06021210 is referenced by 78 patents and cites 9 patents.

In a method of image subtraction a series of frames of a subject are taken using a video camera The subject is illuminated in a manner so that illumination is alternately on then off for successive fields within the image frame. A single frame is grabbed and an absolute difference between the odd field and the even field within that single image frame is determined. The resulting absolute difference image will represent the subject as illuminated by the system illumination only, and not by any ambient illumination, and can then be used to identify the subject in the image.

Title
Image subtraction to remove ambient illumination
Application Number
8/980989
Publication Number
6021210
Application Date
December 1, 1997
Publication Date
February 1, 2000
Inventor
Thomas A Chmielewski Jr
Langhorne
PA, US
Theodore A Camus
Mount Laurel
NJ, US
Agent
Buchanan Ingersoll P C
Assignee
Sensar
NJ, US
IPC
H04N 1/00
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