UBC Theses and Dissertations

UBC Theses Logo

UBC Theses and Dissertations

Near-real-time implementation of multiple light source optical flow Siegerist, Cristina Elena


Multiple light source optical flow is a method to compute a dense, local representation of optical flow. The basic idea is to overcome the aperture problem using multiple images of a moving object acquired simultaneously under different conditions of illumination. Each image provides one linear constraint equation. When the optical flow and the 2D motion field coincide these equations are in the same unknowns. Two equations are enough to calculate both velocity componentss. Three or more images over-determine the system, allowing the calculation of confidence measures and making the computation more robust. This thesis presents a parallel, near-real-time implementation of multiple light source optical flow. Three light sources, one red, one green, and one blue, with negligible overlap in the visible spectrum illuminate the work place from different directions. Three separate black and white images corresponding to the three light sources are acquired simultaneously through a 3 CCD 24 bit RGB camera. The processing is done using a network of six independent processors. The encoded optical flow is displayed on a video monitor. For an image of size 240x240 pixels the processing rate is 4 frames/sec. The range of linear behaviour of the system was studied. A comparison with other methods on a synthetic and a real image sequence is presented.

Item Media

Item Citations and Data


For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.