US 2003/0113032 A1 · Method and apparatus for shoot suppression in image detail enhancement

Abstract

A general shoot suppression method and system for image detail enhancement that provides good suppression in shoot areas while preserving the enhancement (with less or no suppression) in non-shoot areas. Asymmetry checker checks the luminance variation of pixels around the current pixel within a filtering range. Based on the checking result, different patterns of luminance variation in the neighborhood of the current pixel are categorized. Higher suppression is applied to those patterns that are more likely to cause overshoot/undershoot. Optionally, suppression is further associated with the intensity of detail signal at each pixel position. An intensity checker checks the magnitude of the detail signal. If the detail signal is weak at a current pixel position, it is unlikely that obvious shoot artifacts appear at that position, and little or no suppression is applied. Such a method and system provide shoot suppression only in shoot areas while maintaining good enhancement in non-shoot areas.

Claims36

Dependent claims

A method for shoot suppression in image detail enhancement, comprising the steps of:

(a) selecting image details for enhancement, wherein the selected image details are represented by a detail signal;
(b) determining a shoot suppression factor s for the detail signal at each pixel position based on the image characteristics of the pixels neighboring a current image pixel in order to substantially suppress shoot artifacts in the enhanced image details;
and
(c) applying the shoot suppression factor s to the detail signal.

1 more element

A method for shoot suppression in image detail enhancement, wherein selected image details are represented by a detail signal, comprising the steps of:

(a) determining a symmetry factor α based on luminance values of pixels neighboring a current image pixel, wherein the symmetry factor represents amount of symmetry in the luminance curve of the neighboring pixels with reference to the current pixel position;
(b) determining a detail signal intensity factor β based on the intensity of the detail signal at the current pixel position;
(c) determining a shoot suppression factor s based on the symmetry factor α and the intensity factor β, wherein:
if said luminance curve is essentially symmetric, then selecting lower shoot suppression,
if said luminance curve is essentially asymmetric, then selecting higher shoot suppression,
if the detail signal is weak in intensity, then selecting lower or no shoot suppression to allow a better enhancement at that pixel position;
and
(d) applying the shoot suppression factor s to the detail signal, in order to substantially suppress shoot artifacts in the enhanced image details.

5 more elements

A method for enhancing image details in an image signal f, comprising the steps of:

(a) generating a detail signal f2 as a function of the image signal f, the detail signal f2 representing the image details;
(b) determining a shoot suppression factor s for the detail signal f2 at each pixel position based on the image characteristics of the pixels neighboring a current pixel, in order to substantially suppress shoot artifacts in the enhanced image details;
and
(c) applying the shoot suppression factor s to the detail signal f2.

1 more element

An apparatus for shoot suppression in image detail enhancement, wherein selected image details are represented by a detail signal, comprising:

a shoot suppressor that determining a shoot suppression factor s for the detail signal based on the image characteristics of the pixels neighboring a current pixel in order to substantially suppress shoot artifacts in the enhanced image details;
and
a combiner that applies the shoot suppression factor s to the detail signal.

An image enhancement apparatus for enhancing image details in an image signal f, comprising:

(a) a detail signal generator for generating a detail signal f2 as a function of the image signal f, the detail signal f2 representing the image details;
(b) a shoot suppressor that determines a shoot suppression factor s for the detail signal f2 based on the image characteristics of the pixels neighboring a current pixel, in order to substantially suppress shoot artifacts in the enhanced image details;
and
(c) a combiner that applies the shoot suppression factor s to the detail signal f2.

1 more element

Dependencies are inferred from the claim text.

Method and apparatus for shoot suppression in image detail enhancement

Life of this patent

Method and apparatus for shoot suppression in image detail enhancement

Life of this patent

Abstract

Claims36