This paper describes the implementation in silicon of a retina-like sensor characterized by a space-variant resolution similar to that of the human retina. Besides the actual implementation using CMOS technology, the design peculiarities of retina-like sensors are compared with the use of software or hardware electronic remappers. The paper also describes the realization of a retina-like digital camera and its applications for realtime control and image transmission.

Outlines the work of the Interactive Image Based Device for Effective Communication project [IBIDEM] in its aim of developing a video phone useful for lip‐reading by hearing‐impaired people, based on a new generation of space‐variant sensors and using standard telephone lines. The IBIDEM project is constructing a video phone using a camera with a retina‐like sensor, a motorized system for moving the viewpoint of the camera, as well as a display for the transmitted images which will allow high resolution in the area of interest i.e. lips or figures, whilst still maintaining a wide field of view. Experiments have been carried out to evaluate the minimum requirements for the video phone in terms of spatial and temporal resolution and the technical limitations which have to be taken into account in the design of a visual sensor.

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This study was designed to evaluate the picture quality requirements for three visual communication modes: speechreading, fingerspelling, and sign language. Video recordings of everyday spoken, fingerspelled, and signed sentences were made, and some recordings were processed using a computer simulation of the IBIDEM technology: a videophone based on a novel type of visual sensor. This retina-like sensor, implemented in the camera, has a high resolution in the central part and a degrading resolution in the peripheral part of the picture. Two independent variables were examined: frame rate (10 and 15 frames per second) and spatial resolution (6000 and 8000 pixels per frame). Twenty-four people who were prelingually deaf participated, 8 in each communication mode. The results showed a marked effect of frame rate on speechreading. Fingerspelling and sign language were not affected by frame rate, and spatial resolution had no effect on any of the three communication modes.