Image processing apparatus, image processing method, image processing program recording medium, color adjustment method, color adjustment device, and color adjustment control program recording medium

• US 20030043394A1
• Filed: 10/16/2002
• Published: 03/06/2003
• Est. Priority Date: 06/17/1997
• Status: Active Grant

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Nakami, Yoshihiro, Kuwata, Naoki
• Granted Patent: US 7,072,074 B2
• Time in Patent Office: Days
• US Class Current: 358/1.9
• CPC Class Codes: H04N 1/4072 dependent on the contents of the original
• CPC Class Codes: H04N 1/46 Colour picture communication systems
• CPC Class Codes: H04N 1/6027 Correction or control of colour gradation or colour contrast H04N1/6058 takes precedence
• 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
• CPC Class Codes: H04N 9/643 Hue control means, e.g. flesh tone control

Abstract

In conventional image processing techniques, although a certain kind of image adjustment provides a desired effect on an image, it may cause an undesired side effect thereon, resulting in an unsatisfactory result of adjustment.

On a computer serving as the nucleus of image processing, a region applicable to image processing is specified at a step, an object pixel is moved for judging whether or not it belongs to the specified region at the subsequent steps, and then a specified image processing operation is carried out if the object pixel is judged to belong to the specified region. Therefore, adjustment of image data in a certain region does not have an adverse effect on image data in other regions, making it possible to realize satisfactory adjustment in an entire image with ease.

Further, on the computer, chromaticity “x-y” of each pixel is calculated at a step, and statistical calculation is performed at the subsequent steps if a value of chromaticity thus calculated is in a possible chromaticity range. After completion of statistical calculation on all the pixels, an average value is determined at the subsequent step, and a degree of each color adjustment is calculated while taking account of the number of pixels of interest at the subsequent step. In this manner, accurate statistical calculation is performed on color pixels to be adjusted independently of brightness, and a degree of each color adjustment is regulated by taking account of the number of pixels of interest, thereby making it possible to carry out optimum color adjustment processing without giving an adverse effect on colors of surrounding pixels.

Claims

1. An image processing apparatus for inputting photographic image data containing dot-matrix pixels and converting each pixel of said image data according to predetermined correspondence relationship information, comprising:

correspondence relationship holding the unit which holds a plurality of correspondence relationship information for conversion of said image data in combination with applicable object information thereof;

correspondence relationship judging unit which judges each correspondence relationship for converting each pixel of said image data according to said correspondence relationship and applicable object information which is held by said correspondence relationship holding unit; and

image data converting unit which converts each pixel of said image data by referencing each correspondence relationship judged by said correspondence relationship judging unit from said correspondence relationship holding unit.

2. An image processing apparatus as claimed in claim 1, wherein, in said correspondence relationship information holding unit, each correspondence relationship applicable to each part of image being held along with information on each part applicable to each correspondence relationship, and wherein, in the step of forming a judgment on said correspondence relationship, a part of image corresponding to each pixel being detected and each correspondence relationship for conversion being judged through comparing the detected part of image with part information for each correspondence relationship.

3. An image processing apparatus as claimed in claim 1, wherein, in said correspondence relationship information holding unit, a plurality of correspondence relationships being held along with information on chromaticity applicable to each correspondence relationship, and wherein, in said correspondence relationship judgement unit, a value of chromaticity of each pixel being detected and each correspondence relationship for conversion being judged through comparing the detected value of chromaticity with information on chromaticity for each correspondence relationship.

4. An image processing apparatus as claimed in claim 1, wherein, in said correspondence relationship information holding unit, being provided a color conversion table which stores information on correspondence relationship between pre-converted original image data,and post-converted image data.

5. An image processing apparatus as claimed in claim 1, wherein, in said correspondence relationship information holding unit, a plurality of correspondence relationships being realized by changing a degree of correspondence relationship applicability.

6. An image processing apparatus as claimed in claim 1, wherein, in said correspondence relationship information holding unit, a plurality of correspondence relationships applicable to said image data being specified in succession as required.

7. An image processing apparatus as claimed in claim 1, wherein, in said correspondence relationship information holding unit, each correspondence relationship for adjusting brightness according to said image data being held.

8. An image processing apparatus as claimed in claim 1, wherein, in said correspondence relationship information holding unit, each correspondence relationship for adjusting chromaticity according to said image data being held.

9. An image processing apparatus as claimed in claim 1, wherein, in said correspondence relationship information holding unit, each correspondence relationship for adjusting color vividness according to said image data being held.

10. An image processing apparatus as claimed in claim 1, wherein, in said image data converting unit, for pixels in a transition region between regions which being different in terms of correspondence relationship, a level of correspondence relationship is adjusted gradually in image data conversion.

11. An image processing method of inputting photographic image data containing dot-matrix pixels and converting each pixel of said image data according to predetermined correspondence relationship information, comprising the steps of:

holding a plurality of correspondence relationship information for conversion of said image data in combination with applicable objet information thereof;

forming a judgment on each correspondence relationship for converting each pixel of said image data according to said correspondence relationship and applicable object information thus held; and

converting each pixel of said image data according to result of judgment thus formed.

12. A storage medium for recording an image processing program for inputting photographic image data containing dot-matrix pixels on a computer and converting each pixel of said image data according to predetermined correspondence relationship information, said image processing program comprising the steps of:

holding a plurality of correspondence relationship information for conversion of said image data in combination with applicable object information thereof;

forming a judgment on each correspondence relationship for converting each pixel of said image data according to said correspondence relationship and applicable object information thus held; and

converting each pixel of said image data according to result of judgment thus formed.

13. A color adjustment device for performing color separation of color image data for each predetermined element color and adjusting said color image data in enhancement to provide each desired color in result of color image output delivered for each element color by such a device as an image output device, etc., comprising:

chromaticity judging unit which determines a value of chromaticity of each pixel according to said color image data;

object chromaticity pixel statistical calculation unit which performs statistical calculation on pixels having chromaticity values which have been determined to meet a predefined range of chromaticity by said chromaticity judging unit;

color adjustment degree judging unit which determines a degree of color adjustment so as to eliminate a difference between a predetermined optimum value for pixels meeting said predefined range of chromaticity and a result value attained in said statistical calculation and for regulating said degree of color adjustment according to an occupancy ratio of pixels subjected to said statistical calculation to the total number of pixels; and

color adjusting unit which carries out color adjustment of said image data according to the regulated degree of color adjustment.

14. A color adjustment device as claimed in claim 13, wherein:

in said object chromaticity pixel statistical calculating unit, an average;

value of pixels judged to be object pixels being calculated for each element color of color image data;

in said color adjustment degree judging unit, an optimum value of each element color being provided for color image data meeting said predefined range of chromaticity, and a degree of color adjustment being determined according to said optimum value of each element color.

15. A color adjustment device as claimed in claim 13, wherein, in said chromaticity pixel statistical calculating unit, statistical calculation being performed on object chromaticity pixels in a possible range of chromaticity in terms of memory color in psychology.

16. A color adjustment device as claimed in claim 13, wherein, in a color adjustment degree judging unit, a tone curve representing input-output relationship information being used for changing a degree of element color enhancement, and a tone curve being formed according to said degree of color adjustment.

17. A color adjustment method of performing color separation of color image data for each predetermined element color and adjusting said color image data in enhancement to provide each desired color in result of color image output delivered for each element color by such a device as an image output device, etc., comprising the steps of:

determining a value of chromaticity of each pixel according to said color image data;

performing statistical calculation on pixels having chromaticity values which have been determined to meet a predefined range of chromaticity;

determining a degree of color adjustment so as to eliminate a difference between a predetermined optimum value for pixels meeting said predefined range of chromaticity and a result value attained in said statistical calculation;

regulating said degree of color adjustment according to an occupancy ratio of pixels subjected to said statistical calculation to the total number of pixels; and

carrying out color adjustment of said image data according to the regulated degree of color adjustment.

18. A storage medium for recording a color adjustment control program for performing color separation of color image data for each predetermined element color on a computer and adjusting said color image data in enhancement to provide each desired color in result of color image output delivered for each element color by such a device as an image output device, etc., said color adjustment control program comprising the steps of:

determining a value of chromaticity of each pixel according to said color image data,

performing statistical calculation on pixels having chromaticity values which have been determined to meet a predefined range of chromaticity,

determining a degree of color adjustment so as to eliminate a difference between a predetermined optimum value for pixels meeting said predefined range of chromaticity and a result value attained in said statistical calculation;

regulating said degree of color adjustment according to an occupancy ratio of pixels subjected to said statistical calculation to the total number of pixels; and

carrying out color adjustment of said image data according to the regulated degree of color adjustment.