Matching interest points
First Claim
1. A method of matching interest points between images comprising:
- from a dataset of interest points in a first image, the dataset comprising information identifying the position, scale and orientation of each interest point, calculating a first dataset of objects that each relate a base interest point to a satellite interest point, the calculated dataset comprising information identifying the normalized position of the satellite interest point relative to the base interest point and the normalized scale and orientation of the satellite interest point, wherein normalized means expressed relative to the scale and orientation of the base interest point;
from a dataset of interest points in a second image, the dataset comprising information identifying the position, scale and orientation of each interest point, calculating a second dataset of objects that each relate a base interest point to a satellite interest point, the calculated dataset comprising information identifying the normalized position of the satellite interest point relative to the base interest point and the normalized scale and orientation of the satellite interest point, wherein normalized means expressed relative to the scale and orientation of the base interest point;
generating matched pairs of objects by matching objects from the first calculated dataset to objects in the second calculated dataset;
from the matched pairs of objects, determining the interest points in the first dataset that are to be matched with interest points in the second dataset; and
matching the interest points accordingly, wherein, for each base interest point in the first dataset of interest points, the first calculated dataset of objects contains objects that relate that base interest point to a set of satellite interest points that is at most a subset of the remaining interest points in the first dataset of interest points and wherein, for each base interest point in the second dataset of interest points, the second calculated dataset of objects contains objects that relate that base interest point to a set of satellite interest points that is at most a subset of the remaining interest points in the second dataset of interest points.
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Accused Products
Abstract
Interest points are markers anchored to a specific position in a digital image of an object. They are mathematically extracted in such a way that, in another image of the object, they will appear in the same position on the object, even though the object may be presented at a different position in the image, a different orientation, a different distance or under different lighting conditions. The goal is to match interest points in one image with corresponding interest points in another image. Typically, this involves the construction of a descriptor, which is both computationally expensive and resource-intensive. Methods and devices are described that match interest points without the construction of conventional descriptors and that permit the use of spatial coherency information to increase the accuracy of the match.
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Citations
17 Claims
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1. A method of matching interest points between images comprising:
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from a dataset of interest points in a first image, the dataset comprising information identifying the position, scale and orientation of each interest point, calculating a first dataset of objects that each relate a base interest point to a satellite interest point, the calculated dataset comprising information identifying the normalized position of the satellite interest point relative to the base interest point and the normalized scale and orientation of the satellite interest point, wherein normalized means expressed relative to the scale and orientation of the base interest point; from a dataset of interest points in a second image, the dataset comprising information identifying the position, scale and orientation of each interest point, calculating a second dataset of objects that each relate a base interest point to a satellite interest point, the calculated dataset comprising information identifying the normalized position of the satellite interest point relative to the base interest point and the normalized scale and orientation of the satellite interest point, wherein normalized means expressed relative to the scale and orientation of the base interest point; generating matched pairs of objects by matching objects from the first calculated dataset to objects in the second calculated dataset; from the matched pairs of objects, determining the interest points in the first dataset that are to be matched with interest points in the second dataset; and matching the interest points accordingly, wherein, for each base interest point in the first dataset of interest points, the first calculated dataset of objects contains objects that relate that base interest point to a set of satellite interest points that is at most a subset of the remaining interest points in the first dataset of interest points and wherein, for each base interest point in the second dataset of interest points, the second calculated dataset of objects contains objects that relate that base interest point to a set of satellite interest points that is at most a subset of the remaining interest points in the second dataset of interest points. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 17)
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9. A method of matching interest points between images comprising:
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from a first dataset of objects that each relate a base interest point to a satellite interest point in a first image, the first dataset comprising information identifying the normalized position of the satellite interest point relative to the base interest point and the normalized scale and orientation of the satellite interest point, wherein normalized means expressed relative to the scale and orientation of the base interest point, and a second dataset of objects that each relate a base interest point to a satellite interest point in a second image, the second dataset comprising information identifying the normalized position of the satellite interest point relative to the base interest point and the normalized scale and orientation of the satellite interest point, generating matched pairs of objects by matching objects from the first dataset to objects in the second dataset; constructing a first array wherein; each row of the first array represents a particular interest point in the first image; each column of the first array represents a particular interest point in the second image; and each element of the first array has a value that represents the number of matched pairs of objects that relate the interest point of the corresponding row and the interest point of the corresponding column as base interest points; locating an element in the first array that has a value representing a maximum number of matched pairs of objects to identify the pair of interest points corresponding to the row and column of that array element; and matching the pair of interest points so identified, wherein the first array is constructed by; initializing the elements of the first array to default values representative of no matched pairs of objects; and for every matched pair of objects that relates an interest point in the first dataset or image and an interest point in the second dataset or image as base interest points, adjusting the value of the element of the first array that is in the row corresponding to the interest point in the first dataset or image and the column corresponding to the interest point in the second dataset or image, so as to increase by one the number of matched pairs of objects it represents, wherein; each element of the first array has a value equal to the number of matched pairs of objects that relate the interest point of the corresponding row and the interest point of the corresponding column as base interest points. - View Dependent Claims (10, 11, 12, 13, 14, 15)
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16. A method of matching interest points between images comprising:
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from a dataset of interest points in a first image, the dataset comprising information identifying the position, scale and orientation of each interest point, calculating a first dataset of objects that each relate a base interest point to a satellite interest point, the calculated dataset comprising information identifying the normalized position of the satellite interest point relative to the base interest point and the normalized scale and orientation of the satellite interest point, wherein normalized means expressed relative to the scale and orientation of the base interest point; from a dataset of interest points in a second image, the dataset comprising information identifying the position, scale and orientation of each interest point, calculating a second dataset of objects that each relate a base interest point to a satellite interest point, the calculated dataset comprising information identifying the normalized position of the satellite interest point relative to the base interest point and the normalized scale and orientation of the satellite interest point, wherein normalized means expressed relative to the scale and orientation of the base interest point; generating matched pairs of objects by matching objects from the first calculated dataset to objects in the second calculated dataset; constructing a first array wherein; each row of the first array represents a particular base interest point in the first dataset; and each column of the first array represents a particular base interest point in the second dataset; constructing a second array wherein; each row of the second array represents a respective interest point in the first dataset; each column of the second array represents a respective interest point in the second dataset; and the elements of the second array are used to represent the confidence with which the corresponding interest points have been matched and are initialized to default values; initializing the elements of the first array, whereby the value of the element of the first array that is in the row corresponding to a base interest point in the first dataset and the column corresponding to a base interest point in the second dataset, is initialized to the sum over all matched pairs of objects that relate the base interest point of the row to a satellite interest point in the first dataset and the base interest point of the column to a satellite interest point in the second dataset, of the default values of the elements of the second array that are in the respective row corresponding to the satellite interest point in the first dataset and the respective column corresponding to the satellite interest point in the second dataset; locating an element in the first array that has a maximum value to identify the pair of interest points corresponding to the row and column of that array element; and matching the pair of interest points so identified.
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Specification