Source: https://patents.google.com/patent/US10244147B2/en
Timestamp: 2020-01-17 17:34:08
Document Index: 368723753

Matched Legal Cases: ['Application No. 2011', 'Application No. 2012', 'Application No. 2012', 'art.\n4', 'art.\n8', 'Application No. 2012', 'Application No. 2010']

US10244147B2 - Image capturing device and color measurement method for capturing a reference chart and a subject - Google Patents
Image capturing device and color measurement method for capturing a reference chart and a subject Download PDF
US10244147B2
US10244147B2 US15/891,832 US201815891832A US10244147B2 US 10244147 B2 US10244147 B2 US 10244147B2 US 201815891832 A US201815891832 A US 201815891832A US 10244147 B2 US10244147 B2 US 10244147B2
US15/891,832
US20180167534A1 (en
2012-11-28 Priority to US13/687,520 priority patent/US9516179B2/en
2016-10-13 Priority to US15/292,885 priority patent/US9906688B2/en
2018-02-08 Priority to US15/891,832 priority patent/US10244147B2/en
2018-02-08 Application filed by Ricoh Co Ltd filed Critical Ricoh Co Ltd
2018-06-14 Publication of US20180167534A1 publication Critical patent/US20180167534A1/en
2019-03-26 Publication of US10244147B2 publication Critical patent/US10244147B2/en
238000009740 moulding (composite fabrication) Methods 0 description 107
The present application is a continuation of U.S. application Ser. No. 15/292,885, filed Oct. 13, 2016, which is a is a continuation of U.S. application Ser. No. 13/687,520, filed Nov. 28, 2012, which claims priority to and incorporates by reference the entire contents of Japanese Patent Application No. 2011-262646 filed in Japan on Nov. 30, 2011, Japanese Patent Application No. 2012-029920 filed in Japan on Feb. 14, 2012, and Japanese Patent Application No. 2012-239455 filed in Japan on Oct. 30, 2012.
FIG. 4A is a vertical cross-sectional view of an image capturing unit (i.e. a cross-sectional view of the X1-X1 line in FIG. 4B);
The image capturing unit 42 has a housing 421 configured by combining a frame body 422 and a board 423. The frame body 422 is formed to a bottomed tubular shape in which one end side corresponding to the upper surface of the housing 421 is opened. The board 423 is fastened to the frame body 422 by a fastener member 424 to be integrated with the frame body 422 so as to close the opening end of the frame body 422 and configure the upper surface of the housing 421.
Each patch forming the reference patch arrays 401 to 404 for color measurement is used as a specific color criterion reflecting image-capturing conditions at the time the image capturing unit 42 captures an image. The configuration of the reference patch arrays 401 to 404 for color measurement arranged in the reference chart unit 400 is not limited to the arrangement example illustrated in FIG. 5, and an arbitrary patch array can be used. For example, patches capable of specifying the color range as wide as possible may be used, or the reference patch array 401 in the primary colors of YMCK or the reference patch array 403 of the gray scale may be formed with patches having the color measurement values of the ink used in the image forming apparatus 100. Further, the reference patch array 402 in the secondary colors of RGB may be formed with patches having the color measurement values that can produce color by the ink used in the image forming apparatus 100. Still further, it may be possible to use a standard color chart for which color measurement values are defined, such as Japan Color.
Next, a specific example of the color measurement method of the patch image 200 using the color measuring device will be explained in detail with reference to FIGS. 8 to 13. FIG. 8 is a view illustrating an example of image data acquired by capturing the patch image 200 of a color measurement target and the reference chart unit 400 in the sensor unit 430 at the same time. FIG. 9 is a view explaining a specific example of a color measurement method of the patch image 200. FIGS. 10A and 10B are views illustrating a conversion equation to perform conversion between an L*a*b* value and an XYZ value. FIG. 11 is a flowchart illustrating color measurement steps for the patch image 200. FIG. 12 is a flowchart illustrating a modification of color measurement steps for the patch image 200. FIG. 13 is a view explaining a method of specifying an RGB value corresponding to the L*a*b* value of each standard patch.
XYZ color space of (b) of FIG. 9 is obtained by converting the L*a*b* value illustrated in FIG. 9(c) into the XYZ value using a predetermined conversion equation, and by plotting the XYZ value thus converted on the XYZ color space. The L*a*b* value can be converted into the XYZ value by using the conversion equation illustrated as FIG. 10B (Lab⇒XYZ). By contrast, the XYZ value can be converted into the L*a*b* value by using the conversion equation illustrated as FIG. 10A (XYZ⇒Lab). In other words, the L*a*b* value of L*a*b* colorspace (c) illustrated in FIG. 9 and the XYZ value of XYZ color space (b) illustrated in FIG. 9 can be interconverted by using the conversion equations illustrated in FIGS. 10A and 10B.
Y = ( a ⁢ ⁢ 11 a ⁢ ⁢ 12 a ⁢ ⁢ 13 a ⁢ ⁢ 21 a ⁢ ⁢ 22 a ⁢ ⁢ 23 a ⁢ ⁢ 31 a ⁢ ⁢ 32 a ⁢ ⁢ 33 ) ⁢ X ( 1 )
a ⁢ ⁢ 13 = ( x ⁢ ⁢ 4 ⁢ ⁢ y ⁢ ⁢ 1 - x ⁢ ⁢ 1 ⁢ y ⁢ ⁢ 4 ) ⁢ ( x ⁢ ⁢ 2 ⁢ x ⁢ ⁢ 7 - x ⁢ ⁢ 1 ⁢ x ⁢ ⁢ 8 ) - ( x ⁢ ⁢ 7 ⁢ y ⁢ ⁢ 1 - x ⁢ ⁢ 1 ⁢ y ⁢ ⁢ 7 ) ⁢ ( x ⁢ ⁢ 2 ⁢ x ⁢ ⁢ 4 - x ⁢ ⁢ 1 ⁢ x ⁢ ⁢ 5 ) ( x ⁢ ⁢ 3 ⁢ x ⁢ ⁢ 4 - x ⁢ ⁢ 1 ⁢ x ⁢ ⁢ 6 ) ⁢ ( x ⁢ ⁢ 2 ⁢ x ⁢ ⁢ 7 - x ⁢ ⁢ 1 ⁢ x ⁢ ⁢ 8 ) - ( x ⁢ ⁢ 3 ⁢ x ⁢ ⁢ 7 - x ⁢ ⁢ 1 ⁢ x ⁢ ⁢ 9 ) ⁢ ( x ⁢ ⁢ 2 ⁢ x ⁢ ⁢ 4 - x ⁢ ⁢ 1 ⁢ x ⁢ ⁢ 5 ) ( 2 ) a ⁢ ⁢ 23 = ( x ⁢ ⁢ 4 ⁢ y ⁢ ⁢ 2 - x ⁢ ⁢ 1 ⁢ y ⁢ ⁢ 5 ) ⁢ ( x ⁢ ⁢ 2 ⁢ x ⁢ ⁢ 7 - x ⁢ ⁢ 1 ⁢ x ⁢ ⁢ 8 ) - ( x ⁢ ⁢ 7 ⁢ y ⁢ ⁢ 2 - x ⁢ ⁢ 1 ⁢ y ⁢ ⁢ 8 ) ⁢ ( x ⁢ ⁢ 2 ⁢ x ⁢ ⁢ 4 - x ⁢ ⁢ 1 ⁢ x ⁢ ⁢ 5 ) ( x ⁢ ⁢ 3 ⁢ x ⁢ ⁢ 4 - x ⁢ ⁢ 1 ⁢ x ⁢ ⁢ 6 ) ⁢ ( x ⁢ ⁢ 2 ⁢ x ⁢ ⁢ 7 - x ⁢ ⁢ 1 ⁢ x ⁢ ⁢ 8 ) - ( x ⁢ ⁢ 3 ⁢ x ⁢ ⁢ 7 - x ⁢ ⁢ 1 ⁢ x ⁢ ⁢ 9 ) ⁢ ( x ⁢ ⁢ 2 ⁢ x ⁢ ⁢ 4 - x ⁢ ⁢ 1 ⁢ x ⁢ ⁢ 5 ) ( 3 ) a ⁢ ⁢ 33 = ( x ⁢ ⁢ 4 ⁢ y ⁢ ⁢ 3 - x ⁢ ⁢ 1 ⁢ y ⁢ ⁢ 6 ) ⁢ ( x ⁢ ⁢ 2 ⁢ x ⁢ ⁢ 7 - x ⁢ ⁢ 1 ⁢ x ⁢ ⁢ 8 ) - ( x ⁢ ⁢ 7 ⁢ y ⁢ ⁢ 3 - x ⁢ ⁢ 1 ⁢ y ⁢ ⁢ 9 ) ⁢ ( x ⁢ ⁢ 2 ⁢ x ⁢ ⁢ 4 - x ⁢ ⁢ 1 ⁢ x ⁢ ⁢ 5 ) ( x ⁢ ⁢ 3 ⁢ x ⁢ ⁢ 4 - x ⁢ ⁢ 1 ⁢ x ⁢ ⁢ 6 ) ⁢ ( x ⁢ ⁢ 2 ⁢ x ⁢ ⁢ 7 - x ⁢ ⁢ 1 ⁢ x ⁢ ⁢ 8 ) - ( x ⁢ ⁢ 3 ⁢ x ⁢ ⁢ 7 - x ⁢ ⁢ 1 ⁢ x ⁢ ⁢ 9 ) ⁢ ( x ⁢ ⁢ 2 ⁢ x ⁢ ⁢ 4 - x ⁢ ⁢ 1 ⁢ x ⁢ ⁢ 5 ) ( 4 ) a ⁢ ⁢ 12 = ( x ⁢ ⁢ 4 ⁢ y ⁢ ⁢ 1 - x ⁢ ⁢ 1 ⁢ y ⁢ ⁢ 4 ) ⁢ ( x ⁢ ⁢ 3 ⁢ x ⁢ ⁢ 7 - x ⁢ ⁢ 1 ⁢ x ⁢ ⁢ 4 ) - ( x ⁢ ⁢ 7 ⁢ y ⁢ ⁢ 1 - x ⁢ ⁢ 1 ⁢ y ⁢ ⁢ 7 ) ⁢ ( x ⁢ ⁢ 3 ⁢ x ⁢ ⁢ 4 - x ⁢ ⁢ 1 ⁢ x ⁢ ⁢ 6 ) ( x ⁢ ⁢ 2 ⁢ x ⁢ ⁢ 4 - x ⁢ ⁢ 1 ⁢ x ⁢ ⁢ 5 ) ⁢ ( x ⁢ ⁢ 3 ⁢ x ⁢ ⁢ 7 - x ⁢ ⁢ 1 ⁢ x ⁢ ⁢ 9 ) - ( x ⁢ ⁢ 2 ⁢ x ⁢ ⁢ 7 - x ⁢ ⁢ 1 ⁢ x ⁢ ⁢ 8 ) ⁢ ( x ⁢ ⁢ 3 ⁢ x ⁢ ⁢ 4 - x ⁢ ⁢ 1 ⁢ x ⁢ ⁢ 6 ) ( 5 ) a ⁢ ⁢ 22 = ( x ⁢ ⁢ 4 ⁢ y ⁢ ⁢ 2 - x ⁢ ⁢ 1 ⁢ y ⁢ ⁢ 5 ) ⁢ ( x ⁢ ⁢ 3 ⁢ x ⁢ ⁢ 7 - x ⁢ ⁢ 1 ⁢ x ⁢ ⁢ 9 ) - ( x ⁢ ⁢ 7 ⁢ y ⁢ ⁢ 2 - x ⁢ ⁢ 1 ⁢ y ⁢ ⁢ 8 ) ⁢ ( x ⁢ ⁢ 3 ⁢ x ⁢ ⁢ 4 - x ⁢ ⁢ 1 ⁢ x ⁢ ⁢ 6 ) ( x ⁢ ⁢ 2 ⁢ x ⁢ ⁢ 4 - x ⁢ ⁢ 1 ⁢ x ⁢ ⁢ 5 ) ⁢ ( x ⁢ ⁢ 3 ⁢ x ⁢ ⁢ 7 - x ⁢ ⁢ 1 ⁢ x ⁢ ⁢ 9 ) - ( x ⁢ ⁢ 2 ⁢ x ⁢ ⁢ 7 - x ⁢ ⁢ 1 ⁢ x ⁢ ⁢ 8 ) ⁢ ( x ⁢ ⁢ 3 ⁢ x ⁢ ⁢ 4 - x ⁢ ⁢ 1 ⁢ x ⁢ ⁢ 6 ) ( 6 ) a ⁢ ⁢ 32 = ( x ⁢ ⁢ 4 ⁢ y ⁢ ⁢ 3 - x ⁢ ⁢ 1 ⁢ y ⁢ ⁢ 6 ) ⁢ ( x ⁢ ⁢ 3 ⁢ x ⁢ ⁢ 7 - x ⁢ ⁢ 1 ⁢ x ⁢ ⁢ 9 ) - ( x ⁢ ⁢ 7 ⁢ y ⁢ ⁢ 3 - x ⁢ ⁢ 1 ⁢ y ⁢ ⁢ 9 ) ⁢ ( x ⁢ ⁢ 3 ⁢ x ⁢ ⁢ 4 - x ⁢ ⁢ 1 ⁢ x ⁢ ⁢ 6 ) ( x ⁢ ⁢ 2 ⁢ x ⁢ ⁢ 4 - x ⁢ ⁢ 1 ⁢ x ⁢ ⁢ 5 ) ⁢ ( x ⁢ ⁢ 3 ⁢ x ⁢ ⁢ 7 - x ⁢ ⁢ 1 ⁢ x ⁢ ⁢ 9 ) - ( x ⁢ ⁢ 2 ⁢ x ⁢ ⁢ 7 - x ⁢ ⁢ 1 ⁢ x ⁢ ⁢ 8 ) ⁢ ( x ⁢ ⁢ 3 ⁢ x ⁢ ⁢ 4 - x ⁢ ⁢ 1 ⁢ x ⁢ ⁢ 6 ) ( 7 ) a ⁢ ⁢ 11 = y ⁢ ⁢ 1 - a ⁢ ⁢ 12 ⁢ x ⁢ ⁢ 1 - a ⁢ ⁢ 13 ⁢ x ⁢ ⁢ 3 x ⁢ ⁢ 1 ( 8 ) a ⁢ ⁢ 21 = y ⁢ ⁢ 2 - a ⁢ ⁢ 22 ⁢ x ⁢ ⁢ 2 - a ⁢ ⁢ 23 ⁢ x ⁢ ⁢ 3 x ⁢ ⁢ 1 ( 9 ) a ⁢ ⁢ 31 = y ⁢ ⁢ 3 - a ⁢ ⁢ 32 ⁢ x ⁢ ⁢ 2 - a ⁢ ⁢ 33 ⁢ x ⁢ ⁢ 3 x ⁢ ⁢ 1 ( 10 )
The relative positional deviation in the main-scanning direction of the print head 6 located upstream is measured by using the image data of the test pattern 110 captured by the sensor unit 430; measuring gaps between the vertical lines (solid lines) actually formed on the recording medium 16 by shifting the print head 6 by a predetermined gap a; and calculating the difference between the actual positions of the vertical lines (solid lines) formed on the recording medium 16 and the ideal positions of the vertical lines (dotted lines) to be formed on the recording medium 16 when no positional deviation occurs in the main-scanning direction as the amount of positional deviation in the main-scanning direction. The gaps between the vertical lines (solid lines) actually formed on the recording medium 16 are measured by using the black vertical line formed on the leftmost side as a reference line for measuring positional deviation in the main-scanning direction.
To measure the deviation in the sub-scanning direction between the print head 6 located upstream and the print head 6 located downstream, four horizontal lines arranged in the middle in FIG. 14 are used. Among the four horizontal lines, two horizontal lines on the lower side are formed on the recording medium 16 by using the print head 6 located upstream, and two horizontal lines on the upper side are formed on the recording medium 16 by using the print head 6 located downstream. As illustrated in FIG. 17, the distances (β1 and β2) between the respective horizontal lines, and the difference therebetween (Δβ=β1−β2) is calculated as the amount of positional deviation in the sub-scanning direction between the print head 6 located upstream and the print head 6 located downstream. If the positional deviation in the sub-scanning direction between the print head 6 located upstream and the print head 6 located downstream is corrected based on the difference (Δβ), the distances (β1 and β2) between the respective horizontal lines become equal to each other.
Next a specific example of the method for measuring dot diameter in an image using the color measuring device will be described in detail with reference to FIG. 19 and FIG. 20. FIG. 19 is a view illustrating an example of image data acquired by capturing a test pattern 130, which is an image for measuring dot diameter, and the reference chart unit 400 in the sensor unit 430 at the same time. FIG. 20 is a view explaining a method of measuring a dot diameter from image data on the vicinity of the dot included in the test pattern 130.
Similarly, a graph (c) of sensor output values illustrated in FIG. 20 can be obtained by extracting a row of line B in the Y-axis direction illustrated in the diagram (a) in FIG. 20, and connecting values of pixels forming the row of line B with a straight line. Using the predefined threshold value similar to the above, two intersecting points c and d can be obtained when detecting the sensor output values that exceed the threshold value. The size of the dot 131 in the line B can be specified by calculating a distance between the two points c and d. Since in which region of the subject image-capturing area the dot 131 is detected is not known, the process of specifying the size of the dot 131 in the Y-axis direction is performed entirely in the X-axis direction. The largest distance between two points among the distances between two points obtained by the processing described above is the size of the dot 131 in the Y-axis direction.
Therefore, the image capturing unit 42C according to the third modification can reduce the weight of the housing 421 and reduce the power consumption since the opening 425C opened greatly from the bottom surface 421 a to the side wall is formed.
In the image capturing unit 42E according to the fifth modification, an example of the configuration including the opening 425D and the chart plate 410D similar to the image capturing unit 42D according to the fourth modification is described, where the illumination light source 426 is arranged at the position at which the regular reflection light regular-reflected by the subject (i.e., patch image 200) or the reference chart unit 400 does not enter the two-dimensional image sensor 431 of the sensor unit 430. However, in the configuration of the image capturing unit 42, the image capturing unit 42A according to the first modification, the image capturing unit 42B according to the second modification, and the image capturing unit 42C according to the third modification described above, the illumination light source 426 may be arranged at the position at which the regular reflection light regular-reflected by the subject (i.e., patch image 200) or the reference chart unit 400 does not enter the two-dimensional image sensor 431 of the sensor unit 430. In this case as well, effects similar to the image capturing unit 42E according to the fifth modification are obtained.
In the image capturing unit 42F according to the sixth modification, a light path length change member 440 is arranged inside the housing 421. The light path length change member 440 is an optical element that has a refractive index “n” (where “n” is an arbitrary number) and transmits light. The light path length change member 440 is arranged on a light path between the subject (i.e. patch image 200) outside the housing 421 and the sensor unit 430, and has a function of causing an imaging surface of an optical image of the subject (i.e. patch image 200) to approach an imaging surface of an optical image of the reference chart unit 400. That is, in the image capturing unit 42F according to the sixth modification, by arranging the light path length change member 440 on the light path between the subject (i.e. patch image 200) and the sensor unit 430, the imaging surface of the optical image of the subject (i.e. patch image 200) outside the housing 421 and the imaging surface of the reference chart unit 400 inside the housing 421 are both fitted to the sensor surface of the two-dimensional image sensor 431 of the sensor unit 430. Although an example where the light path length change member 440 is placed on the bottom surface 421 a of the housing 421 is illustrated in FIG. 26, the light path length change member 440 does not have to be necessarily placed on the bottom surface 421 a, and an essential requirement is that the light path length change member 440 is placed on a light path between the subject (i.e. patch image 200) outside the housing 421 and the sensor unit 430.
First, at least one of the Lab values and XYZ values as color measurement values of the multiple reference patches KP of the reference sheet KS (in the example of FIG. 32, both the Lab values and the XYZ values) is associated with each patch number and stored in a memory table Tb1 installed in a non-volatile memory 60, or the like inside the color measurement control unit 50, for example. A color measurement value of a reference patch KC is a value acquired in advance by color measurement using a spectroscope BS. If the color measurement value of the reference patch KC is known, the value thereof may be used. In the following, the color measurement value of the reference patch KC stored in the memory table Tb1 will be referred to as “reference color measurement value”.
Next, the reference sheet KS is set on the platen 22; and, by controlling the movement of the carriage 5, image capturing is performed by the image capturing unit 42 using multiple reference patches KC of the reference sheet KS as subjects. The RGB value of the reference patch KC acquired by the image capturing by the image capturing unit 42 is stored in the memory table Tb1 of the non-volatile memory in association with the patch number. That is, the memory table Tb1 stores the color measurement values and RGB values of multiple reference patches KC arranged and formed on the reference sheet KS, in association with the patch number of each of the reference patches KC. In the following, the RGB value of the reference patch KC stored in the memory table Tb1 will be referred to as “reference RGB value.” The reference RGB value is a value reflecting characteristics of the image capturing unit 42.
Also, when the image capturing unit 42 captures the multiple reference patches KC of the reference sheet KS, the reference chart unit 400 installed in the image capturing unit 42 are captured at the same time. The RGB value of each patch of the reference chart unit 400 acquired by the image capturing are stored in the memory table Tb1 of the non-volatile memory 60 in association with the patch numbers. The RGB values of the patches of the reference chart unit 400 stored in the memory table Tb1 by this preprocessing are referred to as “initial reference RGB values”. FIG. 31 is a view illustrating an example of the initial reference RGB value. FIG. 28A illustrates a state where the initial reference RGB value (RdGdBd) is stored in the memory table Tb1 and where, in addition to the initial reference RGB value (RdGdBd), an initial reference Lab value (Ldadbd) acquired by converting the initial reference RGB value (RdGdBd) into the Lab value and an initial reference XYZ value (XdYdZd) acquired by converting the initial reference RGB value (RdGdBd) into the XYZ value are stored in association. Also, FIG. 28B is a scatter diagram plotting the initial reference RGB value of each patch of the reference chart unit 400.
FIG. 30 is a view explaining a process of generating an inter-reference-RGB linear transformation matrix; and FIG. 31 is a view illustrating a relation between the initial reference RGB value and the reference RGB value upon color measurement. Before performing conversion of the color measurement target RGB value into the initialization color measurement target RGB value (RsGsBs) (step S10), the color measurement value calculating unit 531 generates an inter-reference-RGB linear transformation matrix used in this conversion. That is, as illustrated in FIG. 30, the color measurement value calculating unit 531 reads, from the non-volatile memory 60, the initial reference RGB value (RdGdBd) acquired upon preprocessing at the time of the initial state of the image forming apparatus 100 and the reference RGB value upon color measurement (RdsGdsBds) acquired at the time of adjustment of the image forming apparatus 100, and generates the inter-reference-RGB linear transformation matrix to convert the reference RGB value upon color measurement RdsGdsBds into the initial reference RGB value RdGdBd. Sequentially, the color measurement value calculating unit 531 stores the generated inter-reference-RGB linear transformation matrix in the non-volatile memory 60.
Next, the color measurement value calculating unit 531 searches the memory table Tb1 of the non-volatile memory 60 that stores therein a plurality of reference color measurement values (i.e. Lab values) in preprocessing, and, among the reference color measurement values (i.e. Lab values), selects a set of a plurality of patches (i.e. neighborhood-color patches) having reference color measurement values (i.e. Lab values) close to the first Lab value on the Lab space (step S23). As a method of selecting patches of a closer distance, for example, it is possible to employ a method of calculating a distance to the first Lab value for all reference color measurement values (i.e. Lab values) stored in the memory table Tb1 and selecting a plurality of patches having Lab values (in FIG. 32, hatched Lab values) closer to the first Lab value.
Furthermore, the external device 500 may hold the color conversion parameter generated based on the color measurement value of the patch image 200, and correct the image data in the external device 500. In other words, the image forming apparatus transmits the image data to the external device 500 when forming the image. The external device 500 corrects the image data received from the image forming apparatus 100 using the color conversion parameter it holds, and transmits the corrected image data to the image forming apparatus 100. The image forming apparatus 100 forms the image based on the corrected image data received from the external device 500. The image forming apparatus 100 thus can perform image formation of high color reproducibility.
an image sensor configured to substantially simultaneously image-capture a subject and a reference chart, the image sensor having an image-capturing range including a subject image-capturing area in which the subject is captured and a reference chart capturing area in which the reference chart is captured; and
a lens disposed in an optical path of the image sensor, wherein
the subject image-capturing area and the reference chart capturing area are adjacent to each other,
the subject and the reference chart are at positions separated from each other, and
the reference chart is movable with respect to the subject.
2. The image capturing device according to claim 1, wherein the subject image-capturing area and the reference chart capturing area do not overlap each other.
3. The image capturing device according to claim 1, further comprising a processor configured to correct a captured image result of capturing the subject based on a captured image result of capturing the reference chart.
4. The image capturing device according to claim 1, wherein the subject and the reference chart are illuminated in substantially a same illumination condition.
5. The image capturing device according to claim 1, wherein the reference chart includes a plurality of chromatic patches.
6. The image capturing device according to claim 5, wherein the plurality of chromatic patches are divided into blocks.
7. The image capturing device according to claim 1, further comprising a memory configured to store colors of the reference chart.
8. The image capturing device according to claim 3, wherein the processor is configured to perform color measurement on the subject using the corrected captured image result.
9. A color measurement method comprising:
substantially simultaneously image-capturing a subject and a reference chart using a lens and an image sensor; and
correcting a captured image result of capturing the subject based on a captured image result of capturing the reference chart, wherein
a subject image-capturing area in which the subject is captured and a reference chart capturing area in which the reference chart is captured are adjacent to each other,
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