Method and apparatus for contour tracking of an image through a class of non linear filters
First Claim
1. A method for automatically detecting and tracking the contour of a starting image, said starting image being formed by an array of pixels and each pixel having an intensity, being n and m coordinates of a generic pixel, comprising the steps of:
- filtering said starting image through an absolute central moment e(n,m) of the intensity of the pixels of said starting image, wherein said absolute central moment is obtained with the following steps;
determining for each n,m a local mean calculated on a neighborhood about a pixel of coordinates n,m of the starting image, obtaining a first filtered image;
determining for each n,m a sum of absolute differences between the intensity of the pixel having coordinates n,m of the first filtered image and the intensity of all the pixels contained in a neighborhood about said pixel of coordinates n,m of either said starting image or a second filtered image derived from said starting image,wherein said sum of absolute differences is split calculating a sum of positive differences, or positive deviation, and a sum of negative differences, or negative deviation.
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Abstract
A method for automatically detecting and tracking the contour of an image that uses a class of filters, obtained from the first order absolute central moment. The method provides the steps of filtering a starting image through the absolute central moment e(n,m) of the intensity of a pixel of the image, being n and m the coordinates of each pixel, where the absolute central moment is obtained with the following steps: determining for each n,m the local mean calculated in a neighborhood about a pixel of coordinates n,m of the starting image, thus obtaining a first filtered image; determining for each n,m the sum of the absolute differences between the intensity of a pixel of coordinates n,m of the first filtered image and the intensity of all the pixels contained in a neighborhood about a pixel of coordinates n,m of either the starting image or a second filtered image obtained from the starting image.
23 Citations
15 Claims
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1. A method for automatically detecting and tracking the contour of a starting image, said starting image being formed by an array of pixels and each pixel having an intensity, being n and m coordinates of a generic pixel, comprising the steps of:
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filtering said starting image through an absolute central moment e(n,m) of the intensity of the pixels of said starting image, wherein said absolute central moment is obtained with the following steps; determining for each n,m a local mean calculated on a neighborhood about a pixel of coordinates n,m of the starting image, obtaining a first filtered image; determining for each n,m a sum of absolute differences between the intensity of the pixel having coordinates n,m of the first filtered image and the intensity of all the pixels contained in a neighborhood about said pixel of coordinates n,m of either said starting image or a second filtered image derived from said starting image, wherein said sum of absolute differences is split calculating a sum of positive differences, or positive deviation, and a sum of negative differences, or negative deviation. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. Apparatus for contour tracking in video images arranged as succession of photograms, comprising:
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an arithmetic logic unit, one or several filters that calculate a positive deviation ep(n,m) and a negative deviation en(n,m) of an absolute generalized central moment e(n,m) a calculating means residing in said arithmetic unit for obtaining said absolute generalized central moment e(n,m), wherein said calculating means; determines for each n,m a local mean calculated on a neighborhood about a pixel of coordinates n,m of the starting image, obtaining a first filtered image; determines for each n,m a sum of absolute differences between the intensity of the pixel having coordinates n,m of the first filtered image and the intensity of all the pixels contained in a neighborhood about said pixel of coordinates n,m of either said starting image or a second filtered image derived from said starting image, splits said sum of absolute differences calculating a sum of positive differences, or positive deviation, and a sum of negative differences, or negative deviation. - View Dependent Claims (13, 14, 15)
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Specification