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Proceedings Paper

High dynamic range CMOS image sensor with pixel level ADC and in-situ image enhancement
Author(s): Austin V. Harton; Mohamed I. Ahmed; Allyson Beuhler; Francisco Castro; Linda M. Dawson; Barry W. Herold; Gregory Kujawa; King F. Lee; Russell D. Mareachen; Tony J. Scaminaci
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Paper Abstract

We describe a CMOS image sensor with pixel level analog to digital conversion (ADC) having high dynamic range (>100db) and the capability of performing many image processing functions at the pixel level during image capture. The sensor has a 102x98 pixel array and is implemented in a 0.18um CMOS process technology. Each pixel is 15.5um x15.5um with 15% fill factor and is comprised of a comparator, two 10 bit memory registers and control logic. A digital to analog converter and system processor are located off-chip. The photodetector produces a photocurrent yielding a photo-voltage proportional to the impinging light intensity. Once the photo-voltage is less than a predetermined global reference voltage; a global code value is latched into the pixel data buffer. This process prevents voltage saturation resulting in high dynamic range imaging. Upon completion of image capture, a digital representation of the image exists at the pixel array, thereby, allowing image data to be accessed in a parallel fashion from the focal plane array. It is demonstrated that by appropriate variation of the global reference voltage with time, it is possible to perform, during image capture, thresholding and image enhancement operations, such as, contrast stretching in a parallel manner.

Paper Details

Date Published: 7 March 2005
PDF: 11 pages
Proc. SPIE 5677, Sensors and Camera Systems for Scientific and Industrial Applications VI, (7 March 2005); doi: 10.1117/12.586394
Show Author Affiliations
Austin V. Harton, Motorola, Inc. (United States)
Mohamed I. Ahmed, Motorola, Inc. (United States)
Allyson Beuhler, Motorola, Inc. (United States)
Francisco Castro, McAndrews, Held & Malloy, Ltd. (United States)
Linda M. Dawson, Motorola, Inc. (United States)
Barry W. Herold, Motorola, Inc. (United States)
Gregory Kujawa, Motorola, Inc. (United States)
King F. Lee, Motorola, Inc. (United States)
Russell D. Mareachen, Motorola, Inc. (United States)
Tony J. Scaminaci, Motorola, Inc. (United States)

Published in SPIE Proceedings Vol. 5677:
Sensors and Camera Systems for Scientific and Industrial Applications VI
Morley M. Blouke, Editor(s)

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