Paper
7 March 2005 High dynamic range CMOS image sensor with pixel level ADC and in-situ image enhancement
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
Author Affiliations +
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.
© (2005) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Austin V. Harton, Mohamed I. Ahmed, Allyson Beuhler, Francisco Castro, Linda M. Dawson, Barry W. Herold, Gregory Kujawa, King F. Lee, Russell D. Mareachen, and Tony J. Scaminaci "High dynamic range CMOS image sensor with pixel level ADC and in-situ image enhancement", Proc. SPIE 5677, Sensors and Camera Systems for Scientific and Industrial Applications VI, (7 March 2005); https://doi.org/10.1117/12.586394
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CITATIONS
Cited by 7 scholarly publications.
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KEYWORDS
Sensors

Image enhancement

Image sensors

High dynamic range imaging

Image processing

Photodetectors

Analog electronics

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