rate) from the minimum strength (0%) to the maximum strength (100%) for each color chart, that is, changes from black to blue counterclockwise. Show. Specifically, at the position A _3m in the third color chart group 71c, the strength of the color tone of B is {100 × (m−1) ÷ (M−1)}%, and the strength of the color tone of R and G is strong. A color chart having a length of 0% is arranged. 2, the position _{A 31} of the lower end of the third color chart group 71c is arranged color chips of the same black as the position _{A 11,} the position _{A 3M} of the upper end at 100% intensity of the color tone of B, R A blue color chart having 0 and G color strengths of 0% is arranged. The third color chart group 71c is used for inspecting the gradation characteristics between black and blue which is one of the primary colors of additive color mixture.

The color charts constituting the fourth color chart group 71d have the minimum intensity of the B color tone, and the R and G color tones from one end (lower end) to the other end (upper end) of the array. Shows a gradation that increases monotonously (at a constant rate) from the minimum strength to the maximum strength each time, that is, changes from black to yellow clockwise. Specifically, at the position A _4m in the fourth color chart group 71d, the strength of the color tone of R and G is {100 × (m−1) ÷ (M−1)}%, and the strength of the color tone of B is strong. A color chart having a length of 0% is arranged. In FIG. 2, the same black color chart as the position A ₁₁ is arranged at the lower end position A ₄₁ in the fourth color chart group 71 d, and the strengths of the color tones of R and G are both 100 at the upper end position A _{4 M.} %, A yellow color chart having a B color strength of 0% is arranged. The fourth color chart group 71d is used to inspect a gradation characteristic between black and yellow, which is the main color in the endoscopic image.

The color charts constituting the fifth color chart group 71e are arranged such that the color tone of R, G, and B from the one end (left end) to the other end (right end) of the array has the smallest intensity to the maximum for each color chart. It shows a gradation that increases monotonously (at a constant rate) in strength, that is, changes from black to white counterclockwise. Specifically, a color chart having a color tone strength of R, G, and B of {100 × (m−1) ÷ (M−1)}% is arranged at position A _5m in the fifth color chart group 71e. Is done. In FIG. 2, the same black color chart as the position A ₁₁ is arranged at the left end position A ₅₁ in the fifth color chart group 71e, and the strengths of the color tones of R, G, and B are increased at the right end position A _5M. Also, a white color chart that is 100% is arranged. The fifth color chart group 71e is used for inspecting gradation characteristics between black and white.

The color charts constituting the sixth color chart group 71f have the maximum intensity of B and the minimum intensity of G, and from one end (right end) to the other end (left end) of the array. On the other hand, a gradation is shown in which the color tone of R increases monotonously (at a constant rate) from the minimum strength to the maximum strength for each color chart, that is, changes from blue to magenta counterclockwise. Specifically, at position A _6m in the sixth color chart group 71f, the strength of the color tone of R is {100 × (m−1) ÷ (M−1)}%, and the strength of the color tone of G is A color chart having a color tone strength of 0% and a color tone of B being 100% is arranged. In FIG. 2, the same blue color chart as the position A _3M is arranged at the right end position A ₆₁ in the sixth color chart group 71f, and the strengths of the colors R and B are 100% at the left end position A _6M. , A magenta color chart having a G tone strength of 0% is arranged. The sixth color chart group 71f is used to inspect the gradation characteristics between blue and magenta, which are the main colors of the endoscopic image during indigo staining.

The color charts constituting the seventh color chart group 71g have the maximum intensity of the R color tone, the minimum intensity of the G color tone, and from one end (right end) to the other end (left end) of the array. On the other hand, a gradation is shown in which the color tone of B decreases monotonously (at a constant rate) from the maximum strength to the minimum strength for each color chart, that is, changes from magenta to red counterclockwise. Specifically, at the position A _7m in the seventh color chart group 71g, the strength of the color tone of B is {100-100 × (m−1) ÷ (M−1)}%, and the strength of the color tone of R is strong. A color chart having a color tone strength of 100% and a G color tone strength of 0% is arranged. In FIG. 2, the same magenta color chart as the position A _6M is arranged at the right end position A ₇₁ in the seventh color chart group 71g, and the same red color chart as the position A _1M is arranged at the left end position A _7M. . The seventh color chart group 71g is used for examining gradation characteristics between magenta and red, which are main colors in an endoscopic image at the time of examination of the upper digestive tract such as the stomach.

The color charts constituting the eighth color chart group 71h have the R color tone with the maximum intensity and the B color tone with the minimum intensity, and from one end (upper end) to the other end (lower end) of the array. On the other hand, a gradation is shown in which the color tone of G increases monotonously (at a constant rate) from the minimum strength to the maximum strength for each color chart, that is, changes from red to yellow counterclockwise. Specifically, at position A _8m in the eighth color chart group 71h, the strength of the color tone of G is {100 × (m−1) ÷ (M−1)}%, and the strength of the color tone of R is A color chart having a color tone strength of 100% and a B color strength of 0% is arranged. In FIG. 2, the same red color chart as the position A _1M is arranged at the upper end position A ₈₁ in the eighth color chart group 71h, and the same yellow color chart as the position A _4M is arranged at the lower end position A _8M. The The eighth color chart group 71h is used for inspecting gradation characteristics between red and yellow, which are main colors in an endoscopic image at the time of examination of the lower digestive tract such as the large intestine.

Since the color chart of the same black color is disposed at a position A ₁₁ and position A ₃₁ which are adjacent on the color chart 71, is overlapped with the position A ₃₁ and position A _11, the color black, which is arranged at a position A ₁₁ The vote may be used not only as a black color chart constituting the first color chart group 71a but also as a black color chart constituting the third color chart group 71c. Similarly since the same blue color chart in position A _3M and the position A ₆₁ which are adjacent on the color chart 71 is disposed, with overlapping and position A ₆₁ and position A _3M, blue disposed in the position A _3M The color chart may be used not only as the blue color chart constituting the third color chart group 71c but also as the blue color chart constituting the sixth color chart group 71f. Similarly since the color charts of the same magenta to position A _6M and the position A ₇₁ which are adjacent on the color chart 71 is disposed, with overlapping and position A ₇₁ and position A _6M, magenta disposed at the position A _6M The color chart may be used not only as the magenta color chart constituting the sixth color chart group 71f but also as the magenta color chart constituting the seventh color chart group 71g. Similarly since the same red color chart in position A _7M and the position A ₈₁ which are adjacent on the color chart 71 is disposed, with overlapping and position A ₈₁ and position A _7M, red arranged at a position A _7M The color chart may be used not only as the red color chart constituting the seventh color chart group 71g but also as the red color chart constituting the eighth color chart group 71h. Similarly since the color charts of the same yellow is disposed at a position A _8M and the position A _4M adjacent on the color chart 71, is overlapping the position A _8M and the position A _4M, yellow arranged in positions A _4M The color chart may be used not only as the yellow color chart constituting the fourth color chart group 71d but also as the yellow color chart constituting the eighth color chart group 71h. Similarly since the color charts of the same black to position A ₄₁ and position A ₅₁ which are adjacent on the color chart 71 is disposed, with overlapping and position A ₄₁ and position A _51, the black disposed in a position A ₄₁ The color chart may be used not only as the black color chart constituting the fourth color chart group 71d but also as the black color chart constituting the fifth color chart group 71e.

  By sharing the color charts at the ends of these adjacent color chart groups, it is possible to efficiently arrange the color charts on the color chart 71, so that one color chart is enlarged or the color chart group has a color. Measurement accuracy can be increased by increasing the number of votes.

  When inspecting the gradation characteristics, the light emitted from the light source unit 31 is directed from the distal end portion of the scope 10 to an area including all color charts in the color chart 71 as an object to be observed through the light guide 11. Irradiated. The color chart 71 is provided when the color chart 71 is arranged so that the scope 10 is at a distance equivalent to the distance at which the scope 10 is imaged and the center point CP faces the objective optical system 13 when the scope 10 is normally observed. It is desirable that all the color charts constituting the color are set to a size that allows imaging. In order to eliminate the influence of ambient light, it is desirable to shield light other than the light emitted from the light source unit 31 around the color chart 71 and the fixed base 73.

  The reflected light from the color chart 71 is incident on the image sensor of the imaging unit 14 via the objective optical system 13. The image sensor photoelectrically converts the incident light and outputs an image signal. The image signal output from the imaging unit 14 is subjected to the preceding image processing such as YC separation, white balance adjustment, and color correction in the video signal processing unit 15, and is output to the video signal processing unit 33 of the processor 30. In the processor 30, the video signal processing unit 33 performs subsequent image processing to generate a video signal, and the image of the color chart 71 is displayed on the monitor 50.

  The spectral radiance meter 90 is brought close to each of the portions corresponding to the color chart in the color chart image displayed on the monitor 50 to measure the light intensity for each color (for each light wavelength) of the portion, Luminance values, hues, saturations, and the like are calculated, and the characteristics of the portion corresponding to the color chart to be measured of the image subjected to the image processing of the endoscope system 1 are digitized.

  The measurement by the spectral radiance meter 90 is performed for all color charts constituting the color chart 71. That is, all the color charts constituting the color chart 71 are sequentially set as the measurement target color charts. In the present embodiment, the color chart 71 is a circular color chart 71, and the color charts constituting the color chart 71 (first to eighth color chart groups 71a to 71h) are arranged on one circle C. When the color chart 71 is arranged and imaged so that the center point CP faces the objective optical system 13, that is, the optical axis LX of the objective optical system 13 passes through the center point CP, imaging conditions such as peripheral light reduction can be achieved. An image including all color charts arranged on the circle C in the same state can be obtained by a single imaging operation.

  The fixing base 73 is a base for fixing the color chart 71. It is desirable that a positioning member is provided on at least one of the color chart 71 and the fixing base 73 so that the color chart 71 can be attached to the fixing base 71 at a predetermined position. The holding unit 75 holds the tip of the scope 10 and keeps the distance between the color chart 71 on the fixed base 73 and the scope 10 constant.

  Based on the measurement result, the user determines whether or not the gradation characteristics in the image processing of the endoscope system 1 are appropriate. Specifically, the user obtains information corresponding to each digitized color chart for each color of the portion corresponding to each color chart in an image subjected to image processing in a normal endoscope system 1 (light wavelength). And the numerical value (ideal gradation characteristic) assumed when the light intensity is measured, and the gradation characteristic for each color in the image processing is grasped. For example, as a measurement result, the luminance value of an image on which a color chart to be measured is displayed is represented as a numerical value (not shown). It is determined whether or not it has a tone characteristic. Such a determination result is used to determine a design value of each part related to image processing.

  In addition, the measurement result is represented by a graph (L * a * b * color system, see FIG. 5) in which the hue and saturation of the image on which the color chart to be measured is displayed are displayed. It is determined whether or not the image has an appropriate gradation characteristic based on the magnitude of the deviation from the case of a proper gradation characteristic.

In the color chart image displayed on the monitor 50, the position from the corresponding portion to the color vote arranged black A _11, the portion corresponding to the red color chips are arranged in positions A _1M of the first color chart group 71a Are sequentially measured, and the hue and saturation of the image corresponding to each color chart are plotted in the L * a * b * color system, the first position located in the first quadrant from the origin O. A trajectory along the first line segment L1 up to one point P1 is represented. In the color chart image displayed on the monitor 50, the part corresponding to the green color chart arranged at the position A _2M from the part corresponding to the black color chart arranged at the position A ₂₁ of the second color chart group 71b. Are sequentially measured, and the hue and saturation of the image corresponding to each color chart are plotted in the L * a * b * color system, the second position is located on the second quadrant from the origin O. A trajectory along the second line segment L2 up to two points P2 is represented. In the color chart image displayed on the monitor 50, the portion corresponding to the blue color chart arranged at the position A _3M from the portion corresponding to the black color chart arranged at the position A ₃₁ of the third color chart group 71c. Are sequentially measured, and the hue and saturation of the image corresponding to each color chart are plotted in the L * a * b * color system, the first position located on the fourth quadrant from the origin O. A trajectory along the third line segment L3 up to three points P3 is represented. In the color chart image displayed on the monitor 50, the portion corresponding to the yellow color chart arranged at the position A _4M from the portion corresponding to the black color chart arranged at the position A ₄₁ of the fourth color chart group 71d. Are sequentially measured, and the hue and saturation of the image corresponding to each color chart are plotted in the L * a * b * color system, the first in the positive direction of the b * axis from the origin O. A trajectory along the fourth line L4 up to the four points P4 is represented. In the color chart image displayed on the monitor 50, the portion corresponding to the white color chart arranged at the position A _5M from the portion corresponding to the black color chart arranged at the position A ₅₁ of the fifth color chart group 71e. Are sequentially measured and the hue and saturation of the image corresponding to each color chart are plotted in the L * a * b * color system, a locus concentrated near the origin O is represented. . In the color chart image displayed on the monitor 50, the portion corresponding to the magenta color chart arranged at the position A _6M from the portion corresponding to the blue color chart arranged at the position A ₆₁ of the sixth color chart group 71f. Are sequentially measured, and the hue and saturation of the image corresponding to each color chart are plotted in the L * a * b * color system, the third point P3 to the fourth quadrant and A trajectory along the fifth line segment L5 from the third point P3 to the fifth point P5 located in the positive direction of the a * axis and in the positive direction of the b * axis is represented. In the color chart image displayed on the monitor 50, the part corresponding to the red color chart arranged at the position A _7M from the part corresponding to the magenta color chart arranged at the position A ₇₁ of the seventh color chart group 71g. Are sequentially measured, and the hue and saturation of the image corresponding to each color chart are plotted in the L * a * b * color system, rather than the fifth point P5 to the fifth point P5. A locus along the sixth line segment L6 to the first point P1 located in the minus direction of the a * axis and in the plus direction of the b * axis is represented. In the color chart image displayed on the monitor 50, the portion corresponding to the yellow color chart arranged at the position A _8M from the portion corresponding to the red color chart arranged at the position A ₈₁ of the eighth color chart group 71h. Are sequentially measured, and the hue and saturation of the image corresponding to each color chart are plotted in the L * a * b * color system, from the first point P1 to the fourth point P4. A trajectory along the seventh line segment L7 is represented.

Note that the amount of light emitted from the light source 31a to the color chart 71 through the light guide 11 before the inspection of the gradation characteristics is set to a predetermined amount for inspection of the gradation characteristics depending on the opening of the diaphragm 31b. Adjusted. When performing such light amount adjustment, the control unit 35 of the processor 30 is based on the Y signal separated in the video signal processing unit 15 and the white color arranged at the right end position A _5M of the fifth color chart group 71e. The luminance value Y of the area where the color chart is imaged is calculated, and the opening of the diaphragm 31b is adjusted so that the luminance value Y becomes the inspection luminance value y1 corresponding to the predetermined light amount for inspection of the gradation characteristics. . If the periphery of the arc-shaped color chart in the color chart 71 uses the same white color chart as _A5M , the peripheral portion may be imaged and used for luminance adjustment. However, the calculation of the luminance value Y may be performed by another device connected to the processor 30 and the adjustment of the opening of the diaphragm 31b corresponding to the inspection luminance value y1 may be performed manually or automatically. Alternatively, the luminance value Y may be calculated from an image obtained by taking the image signal output from the processor 30 into the video board, or the luminance value Y obtained by the spectral radiance meter 90 may be used. Good.

  In the present embodiment, it is possible to inspect gradation characteristics in image processing of the endoscope system 1 based on an image obtained by imaging the color chart 71. Since the gradation characteristic can be grasped in a numerical state such as a luminance value, whether the gradation characteristic in the endoscope system 1 is objectively appropriate by comparing with the numerical value in the case of the ideal gradation characteristic. It becomes possible to determine whether or not. The digitization of the characteristics of the image subjected to the image processing is included in the image signal output from the processor 30 as well as measuring the light intensity in the image displayed on the monitor with the spectral radiance meter. It is conceivable to calculate from a luminance signal or the like, or to calculate a luminance value from an image obtained by taking an image signal output from the processor 30 into a video board.

  Further, since the color chart 71 has color charts arranged so as to show gradation, the intensity of light for each color (for each wavelength of light) in an image subjected to image processing in a normal endoscope system 1 is measured. The numerical value assumed in this case shows a change with a specific law for each adjacent color chart, and it becomes possible to know the gradation characteristics by easily comparing with the actual measurement result.

  In the present embodiment, a mode in which the tone characteristics of the endoscope system 1 are inspected using the color chart 71 composed of eight color chart groups (first to eighth color chart groups 71a to 71h) will be described. However, the number of color chart groups is not limited to this. For example, if the color chart 71 including at least the first to third color chart groups 71a to 71c is used, it is possible to inspect the gradation characteristics regarding the three primary colors of additive color mixing, red, green, and blue.

It is a lineblock diagram of an endoscope system in this embodiment. It is a block diagram of the color chart used for the gradation characteristic test | inspection in this embodiment. It is a block diagram of a color chart in which the inner area of the small circle does not form a color chart. It is a block diagram of the color chart in which the part of the arc which comprises the sector of a color chart is a straight line. It is a graph shown in the L * a * b * color system in which the hue and saturation of a portion where a color chart to be measured in a color chart image is displayed as a gradation characteristic inspection result.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Endoscope system 10 Scope 11 Light guide 13 Objective optical system 14 Imaging part 15 Image | video signal processing part 30 Processor 31 Light source part 31a Light source 31b Aperture 33 Video signal processing part 35 Control part 50 Monitor 70 Gradation inspection apparatus 71 Color chart 73 Fixed base 75 Holder 90 Spectral radiance meter

Claims (10)

Comprising first to third color chart groups each having a plurality of color charts arranged on an arc;
The color charts constituting the first to third color chart groups are arranged on one circle,
The color chart constituting the first color chart group shows a gradation that changes from black to red from one end to the other end, and the color chart constituting the second color chart group is: The gradation that changes from black to green from one end to the other end is shown, and the color chart constituting the third color chart group changes from black to blue from one end to the other end. A color chart characterized by changing gradations.   The color chart according to claim 1, wherein a surface imaged by a scope of an endoscope apparatus is made of a matte material. Further comprising a fourth color chart group having a plurality of color charts arranged on an arc, the color charts constituting the first to fourth color chart groups are arranged on the circle,
2. The color chart according to claim 1, wherein the color chart constituting the fourth color chart group exhibits a gradation that changes from black to yellow from one end toward the other end. A fifth color chart group having a plurality of color charts arranged on an arc is further provided, and the color charts constituting the first to third color chart groups and the fifth color chart group are on the circle. Lined up
2. The color chart according to claim 1, wherein the color chart constituting the fifth color chart group exhibits a gradation that changes from black to white from one end toward the other end. A sixth color chart group having a plurality of color charts arranged on an arc is further provided, and the color charts constituting the first to third color chart groups and the sixth color chart group are on the circle. Lined up
2. The color chart according to claim 1, wherein the color charts constituting the sixth color chart group exhibit a gradation that changes from blue to magenta from one end toward the other end. A seventh color chart group having a plurality of color charts arranged on an arc is further provided, and the color charts constituting the first to third color chart groups and the seventh color chart group are on the circle. Lined up
The color chart according to claim 1, wherein the color charts constituting the seventh color chart group exhibit a gradation that changes from magenta to red from one end to the other end. An eighth color chart group having a plurality of color charts arranged on an arc is further provided, and the color charts constituting the first to third color chart groups and the eighth color chart group are on the circle. Lined up
2. The color chart according to claim 1, wherein the color chart constituting the eighth color chart group exhibits a gradation that changes from red to yellow from one end toward the other end. Further comprising fourth to eighth color chart groups each having a plurality of color charts arranged on an arc, the color charts constituting the first to eighth color chart groups are arranged on the circle,
The color chart constituting the fourth color chart group shows a gradation that changes from black to yellow from one end to the other end,
The color chart constituting the fifth color chart group shows a gradation that changes from black to white from one end to the other end,
The color charts constituting the sixth color chart group show a gradation that changes from blue to magenta from one end to the other end,
The color charts constituting the seventh color chart group show a gradation that changes from magenta to red from one end to the other end,
2. The color chart according to claim 1, wherein the color chart constituting the eighth color chart group exhibits a gradation that changes from red to yellow from one end toward the other end.   The first to eighth color chart groups are the second color chart group, the fifth color chart group, the fourth color chart group, the first color chart group from the first color chart group 71a clockwise or counterclockwise. The color chart according to claim 8, wherein the color chart group is arranged in the order of an 8-color chart group, the seventh color chart group, the sixth color chart group, and the third color chart group.   Sharing the black color chart arranged at the one end of the first color chart group and the black color chart arranged at the one end of the third color chart group, The blue color chart arranged at the other end and the blue color chart arranged at the one end of the sixth color chart group are shared, and arranged at the other end of the sixth color chart group. The magenta color chart and the magenta color chart arranged at the one end of the seventh color chart group, the red color chart arranged at the other end of the seventh color chart group, and the Sharing the red color chart arranged at the one end of the eighth color chart group, the yellow color chart arranged at the other end of the eighth color chart group, and the fourth color chart group Shared with the yellow color chart arranged at the other end, and arranged at the one end of the black color chart and the fifth color chart group arranged at the one end of the fourth color chart group. Black Color chart according to claim 9, wherein at least one of the color chart shared characterized in that it is the color chips are arranged to take place.

Images