Colorimetric value acquisition method, image forming device, and colorimetric value acquisition control program

• US 9,800,766 B2
• Filed: 11/02/2016
• Issued: 10/24/2017
• Est. Priority Date: 11/05/2015
• Status: Active Grant

• Current Assignee: Konica Minolta Inc.
• Original Assignee: Konica Minolta Inc.
• Inventors: Tsuji, Kosuke
• Primary Examiner(s): Vo, Quang N
• Application Number:
  US15/341,689
• Publication Number:
  US 20170134618A1
• Time in Patent Office: 356 Days
• CPC Class Codes: H04N 1/00023 Colour systems
• CPC Class Codes: H04N 1/00034 Measuring, i.e. determining a quantity by comparison with a standard H04N1/00031 takes precedence
• CPC Class Codes: H04N 1/00045 using a reference pattern designed for the purpose, e.g. a test chart
• CPC Class Codes: H04N 1/00063 using at least a part of the apparatus itself, e.g. self-testing
• CPC Class Codes: H04N 1/6008 with primary colour signals, e.g. RGB or CMY(K)
• CPC Class Codes: H04N 1/6044 involving a sensor integrated in the machine or otherwise specifically adapted to read the test pattern
• CPC Class Codes: H04N 1/6086 by scene illuminant, i.e. conditions at the time of picture capture, e.g. flash, optical filter used, evening, cloud, daylight, artificial lighting, white point measurement, colour temperature
• CPC Class Codes: H04N 1/646 Transmitting or storing colour television type signals, e.g. PAL, Lab; Their conversion into additive or subtractive colour signals or vice versa therefor H04N1/642, H04N1/644 take precedence
• CPC Class Codes: H04N 2201/0094 Multifunctional device, i.e. a device capable of all of reading, reproducing, copying, facsimile transception, file transception

Abstract

A colorimetric value acquisition method in a system including a printing unit, a scanner, and a colorimetric unit, wherein the system executes: first processing to cause the printing unit to print a first chart, to cause the scanner to measure all the patches to acquire RGB values, to cause the colorimetric unit to measure all the patches to acquire colorimetric values, and to create a scanner profile; second processing to cause the printing unit to print a second chart, to cause the scanner to measure all the patches to acquire RGB values, and to cause the colorimetric unit to measure a part of the patches; third processing to specify an RGB value; fourth processing to calculate a difference between the RGB value and an RGB value; fifth processing to calculate a corrected RGB value; and sixth processing to acquire an estimated colorimetric value and output the estimated colorimetric value.

Claims

1. A colorimetric value acquisition method in a system including a printing unit, a scanner configured to acquire an RGB value by measuring an image formed by the printing unit, and a colorimetric unit configured to acquire a colorimetric value formed of an L*a*b* value or an XYZ value by measuring an image formed by the printing unit, wherein the system executes:

first processing configured to cause the printing unit to print a first chart in which patches are rearranged in advance such that a flare level is uniform, to cause the scanner to measure all the patches of the first chart to acquire RGB values, to cause the colorimetric unit to measure all the patches to acquire colorimetric values, and to create a scanner profile by correlating the RGB values with the colorimetric values;

second processing configured to cause the printing unit to print a second chart in which patches are rearranged in advance such that a flare level is uniform, to cause the scanner to measure all the patches of the second chart to acquire RGB values, and to cause the colorimetric unit to measure a part of the patches to acquire colorimetric values;

third processing configured to specify an RGB value corresponding to each of the colorimetric values acquired in the second processing using the scanner profile;

fourth processing configured to calculate a difference between the RGB value specified in the third processing and an RGB value of each of the part of the patches acquired in the second processing;

fifth processing configured to calculate a corrected RGB value by applying the difference to an RGB value of each of the patches acquired in the second processing; and

sixth processing configured to acquire an estimated colorimetric value corresponding to the corrected RGB value using the scanner profile, and to output the estimated colorimetric value for color management of the system.

2. The colorimetric value acquisition method according to claim 1, wherein the system further executes seventh processing configured to create a printer profile using the estimated colorimetric value.

3. The colorimetric value acquisition method according to claim 1, wherein the part of the patches is one patch at a specific position of the second chart.

4. The colorimetric value acquisition method according to claim 1, wherein each of the first processing and the second processing includes processing configured to cause the scanner to measure all patches of a chart to acquire RGB values, and to make a flare level in the chart uniform by rearranging the patches such that a variation of an average RGB value obtained by averaging RGB values of patches in a small patch group including a patch to be measured and a patch near the patch in the chart is within a predetermined range.

5. An image forming device provided with a printing unit, an in-line scanner configured to acquire an RGB value by measuring an image formed by the printing unit, and an in-line colorimetric unit configured to acquire a colorimetric value formed of an L*a*b* value or an XYZ value by measuring an image formed by the printing unit, comprising:

a profile creating unit configured to cause the printing unit to print a first chart in which patches are rearranged in advance such that a flare level is uniform, to cause the in-line scanner to measure all the patches of the first chart to acquire RGB values, to cause the in-line colorimetric unit to measure all the patches to acquire colorimetric values, and to create a scanner profile by correlating the RGB values with the colorimetric values;

a correction amount calculating unit configured to cause the printing unit to print a second chart in which patches are rearranged in advance such that a flare level is uniform, to cause the in-line scanner to measure all the patches of the second chart to acquire RGB values, to cause the in-line colorimetric unit to measure a part of the patches to acquire colorimetric values, to specify an RGB value corresponding to each of the acquired colorimetric values using the scanner profile, and to calculate a difference between the RGB value specified using the scanner profile and an RGB value of each of the part of the patches acquired by measurement with the in-line scanner; and

a colorimetric value estimating unit configured to calculate a corrected RGB value by applying the difference to an RGB value of each of the patches acquired by measurement with the in-line scanner, to acquire an estimated colorimetric value corresponding to the corrected RGB value using the scanner profile, and to output the estimated colorimetric value for color management of the image forming device.

6. The image forming device according to claim 5, wherein the profile creating unit creates a printer profile using the estimated colorimetric value.

7. The image forming device according to claim 5, wherein the part of the patches is one patch at a specific position of the second chart.

8. The image forming device according to claim 5, further comprising a patch rearranging unit configured to cause the in-line scanner to measure all patches of a chart to acquire RGB values, and to make a flare level in the chart uniform by rearranging the patches such that a variation of an average RGB value obtained by averaging RGB values of patches in a small patch group including a patch to be measured and a patch near the patch in the chart is within a predetermined range.

9. A non-transitory recording medium storing a computer readable program configured to control acquisition of a colorimetric value, operated by a system including an image forming device provided with a printing unit, an in-line scanner configured to acquire an RGB value by measuring an image formed by the printing unit, and an in-line colorimetric unit configured to acquire a colorimetric value formed of an L*a*b* value or an XYZ value by measuring an image formed by the printing unit, wherein the program causes a control device in the system to execute:

first processing configured to cause the printing unit to print a first chart in which patches are rearranged in advance such that a flare level is uniform, to cause the in-line scanner to measure all the patches of the first chart to acquire RGB values, to cause the in-line colorimetric unit to measure all the patches to acquire colorimetric values, and to create a scanner profile by correlating the RGB values with the colorimetric values;

second processing configured to cause the printing unit to print a second chart in which patches are rearranged in advance such that a flare level is uniform, to cause the in-line scanner to measure all the patches of the second chart to acquire RGB values, and to cause the in-line colorimetric unit to measure a part of the patches to acquire colorimetric values;

third processing configured to specify an RGB value corresponding to each of the colorimetric values acquired in the second processing using the scanner profile;

fourth processing configured to calculate a difference between the RGB value specified in the third processing and an RGB value of each of the part of the patches acquired in the second processing;

fifth processing configured to calculate a corrected RGB value by applying the difference to an RGB value of each of the patches acquired in the second processing; and

sixth processing configured to acquire an estimated colorimetric value corresponding to the corrected RGB value using the scanner profile, and to output the estimated colorimetric value for color management of the image forming device.

10. The non-transitory recording medium storing a computer readable program configured to control acquisition of a colorimetric value according to claim 9, wherein the program further causes the control device to execute seventh processing configured to create a printer profile using the estimated colorimetric value.

11. The non-transitory recording medium storing a computer readable program configured to control acquisition of a colorimetric value according to claim 9, wherein the part of the patches is one patch at a specific position of the second chart.

12. The non-transitory recording medium storing a computer readable program configured to control acquisition of a colorimetric value according to claim 9, wherein each of the first processing and the second processing includes processing configured to cause the in-line scanner to measure all patches of a chart to acquire RGB values, and to make a flare level in the chart uniform by rearranging the patches such that a variation of an average RGB value obtained by averaging RGB values of patches in a small patch group including a patch to be measured and a patch near the patch in the chart is within a predetermined range.