# US 12,118,699 B2 · Luminance correction apparatus

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- Number: US 12,118,699 B2
- Document ID: US12118699B2
- Status: Granted
- Kind: B2
- Application number: 17/544,774
- Filed: 2021-12-07
- Published: 2022-06-16
- Granted: 2024-10-15
- Earliest claimed: 2020-12-11
- Assignees: Sharp Kabushiki Kaisha
- Applicants: Sharp Kabushiki Kaisha
- Inventors: Yuichi Yoshida
- Web page: https://patentgrep.com/patent/US12118699B2

## CPC

- G06T 5/92: based on global image properties
- G06V 10/60: relating to illumination properties, e.g. using a reflectance or lighting model
- G06V 10/758: {Involving statistics of pixels or of feature values, e.g. histogram matching}
- G06T 2207/20208: High dynamic range [HDR] image processing
- G06T: IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
- G06V: IMAGE OR VIDEO RECOGNITION OR UNDERSTANDING

## Abstract

An image processing apparatus includes an image processing unit configured to generate a second image obtained by performing predetermined image processing on a first image representing an input image, a determination unit configured to determine a luminance correction range on the basis of image information in one of a high luminance range and a low luminance range determined in accordance with the image processing, and a luminance correction unit configured to correct a luminance value in the luminance correction range determined by the determination unit for the second image.

## Claims

### Claim 1

A luminance correction apparatus comprising:
at least one processor; and
at least one non-transitory computer-readable medium coupled to the at least one processor and storing one or more computer executable instructions that, when executed by the at least one processor, cause the luminance correction apparatus to:
generate a second image obtained by performing predetermined image processing on a first image representing an input image;
determine a luminance correction range based on image information in one of a high luminance range or a low luminance range determined according to the predetermined image processing;
correct a luminance value in the determined luminance correction range for the second image;
set a first weight coefficient and a second weight coefficient based on a number of pixels having a luminance within one of the high luminance range or the low luminance range in one of the first image or the second image;
determine an upper limit of the luminance correction range by a weighted average of an upper limit of a luminance in the first image and an upper limit of a luminance in the second image, using the first weight coefficient; and
determine a lower limit of the luminance correction range by a weighted average of a lower limit of a luminance in the first image and a lower limit of a luminance in the second image, using the second weight coefficient.

### Claim 2

A luminance correction apparatus comprising:
at least one processor; and
at least one non-transitory computer-readable medium coupled to the at least one processor and storing one or more computer executable instructions that, when executed by the at least one processor, cause the luminance correction apparatus to:
generate a second image obtained by performing predetermined image processing on a first image representing an input image;
determine a luminance correction range based on image information in one of a high luminance range or a low luminance range determined according to the predetermined image processing;
correct a luminance value in the determined luminance correction range for the second image;
set a first weight coefficient and a second weight coefficient based on a size of one of the high luminance range or the low luminance range in one of the first image or the second image;
determine an upper limit of the luminance correction range by a weighted average of an upper limit of a luminance in the first image and an upper limit of a luminance in the second image, using the first weight coefficient; and
determine a lower limit of the luminance correction range by a weighted average of a lower limit of a luminance in the first image and a lower limit of a luminance in the second image, using the second weight coefficient.

### Claim 3 (depends on 2)

The luminance correction apparatus according to claim 2, wherein the one or more computer-executable instructions, when executed by the at least one processor, further cause the luminance correction apparatus to determine the luminance correction range according to the image information if the size included in the image information is greater than a predetermined value.

### Claim 4

A method for luminance correction, the method comprising:
generating a second image obtained by performing predetermined image processing on a first image representing an input image;
determining a luminance correction range based on image information in one of a high luminance range or a low luminance range determined according to the predetermined image processing;
correcting a luminance value in the determined luminance correction range for the second image;
setting a first weight coefficient and a second weight coefficient based on a number of pixels having a luminance within one of the high luminance range or the low luminance range in one of the first image or the second image;
determining an upper limit of the luminance correction range by a weighted average of an upper limit of a luminance in the first image and an upper limit of a luminance in the second image, using the first weight coefficient; and
determining a lower limit of the luminance correction range by a weighted average of a lower limit of a luminance in the first image and a lower limit of a luminance in the second image, using the second weight coefficient.

### Claim 5

A method for luminance correction, the method comprising:
generating a second image obtained by performing predetermined image processing on a first image representing an input image;
determining a luminance correction range based on image information in one of a high luminance range or a low luminance range determined according to the predetermined image processing;
correcting a luminance value in the determined luminance correction range for the second image;
setting a first weight coefficient and a second weight coefficient based on a size of one of the high luminance range or the low luminance range in one of the first image or the second image;
determining an upper limit of the luminance correction range by a weighted average of an upper limit of a luminance in the first image and an upper limit of a luminance in the second image, using the first weight coefficient; and
determining a lower limit of the luminance correction range by a weighted average of a lower limit of a luminance in the first image and a lower limit of a luminance in the second image, using the second weight coefficient.

### Claim 6

A non-transitory computer-readable medium storing computer executable instructions that, when executed by at least one processor, cause the at least one processor to:
generate a second image obtained by performing predetermined image processing on a first image representing an input image;
determine a luminance correction range based on image information in one of a high luminance range or a low luminance range determined according to the predetermined image processing;
correct a luminance value in the determined luminance correction range for the second image;
set a first weight coefficient and a second weight coefficient based on a number of pixels having a luminance within one of the high luminance range or the low luminance range in one of the first image or the second image;
determine an upper limit of the luminance correction range by a weighted average of an upper limit of a luminance in the first image and an upper limit of a luminance in the second image, using the first weight coefficient; and
determine a lower limit of the luminance correction range by a weighted average of a lower limit of a luminance in the first image and a lower limit of a luminance in the second image, using the second weight coefficient.

### Claim 7

A non-transitory computer-readable medium storing computer executable instructions that, when executed by at least one processor, cause the at least one processor to:
generate a second image obtained by performing predetermined image processing on a first image representing an input image;
determine a luminance correction range based on image information in one of a high luminance range or a low luminance range determined according to the predetermined image processing;
correct a luminance value in the determined luminance correction range for the second image;
set a first weight coefficient and a second weight coefficient based on a size of one of the high luminance range or the low luminance range in one of the first image or the second image;
determine an upper limit of the luminance correction range by a weighted average of an upper limit of a luminance in the first image and an upper limit of a luminance in the second image, using the first weight coefficient; and
determine a lower limit of the luminance correction range by a weighted average of a lower limit of a luminance in the first image and a lower limit of a luminance in the second image, using the second weight coefficient.