High Precision Image Centroid Computation via an Adaptive K-Winner-Take-all Circuit in Conjunction with a Dynamic Element Matching Algorithm for Star Tracking Applications: ISCAS 2002 Special Issue on Smart Sensors (Guest Editors: Orly Yadid-Pecht and Ralph Etienne-Cummings)

Authors: Fish A.¹; Akselrod D.²; Yadid-Pecht O.³

Source: Analog Integrated Circuits and Signal Processing, Volume 39, Number 3, June 2004 , pp. 251-266(16)

Publisher: Springer

Abstract:

An approach for implementing a high precision image target centroid—center of mass (COM) detection system via an adaptive K-winner-take-all (WTA) circuit in conjunction with a 2-D dynamic element matching (DEM) algorithm implementation for image sensor arrays is proposed. The proposed system outputs a high precision COM location of the most salient target in a programmable active region of the field of view (FOV) for star tracking purposes and is suitable for real time applications. The system allows target selection and locking with multiple targets tracking capability. This solution utilizes the separability property of the COM, and therefore reduces the computational complexity by utilizing 1-D circuits for the computation. The DEM algorithm, commonly used in ADC and DAC circuits, allows reducing the required WTA circuit precision to 5–6 bits, while still achieving a high output precision. Simulation results prove the concept and demonstrate the high precision COM result. In addition, a possible low-level hardware implementation is described.

Keywords: APS; CMOS imager; center of mass; COM; centroid; K-WTA circuit; K-Winner-take-all circuit; dynamic element matching; DEM; star-tracking; image processing

Document Type: Research article

DOI: 10.1023/B:ALOG.0000029661.59987.3c

Affiliations: 1: The VLSI Systems Center, Ben-Gurion University, Beer-Sheva, Israel 2: Motorola Semiconductor, Herzlia, Israel 3: The VLSI Systems Center, Ben-Gurion University, Beer-Sheva, Israel., Email: oyp@ee.bgu.ac.il

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