Image processing apparatus, image processing system, image processing method, and recording medium

Patent metadata

Field	Value
Publication number	US-10970828-B2
Application number	US-201916701219-A
Country	US
Kind code	B2
Filing date	Dec 3, 2019
Priority date	Dec 21, 2018
Publication date	Apr 6, 2021
Grant date	Apr 6, 2021

Abstract

An image processing apparatus includes circuitry configured to: acquire a plurality of pieces of image data; determine, for each of the plurality of pieces of image data, a first representative color indicating a feature of a color representative of the image data, based on pixel values of the image data; calculate, based on the determined first representative color of the plurality of pieces of image data, a second representative color indicating a feature of a color representative of the plurality of pieces of image data; calculate, based on the first representative color and the second representative color of image data to be corrected, a correction parameter for color correction of the image data to be corrected among the plurality of pieces of image data; and perform the color correction on the image data to be corrected using the calculated correction parameter.

First claim

What is claimed is:

1. An image processing apparatus comprising circuitry configured to:
classify pixels of image data into clusters;
calculate, for each of the clusters, a representative pixel value indicating a feature of a color representative of the cluster;
determine a first representative luminance value indicating luminance characteristics representative of the image data based on the representative pixel value of each of the clusters; and
calculate a correction parameter for brightness correction of the image data using the determined first representative luminance value; and
perform the brightness correction on the image data using the calculated brightness correction parameter.

2. The image processing apparatus according to claim 1 ,
wherein the circuitry is further configured to calculate the brightness correction parameter using a look up table (LUT) that corresponds to the determined first representative brightness value.

3. The image processing apparatus according to claim 1 ,
wherein
the circuitry is further configured to:
determine the first representative luminance value for each of the plurality of pieces of image data;
calculate a second representative luminance value indicating luminance characteristics representative of the plurality of pieces of image data based on the determined first representative luminance value for each of the plurality of pieces of image data;
calculate the brightness correction parameter for the brightness correction of a piece of image data to be corrected, using the first representative luminance value and the calculated second representative luminance value for the piece of image data to be corrected; and
perform the brightness correction on the piece of image data to be corrected using the calculated brightness correction parameter.

4. The image processing apparatus according to claim 3 ,
wherein the circuitry is further configured to:
determine whether the first representative luminance value of each of the plurality of pieces of image data is within a predetermined luminance range; and
calculate the second representative luminous value using the first representative luminance value determined to be within the predetermined luminance.

5. The image processing apparatus according to claim 2 ,
wherein the circuitry is further configured to:
select a cluster including the greatest number of first representative luminance values from the clusters obtained by the clustering process; and
calculate, as the second representative luminance value, a representative luminance value representative of the selected cluster.

6. The image processing apparatus according to claim 3 ,
wherein the circuitry is further configured to:
determine whether the first representative luminance value of each of the plurality of pieces of image data is within a predetermined luminance range;
calculate the brightness correction parameter using the first representative luminance value determined to be within the predetermined luminance range and the second representative luminance value calculated using the first representative luminance value determined to be within the predetermined luminance range when determining the first representative luminance value for the piece of image data to be corrected is within the predetermined luminance range; and
calculate the brightness correction parameter using the first representative luminance value determined to be outside the predetermined luminance range when determining the first representative luminance value for the piece of image data to be corrected is outside the predetermined luminance range.

7. The image processing apparatus according to claim 1 ,
wherein the circuitry is further configured to:
determine, for each of the plurality of pieces of image data, a first representative color indicating a feature of a color representative of a corresponding set of image data, based on each pixel value of pixels constituting an image associated with the corresponding set of image data;
calculate a second representative color indicating a feature of a color representative of the plurality of pieces of image data based on the determined first representative color of each of the plurality of pieces of image data;
calculate a correction parameter for color correction of a piece of image data to be corrected, using the first representative color and the second representative color for the piece of image data to be corrected; and
perform the brightness correction and the color correction on the piece of image data to be corrected, using the brightness correction parameter and the correction parameter.

Assignees

• SUITOH Hiroshi
• Ricoh Co Ltd

Inventors

• SUITOH Hiroshi

Classifications

• G06T11/10

  Texturing; Colouring; Generation of textures or colours (retouching, inpainting or scratch removal G06T5/77) · CPC title

• G06T2207/10024

  Color image · CPC title

• G06T7/90 Primary

  Determination of colour characteristics · CPC title

• G06T7/97

  Determining parameters from multiple pictures (depth or shape recovery from multiple images G06T7/55; stereo camera calibration G06T7/85) · CPC title

• H04N1/62

  Retouching, i.e. modification of isolated colours only or in isolated picture areas only · CPC title