NOISE REDUCED COLOR IMAGE USING PANCHROMATIC IMAGE

• US 20110096987A1
• Filed: 01/03/2011
• Published: 04/28/2011
• Est. Priority Date: 05/23/2007
• Status: Active Grant

• Current Assignee: Omnivision Technologies Incorporated (Will Semiconductor Co., Ltd. Shanghai)
• Original Assignee: Omnivision Technologies Incorporated (Will Semiconductor Co., Ltd. Shanghai)
• Inventors: Hamilton, John F. JR., Morales, Efrain O.
• Granted Patent: US 8,224,085 B2
• Time in Patent Office: Days
• US Class Current: 382/167
• CPC Class Codes: G06T 2207/10016 Video; Image sequence
• CPC Class Codes: G06T 2207/10024 Color image
• CPC Class Codes: G06T 3/4015 Image demosaicing, e.g. colour filter arrays [CFA] or Bayer patterns
• CPC Class Codes: G06T 5/002 Denoising; Smoothing noise processing or correction adapted to be used in an image pickup device containing and electronic image sensor H04N23/81, H04N25/60 - H04N25/67
• CPC Class Codes: G06T 5/20 using local operators
• CPC Class Codes: G06T 5/50 using two or more images, e.g. averaging or subtraction
• CPC Class Codes: G06T 5/70 Denoising; Smoothing
• CPC Class Codes: H04N 23/661 Transmitting camera control signals through networks, e.g. control via the Internet
• CPC Class Codes: H04N 23/843 Demosaicing, e.g. interpolating colour pixel values
• CPC Class Codes: H04N 25/133 including elements passing panchromatic light, e.g. filters passing white light
• CPC Class Codes: H04N 25/135 based on four or more different wavelength filter elements

Abstract

A method for producing a noise-reduced digital color image, includes providing an image having panchromatic pixels and color pixels corresponding to at least two color photoresponses; providing from the image a panchromatic image and at least one color image; and using the panchromatic image and the color image to produce the noise-reduced digital color image by setting a plurality of color characteristics equal to the corresponding panchromatic characteristics at each color pixel location.

Claims

1. A method for providing a noise-reduced value for a color pixel from a digital image having panchromatic pixels and color pixels, comprising:

a. providing a first image having sparsely sampled panchromatic pixels and color pixels corresponding to at least two color photoresponses;

b. interpolating the panchromatic pixels to provide a full-resolution panchromatic image; and

c. providing a noise-reduced value for a particular color pixel in the first image, by;

i. selecting a neighborhood of color pixels surrounding and including the particular color pixel, each selected color pixel having a value and having the same color photoresponse as the particular color pixel;

ii. selecting a neighborhood of panchromatic pixels from the full-resolution panchromatic image, each selected panchromatic pixel having a value and being associated by location with a color pixel in the selected neighborhood of color pixels; and

iii. using the values of the pixels from the selected neighborhoods of color and panchromatic pixels to provide the noise reduced value for the particular color pixel.

2. The method of claim 1 wherein step c(iii) includes using means or medians calculated from the values of the pixels from the selected neighborhoods to provide the noise-reduced value for the particular color pixel.

3. The method of claim 2 wherein the means or medians are means or medians of directional gradients.

4. The method of claim 3 wherein the gradients are weighted.