Method and system for processing images

• US 6,912,004 B1
• Filed: 07/16/1999
• Issued: 06/28/2005
• Est. Priority Date: 09/15/1998
• Status: Expired due to Term

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Phase One A/S
• Inventors: Jønsson, Michael, Knudsen, Niels V.
• Primary Examiner(s): Christensen, Andrew
• Assistant Examiner(s): Tran, Nhan
• Application Number:
  US09/354,847
• Time in Patent Office: 2,174 Days
• Field of Search: 358/525, 358/518, 348/241, 348/246, 348/251, 348/273, 348/222.1, 348/242, 348/272, 348277-280, 382/300
• US Class Current: 348/273
• 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: G06T 3/4015 Image demosaicing, e.g. colour filter arrays [CFA] or Bayer patterns

Abstract

A method and a system for processing images using interpolating. A variation value for different sets of pixels is determined, and the set of pixels with the highest correlation (lowest numeric value) is selected. A missing color at a given pixel is expressed in terms of the information contained in the selected set of pixels. If the variation value is below a certain threshold, due to noise or other factors, an alternative set of pixels using a different variation method may be selected. The missing color is estimated as a weighted sum of, e.g., the green samples divided by the weighted sum of, e.g., the red samples multiplied by the sampled value from the pixel to be estimated.

Claims

1. An image processing method comprising:

dividing an image into a matrix of pixels for holding color values;

forming a first set of pixels that are positioned adjacent to a selected pixel;

calculating a first variation value;

forming a second set of pixels that are positioned adjacent to the selected pixel;

calculating a second variation value;

comparing the first and second variation values and selecting the set of pixels having a lowest variation value; and

calculating a first color value of the selected pixel by calculating the first color value from first color values of the selected set of pixels,

wherein said calculating a first variation value and said calculating a second variation value respectively comprise

calculating a ratio between first color values and second color values of abutting pixels of the respective set of pixels,

calculating a mean value of the calculated ratios, and

calculating a variation value of the respective set of pixels as a sum of an absolute value of a difference between each of the ratios and the mean value.

3. The method according to claim 1, further comprising forming the sets of pixels to be arranged in rows at an angle of approximately 45 degrees relative to rows and columns of the pixels in the image, and in rows and columns parallel to the rows and columns of the pixels in the image.

4. The method according to claim 1, further comprising forming the sets of pixels to be arranged in rows at an arbitrary angle relative to rows and columns of the pixels in the image.

5.The method according to claim 1, further comprising forming the sets of pixels to take any form.

2. An image processing method comprising:

dividing an image into a matrix of pixels for holding color values;

forming a first set of pixels that are positioned adjacent to a selected pixel;

calculating a first variation value using ratios between color values of the pixels of the first set;

forming a second set of pixels that are positioned adjacent to the selected pixel;

calculating a second variation value using ratios between color values of the pixels of the second set;

comparing the first and second variation values and selecting the set of pixels having a lowest variation value;

calculating a weighted sum of second color values of the selected set of pixels;

calculating a weighted sum of first color values of the selected set of pixels; and

calculating the first color value of the selected pixel by multiplying a second color value of the selected pixel with a ratio between the weighted sums of the first color values and the second color values.

5. The method according to claim 2, further comprising forming the sets of pixels to be arranged in rows at an angle of approximately 45 degrees relative to rows and columns of the pixels in the image, and in rows and columns parallel to the rows and columns of the pixels in the image.

6. The method according to claim 2, further comprising forming the sets of pixels to be arranged in rows at an arbitrary angle relative to rows and columns of the pixels in the image.

7. The method according to claim 2, further comprising forming the sets of pixels to take any form.