Image processing apparatus and image processing method

Patent metadata

Field	Value
Publication number	US-10764468-B2
Application number	US-201816040221-A
Country	US
Kind code	B2
Filing date	Jul 19, 2018
Priority date	Jul 26, 2017
Publication date	Sep 1, 2020
Grant date	Sep 1, 2020

Abstract

An apparatus includes an image generation unit configured to generate, from an input image, a hierarchical image including a plurality of images different in frequency band from one another, a first gain map generation unit configured to generate a first gain map with use of the hierarchical image and a first tone characteristic, a second gain map generation unit configured to generate a second gain map with use of the first gain map and a second tone characteristic, and a processing unit configured to apply the second gain map to the input image.

First claim

What is claimed is:

1. An apparatus comprising:
an image generation unit configured to generate, from an input image, a hierarchical image including a plurality of images different in frequency band from one another;
a first gain map generation unit configured to generate a first gain map with use of the hierarchical image and a first tone characteristic;
a correction gain map generation unit configured to generate a correction gain map based on the first gain map and a second tone characteristic;
a second gain map generation unit configured to correct the first gain map with use of the correction gain map to generate a second gain map; and
a processing unit configured to apply the second gain map to the input image,
wherein the second tone characteristic has a characteristic of cancelling tone conversion by the first tone characteristic with a signal value after application of the first tone characteristic to the input image as a horizontal axis.

2. The apparatus according to claim 1 , wherein the first and second gain map indicate a gain to be applied according to a position within the image.

3. A method comprising:
generating, from an input image, a hierarchical image including a plurality of images different in frequency band from one another;
generating a first gain map with use of the hierarchical image and a first tone characteristic;
generating a correction gain map based on the first gain map and a second tone characteristic;
correcting the first gain map with use of the correction gain map to generate a second gain map; and
applying the second gain map to the input image,
wherein the second tone characteristic has a characteristic of cancelling tone conversion by the first tone characteristic with a signal value after application of the first tone characteristic to the input image as a horizontal axis.

4. The method according to claim 3 , wherein the first and second gain map indicate a gain to be applied according to a position within the image.

5. A non-transitory computer readable storage medium storing a computer-executable program of instructions for causing a computer to perform a method comprising:
generating, from an input image, a hierarchical image including a plurality of images different in frequency band from one another;
generating a first gain map with use of the hierarchical image and a first tone characteristic;
generating a correction gain map based on the first gain map and a second tone characteristic;
correcting the first gain map with use of the correction gain map to generate a second gain map; and
applying the second gain map to the input image,
wherein the second tone characteristic has a characteristic of cancelling tone conversion by the first tone characteristic with a signal value after application of the first tone characteristic to the input image as a horizontal axis.

6. The non-transitory computer readable storage medium according to claim 5 , wherein the first and second gain map indicate a gain to be applied according to a position within the image.

Assignees

• Canon Kk

Inventors

• Kimura Naoto

Classifications

• H04N1/407

  Control or modification of tonal gradation or of extreme levels, e.g. background level · CPC title

• H04N1/393

  Enlarging or reducing · CPC title

• G06T5/20

  using local operators · CPC title

• H04N1/4074 Primary

  using histograms · CPC title

• G06T5/009

  Physics · mapped topic