Picture image processing apparatus and method, and picture processing system

• US 20020191204A1
• Filed: 06/05/2002
• Published: 12/19/2002
• Est. Priority Date: 06/07/2001
• Status: Active Grant

• Current Assignee: Noritsu Koki Co., Ltd.
• Original Assignee: Noritsu Koki Co., Ltd.
• Inventors: Nishi, Noriyuki, Kuramoto, Hisakazu, Dedachi, Shoichi, Nakano, Keiji
• Granted Patent: US 7,221,476 B2
• Time in Patent Office: Days
• US Class Current: 358/1.9
• CPC Class Codes: G06T 7/90 Determination of colour characteristics
• CPC Class Codes: G06V 10/56 relating to colour
• CPC Class Codes: G06V 10/98 Detection or correction of errors, e.g. by rescanning the pattern or by human intervention; Evaluation of the quality of the acquired patterns
• CPC Class Codes: G06V 10/993 Evaluation of the quality of the acquired pattern
• CPC Class Codes: H04N 1/6027 Correction or control of colour gradation or colour contrast H04N1/6058 takes precedence

Abstract

A picture image processing apparatus is provided with a hue calculating portion for calculating a hue pixel by pixel based on a RGB data, a first sampling portion for sampling pixels having a hue corresponding to a skin color from the RGB data, a first characteristic quantity calculating portion for calculating a first characteristic quantity representing a characteristic of the RGB data of the pixels sampled by the first sampling portion, a second sampling portion for sampling the pixels located in a central part of an image area, a second characteristic quantity calculating portion for calculating a second characteristic quantity representing a characteristic of the RGB data of the pixels sampled by the second sampling portion, a correction amount calculating portion for calculating a density correction amount using the first and second characteristic quantities, and a density correcting portion for correcting the density of the RGB data using the density correction amount. The density of a main subject in the image can be properly corrected.

Claims

1. A picture image processing apparatus, comprising:

an image storage portion which stores RGB data pixel by pixel which data is obtained from a photographed film image while being separated into color components of R, G, B;

a hue calculator which calculates a hue pixel by pixel based on the RGB data;

a first sampling device which samples pixels having a hue corresponding to a skin color from the RGB data;

a first characteristic quantity calculator which calculates a first characteristic quantity representing a characteristic of the RGB data of the pixels sampled by the first sampling device;

a second sampling device which samples the pixels located in a central part of an image area;

a second characteristic quantity calculator which calculates a second characteristic quantity representing a characteristic of the RGB data of the pixels sampled by the second sampling device;

a correction amount calculator which calculates a density correction amount using the first and second characteristic quantities; and

a density corrector which applies a density correction to the RGB data using the density correction amount.

2. A picture image processing apparatus according to claim 1, wherein the correction amount calculator normalizes a group of the first characteristic quantities and a group of the second characteristic quantities of the RGB data of a plurality of standard photographed images, applies Schmidt orthogonalization to the normalized two groups, and calculates a density correction amount by an equation defined by a factor obtained by normalizing the orthogonalized two groups again and variables including the first and second characteristic quantities.

3. A picture image processing apparatus according to claim 2, wherein the first characteristic quantity calculator calculates a deviation of a histogram whose horizontal axis represents the value of the RGB data and whose vertical axis represents the number of the pixels from an average value of the RGB data of the standard photographed image as the first characteristic quantity.

4. A picture image processing apparatus according to claim 3, wherein the second characteristic quantity calculator calculates an average value of R data of the RGB data as the second characteristic quantity.

5. A picture image processing apparatus according to claim 4, wherein the density corrector applies the density correction by adding the density correction amount to the RGB data.

6. A picture image processing apparatus according to claim 1, wherein the first characteristic quantity calculator calculates a deviation of a histogram whose horizontal axis represents the value of the RGB data and whose vertical axis represents the number of the pixels from an average value of the RGB data of the standard photographed image as the first characteristic quantity.

7. A picture image processing apparatus according to claim 1, wherein the second characteristic quantity calculator calculates an average value of R data of the RGB data as the second characteristic quantity.

8. A picture image processing apparatus according to claim 1, wherein the density corrector applies the density correction by adding the density correction amount to the RGB data.

9. A picture processing system, comprising:

a picture image processing apparatus including;

an image storage portion which stores RGB

data pixel by pixel which data is obtained from a photographed film image while being separated into color components of R, G, B;

a hue calculator which calculates a hue pixel by pixel based on the RGB data;

a first sampling device which samples pixels having a hue corresponding to a skin color from the RGB data;

a first characteristic quantity calculator which calculates a first characteristic quantity representing a characteristic of the RGB data of the pixels sampled by the first sampling device;

a second sampling device which samples the pixels located in a central part of an image area;

a second characteristic quantity calculator which calculates a second characteristic quantity representing a characteristic of the RGB data of the pixels sampled by the second sampling device;

a correction amount calculator which calculates a density correction amount using the first and second characteristic quantities; and

a density corrector which applies a density correction to the RGB data using the density correction amount; and

an image exposing apparatus including an image exposure head for exposing a printing sheet by converting a RGB data into a light signal.

10. A picture processing system according to claim 9, wherein the correction amount calculator normalizes a group of the first characteristic quantities and a group of the second characteristic quantities of the RGB data of a plurality of standard photographed images, applies Schmidt orthogonalization to the normalized two groups, and calculates a density correction amount by an equation defined by a factor obtained by normalizing the orthogonalized two groups again and variables including the first and second characteristic quantities.

11. A picture processing system according to claim 10, wherein the first characteristic quantity calculator calculates a deviation of a histogram whose horizontal axis represents the value of the RGB data and whose vertical axis represents the number of the pixels from an average value of the RGB data of the standard photographed image as the first characteristic quantity.

12. A picture processing system according to claim 11, wherein the second characteristic quantity calculator calculates an average value of R data of the RGB data as the second characteristic quantity.

13. A picture processing system according to claim 12, wherein the density corrector applies the density correction by adding the density correction amount to the RGB data.

14. A picture processing system according to claim 9, wherein the first characteristic quantity calculator calculates a deviation of a histogram whose horizontal axis represents the value of the RGB data and whose vertical axis represents the number of the pixels from an average value of the RGB data of the standard photographed image as the first characteristic quantity.

15. A picture processing system according to claim 9, wherein the second characteristic quantity calculator calculates an average value of R data of the RGB data as the second characteristic quantity.

16. A picture processing system according to claim 9, wherein the density corrector applies the density correction by adding the density correction amount to the RGB data.

17. A picture image processing method, comprising:

a hue calculating step of calculating a hue for each pixel based on RGB data obtained by separating a photographed film image into color components of R, G and B and stored pixel by pixel in a storage portion;

a first sampling step of sampling the pixels having a hue corresponding to a skin color from the RGB data;

a first characteristic quantity calculating step of calculating a first characteristic quantity representing a characteristic of the RGB data of the pixels sampled in the first sampling step;

a second sampling step of sampling the pixels located in a central part of an image area;

a second characteristic quantity calculating step of calculating a second characteristic quantity representing a characteristic of the RGB data of the pixels sampled in the second sampling step;

a density correction amount calculating step of calculating a density correction amount using the first and second characteristic quantities; and

a density correcting step of applying a density correction to the RGB data using the calculated density correction amount.