Image correction apparatus

• US 7,539,342 B2
• Filed: 05/12/2005
• Issued: 05/26/2009
• Est. Priority Date: 05/13/2004
• Status: Active Grant

• Current Assignee: Omron Corporation
• Original Assignee: Omron Corporation
• Inventors: Tabata, Naohiro, Yoshida, Yoko
• Primary Examiner(s): Hung; Yubin
• Application Number:
  US11/127,109
• Publication Number:
  US 20050271295A1
• Time in Patent Office: 1,475 Days
• Field of Search: 382/162, 382/167, 382/254, 382/274, 382/275, 345/589, 358/518, 358/520
• US Class Current: 382/167
• CPC Class Codes: G06T 2207/10024 Color image
• CPC Class Codes: G06T 2207/20012 Locally adaptive
• CPC Class Codes: G06T 2207/30201 Face
• CPC Class Codes: G06T 5/40 using histogram techniques
• CPC Class Codes: G06T 5/70 Denoising; Smoothing
• CPC Class Codes: G06T 5/94 based on local image properties, e.g. for local contrast enhancement
• CPC Class Codes: G06T 7/136 involving thresholding
• CPC Class Codes: H04N 1/6086 by scene illuminant, i.e. conditions at the time of picture capture, e.g. flash, optical filter used, evening, cloud, daylight, artificial lighting, white point measurement, colour temperature
• CPC Class Codes: H04N 1/62 Retouching, i.e. modification of isolated colours only or in isolated picture areas only
• CPC Class Codes: H04N 1/628 Memory colours, e.g. skin or sky

Abstract

An object of the invention is to provide an apparatus which performs correction only to a high-brightness portion generated in a particular region, in which a decrease in brightness is necessary, and glaze is removed or reduced. A correction process in which the brightness or the lightness is decreased is simply performed to a pixel in which the brightness or the lightness is high, but a predetermined region (for example, face, eyes, and mouth) of a subject is detected and a degree of correction of each pixel is determined based on the detection result (a position and a color of the predetermined region). Therefore, the region in which the decrease in brightness is not necessary is maintained at high brightness, and the image correction is performed only to the region in which the decrease in brightness is necessary (for example, the region in which the glaze of a skin is generated).

Claims

1. An image correction method comprising:

a step in which a digital computing apparatus detects a predetermined region of a subject from an inputted image;

a step in which said apparatus computes an intensity value indicating how close a color component of a pixel is to a dominant color component of the detected predetermined region; and

a step in which said apparatus performs image correction to the pixel such that brightness or lightness of the pixel is decreased, wherein the information processing apparatus determines a degree of correction to be performed to the pixel based on the intensity value and the brightness or lightness of the pixel of the inputted image.

2. An image correction apparatus comprising:

a detection device configured to detect a predetermined region of a subject from an inputted image;

an intensity value computing device configured to compute an intensity value indicating how close a color component of a pixel is to a dominant color component of the detected predetermined region; and

a correction device configured to perform image correction to the pixel such that brightness or lightness of the pixel is decreased, wherein the correction device determines a degree of correction performed to the pixel based on the intensity value and the brightness or the lightness of the pixel of the inputted image.

3. An image correction apparatus according to claim 2, wherein the correction device weakens the degree of correction used to compute a color component close to the color component of the pixel of the inputted image, as the intensity value of the pixel indicates that the color component is farther away from the dominant color component of the predetermined region, and as the brightness or the lightness of the pixel has a lower value, wherein the color component close to the color component of the pixel becomes the color component of the pixel;

and

the correction device strengthens the degree of correction used to compute the color component, as the intensity value of the pixel indicates that the color component is closer to the dominant color component of the predetermined region, and as the brightness or the lightness of the pixel has a higher value, the color component in which the brightness or the lightness is decreased becomes the color component of the pixel.

4. An image correction apparatus according to claim 2, further comprising a blurring device which performs a blurring process to the inputted image, wherein the correction device weakens the degree of correction used to compute the color component close to the color component of the pixel of the inputted image, as the intensity value-of the pixel indicates that the color component is farther away from the dominant color component of the predetermined region, and as the brightness or the lightness of the pixel has a lower value, the color component closer to the color component of the pixel becomes the color component of the pixel;

and

the correction device strengths the degree of correction to compute the color component close to the color component, as the intensity value of the pixel indicates that the color component is closer to the dominant color component of the predetermined region, and as the brightness or the lightness of the pixel has a higher value, the color component closer to the color component of the pixel becomes the color component of the pixel.

5. An image correction apparatus according to claim 4, wherein the blurring device performs the blurring process by using only the pixel having a value indicating that the intensity value is close to the dominant color component of the predetermined region.

12. An image correction apparatus according to claims 2 or 8, wherein the correction device determines an estimated domain which includes a person'"'"'s face based on the position of the detected predetermined region, and performs the image correction to each of a plurality of pixels included in the domain, based on the brightness or the lightness of each pixel in the domain.

13. An image correction apparatus according to claims 2 or 8, wherein the correction device determines an estimated domain where glaze is generated on the skin of a person'"'"'s face based on the position of the detected predetermined region, and performs the image correction to the pixels, included in the domain, based on the brightness or the lightness of each pixel.

14. An image correction apparatus according to claims 2 or 8, wherein the correction device estimates a position of eyes and/or mouth based on the position of the detected predetermined region, and performs the image correction to a plurality of pixels in a domain, except for the eyes and/or mouth, based on the brightness or the lightness of each respective pixel in the domain.

15. An image correction apparatus as in any one of claims 2 or 8, wherein the correction device obtains the degree of correction for the pixel which includes performing a smoothing process on the original image.

6. A computer-readable medium encoded with a computer program which causes a digital computing apparatus to execute the steps of:

detecting a predetermined region of a subject from an inputted image;

computing an intensity value indicating how close a color component of each of a plurality of pixels of the inputted image is to a dominant color component of the detected predetermined region; and

performing image correction to each of the plurality of pixels of the inputted image such that brightness or lightness of each respective pixel is decreased, the performing step determining a degree of correction to be performed to each respective pixel based on the intensity value and the brightness or the lightness of each respective pixel of the inputted image.

7. An image correction method comprising:

a step in which a digital computing apparatus detects a predetermined region of a subject from an inputted image;

a step in which said apparatus computes an intensity value indicating how close a color component of a pixel is to a dominant color component of the detected predetermined region; and

a step in which said apparatus performs image correction to the pixel such that brightness or lightness is decreased, wherein the information processing apparatus determines a degree of correction performed to the pixel based on a position of the detected predetermined region, the intensity value, and the brightness or the lightness of the pixel of the inputted image.

8. An image correction apparatus comprising:

a detection device configured to detect a predetermined region of a subject from an inputted image;

an intensity value computing device configured to compute an intensity value indicating how close a color component of a pixel is to a dominant color component of the detected predetermined region; and

a correction device configured to perform image correction to the pixel such that brightness or lightness of the pixel is decreased, wherein the correction device determines a degree of correction to be performed to the pixel based on a position of the detected predetermined region, the intensity value, and the brightness or the lightness of each pixel of the inputted image.

9. An image correction apparatus according to claim 8, wherein the correction device weakens the degree of correction used to compute a color component close to the color component of the pixel of the inputted image, as the intensity value of the pixel indicates that the color component is farther away from the dominant color component of the predetermined region, and as the brightness or the lightness of the pixel has a lower value, wherein the color component close to the color component of the pixel becomes the color component of the pixel;

and

the correction device strengthens the degree of correction used to compute the color component, as the intensity value of the pixel indicates that the color component is closer to the dominant color component of the predetermined region, and as the brightness or the lightness of the pixel has a higher value, the color component in which the brightness or the lightness is decreased becomes the color component of the pixel.

10. An image correction apparatus according to claim 8, further comprising a blurring device which performs a blurring process to the inputted image,

wherein the correction device weakens the degree of correction used to compute the color component close to the color component of the pixel of the inputted image, as the intensity value-of the pixel indicates that the color component is farther away from the dominant color component which of the predetermined region, and as the brightness or the lightness of the pixel has a lower value, the color component closer to the color component of the pixel becomes the color component of the pixel;

and

the correction device strengths the degree of correction to compute the color component close to the color component, as the intensity value of the pixel indicates that the color component is closer to the dominant color component of the predetermined region, and as the brightness or the lightness of the pixel has a higher value, the color component closer to the color component of the pixel becomes the color component of the pixel.

11. An image correction apparatus according to claim 10, wherein the blurring device performs the blurring process by using only the pixel having a value indicating that the intensity value is close to the dominant color component of the predetermined region.

16. A computer-readable medium encoded with a computer program which caused a digital computing apparatus to execute the steps of:

detecting a predetermined region of a subject from an inputted image;

computing an intensity value indicating how close a color component of a pixel of a plurality of pixels is to a dominant color component of the detected predetermined region for each pixel of the plurality of pixels; and

performing image correction to each pixel of the plurality of pixels such that brightness or lightness of each respective pixel is decreased, the image correction performing step determining a degree of correction to be performed to each pixel of the plurality of pixels based on a position of the detected predetermined region, the intensity value, and the brightness or the lightness of each pixel of the inputted image.

17. An image correction apparatus comprising:

a detection device configured to detect a predetermined region of a subject from an inputted image;

an intensity obtaining unit configured to determine an intensity value for each of a plurality of pixels in the predetermined region based on a brightness or lightness of each respective pixel, a threshold value and a skin intensity value of each respective pixel; and

a correction unit configured to perform image correction to each respective pixel such that brightness or lightness of the pixel is decreased based on the respective intensity value.

18. An image correction apparatus comprising:

a detection device configured to detect a predetermined region of a subject from an inputted image;

a domain determination unit which determines a domain, where image correction is preformed, based on a position of the predetermined region and the brightness or lightness of each pixel of the inputted image;

an intensity obtaining unit configured to determine an intensity value for each of a plurality of pixels in the predetermined region based on the brightness or lightness of each respective pixel of the inputted image, a threshold value and a skin domain, that is based on skin intensity values of pixels of the inputted image; and

a correction unit configured to perform image correction to each pixel of the domain such that brightness or lightness of each respective pixel of the domain is decreased based on the respective intensity value.