Patent ID: 7586502

Claim:
Data processing apparatus arranged to receive successive images from a video camera, the apparatus comprising: a motion detector operable to detect inter-image motion in an image region associated with a control function of the data processing apparatus; initiating logic operable to initiate the control function if inter-image motion is detected in the image region in respect of at least a threshold number of the images within a test group of the images; incrementing logic operable to increment a detection variable by an increment amount at each image in which inter-image motion is detected in the image region; decrementing logic operable to decrement the detection variable by a decrement amount at each image in which inter-image motion is not detected in the image region; and a threshold detector operable to detect whether the detection variable has exceeded a threshold amount and, if so, to activate the control function, wherein the decrement amount is substantially constant for each image in which inter-image motion is not detected in the image region.