Feature tracking using a dense feature array
AssigneeSynaPix, Inc.
InventorPhilip R. Moorby
Life of this patent
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Abstract
A method for feature tracking across a plurality of related image frames by developing a dense array of features and their paths as a deformable, regularly spaced grid, with vectors for each nodal feature point in the grid being derived through a process related to optical flow. The resulting dense feature array can be applied to techniques such as tracking two-dimensional shapes across frames, estimating three-dimensional paths of selected feature points, estimating three-dimensional camera paths from multiple feature points, or recovering estimated three-dimensional scene structure (including estimated depths of object surfaces) from feature tracking data.
Claims12
A method for deriving an array of feature points from a sequence of input images of a three dimensional structure of a scene, comprising the steps of:
- (a) forming an image pyramid from the image sequence, with images at a bottom level of the pyramid representing the image at a relatively high level of resolution, and images at subsequently higher levels of the pyramid representing filtered and reduced versions of the images, to provide representations of each image in the sequence of images at multiple resolutions;
- (b) at each level of the pyramid, determining an initial grid of nodes for the first image in the sequence, the grid being composed of a regularly spaced array of nodes, the nodes associated with locations in space that are independent of, and at a higher resolution than the locations of specific pixels in the input image sequence, and the grid associated with the highest level of resolution being a dense array;
- (c) tracking the nodes of a selected grid of nodes among successive images in the sequence at a given level of the pyramid using a feature tracking function that determines a motion path for at least a selected set of nodes from image to image and storing such motion paths as grid node tracking information;
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- (d) using the grid node tracking information within the pyramid as an array of feature points and associated image tracking data in a subsequent image processing algorithm to determine aspects of the three-dimensional structure of a scene from which the image sequence was captured.
Dependencies are inferred from the claim text.