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Non-Invasive Sensors™

The Company is developing a family of photo-detectors that have a structure eminently suitable for non-invasive monitoring of physiological analytes in-vivo, specifically, blood glucose. We are developing a family of smart analog vision chips and ancillary software capable to adaptively select image processing parameters and regions of interest in the field of view. This family of devices is highly relevant to our approach to real-time control and prediction of biological processes, because it can be configured to embed prior knowledge algorithms to perform image pre-selection.
Centroid computation in W&S: When an electron cloud lands on the pattern, if collected charges QS, QW are as shown, and Q0 for the substrate, the (X,Y) coordinates of the centroid can be computed with the simple formulas:

X = 2.QS / (QS + QW + Q0)
Y = 2.QW / (QS + QW + Q0)

The new vision chips will use semiconductor Wedge&Strip (W&S) detector arrays with spatial prefiltering implemented via image algebra. The W&S detector locates the individual incident light events, building the image as they accumulate. Our unique analog mode centroid computation circuitry facilitates on-chip data processing, while an undemanding geometry simplifies electronics fabrication.

Proof-of-concept work shows that W&S - based systems will be equivalent in performance to existing massively parallel CCD vision processors but will cost significantly less to produce and integrate.

The research phase of this project was sponsored by ARPA/BMDO/IST and managed by the US Army Space and Missile Defense Command, Huntsville, Alabama. The Advanced Devices and Applications Group at Sandia National Laboratories (Processing and Prototyping Group) implemented the innovative device solutions which led to 6-inch active area prototype W&S wafers: yes, you read that right - six inch active area.
For more information about our work, please consult SPIE Proceedings Vol. 3234:

Design and Manufacturing of WDM Devices

Editor(s): Ray T. Chen, Univ. of Texas/Austin, Austin, TX, USA; Louis S. Lome, Ballistic Missile Defense Organization, Arlington, VA, USA. ISBN: 0-8194-2667-9, 238 pages Published 1998
Meeting Date: 11/02 - 11/05/97, Dallas, TX, USA

Paper #: 3234-21
Efficient imaging with integrated optoelectronics: I. Overview and some applications, pp.184-191 Author(s):  Aureliu M. Porumbescu, Array Vision Engineering Co., Alachua, FL, USA; Gerhard X. Ritter, Univ. of Florida, Gainesville,   FL, USA; Mark S. Schmalz, Univ. of Florida, Gainesville, FL, USA; Joseph N. Wilson, Univ. of Florida, Gainesville, FL, USA; Vincent M. Hietala, Sandia National Labs., Albuquerque, NM, USA; James G. Fleming, Sandia National Labs., Albuquerque, NM, USA.

Abstract: We report on AVE's research on a new family of smart analog vision chips and ancillary software capable to adaptively select image processing parameters and regions of interest in the field of view. The project aims to adapt the wedge- and-strip (WS) position-sensitive configuration to real- time, multi-object detection. To that end, we use semiconductor WS detector (WESD) arrays with spatial prefiltering implemented via image algebra. The WESD   have the ability to locate the centroid of an incident light spot and, with appropriate prefiltering, to locate the centroids of multiple light spots. A unique analog mode centroid computation scheme facilitates on-chip data processing, while an overall undemanding geometry simplify electronics fabrication. Based on results of preliminary design and analysis, very significant cost reductions over existing massively parallel vision processors are foreseen. Superior optical resolution results even when the sensor is manufactured with 'coarse line width' semiconductor
processing technology, which may lead to detectors with large photosensitive areas. Departing from photo-sensitive element miniaturization provides the opportunity to launch a new class of vision chips, with active area limited only by the semiconductor wafer size used to manufacture the array. We suggest several applications of this new technology, including an efficient and robust WDM demultiplexing device.

Paper #: 3234-29
Efficient imaging with integrated optoelectronics: II. Massively parallel analog vision chip, pp.192-205 Author(s):  Mark S. Schmalz, Univ. of Florida, Gainesville, FL, USA; Gerhard X. Ritter, Univ. of Florida, Gainesville, FL, USA;  Joseph N. Wilson, Univ. of Florida, Gainesville, FL, USA; Aureliu M. Porumbescu, Array Vision Engineering Co.,    Alachua, FL, USA.

Abstract: Real-time multi-object detection has been an elusive goal of automated target recognition (ATR) scenarios that employ on- board millimeter-scale processors at low light levels and reduced power requirements. This paper discusses an adaptation of the wedge-and -strip anode to yield design analyses for a silicon wedge-and-strip detector (WESD). In practice, a WESD could compute the centroid of an incident light-spot and, with appropriate prefiltering can locate centroids of multiple light-spots. Due to on-chip processing and a nondemanding geometry, the WESD approach drastically reduces electronics fabrication complexity and cost. Based on results of preliminary design and analysis, significant cost reductions over existing massively parallel vision processors (MPVPs) are foreseen for object location via centroid computation. Algorithms and simulations are expressed in image algebra, a  rigorous, concise, computationally complete notation that unifies linear and nonlinear mathematics in the image domain. Developed at University of Florida over the past decade, image algebra is a unifying language for image and signal processing that has been implemented on numerous workstations and parallel computers. Thus, our algorithms are rigorous and widely portable. Circuit analysis emphasizes effects of capacitance and electrode configuration on WESD spatial resolution. Simulation results show that the WESD has centroid computation accuracy comparable to equivalent-resolution array detectors supported by on-board MPVPs. Additional technical discussion pertains to the feasibility of space- division multiplexing for multi-object detection and location at video rates.

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