Method and apparatus for monitoring a passageway using 3D images
AssigneeCognex Technology and Investment Corporation
InventorsSanjay Nichani, David Schatz
Life of this patent
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Abstract
A stereo imaging based vision system is calibrated to provide heights above the ground plane for any point in the field of view. Therefore, when any object enters the field of view, it generates interest points called “features,” the heights of which are measured relative to the ground plane. These points are then clustered in 3D space to provide “objects.” These objects are then tracked in multiple frames to provide “trajectories.” Such a system could then control alarm signals or actuate gates or motion control devices, for example, based on the various pieces of information generated about the object.
Claims14
A method of controlling an object's motion through a viewed space compromising:
- acquiring a stereo image of said viewed space wherein stereo image comprises an image set;
- computing a set of 3D features from said stereo image;
- filtering from said set of 3D features to generate a set of filtered 3D features;
- computing a trajectory of said set of filtered 3D features;
- and
- generating a control signal influencing said object's motion in response to said trajectory;
- wherein said step of computing a set of 3D features includes the steps of:
- edge-processing said stereo image to generate a plurality of connected edgelets;
- identifying connected edgelets having length greater than a predetermined threshold as features;
- matching features to generate disparities generated from different images in said image set;
- and
- computing 3D locations of feature points according to at least said disparities.
A method of determining an object's trajectory comprising:
- viewing an area with stereo cameras to generate a stereo image;
- edge-processing said stereo image to generate a plurality of connected edgelets;
- identifying connected edgelets having length greater than a predetermined threshold as features;
- measuring a height of said features relative to a ground plane;
- clustering said features having a height above said ground plane in 3D space to generate objects;
- and
- tracking said objects in multiple frames.
Dependencies are inferred from the claim text.