Abstract: Systems and methods for motion capture are disclosed. In one arrangement a plurality of cameras are provided and a processing unit is configured to perform processing using image data from each of the plurality of cameras. Each of the cameras comprises an accelerometer and the processing unit is configured to perform processing that is dependent on an output from the accelerometers. In another arrangement each of the cameras comprises a temperature sensor and the processing unit is configured to perform processing that is dependent on an output from the temperature sensors.

Abstract: A camera unit that captures still images determines whether the camera unit is outdoors or indoors, and in dependence on that an exposure mask of weights in respect of areas of an image to be an outdoor or indoor exposure mask is selected. The outdoor exposure mask has weights in respect of areas of the image corresponding to a lower region of a scene being imaged and weights in respect of areas of the image corresponding to an upper region of a scene being imaged in a ratio that is greater than the corresponding ratio in the indoor exposure mask. A brightness measure of the overall brightness of captured images is derived from the brightness of areas of the images weighted by the selected exposure mask. The exposure of captured images is controlled in dependence on the brightness measures of previously captured images.

Abstract: Blobs are detected in an image using closed curves having a predetermined shape such as a circle. Positions in the image are analysed. The size is determined at which there is a maximum in the differential of the average intensity around a closed curve with respect to the size of the closed curve. Detection scores are derived, representing the proportion of rays, out of a plurality of rays crossing a closed curve of the determined size, along which the intensity differential across the closed curve exceeds a contrast threshold. Detection of blobs is performed on the basis of the detection scores exceeding a threshold. Pixels of a detected blob are segmented for calculation of a centroid using a blob-separation threshold which is the average intensity around the closed curve of the determined size. The technique allows accurate and rapid detection of blobs of the predetermined shape.