Abstract: A system for measuring relative angular position about a roll-axis, a yaw-axis, and a pitch-axis includes a source assembly and a receiver assembly. A source assembly emits a rotationally polarized carrier wave laser beam. A laser beam from a laser diode is directed through a linear polarizer and then through the center of a rotating half-wave plate. The plate is secured to a hollow shaft of an electric motor. The beam travels through the plate and through the hollow shaft. A reference signal corresponding to the rotational modulation imposed by the rotating plate is obtained using a flag which is secured to the shaft and positioned to actuate an optical encoder. After leaving the source assembly and reaching the receiver assembly, the beam travels through another linear polarizer, a neutral density filter, and an aplanatic achromatic lens to a two-dimensional position sensing detector. In response to the beam, the position sensing detector produces output signals that correspond to the position of the beam.

Abstract: A hand-held apparatus and process for measuring the gap and mismatch of two adjacent surfaces. The apparatus includes two strobe lights positioned within a hand-held housing. An optical interface within the housing directs a portion of the light generated by each light source into substantially parallel planes which are projected out of the opening of the housing at converging angles onto the surfaces to be measured. A camera within the housing captures the resulting image and generates a signal corresponding to the image. A signal processor which includes a frame grabber card processes the signal generated by the array of detectors to thereby calculate the amount of gap and mismatch between the surfaces being measured.

Abstract: An optical measurement device produces quality light scatter measurements using Bidirectional Reflective Distribution Function (BRDF) techniques to analyze data generated from an accurate, portable, relatively inexpensive scatterometer. The scatterometer is provided with interchangeable scanning heads, each scanning head being equipped with ROM data storage containing certain configuration information about the scanning head. The use of the interchangeable scanning heads allows the present invention to make measurements of light scatter for a wide variety of applications and samples under a variety of environmental conditions where scatter measurement has previously not been feasible.