Digital Video Content Fingerprinting Based on Scale Invariant Interest Region Detection with an Array of Anisotropic Filters
First Claim
1. A method of applying an array of anisotropic filters for image scale-space analysis, the method comprising:
- forming an array of elliptic-shaped anisotropic filters with a first scale parameter in the x direction (sx) and a second scale parameter in the y direction (sy) as scale parameters (sx, sy), wherein the sx and the sy scale parameters are separately varied to provide accurate region characterization;
analyzing scale space for a selected frame by the array of elliptic-shaped anisotropic filters of finite spatial support corresponding to selected different values of the (sx) and (sy) scale parameters;
computing a Hessian determinant response image for each elliptic-shaped anisotropic filter of finite spatial support corresponding to selected pairs (sx, sy) of scale parameters; and
determining a set of local maxima in contiguous 4-dimensional scale-space volumes of the Hessian determinant response images with coordinates (x, y, sx, sy).
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Abstract
Video sequence processing is described with various filtering rules applied to extract dominant features for content based video sequence identification. Active regions are determined in video frames of a video sequence. Video frames are selected in response to temporal statistical characteristics of the determined active regions. A two pass analysis is used to detect a set of initial interest points and interest regions in the selected video frames to reduce the effective area of images that are refined by complex filters that provide accurate region characterizations resistant to image distortion for identification of the video frames in the video sequence. Extracted features and descriptors are robust with respect to image scaling, aspect ratio change, rotation, camera viewpoint change, illumination and contrast change, video compression/decompression artifacts and noise. Compact, representative signatures are generated for video sequences to provide effective query video matching and retrieval in a large video database.
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Citations
20 Claims
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1. A method of applying an array of anisotropic filters for image scale-space analysis, the method comprising:
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forming an array of elliptic-shaped anisotropic filters with a first scale parameter in the x direction (sx) and a second scale parameter in the y direction (sy) as scale parameters (sx, sy), wherein the sx and the sy scale parameters are separately varied to provide accurate region characterization; analyzing scale space for a selected frame by the array of elliptic-shaped anisotropic filters of finite spatial support corresponding to selected different values of the (sx) and (sy) scale parameters; computing a Hessian determinant response image for each elliptic-shaped anisotropic filter of finite spatial support corresponding to selected pairs (sx, sy) of scale parameters; and determining a set of local maxima in contiguous 4-dimensional scale-space volumes of the Hessian determinant response images with coordinates (x, y, sx, sy). - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method of applying an array of anisotropic filters for image scale-space analysis, the method comprising:
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applying an array of discretized rectangular-shaped anisotropic filters of finite spatial support corresponding to different values of a first scale parameter in the x direction (sx) and a second scale parameter in the y direction (sy) to interest points in a selected frame; forming a Hessian determinant response image with pixels representing a determinant of a Hessian matrix for each anisotropic filter of the array of discretized rectangular-shaped anisotropic filters with the finite spatial support corresponding to the sx and sy scale values; interpolating a subset of non-interpolated local maxima that exceed a specified magnitude threshold to generate interpolated local maxima values, wherein the non-interpolated local maxima are computed for each spatial-scale 4-dimensional pixel volume constructed at equidistant spatial locations in the Hessian determinant response image; and generating a multi-dimensional descriptor in a region centered at an (x,y) refined interest point, the region having a rectangular spatial extent proportional to the sx and sy scale values, wherein the sx and sy values and the x and y position values are based on the interpolated local maxima values. - View Dependent Claims (10, 11, 12, 13, 14)
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15. A computer readable non-transitory medium storing a computer program which causes a computer system to perform a method of applying an array of anisotropic filters for image scale-space analysis, the method comprising:
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applying an array of discretized rectangular-shaped anisotropic filters of finite spatial support corresponding to different values of a first scale parameter in the x direction (sx) and a second scale parameter in the y direction (sy) to interest points in a selected frame; forming a Hessian determinant response image with pixels representing a determinant of a Hessian matrix for each anisotropic filter of the array of discretized rectangular-shaped anisotropic filters with the finite spatial support corresponding to the sx and sy scale values; interpolating a subset of non-interpolated local maxima that exceed a specified magnitude threshold to generate interpolated local maxima values, wherein the non-interpolated local maxima are computed for each spatial-scale 4-dimensional pixel volume constructed at equidistant spatial locations in the Hessian determinant response image; and generating a multi-dimensional descriptor in a region centered at an (x,y) refined interest point, the region having a rectangular spatial extent proportional to the sx and sy scale values, wherein the sx and sy values and the x and y position values are based on the interpolated local maxima values. - View Dependent Claims (16, 17, 18, 19, 20)
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Specification