Patent ID: 8654099

Claim:
Data processing apparatus arranged to receive successive images from a video camera, the apparatus comprising: means for detecting inter-image motion for selected points in an image region associated with a control function of the data processing apparatus; and means for executing the control function if inter-image motion is detected in the image region; in which the detecting means is arranged to: identify test points in a currently received image which are detected to have a correspondence with respective points in a preceding received image, for each test point, detect whether a point in the current image, which correlates with the point in the preceding image corresponding to that test point, is within a threshold image distance of that test point, select, as a selected point for use by the detecting means, a test point for which the point in the current image, which correlates with the point in the preceding image corresponding to that test point, is within a threshold image distance of that test point, and deselect other test points; and difference measuring means for generating difference data and for subsequently smoothing the difference data, the difference data comprising a set of values proportional to the difference in pixel values between two successive images, in which the difference measuring means is further configured to apply a threshold to the difference data at a difference threshold level, and output resulting binary difference data, and in which the means for detecting inter-image motion is configured to discard, prior to any selection of test points in the current image based upon correspondence with the points in the preceding image, points in the preceding image for which the equivalent position in the difference image shows a difference below the difference threshold level.