Rca Inc.

Horatio N Crooks

Peter D Southgate

Martin J Kelly, Jr

Topographical defect detecting apparatus and process for optically inspecting a circular or spiral track surface defining a diffraction grating such as exists on a video disc or optical disc record. Light from a substantially point source illuminates the track surface. Diffracted reflections from the surface are viewed by the human eye with or without the aid of a TV camera and monitor. Non-uniformities in track spacing and deviation from average surface flatness are readily observable.

Detection of defects in a circular or spiral diffraction grating

The record side identification device for a video disc player includes a pair of switches. The order of closure of the switches depends upon which side of the record carrying caddy is uppermost in the player. A circuit means, responsive to the sequence of operation of the switches, lights appropriate one of the lamps to provide an indication of the record side subject to play.

Video disc player having record side identifying apparatus

The spatial field is sequentially convolved at each of a plurality of uniformly-spaced intervals along a field dimension with a given type of limited spatial extent kernel function which preferably has a one-octave spatial bandwidth. Convolution combining means derives an output only if the q'th power of the sequential convolutions exceed a threshold corresponding to the just-noticeable presence of spatial frequencies within the spatial bandwidth of the kernel function.

Apparatus for discerning the noticeable presence of spatial fluctuations

A bimorph element is interposed between a supporting structure of a video disc player and a support member. A replaceable pickup arm unit carrying a signal pickup which is subject to engagement with a spirally grooved video disc record is releasably secured to the support member. The bimorph element selectively deflects the support member in a manner that displaces the groove-riding signal pickup radially of the disc record.

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Indianapolis, IN, United States of America

Horatio N Crooks