Color measurement system to correct color data corresponding to a ratio of detected distance to a reference distance

1. A color measuring device, comprising: a housing; a reference chart held to the housing; a sensor to capture, from inside the housing, image data of a two-dimensional region that includes the reference chart and an area outside the housing, the sensor being held by the housing, the captured image data including subject image data of a subject whose color is to be measured, the subject being located in the area outside the housing; an illumination light source to illuminate the region from inside the housing, the illumination light source being held by the housing; a detector to detect a distance between predetermined two points within the subject image data obtained by the sensor; a correcting unit configured to correct the subject image data obtained from the sensor according to a ratio of the detected distance to a reference distance; and a calculating unit configured to calculate a colorimetric value of the subject based on the subject image data corrected by the correcting unit.

2. The color measuring device according to claim 1 , further comprising: a determining unit configured to determine a shape distortion of an image of the subject; and a deciding unit configured to decide whether the subject image data is to be used to calculate the colorimetric value of the subject based on the presence or absence of the shape distortion or a type of the shape distortion.

3. The color measuring device according to claim 2 , further comprising: a suction amount adjusting unit configured to adjust an amount of suction generated by a sucking unit for holding the subject on a holding member when the shape distortion is distortion of a predetermined pattern.

4. The color measuring device according to claim 1 , further comprising, a position adjusting unit configured to adjust a position of the housing in an optical axis direction of the sensor such that a difference between the detected distance and the reference distance approximates to zero.

5. The color measuring device according to claim 1 , further comprising: a position adjusting unit configured to adjust a position of the housing in an optical axis direction of the sensor such that a difference between the detected distance between the two points and the reference distance approximates a predetermined value.

6. The color measuring device according to claim 1 , wherein the detector detects the distance between the two points from the subject image data including the subject.

7. The color measuring device according to claim 1 , wherein the detector detects the reference distance from an image of the reference chart included in the image data.

8. The color measuring device of claim 1 , wherein the detector detects the distance between the predetermined two points and the predetermined two points are set to have a predetermined distance therebetween.

9. An image forming apparatus comprising: an image output unit configured to output an image to a recording medium; and the color measuring device according to claim 1 , wherein the color measuring device calculates a colorimetric value of the image using the image output from the image output unit as the subject.

10. A color measuring method executed in a color measuring device that includes a housing, a reference chart held to the housing, a sensor configured to capture, from inside the housing, image data of a two-dimensional region that includes the reference chart and an area outside the housing, the sensor being held by the housing, the captured image data including subject image data of a subject whose color is to be measured, the subject being located in the area outside the housing, and an illumination light source to illuminate the region from inside the housing, the illumination light source being held by the housing, the color measuring method comprising: detecting a distance between predetermined two points within the subject image data obtained by the sensor; correcting the subject image data obtained from the sensor according to a ratio of the detected distance to a reference distance; and calculating a colorimetric value of the subject based on the corrected subject image data.

11. The color measuring method of claim 10 , wherein the predetermined two points are set to have a predetermined distance therebetween.

12. An image forming apparatus, comprising: a housing; a reference chart held to the housing; a sensor to capture, from inside the housing, image data of a two-dimensional region that includes the reference chart and an area outside the housing, the sensor being held by the housing, the captured image data including subject image data of a subject whose color is to be measured, the subject being located in the area outside the housing; an illumination light source to illuminate the region from inside the housing, the illumination light source being held by the housing; a detector to detect a distance between predetermined two points within the subject image data obtained by the sensor; a correcting unit configured to correct the subject image data obtained from the sensor according to a ratio of the detected distance to a reference distance; and an image forming unit configured to change an amount of recording liquid used to form an image on a recording medium based on the subject image data corrected by the correcting unit.

13. The image forming apparatus of claim 12 , wherein the detector detects the distance between the predetermined two points and the predetermined two points are set to have a predetermined distance therebetween.