Yoshiro Suemoto

Laser heterodyne and homodyne measurements of impulsive displacement

Abstract An increase of reliability is described for the measurement of impulsive displacement by using two different techniques, laser heterodyne and laser homodyne methods. The absolute values obtained by the two methods coincided within experimental errors for the measurement of repetitively impulsive displacement of a speaker cone.

Accurate position detection of targets in noise image

Abstract Targets at various positions in a noise image were detected by the optical matched filtering technique. In this case the thermoplastic optical recorder was used as a matched filter recorder. High accuracy of position detection was obtained, i.e. the position error was 2% or less.

Fiber optic heterodyne displacement detection in wide dynamic range

Abstract The dynamic range of displacement measurements was experimentally estimated for the case of laser heterodyne technique with fiber optics. Even using flexible fiber optics, a wide dynamic range of 10 5 order, i.e. from 100 μm to 10 A displacement, was obtained.

Some Improvements In The Thermoplastic Device

Alternative use of sensitizing material and improvement of ion charging in the thermoplastic optical recording device are described which were effective for getting noise free clean images. Sensitizing material that shows less absorption and scattering was chosen for the photoconductor part of active layers in the thermoplastic element. Using a scorotron charging device provided with ion decelerating grid wires, uniform noise free reconstructed images were obtained. Precise measurement and control of the temperature of the plastics revealed that repetitive use of the thermoplastic element should be stopped before hardening of the plastic occurs. The effects of the above improvements are shown by demonstrating clearer reconstructed images and more accurate processed images.

Dimensional Measurement Of Moving Holes Using Spatial Filtering

The measurement of the size of moving holes is described by processing their image using spatial filtering and converting their size to electrical signal. In the present case, the shape of the hole was assumed to be circular and the band-pass filter giving high sensitiv-ity was designed. In deciding the aperture size for the photodetector, tolerance to position fluctuation of the moving holes was taken into consideration. Dealing with the holes of various size within 30011m ±10% diameter, the accuracy obtained was within l%,i.e. 3μm. Moving speed of the holes was 20cm/sec and their position fluctuation was allowable near to their size.