Automatic scene calibration method for video analytics
First Claim
1. A method for automated scene calibration, comprising:
- determining a blob from a current video frame;
identifying the blob as associated with an object, the blob including pixels that represent at least a portion of the object;
determining, using the blob, a ground plane for the current video frame, wherein the ground plane represents a surface upon which the object is positioned;
selecting approximate three-dimensional points on the ground plane;
estimating extrinsic parameters for a camera model;
determining, using the camera model and the estimated extrinsic parameters, two-dimensional coordinates within the current video frame that correspond to the approximate three-dimensional points; and
determining, using the two-dimensional coordinates and the ground plane, values for a homographic matrix, wherein a homographic transformation using the values for the homographic matrix provides a mapping from the two-dimensional coordinates in the current video frame to three-dimensional real-world points.
1 Assignment
0 Petitions
Accused Products
Abstract
To determine real-world information about objects moving in a scene, the camera capturing the scene is typically calibrated to the scene. Automatic scene calibration can be accomplished using people that are found moving about in the scene. During a calibration period, a video content analysis system processing video frames from a camera can identify blobs that are associated with people. Using an estimated height of a typical person, the video content analysis system can use the location of the person'"'"'s head and feet to determine a mapping between the person'"'"'s location in the 2-D video frame and the person'"'"'s location in the 3-D real world. This mapping can be used to determine a cost for estimated extrinsic parameters for the camera. Using a hierarchical global estimation mechanism, the video content analysis system can determine the estimated extrinsic parameters with the lowest cost.
-
Citations
30 Claims
-
1. A method for automated scene calibration, comprising:
-
determining a blob from a current video frame; identifying the blob as associated with an object, the blob including pixels that represent at least a portion of the object; determining, using the blob, a ground plane for the current video frame, wherein the ground plane represents a surface upon which the object is positioned; selecting approximate three-dimensional points on the ground plane; estimating extrinsic parameters for a camera model; determining, using the camera model and the estimated extrinsic parameters, two-dimensional coordinates within the current video frame that correspond to the approximate three-dimensional points; and determining, using the two-dimensional coordinates and the ground plane, values for a homographic matrix, wherein a homographic transformation using the values for the homographic matrix provides a mapping from the two-dimensional coordinates in the current video frame to three-dimensional real-world points. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 29, 30)
-
-
10. An apparatus, comprising:
-
a memory configured to store video data; and a processor configured to; determine a blob from a current video frame; identify the blob as associated with an object, the blob including pixels that represent at least a portion of the object; determine, using the blob, a ground plane for the current video frame, wherein the ground plane represents a surface upon which the object is positioned; select approximate three-dimensional points on the ground plane; estimate extrinsic parameters for a camera model; determine, using the camera model and the estimated extrinsic parameters, two-dimensional coordinates within the current video frame that correspond to the approximate three-dimensional points; and determine, using the two-dimensional coordinates and the ground plane, values for a homographic matrix, wherein a homographic transformation using the values for the homographic matrix provides a mapping from the two-dimensional coordinates in the current video frame to three-dimensional real-world points. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
-
-
23. A non-transitory computer-readable medium having stored thereon instructions that, when executed by one or more processors, cause the one or more processors to:
-
determine a blob from a current video frame; identify the blob as associated with an object, the blob including pixels that represent at least a portion of the object; determine, using the blob, a ground plane for the current video frame, wherein the ground plane represents a surface upon which the object is positioned; select approximate three-dimensional points on the ground plane; estimate extrinsic parameters for a camera model; determine, using the camera model and the estimated extrinsic parameters, two-dimensional coordinates within the current video frame that correspond to the approximate three-dimensional points s; and determine, using the two-dimensional coordinates and the ground plane, values for a homographic matrix, wherein a homographic transformation using the values for the homographic matrix provides a mapping from the two-dimensional coordinates in the current video frame to three-dimensional real-world points. - View Dependent Claims (24, 25, 26, 27, 28)
-
Specification