Image processing apparatus, image processing method and program therefor

• US 20040125387A1
• Filed: 08/14/2003
• Published: 07/01/2004
• Est. Priority Date: 12/27/2002
• Status: Active Grant

• Current Assignee: Fuji Xerox Company Limited (Xerox Holdings Corp.)
• Original Assignee: Fuji Xerox Company Limited (Xerox Holdings Corp.)
• Inventors: Nagao, Takashi, Seki, Noriaki, Sasaki, Makoto, Hibi, Yoshiharu, Okutsu, Masaru
• Granted Patent: US 7,663,779 B2
• Time in Patent Office: Days
• US Class Current: 358/1.2
• 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
• CPC Class Codes: H04N 1/3935 with modification of image resolution, i.e. determining the values of picture elements at new relative positions

Abstract

When the size output for an image is equal to or smaller than a predetermined value (e.g., index printing), a printing apparatus performs an image expansion/reduction process by using an interpolation method whereby high speed processing is enabled while an inferior image quality is provided, or when the output size is greater than a predetermined value (e.g., the normal printing of a single sheet), employs an interpolation method for a high quality image to perform the expansion/reduction. Further, when the output image size is equal to or smaller than the predetermined value, the printing apparatus 1 skips the noise reduction process and the sharpening process to increase the processing speed.

Claims

1. An image processing apparatus comprising:

a first image expansion/reduction unit for employing a first method to change the size of a digital image;

a second image expansion/reduction unit for employing a second method to change the size of a digital image; and

a controller for selecting either the first image expansion/reduction unit or the second image expansion/reduction unit in accordance with the output size of a digital image.

2. The image processing apparatus according to claim 1, wherein

the first image expansion/reduction unit changes the size of a digital image at a higher image quality than the second image expansion/reduction unit does, and wherein

the controller selects the first image expansion/reduction unit when the output size of the digital image is greater than a predetermined value, or selects the second image expansion/reduction unit in other cases.

3. The image processing apparatus according to claim 1, wherein

the first image expansion/reduction unit changes the size of a digital image at a higher speed than the second image expansion/reduction unit does, and wherein

the controller selects the first image expansion/reduction unit when the output size of the digital image is greater than a predetermined value, or selects the second image expansion/reduction unit in other cases.

4. The image processing apparatus according to claim 1, further comprising:

an image restoration unit for performing image restoration for a digital image, wherein

the controller changes the contents of the image restoration process performed by the image restoration unit in accordance with the output size of a digital image.

5. The image processing apparatus according to claim 4, wherein

when the output size of the digital image is greater than the predetermined value, the controller permits the image restoration unit to perform a color correction process and a sharpening process at a specific image quality, and in the other cases, permits the image restoration unit to perform the color correction process and/or the sharpening process at a lower image quality than the predetermined image quality.

6. The image processing apparatus according to claim 4, wherein

the image restoration unit performs the color correction process, the sharpening process and a noise reduction process, and wherein

when the output size of the digital image is greater than the predetermined value, the controller permits the image restoration unit to perform the color correction process, the sharpening process and the noise reduction process, and in the other cases, inhibits, at the least, the performance of either the sharpening process or the noise reduction process by the image restoration unit.

7. The image processing apparatus according to claim 4, further comprising:

a parameter setup unit for setting correction parameters based on a reduced image for a digital image, or an image segment extracted from the digital image, wherein

the image restoration unit performs either the color correction process or the sharpening process in accordance with the correction parameters.

8. The image processing apparatus according to claim 4, further comprising:

a reading unit for reading, from a plurality of additional data sets accompanying a digital image, one set of additional data consonant with the output size of the digital image, wherein

the image restoration unit performs the image restoration process in accordance with the additional data obtained by the reading unit.

9. The image processing apparatus according to claim 4, wherein

the first and the second image expansion/reduction units perform an expansion or reduction process for a first direction in a digital image and a-second direction perpendicular to the first direction, and wherein

the controller permits the first and the second image expansion/reduction units and the image restoration unit to respectively perform the expansion or reduction process for the first direction, the expansion or reduction process for the second direction, and the image restoration process, in the order in which the number of pixels to be processed for a digital image is minimized.

10. The image processing apparatus according to claim 6, wherein

the first and the second image expansion/reduction units reduct a digital image based on an interpolation coefficient providing noise reduction effects, and wherein

when the reduction process is performed based on the interpolation coefficient providing the noise reduction effects, the controller inhibits the performance of the noise reduction process by the image restoration unit.

11. The image processing apparatus according to claim 6, wherein

the first and the second image expansion/reduction units expand a digital image based on an interpolation coefficient providing sharpness enhancing effects, and wherein

when the expansion process is performed based on the interpolation coefficient providing the sharpness enhancing effects, the controller inhibits the performance of the sharpening process by the image restoration unit.

12. An image processing apparatus comprising:

an image expansion/reduction unit for changing the size of a digital image;

an image restoration unit for performing an image restoration process for the digital image; and

a controller for, in accordance with the output size of the digital image, controlling the contents of the image restoration process performed by the image restoration unit.

13. The image processing apparatus according to claim 12, wherein

the image restoration unit performs a color correction process for the digital image, and in accordance with the output size of the digital image, the controller controls the contents of the color correction process performed by the image restoration unit.

14. The image processing apparatus according to claim 12, wherein

the image restoration unit performs a sharpening process for the digital image, and wherein

in accordance with the output size of the digital image, the controller controls the contents of the sharpening process performed by the image restoration unit.

15. The image processing apparatus according to claim 12, wherein

the image restoration unit performs a noise reduction process for the digital image, and wherein

in accordance with the output size of the digital image, the controller controls the contents of the noise reduction process performed by the image restoration unit.

16. The image processing apparatus according to claim 12, wherein

when the size of the digital image changed by the image expansion/reduction unit is greater than a predetermined value, the controller controls the image restoration unit to obtain a higher image quality than in the other cases.

17. An image processing method comprising:

selecting either a first expansion/reduction method or a second expansion/reduction method in accordance with the output size of a digital image; and

changing the size of the digital image using the selected first or second expansion/reduction method.

18. An image processing method comprising:

determining the contents of an image restoration process in accordance with the output size of a digital image; and

performing the image restoration process for the digital image based on the contents that have been determined.

19. A program that permits a computer included in an image processing apparatus, comprising:

selecting either a first expansion/reduction method or a second expansion/reduction method in accordance with the output size of a digital image; and

changing the size of the digital image using the selected first or second expansion/reduction method.

20. A program that permits a computer included in an image processing apparatus, comprising:

determining the contents of an image restoration process in accordance with the output size of a digital image; and

performing the image restoration process for the digital image based on the determined contents.