Producing low resolution images

• US 7,769,230 B2
• Filed: 11/30/2006
• Issued: 08/03/2010
• Est. Priority Date: 11/30/2006
• Status: Active Grant

• Current Assignee: Omnivision Technologies Incorporated (Will Semiconductor Co., Ltd. Shanghai)
• Original Assignee: Eastman Kodak Company
• Inventors: Enge, Amy D., Pillman, Bruce H., Hamilton, John F. Jr., O'Brien, Michele, DeWeese, Thomas E.
• Primary Examiner(s): Do; Anh Hong
• Application Number:
  US11/565,157
• Publication Number:
  US 20080131028A1
• Time in Patent Office: 1,342 Days
• Field of Search: 382/162, 382/167, 382/152, 382/299, 345/22, 359/19, 358/500, 358/527, 349/62, 349/104, 348/241, 348/222.1, 348/223.1, 348/E5.041, 348/E9.01
• US Class Current: 382/167
• CPC Class Codes: H04N 23/76 by influencing the image signals
• 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 of processing an array of pixels captured by an image capture device, includes providing a first two-dimensional array having first and second groups of pixels wherein pixels from the first group of pixels have narrower spectral photoresponses than pixels from the second group of pixels and wherein the first group of pixels has individual pixels that have spectral photoresponses that correspond to a set of at least two colors and the placement of the first and second groups of pixels define a pattern that has a minimal repeating unit arranged to permit the reproduction of a captured color image under different lighting conditions; responding to ambient lighting conditions, whether panchromatic pixels are to be combined with color pixels; combining pixels to produce a second two-dimensional array of pixels which has fewer pixels than the first two-dimensional array of pixels; and correcting the color pixels.

Claims

1. A method of processing an array of pixels captured by an image capture device, comprising:

(a) providing a first two-dimensional array having first and second groups of pixels wherein pixels from the first group of pixels have narrower spectral photoresponses than pixels from the second group of pixels and wherein the first group of pixels has individual pixels that have spectral photoresponses that correspond to a set of at least two colors and the placement of the first and second groups of pixels define a pattern that has a minimal repeating unit including at least twelve pixels, the minimal repeating unit having a plurality of cells wherein each cell has at least two pixels representing a specific color selected from the first group of pixels and a plurality of pixels selected from the second group of pixels arranged to permit the reproduction of a captured color image under different lighting condition;

using a digital signal processor to perform the following steps;

(b) determining in response to ambient lighting conditions, whether panchromatic pixels are to be combined with color pixels;

(c) combining pixels determined from step (b) to produce a second two-dimensional array of pixels which has fewer pixels than the first two-dimensional array of pixels; and

(d) correcting the color pixels produced in step (c).

2. The method of claim 1 wherein the first two-dimensional array has the following minimal repeating unit:

3. The method of claim 1 wherein ambient lighting conditions are determined from the value in one or more panchromatic pixels.

4. The method of claim 1 wherein step (c) includes analog combining of color pixels with panchromatic pixels.

5. The method of claim 1 wherein the first two-dimensional array has the following minimal repeating unit:

6. The method of claim 5 wherein step (c) includes analog combining of color pixels with panchromatic pixels.

7. The processing method of claim 1 wherein step (d) involves correction that is also dependent on ambient lighting level.

8. A method of converting a high resolution color digital image captured by a electronic sensor into a lower resolution color digital image, including:

(a) using the electronic sensor to capture a first two-dimensional array of pixels, having first and second groups of pixels wherein pixels from the first group of pixels have narrower spectral photoresponses than pixels from the second group of pixels and wherein the first group of pixels has individual pixels that have spectral photoresponses that correspond to a set of at least two colors and the placement of the first and second groups of pixels define a pattern that has a minimal repeating unit including at least twelve pixels, the minimal repeating unit having a plurality of cells wherein each cell has at least two pixels representing a specific color selected from the first group of pixels and a plurality of pixels selected from the second group of pixels arranged to permit the reproduction of a captured color image under different lighting conditions;

(b) analog combining pixels in the first two-dimensional array of pixels to produce a second two-dimensional array including at least some composite pixels and also having non-regular spacing;

using a digital signal processor to perform the following steps;

(c) computing a third two-dimensional array of pixels with regular spacing; and

(d) correcting the regularized third two-dimensional array of pixels to produce a corrected image with reduced artifacts.

9. The method of claim 8 wherein there is a stream of digital images, each one of which is processed in accordance with claim 8.