Image processing apparatus, computer readable medium storing program, image processing method, and computer data signal

• US 20080025625A1
• Filed: 04/23/2007
• Published: 01/31/2008
• Est. Priority Date: 07/28/2006
• Status: Active Grant

• Current Assignee: Fuji Xerox Company Limited (Xerox Holdings Corp.)
• Original Assignee: Fuji Xerox Company Limited (Xerox Holdings Corp.)
• Inventors: Ishizaka, Kanya
• Granted Patent: US 8,098,960 B2
• Time in Patent Office: Days
• US Class Current: 382/248
• CPC Class Codes: G06T 3/4007 based on interpolation, e.g. bilinear interpolation image demosaicing G06T3/4015; edge-driven or edge-based scaling G06T3/403

Abstract

An image processing apparatus includes: a table generation unit that generates a table in which a coefficient set including predetermined weighting coefficients and pixels contained in a resolution converted image are related to each other on the basis of a size of an input image and a size of a resolution converted image; a coefficient selecting unit that selects a coefficient set to be applied for a calculation of a pixel value in the resolution converted image out of plural coefficient sets on the basis of a table generated by the table generation unit; and a pixel value calculating unit that calculates pixel values to be used in the resolution converted image resulting from the resolution conversion of the input image on the basis of the coefficient set selected by the coefficient selecting unit and plural pixel values contained in the input image.

Claims

1. An image processing apparatus, comprising:

a table generation unit that generates a table in which a coefficient set including predetermined weighting coefficients and pixels contained in a resolution converted image are related to each other on the basis of a size of an input image and a size of a resolution converted image;

a coefficient selecting unit that selects a coefficient set to be applied for a calculation of a pixel value in the resolution converted image out of a plurality of coefficient sets on the basis of a table generated by the table generation unit; and

a pixel value calculating unit that calculates pixel values to be used in the resolution converted image resulting from the resolution conversion of the input image on the basis of the coefficient set selected by the coefficient selecting unit and a plurality of pixel values contained in the input image.

2. The image processing apparatus according to claim 1, wherein a total sum of weighting coefficients contained in each of the coefficient sets is equal to 1, and a denominator of the weighting coefficients is a power of 2.

3. The image processing apparatus according to claim 1, wherein the plurality of coefficient sets differing from one another have at least one weighting coefficient of the same value.

4. The image processing apparatus according to claim 1, wherein a shift value for the input image is related to each of the coefficient sets;

and

the pixel value calculating unit determines, on the basis of the shift value relating to a coefficient set selected by the coefficient selecting unit, a pixel position of the input image to be used for calculating pixel values of a resolution converted image.

5. The image processing apparatus according to claim 1, further having:

a range setting unit that determines a range of selectable coefficient sets,

wherein the coefficient selecting unit selects an applicable coefficient set out of a group of coefficient sets contained in the range set by the range setting unit.

6. The image processing apparatus according to claim 1, further having:

a filtering processing unit that applies filtering that depends on the input image'"'"'s condition or a user'"'"'s instruction to the pixel value of the resolution converted image calculated by the pixel value calculating unit.

7. The image processing apparatus according to claim 1, further having:

a gray scale converting unit that, where the input image is a binary image, convert the input image to a gray scale image,

wherein the pixel value calculating unit calculates the pixel value of the resolution converted image on the basis of the pixel value of the image converted into a gray scale image by the gray scale converting unit,

the apparatus further having;

a binary converting unit that applies binary conversion by a binarization method depending on the input image'"'"'s condition to the pixel value of the resolution converted image calculated by the pixel value calculating unit.

8. The image processing apparatus according to claim 1, further having:

a binary converting unit that applies binary conversion, where an output image is a binary image, by varying a binarization threshold value in proportion to a ratio of the area between the input image and the output image.

9. A computer readable medium storing a program causing a computer to execute a process comprising:

generating a table in which a coefficient set including predetermined weighting coefficients and pixels contained in a resolution converted image are related to each other on the basis of a size of an input image and a size of a resolution converted image;

selecting a coefficient set to be applied for a calculation of a pixel value in the resolution converted image out of a plurality of coefficient sets on the basis of the generated table; and

calculating pixel values to be used in the resolution converted image resulting from the resolution conversion of the input image on the basis of the selected coefficient set and a plurality of pixel values contained in the input image.

10. An image processing method, comprising:

generating a table in which a coefficient set including predetermined weighting coefficients and pixels contained in a resolution converted image are related to each other on the basis of a size of an input image and a size of a resolution converted image;

selecting a coefficient set to be applied for a calculation of a pixel value in the resolution converted image out of a plurality of coefficient sets on the basis of the generated table; and

calculating pixel values to be used in the resolution converted image resulting from the resolution conversion of the input image on the basis of the selected coefficient set and a plurality of pixel values contained in the input image.

11. A computer data signal embodied in a carrier wave for enabling a computer to perform a process for an image processing, the process comprising:

generating a table in which a coefficient set including predetermined weighting coefficients and pixels contained in a resolution converted image are related to each other on the basis of a size of an input image and a size of a resolution converted image;

selecting a coefficient set to be applied for a calculation of a pixel value in the resolution converted image out of a plurality of coefficient sets on the basis of the generated table; and

calculating pixel values to be used in the resolution converted image resulting from the resolution conversion of the input image on the basis of the selected coefficient set and a plurality of pixel values contained in the input image.