System and method for reducing noise in images

• US 20030095206A1
• Filed: 05/28/2002
• Published: 05/22/2003
• Est. Priority Date: 09/10/2001
• Status: Active Grant

• Current Assignee: Jaldi Semiconductor Corporation (Pixelworks Incorporated)
• Original Assignee: Jaldi Semiconductor Corporation (Pixelworks Incorporated)
• Inventors: Wredenhagen, G. Finn, Elias, Andrew
• Granted Patent: US 6,933,983 B2
• Time in Patent Office: Days
• US Class Current: 348/448
• CPC Class Codes: G06T 2207/10016 Video; Image sequence
• CPC Class Codes: G06T 2207/20192 Edge enhancement; Edge preservation
• 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 5/70 Denoising; Smoothing
• CPC Class Codes: G06T 7/40 Analysis of texture depth or shape recovery from texture G06T7/529
• CPC Class Codes: H04N 5/208 for compensating for attenuation of high frequency components, e.g. crispening, aperture distortion correction
• CPC Class Codes: H04N 5/21 Circuitry for suppressing or minimising disturbance, e.g. moiré or halo

Abstract

A method is provided for selecting a filter for interpolating a target pixel for reducing noise in an image. The method comprises the following steps. A plurality of pixels along a predetermined contour is compared with a plurality of predefined patterns. The patterns represent visually significant patterns possible along said contour. A filter is selected from a predefined set of filters in accordance with the results of the comparison.

Claims

1. A method for selecting a filter for interpolating a target pixel for reducing noise in an image, said method comprising the steps of:

a) comparing a plurality of pixels along a predetermined contour with a plurality of predefined patterns, said patterns representing visually significant patterns possible along said contour; and

b) selecting a filter from a predefined set of filters in accordance with said results of said comparison.

2. A method as defined in claims 1, wherein said method further includes the step of comparing a difference between ones of said plurality of pixels with at least one predefined thresholds, said filter being selected in accordance with said threshold comparison as well as said pattern comparison.

3. A method as defined in claim 1, wherein said method further includes the step of estimating an amount out noise in said image, whereby said set of filters is selection from a plurality of filters in accordance with said estimated amount of noise.

4. A method as defined in claim 3, wherein said method for estimating said amount of noise in said image includes the steps of:

a) comparing a plurality of pixels on a pixel window with at least one noise template;

b) recording each match of said pixel window with said noise template in accordance with a magnitude difference of predefined ones of said plurality of pixels in said pixel window; and

c) determining a number of occurrences of said matches;

wherein said amount of noise in said image is associate with a frequency of said number of occurrence of said matches.