Methods and systems for tracking objects in videos and images using a cost matrix
First Claim
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1. An optimizer-reduced cost matrix for object tracking across consecutive video frames for optimal object assignment, said system comprising of:
- an optimizer;
encoded instructions stored in a non-transitory storage element, wherein the encoded instructions when implemented by a processor, configure the system to;
obtain pixel values of captured feature points across at least a first video frame and a second video frame;
detect at least one object in the first video frame and at least one candidate object in the second video frame and store pixel values corresponding to the at least one detected object in the first video frame and the at least one detected candidate object in the second video frame;
compute a cost function value between at least one detected object in the first video frame and at least one detected candidate object in the second video frame based on;
a visual dissimilarity between the object and the candidate object based on the stored pixel values;
a physical distance between the object and the candidate object based on the stored pixel values; and
a difference between an expected location of the object in the second video frame and the candidate object based on the stored pixel values and storing the computed cost functions in a cost matrix;
reduce a size of the cost matrix via the optimizer by checking the cost function values in each column to identify the value that is significantly smaller than others, and then values in the corresponding row are then compared to the values of all other objects to identify the smallest value for marking, repeating for all columns and rows of the cost matrix that have one or more marked elements are removed; and
apply the reduced cost matrix via the optimizer to execute optimal object assignment for the tracked objects across consecutive video frames.
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Abstract
The present invention discloses methods, systems, and computer programmable products for tracking objects across a first frame and a second frame of a video. An object tracking system computes a cost function between each object in the first frame and each object in the second frame. Further, a pair of objects is selected from the first frame and the second frame based on a pre-defined criteria which is based on the computed cost function. Thereafter, the object tracking system established a correspondence between the selected pair of objects.
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Citations
20 Claims
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1. An optimizer-reduced cost matrix for object tracking across consecutive video frames for optimal object assignment, said system comprising of:
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an optimizer; encoded instructions stored in a non-transitory storage element, wherein the encoded instructions when implemented by a processor, configure the system to; obtain pixel values of captured feature points across at least a first video frame and a second video frame; detect at least one object in the first video frame and at least one candidate object in the second video frame and store pixel values corresponding to the at least one detected object in the first video frame and the at least one detected candidate object in the second video frame; compute a cost function value between at least one detected object in the first video frame and at least one detected candidate object in the second video frame based on;
a visual dissimilarity between the object and the candidate object based on the stored pixel values;
a physical distance between the object and the candidate object based on the stored pixel values; and
a difference between an expected location of the object in the second video frame and the candidate object based on the stored pixel values and storing the computed cost functions in a cost matrix;reduce a size of the cost matrix via the optimizer by checking the cost function values in each column to identify the value that is significantly smaller than others, and then values in the corresponding row are then compared to the values of all other objects to identify the smallest value for marking, repeating for all columns and rows of the cost matrix that have one or more marked elements are removed; and apply the reduced cost matrix via the optimizer to execute optimal object assignment for the tracked objects across consecutive video frames. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method for executing optimal object assignment across consecutive video frames based on a optimizer-reduced cost matrix, said method comprising the steps of:
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obtaining pixel values of captured feature points across at least a first video frame and a second video frame by means of a video capture; detecting at least one object in the first video frame and at least one candidate object in the second video frame and store pixel values corresponding to the at least one detected object in the first video frame and the at least one detected candidate object in the second video frame; computing a cost function between at least one detected object in the first video frame and at least one detected candidate object in the second video frame based on;
a visual dissimilarity between the object and the candidate object based on the stored pixel values, a physical distance between the object and the candidate object based on the stored pixel values, and a difference between an expected location of the object in the second video frame and the candidate object based on the stored pixel values and storing the cost functions computed;reducing a size of the cost matrix via an optimizer by checking the cost function values in each column to identify the value that is significantly smaller than others, and then values in the corresponding row are then compared to the values of all other objects to identify the smallest value for marking, repeating for all columns and rows of the cost matrix that have one or more marked elements are removed; and applying the reduced cost matrix via the optimizer to execute optimal object assignment for the tracked objects across consecutive video frames, whereby object assignment is optimized by at least one of decreasing an amount of computation, reducing power consumption, or increasing assignment speed and accuracy. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19)
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20. An optimized system executing efficient object assignment from a reduced cost matrix, said system comprising of:
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an optimizer; encoded instructions stored in a non-transitory storage element, wherein the encoded instructions when implemented by a processor, configure the system to; obtain pixel values of captured feature points across at least a first video frame and a second video frame; generate a cost function between a plurality of detected objects and a candidate objects by evaluating pixel values of captured feature points in the first video frame and the second video frame based on;
a visual dissimilarity between the object and the candidate object, a physical distance between the object and the candidate object, and a difference between an expected location of the object in the second video frame and the candidate object and storing the cost functions computed in a form of a two-dimensional cost matrix;reduce a size of the cost matrix via the optimizer by checking the cost function values in each column to identify the value that is significantly smaller than others, and then values in the corresponding row are then compared to the values of all other objects to identify the smallest value for marking, repeating for all columns and rows of the cost matrix that have one or more marked elements are removed; and apply the reduced cost matrix to select one or more pairs of objects from the stored values based on a pre-determined criteria, wherein the object and the candidate object belong to a pair of the one or more pairs of objects, and thereby, executing efficient object tracking by at least one of decreasing the time required to select the one or more pairs of objects from the optimizer-reduced cost matrix, decreasing an amount of computation, reducing power consumption, or increasing assignment speed and accuracy.
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Specification