Image processing apparatus, image processing method, and storage medium

Patent metadata

Field	Value
Publication number	US-9413925-B2
Application number	US-201414520755-A
Country	US
Kind code	B2
Filing date	Oct 22, 2014
Priority date	Oct 30, 2013
Publication date	Aug 9, 2016
Grant date	Aug 9, 2016

Abstract

An image processing apparatus comprises a detection unit configured to detect a person region included in an image, a first calculation unit configured to calculate first tone characteristics based on information concerning the person region detected by the detection unit, a second calculation unit configured to calculate second tone characteristics based on predetermined tone characteristics and the first tone characteristics calculated by the first calculation unit, and an image processing unit configured to perform tone correction processing by using the second tone characteristics calculated by the second calculation unit.

First claim

What is claimed is:

1. An image processing apparatus comprising:
at least one hardware processor or circuit implementing the functions of a detection unit, a first calculation unit, a second calculation unit and an image processing unit, wherein:
the detection unit is configured to detect a person region included in an image;
the first calculation unit is configured to calculate first tone characteristics based on information concerning the person region detected by said detection unit;
the second calculation unit is configured to calculate second tone characteristics based on predetermined tone characteristics and the first tone characteristics calculated by said first calculation unit; and
the image processing unit is configured to perform tone correction processing by using the second tone characteristics calculated by stud second calculation unit.

2. The apparatus according to claim 1 , wherein said first calculation unit calculates a gain amount corresponding to the first tone characteristics based on a representative luminance value of the person region detected by said detection unit, and calculates an input value range in which the first tone characteristics are configured to be used, based on a luminance distribution of the person region detected by said detection unit.

3. The apparatus according to claim 2 , wherein said second calculation unit calculates the second tone characteristics so as to apply tone characteristics obtained by performing weighted addition of the predetermined tone characteristics and the first tone characteristics to the input value range in which the first tone characteristics are configured to be used.

4. The apparatus according to claim 2 , wherein said second calculation unit calculates the second tone characteristics so as to apply the predetermined tone characteristics to an input value range in which the first tone characteristics are not configured to be used.

5. The apparatus according to claim 1 , wherein the at least one hardware processor or circuit further implements the functions of a determination unit configured to determine an evaluation value of the person region detected by said detection unit,
wherein said second calculation unit calculates the second tone characteristics by performing weighted addition of the predetermined tone characteristics and the first tone characteristics based on the evaluation value determined by said determination unit.

6. The apparatus according to claim 5 , wherein said determination unit determines the evaluation value based on a size of person region detected by said detection unit.

7. The apparatus according to claim 5 , wherein said determination unit determines the evaluation value based on a position of the person region detected by said detection unit within the image.

8. The apparatus according to claim 1 , wherein the at least one hardware processor or circuit further implements the functions of a backlit determination unit configured to determine whether the person region detected by said detection unit in a backlit state,
wherein a person region in which the first tone characteristics are calculated is a person region in a backlit state which is detected by said backlit determination unit.

9. The apparatus according to claim 2 , wherein the at least one hardware processor or circuit further implements the functions of a hair region detection unit configured to detect a hair region of the person region detected by said detection unit,
wherein said first calculation unit calculates a gain amount corresponding to the first tone characteristics by referring to a luminance of a face skin region of the person region detected by said detection unit and a luminance of a hair region of the person detected by said hair region detection unit.

10. An image processing apparatus comprising:
at least one hardware processor or circuit implementing the functions of a detection unit, a first calculation unit, and an image processing unit, wherein:
the detection unit is configured to detect a person region included in an image;
the first calculation unit is configured to calculate first tone characteristics based on information concerning the person region detected by said detection unit; and
the image processing unit is configured to generate a tone-corrected image by performing weighted addition of an image generated by predetermined tone characteristics and an image generated by first tone characteristics calculated by said first calculation unit.

11. An image processing method comprising:
a detection step of detecting a person region included in an image;
a first calculation step of calculating first tone characteristics based on information concerning the person region detected in the detection step;
a second calculation step of calculating second tone characteristics based on predetermined tone characteristics and the first tone characteristics calculated in the first calculation step; and
an image processing step of performing tone correction processing by using the second tone characteristics calculated in the second calculation step.

12. A non-transitory computer readable storage medium storing a program for causing a computer to execute each step of an image processing method defined in claim 11 .

13. An image processing method comprising:
a detection step of detecting a person region included in an image;
a first calculation step of calculating first tone characteristics based on information concerning the person region detected in the detection step; and
an image processing step of generating a tone-corrected image by performing weighted addition of an image generated by predetermined tone characteristics and an image generated by first tone characteristics calculated in the first calculation step.

14. A non-transitory computer readable storage medium storing a program for causing a computer to execute each step of an image processing method defined in claim 13 .

Assignees

• Canon Kk

Inventors

• Sasaki Takashi

Classifications

• G06V10/50

  by performing operations within image blocks; by using histograms, e.g. histogram of oriented gradients [HoG]; by summing image-intensity values; Projection analysis · CPC title

• H04N1/4072

  dependent on the contents of the original · CPC title

• H04N1/628

  Memory colours, e.g. skin or sky · CPC title

• H04N1/6027 Primary

  Correction or control of colour gradation or colour contrast (H04N1/6058 takes precedence) · CPC title

• G06T2207/30196

  Human being; Person · CPC title