Abstract: A processing circuit for a digital camera system enables capture of a visual event which falls within some user-defined range. A digital camera converts a target image into a set of digital data signals, each signal representing the brightness level of a pixel in a matrix. A memory stores a mask also comprising a matrix of pixels. As the digital camera scans the target image, each data pixel from the camera is compared to a corresponding pixel in the mask and differences in brightness between the two are counted. When the count reaches some predetermined valve, the current frame of video data is saved for further analysis and/or display.

Abstract: A signal processing circuit for enabling a computer to quickly scan a memory having stored signals which represent a video image includes a flag generator responsive to a lit pixel detector for providing a flag signal to the memory to be stored in an address location indicating the presence of at least one lit pixel in that row. Incoming video, which includes data and sync signals, is digitized and examined by the lit pixel detector and a flag signal is clocked into memory at a predetermined address. The computer scans these address locations, which lie in a single column, to determine the identity of rows having a flag signal. This eliminates the need for the computer to scan the entire address space to locate an object of interest.