INEXPENSIVE RANGE CAMERA OPERATING AT VIDEO SPEED

An optoelectronic device has been developed and built that acquires an d displays the range data of an object surface in space in video real time. The recovery of depth is performed with active triangulation. A galvanometer scanner system sweeps a sheet of light across the object at a video field rate of 50 Hz. High-speed signal processing is achiev ed through the use of a special optical sensor and hardware implementa tion of the simple electronic-processing steps. Fifty range maps are g enerated per second and converted into a European standard video signa l where the depth is encoded in gray levels or color. The image resolu tion currently is 128 x 500 pixels with a depth accuracy of 1.5% of th e depth range. The present setup uses a 500-mW diode laser for the gen eration of the light sheet. A 45-mm imaging lens covers a measurement volume of 93 mm x 61 mm x 63 mm at a medium distance of 250 mm from th e camera, but this can easily be adapted to other dimensions.