Background estimation and segmentation based on range and color
First Claim
1. A method for distinguishing between background and foreground objects in an image, comprising the steps of:
- i) determining respective range values for pixels in each of a plurality of related images;
ii) determining respective intensity values for pixels in each of said plurality of related images;
iii) establishing a multi-dimensional background model for at least some of said pixels on the basis of said range values and said intensity values;
iv) comparing the range value for a particular pixel in a given image with the background model for that pixel, and labeling the pixel as a foreground pixel if the range value differs from the background model by a range threshold; and
v) comparing the intensity value for said particular pixel in a given image with the background model for that pixel, and labeling the pixel as a foreground pixel if the intensity value differs from the background model by an intensity threshold.
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Accused Products
Abstract
Segmentation of background and foreground objects in an image is based upon the joint use of range and color data. Range-based data is largely independent of color image data, and hence not adversely affected by the limitations associated with color-based segmentation, such as shadows and similarly colored objects. Furthermore, color segmentation is complementary to range measurement in those cases where reliable range data cannot be obtained. These complementary sets of data are used to provide a multidimensional background estimation. The segmentation of a foreground object in a given frame of an image sequence is carried out by comparing the image frames with background statistics relating to range and normalized color, using the sets of statistics in a complementary manner. A background model is determined by estimating using a multidimensional histogram, recording pixel values, configuring the pixel values into a cluster, and selecting a largest cluster as representing the background model.
97 Citations
28 Claims
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1. A method for distinguishing between background and foreground objects in an image, comprising the steps of:
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i) determining respective range values for pixels in each of a plurality of related images; ii) determining respective intensity values for pixels in each of said plurality of related images; iii) establishing a multi-dimensional background model for at least some of said pixels on the basis of said range values and said intensity values; iv) comparing the range value for a particular pixel in a given image with the background model for that pixel, and labeling the pixel as a foreground pixel if the range value differs from the background model by a range threshold; and v) comparing the intensity value for said particular pixel in a given image with the background model for that pixel, and labeling the pixel as a foreground pixel if the intensity value differs from the background model by an intensity threshold. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. A system for identifying foreground objects in an image comprising:
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a sensor which determines intensity values for pixels within an image; a range processor which determines distance values for pixels within said image; a background estimator which computes a multi-dimensional background model for said pixels on the basis of said intensity values and said distance values; and a discriminator which compares intensity and distance values for pixels in an image to said background model and determines whether said pixels represent a foreground object. - View Dependent Claims (21, 22, 23, 24, 25, 26, 27, 28)
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Specification