Hughes Electronics Corporation

Hughes Aircraft Company

Robert L Sendall

Michael Y Pines

Stephen P Shaffer

Russell K Jones

Chuong D Dan

Raymond L McKeefery

Marvin J Ramirez

Donald K Knight

A thermal imaging device (10) includes a detector (50) having a linearly-arrayed plurality of spaced apart detector elements (50') upon which portions of a viewed scene are sequentially scanned by a scanner (22) in order to capture image information from the scene. A display device (22, 62, 66) similarly includes a first linear array of plural spaced apart light emitting diodes (LEDs) (62') which provide light scanned by the same scanner (22) to a user of the thermal imaging device (10) to provide an image replicating the viewed scene. The LEDs (62') of the display (22, 62, 66) are configured so that sequential portions of the image are interlaced and partially overlapped by the scanner (22) to provide a flat visual field which is free of raster lines. The display device (22, 62, 66) includes a second linearly-arrayed plurality of symbology LEDs (198) which are configured and positioned relative to the first plurality of LEDs (62') so that light from these LEDs is interlaced but not overlapped and so that symbology imagery presented by the second plurality of LEDs (198) is superimposed on the scene image presented to the user of the thermal imaging device (10).

Thermal imaging device with scanned light emitting diodes (LEDs) having

An imaging device (10) includes an array (18) of picture elements (16) or pixels, each of which is responsive to incident radiant energy to provide an output signal. The array (18) consists of pixels (16) in adjacent horizontal rows, each row having a certain pitch (P) or center-to-center distance between pixels. Each alternate row is horizontally offset by a distance equal to one-half of a row pitch from each adjacent row to form a 'brick wall' or quincunx pattern. An azimuthal traverse of the quincunx focal plane array (18) provides twice the azimuthal resolution and approximately 140 percent of the minimum resolvable temperature measurement capability of conventional focal plane arrays.

Quincunx sampling grid for staring array

Apparatus and methods for providing nonuniformity compensation of staring infrared focal plane array imaging systems, or other video imaging ssytem, or the like. The invention comprises a processor which implements nonuniformity compensation of the detectors comprising the array. The processor generates compensation terms that are stored in an offset term memory and which are subsequently combined with the output signals from the array. The processing accomplished by the present invention normalizes all detector elements in the array such that they all appear to respond to infrared energy in an identical manner. The processor comprises a median filter which selectively implements cross (X) shaped and plus (+) shaped filters. An antimedian calculator computes the antimedian of the output of the median filter. This value comprises the difference between the central pixel of a respective filter and the median value of all pixels in the cross (X) or plus (+) shaped filter. A third filter samples each of the signals from the detector array and compares them to a preset value indicative of an anticipated scene intensity level determined by the operator to provide an output signal indicative of the difference. Control circuity selects which output signal of the filter circuits is to be used to compensate the detector signals during a particlar video field. The ouptut signals of the antimedian calculator and average filter comprise sign information which is indicative whether the central pixel value is less than, equal to or greater than the median, or whether the central pixel is less than, equal to or greater than the preset value, respectively. The control circuitry increments or decrements the value of the offset terms stored in the offset term memory in resonse to the signal provided by the selected antimedian calculator or third filter, and convergence rate information supplied by the control circuitry which controls the rate of convergence of the offset terms toward the scene average.

Scene based nonuniformity compensation for starting focal plane arrays

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Chatsworth, CA, United States of America

Robert L Sendall