William E. Glenn

Matching region for damped piezoelectric ultrasonic apparatus

An acoustic impedance match between an ultrasonic transducer and an adjacent transmission medium is obtained, with performance over a relatively wide bandwidth, by providing a special matching region between the transducer and the transmission medium. The matching region includes a layer having a multiplicity of tapered elements. Each of the elements tapers down in size in the direction away from the transducer.

HDTV Compatible Transmission System

Psychophysical measurements of vision have been used to design a compatible HDTV transmission system. A standard 525-line NTSC transmission is combined with a detail transmission in an additional half-channel of bandwidth to recreate an 1125-line HDTV image. The concept also makes possible the construction of a bichannel HDTV camera that uses progressive scanning of the high-resolution information at modest bandwidths. This camera has been demonstrated with both a standard 525-line NTSC output and an 1125-line HDTV output.

High Definition Television Compatible Transmission System

A bi-channel HDTV transmission system has been developed that digitally filters the video signal in accordance with known spatiotemporal properties of the bi-channel visual of system. Differential processing of high and low spatial-frequency information yields several distinct advantages that include: compatibility with existing broadcast systems and improved spatial resolution for both moving and stationary HDTV images with a reduced bandwidth.

Discrimination of sharpness in a televised moving image

Abstract Sharpness discrimination between televised moving images of full (300-line) and half (150-line) resolution was measured psychophysically for seven observes. The velocities of image motion were chosen to be within a range that permitted accurate visual tracking. Paradoxically, the results suggested that contrast of low-spatial-frequency information is more important for enhancing apparent sharpness than is high spatial resolution in a moving image. This finding becomes understandable when considered in relation to performance characteristics of the human visual system.

A Fiber-Optic Magnifying Display Panel

A fiber-optic display panel is described and demonstrated which magnifies the input image and produces a coherent display on a panel which is black by reflected light.

The Design Of Systems That Display Moving Images Based On Spatio-Temporal Vision Data

Television systems that display moving images can be designed to have a temporal response as a function of spatial frequency that matches the performances of the visual system. These designs can improve the performance of cameras, signal processing, signal transmission, computer graphic image generation and image displays. The design analysis, based on psychophysical measurements in luminance and color, must include both conditions of fixation and of tracking moving objects in the image by the viewer. Bandwidth reduced systems can be designed using this analysis which produce good perceived sharpness of moving objects with minimum image artifacts.

Current Status Of HDTV Development

High definition television (HDTV) is now being used to produce program material and will soon be available as a consumer product. This paper discusses the design of HDTV displays, the proposed signal transmission systems and the basic research in vision that can be used to improve the design in all aspects of the HDTV system.