US 6,141,433 AGranted

System and method for segmenting image regions from a scene likely to represent particular objects in the scene

AssigneeNCR Corporation

InventorsMichael C. Moed, Ralph N. Crabtree

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Abstract

A system and method for extracting image information from a video frame for regions of a the video frame that likely are objects of interest in a scene. An initial region set is generated by comparing luminance image information and color image information of a video frame with luminance image information and color image information of a background image for the scene. A high confidence region set is generated comprising regions from the initial based upon edge information of the regions and edge information in the background image. A final region set is generated by combining one or more regions in the high confidence region set if such combinations satisfy predetermined criteria, including size, region proximity and morphological region dilation.

Claims38

Dependent claims

A method for extracting image information from a video frame for regions of the video frame that likely are objects of interest in a scene, comprising steps of:.

(a) generating a first set of regions based upon differences between image information for the video frame and image information for a background image of the scene;
(b) generating a second set of regions from the first set of regions based upon edge information for regions in the first set and edge information for the background image, wherein the step of generating a second set of regions comprises steps of:
(b)(1) extracting edge information from each region in the first set of regions;
(b)(2) extracting edge information for the background image;
(b)(3) comparing edge information for each region of the first set of regions with edge information for the background image;
(b)(4) generating a confidence value for each region in the first set of regions depending on whether pixels of a region and corresponding pixels in the background image represent edge information, wherein the step of generating a confidence value for each region in the first set of regions comprises steps of:
examining each pixel of a region;
if the pixel in the region represents an edge and a corresponding pixel in the background image represents an edge, then reducing the confidence value for the region;
if the pixel in the region does not represent an edge and a corresponding pixel in the background image represents an edge, then increasing the confidence value for the region;
and
if the pixel in the region represents an edge and a corresponding pixel in the background image does not represent an edge, then increasing the confidence value for the region;
(b)(5) retaining regions from the first set of regions which have a confidence value greater than a predetermined confidence threshold;
and
(c) generating a third set of regions from the second set of regions by combining regions in the second set with each other if resulting combined regions satisfy predetermined criteria.

11 more elements

A system for extracting image information from a video frame for regions of the video frame that likely are objects of interest in a scene, comprising:

(a) a video camera positioned to monitor the scene and generating video signals representing activity within the scene;
(b) a frame grabber coupled to the video camera to generate a stream of video frames from the video signal, each video frame comprising image information of the scene at an instant of time;
(c) a processor coupled to the frame grabber, the processor being programmed to:
(c)(1) generate a first set of regions based upon differences between image information for the video frame and image information for a background image of the scene;
(c)(2) generate a second set of regions from the first set of regions based upon edge information for regions in the first set and edge information for the background image by:
(c)(2)(i) extracting edge information from each region in the first set of regions;
(c)(2)(ii) extracting edge information for the background image;
(c)(2)(iii) comparing edge information for each region of the first set of regions with edge information for the background image;
(c)(2)(iv) generating a confidence value for each region in the first set of regions depending on whether pixels of a region and corresponding pixels in the background image represent edge information, wherein the processor is programmed to generate a confidence value for each region in the first set of regions by:
examining each pixel of a region;
if the pixel in the region represents an edge and a corresponding pixel in the background image represents an edge, then reducing the confidence value for the region;
if the pixel in the region does not represent an edge and a corresponding pixel in the background image represents an edge, then increasing the confidence value for the region;
and
if the pixel in the region represents an edge and a corresponding pixel in the background image does not represent an edge, then increasing the confidence value for the region;
and
(c)(2)(v) retaining regions from the first set of regions which have a confidence value greater than a predetermined confidence threshold;
and
(c)(3) generate a third set of regions from the second set of regions by combining regions in the second set with each other if resulting combined regions satisfy predetermined criteria.

15 more elements

A computer-readable medium storing executable instructions which cause a computer to extract image information from a video frame for regions of the video frame that likely are objects of interest in the scene, by:

(a) generating a first set of regions based upon differences between image information for the video frame and image information for a background image of the scene;
(b) generating a second set of regions from the first set of regions based upon edge information for regions in the first set and edge information for the background image and generating a second set of regions, wherein the step of generating the second set of regions comprises steps of
(b)(1) extracting edge information from each region in the first set of regions;
(b)(2) extracting edge information for the background image;
(b)(3) comparing edge information for each region of the first set of regions with edge information for the background image;
(b)(4) generating a confidence value for each region in the first set of regions depending on whether pixels of a region and corresponding pixels in the background image represent edge information, wherein the instructions for generating a confidence value for each region in the first set comprise instructions for:
examining each pixel of a region;
if the pixel in the region represents an edge and a corresponding pixel in the background image represents an edge, then reducing the confidence value for the region;
if the pixel in the region does not represent an edge and a corresponding pixel in the background image represents an edge, then increasing the confidence value for the region;
and
if the pixel in the region represents an edge and a corresponding pixel in the background image does not represent an edge, then increasing the confidence value for the region;
(b)(5) retaining regions from the first set of regions which have a confidence value greater than a predetermined confidence threshold;
and
(c) generating a third set of regions from the second set of regions by combining regions in the second set with each other if resulting combined regions satisfy predetermined criteria.

11 more elements

Dependencies are inferred from the claim text.