# US 2013/0155427 A1 · Image processing apparatus, image processing method, and storage medium

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- Number: US 2013/0155427 A1
- Document ID: US20130155427A1
- Status: Published application
- Kind: A1
- Application number: 13/711,503
- Filed: 2012-12-11
- Published: 2013-06-20
- Earliest claimed: 2011-12-15
- Assignees: Canon Kabushiki Kaisha
- Inventors: Yukichika Ichihashi
- Web page: https://patentgrep.com/patent/US20130155427A1

## CPC

- H04N 1/60: Colour correction or control {(H04N1/54 takes precedence)}
- H04N 1/6033: {using test pattern analysis (H04N1/6055 takes precedence)}
- H04N 1/6097: {depending on the characteristics of the output medium, e.g. glossy paper, matt paper, transparency or fabrics}
- H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION

## Abstract

An image processing apparatus includes an obtaining unit configured to obtain a gamma correction table used for image formation on non-reference paper using a correlation between a characteristic of reference paper and a characteristic of the non-reference paper and a gamma correction table obtained through calibration using the reference paper, a first reading unit configured to form a pattern on plain paper and read the formed pattern, a second reading unit configured to form a pattern on an image bearing member and read the formed pattern, a comparison unit configured to compare a value read by the first reading unit with a value ready by the second reading unit, and a correction unit configured to correct the characteristic indicating the correlation used for obtaining the gamma correction table for the non-reference paper by the obtaining unit when a difference of values compared by the comparison unit exceeds a first threshold.

## Claims

### Claim 1

An image processing apparatus comprising:
an obtaining unit configured to obtain a gamma correction table to be used at the time of image formation on non-reference paper by using a correlation between a characteristic of reference paper and a characteristic of the non-reference paper and a gamma correction table obtained by executing calibration using the reference paper;
a first reading unit configured to form a pattern on plain paper and to read the formed pattern;
a second reading unit configured to form a pattern on an image bearing member and to read the formed pattern;
a comparison unit configured to compare a value read by the first reading unit with a value read by the second reading unit; and
a correction unit configured to correct the characteristic indicating the correlation to be used at the time of obtaining the gamma correction table for the non-reference paper by the obtaining unit when a difference of the values compared by the comparison unit exceeds a first threshold.

### Claim 2 (depends on 1)

The image processing apparatus according to claim 1, wherein, when the comparison unit compares the value read by the first reading unit with the value read by the second unit, the first reading unit reads a portion having a highest density in the pattern formed on the plain paper.

### Claim 3 (depends on 1)

The image processing apparatus according to claim 1, wherein a value provided by reading the pattern formed on the image bearing member is stored beforehand.

### Claim 4 (depends on 1)

The image processing apparatus according to claim 1, wherein, when a difference of the compared values exceeds a second threshold, an instruction for using the non-reference paper to execute calibration is displayed on an operation unit.

### Claim 5

An image processing method comprising:
obtaining a gamma correction table to be used at the time of image formation on non-reference paper by using a correlation between a characteristic of reference paper and a characteristic of the non-reference paper and a gamma correction table obtained by executing calibration using the reference paper;
forming a pattern on plain paper and reading the formed pattern in a first reading step;
forming a pattern on an image bearing member and reading the formed pattern in a second reading step;
comparing a value read in the first reading step with a value read in the second reading step; and
correcting the characteristic indicating the correlation to be used at the time of obtaining the gamma correction table for the non-reference paper when a difference of the compared values exceeds a first threshold.

### Claim 6 (depends on 5)

The image processing method according to claim 5, further comprising reading, when the value read in the first reading step with the value ready by the second reading step are compared, a portion having a highest density in the pattern formed on the plain paper in the first reading step.

### Claim 7 (depends on 5)

The image processing method according to claim 5, further comprising storing a value provided by reading the pattern formed on the image bearing member beforehand.

### Claim 8 (depends on 5)

The image processing method according to claim 5, further comprising, displaying on an operation unit, when a difference of the compared values exceeds a second threshold, an instruction for using the non-reference paper to execute calibration.

### Claim 9 (depends on 5)

A computer-readable storage medium storing a program that causes a computer to execute the image processing method according to claim 5.