Hughes Aircraft Company

Raytheon Company

Edward J Dragavon

Robert Zwirn

Eugene W Opittek

David J Ketcham

Brian Smithgall

An imaging system. In some embodiments, the system includes an image multiplexer, an imaging lens, a coded mask, an array detector comprising an array of pixels, and a processing circuit. The imaging lens and the image multiplexer are configured to superimpose a plurality of fields of view onto the array detector. The image multiplexer is controllable to shift each field of view by a respective image offset, and the coded mask is controllable to shade each of the pixels with a respective individual mask pattern.

Optical multiplexing and overlaid subpixel processing

In this invention, the resolution is enhanced by first effectively decreasing the scan angle subtended between adjacent samples significantly below that of the Rayleigh limit to obtain an image blurred by the point spread function (or diffraction pattern) of the aperture. The next step is to process this blurred image to at least partially remove the blur. The unblurring process consists of convolving this finely sampled blurred image with a specially designed convolution mask. This mask effectively outputs an enhanced pixel at each step of the convolution. The mask simultaneously performs the equivalent of the following operations:

Resolution enhancement and zoom by degradation estimates

A histogram equalization system that adaptively redistributes the intensity coding of the video in order to provide an equal number of elements at all display intensity levels. The actual amplitude value of the input video as stored in an integrator, for example, is utilized to address a random access memory which originally is loaded with all zeros. The memory is organized such that there are as many addressable words as there are possible video intensity values carried in the integrator thereby building up a histogram within the memory. Upon completion of the histogram, a constant equal to the number of picture elements corresponding to the data used to form the histogram divided by the number of values to which it is desired to truncate, is utilized in a comparator as the histogram memory is sequentially read out and accumulated to determine the truncation points. A latching circuit is filled with the truncation point values and these points are used in a truncation logic circuit responding to the input video signal to reduce the number of video bits. The truncated signal increases the sensitivity to localized signal variations of a scene so as to increase the detail of the gray scale region requiring additional intensity codes.

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Los Angeles, CA, United States of America

Edward J Dragavon