Abstract: The detector elements are larger than an image of the spot on the array would be, but an image is not formed on the array. Instead, the beam shaping element enlarges the size of the area of illumination on the array slightly, and mixes, or homogenizes, the light. This destroys the image and the intensity variations originating at the spot on the surface that would be contained in the image. The enlargement of the area of illumination together with the homogenization allow the position of the beam on the array to be determined to a resolution of about {fraction (1/10)}th of the width of a detector element. This position is then converted to an absolute distance output which may be read by digital or analog means.

Abstract: An optical scanning rangefinder has been developed that creates a depth map of its surroundings by scanning a beam of modulated, collimated light and observing reflections from proximate surfaces. The scanning system uses dual rotating prisms to deflect the transmitted beam and collect a portion of the reflected light, which is focused on a photodetector and converted to an electrical signal. This signal is amplified, AC coupled, and inverted. The inverted signal drives the modulator for the light source. When sufficient light is received by the detector, this sytem forms an oscillator, the frequency of which depends on the distance to the illuminated surface. This frequency can easily be measured to a high degree of accuracy, and the distance to the surface derived from it. The scanner achieves a field of view of 360 degrees horizontally by 52 degrees vertically.