Van der Spiegel, Jan
Loading...
Email Address
ORCID
Disciplines
Electrical and Electronics
Research Projects
Organizational Units
Position
Professor of Electrical Science and Engineering
Introduction
Research Interests Vision Sensors
Research Interests
Search Results
Now showing 1 - 10 of 47
Publication Robust Classification of Stop Consonants Using Auditory-Based Speech Processing(2001-05-07) Abdelatty Ali, Ahmed M; Van der Spiegel, Jan; Mueller, PaulIn this work, a feature-based system for the automatic classification of stop consonants, in speaker independent continuous speech, is reported. The system uses a new auditory-based speech processing front-end that is based on the biologically rooted property of average localized synchrony detection (ALSD). It incorporates new algorithms for the extraction and manipulation of the acoustic-phonetic features that proved, statistically, to be rich in their information content. The experiments are performed on stop consonants extracted from the TIMIT database with additive white Gaussian noise at various signal-to-noise ratios. The obtained classification accuracy compares favorably with previous work. The results also showed a consistent improvement of 3% in the place detection over the Generalized Synchrony Detector (GSD) system under identical circumstances on clean and noisy speech. This illustrates the superior ability of the ALSD to suppress the spurious peaks and produce a consistent and robust formant (peak) representation.Publication A Fully Integrated CMOS Phase-Locked Loop With 30MHz to 2GHz Locking Range and ±35 ps Jitter(2003-07-01) Xu, Chao; Laker, Kenneth R; Sargeant, Winslow; Van der Spiegel, JanA fully integrated phase-locked loop (PLL) fabricated in a 0.24μm, 2.5v digital CMOS technology is described. The PLL is intended for use in multi-gigabit-per-second clock recovery circuits in fiber-optic communication chips. This PLL first time achieved a very large locking range measured to be from 30MHz up to 2GHz in 0.24μm CMOS technologies. Also it has very low peak-to-peak jitter less than ±35ps at 1.25GHz output frequency.Publication A Low Distortion MOS Sampling Circuit(2002-05-26) Sonkusale, Sameer R.; Van der Spiegel, JanThis paper presents a sampling technique with reduced distortion for use in a sample-and-hold circuit for high resolution analog-to-digital converters and switched capacitor filters. The technique involves bootstrapping both the gate and the bulk terminal of the sampling switch to improve linearity. Circuit implementation and SPICE level simulation results are presented.Publication A Spectral Conversion Approach to Feature Denoising and Speech Enhancement(2005-09-01) Mouchtaris, Athanasios; Van der Spiegel, Jan; Mueller, Paul; Tsakalides, P.In this paper we demonstrate that spectral conversion can be successfully applied to the speech enhancement problem as a feature denoising method. The enhanced spectral features can be used in the context of the Kalman filter for estimating the clean speech signal. In essence, instead of estimating the clean speech features and the clean speech signal using the iterative Kalman filter, we show that is more efficient to initially estimate the clean speech features from the noisy speech features using spectral conversion (using a training speech corpus) and then apply the standard Kalman filter. Our results show an average improvement compared to the iterative Kalman filter that can reach 6 dB in the average segmental output Signal-to-Noise Ratio (SNR), in low input SNR's.Publication Hardware Implementation of a Visual-Motion Pixel Using Oriented Spatiotemporal Neural Filters(1999-09-01) Etienne-Cummings, Ralph; Van der Spiegel, Jan; Mueller, PaulA pixel for measuring two-dimensional (2-D) visual motion with two one-dimensional (1-D) detectors has been implemented in very large scale integration. Based on the spatiotemporal feature extraction model of Adelson and Bergen, the pixel is realized using a general-purpose analog neural computer and a silicon retina. Because the neural computer only offers sum-and-threshold neurons, the Adelson and Bergen's model is modified. The quadratic nonlinearity is replaced with a full-wave rectification, while the contrast normalization is replaced with edge detection and thresholding. Motion is extracted in two dimensions by using two 1-D detectors with spatial smoothing orthogonal to the direction of motion. Analysis shows that our pixel, although it has some limitations, has much lower hardware complexity compared to the full 2-D model. It also produces more accurate results and has a reduced aperture problem compared to the two 1-D model with no smoothing. Real-time velocity is represented as a distribution of activity of the 18 X and 18 Y velocity-tuned neural filtersPublication Fabrication of a Dual-Tier Thin Film Micro Polarization Array(2007-04-16) Gruev, Viktor; Ortu, Alessandro; Van der Spiegel, Jan; Lazarus, Nathan; Engheta, NaderA thin film polarization filter has been patterned and etched using reactive ion etching (RIE) in order to create 8 by 8 microns square periodic structures. The micropolarization filters retain the original extinction ratios of the unpatterned thin film. The measured extinction ratios on the micropolarization filters are ~1000 in the blue and green visible spectrum and ~100 in the red spectrum. Various gas combinations for RIE have been explored in order to determine the right concentration mix of CF4 and O2 that gives optimum etching rate, in terms of speed and under-etching. Theoretical explanation for the optimum etching rate has also been presented. In addition, anisotropic etching with 1μm under cutting of a 10μm thick film has been achieved. Experimental results for the patterned structures under polarized light are presented. The array of micropolarizers will be deposited on top of a custom made CMOS imaging sensor in order to compute the first three Stokes parameters in real time.Publication Linear Current-Mode Active Pixel Sensor(2007-11-01) Philipp, Ralf M; Gruev, Viktor; Orr, David; Van der Spiegel, Jan; Etienne-Cummings, RalphA current mode CMOS active pixel sensor (APS) providing linear light-to-current conversion with inherently low fixed pattern noise (FPN) is presented. The pixel features adjustable-gain current output using a pMOS readout transistor in the linear region of operation. This paper discusses the pixel’s design and operation, and presents an analysis of the pixel’s temporal noise and FPN. Results for zero and first-order pixel mismatch are presented. The pixel was implemented in a both a 3.3 V 0.35 µm and a 1.8 V 0.18 µm CMOS process. The 0.35 µm process pixel had an uncorrected FPN of 1.4%/0.7% with/without column readout mismatch. The 0.18 µm process pixel had 0.4% FPN after delta-reset sampling (DRS). The pixel size in both processes was 10 X 10 µm2, with fill factors of 26% and 66%, respectively.Publication Biologically Inspired Vision Sensor for the Detection of Higher-Level Image Features(2003-12-16) Van der Spiegel, Jan; Nishimura, MasatoshiThe paper briefly reviews certain aspects of the biological visual system and presents a smart vision sensor for the detection of higher-level features. The visual system processes information in a hierarchical manner starting from the retina up to the visual cortex. It decomposes the image in simple features (edges, orientation, line stops, corners, etc) using spatial and temporal information. At the higher level it integrates these primitive features, resulting in the recognition of complex objects. The sensor described in the paper is loosely modeled after the visual system and incorporates pixel level, programmable elements which extract orientation, end stops, corners and junctions from a line drawing. The architecture resembles a CNN-UM that can be programmed with a 30-bit word. The 16 x 16 pixels array detects these higher-level features in about 54 μseconds.Publication Multi-Frequency Pierce Oscillators Based On Piezoelectric AlN Contour-Mode MEMS Resonators(2008-09-01) Zuo, Chengjie; Sinha, Nipun; Van der Spiegel, Jan; Piazza, GianlucaThis paper reports on the first demonstration of multi-frequency (176, 222, 307, and 482 MHz) oscillators based on piezoelectric AlN contour-mode MEMS resonators. All the oscillators show phase noise values between –88 and –68 dBc/Hz at 1 kHz offset and phase noise floors as low as –160 dBc/Hz at 1 MHz offset. The same Pierce circuit design is employed to sustain oscillations at the 4 different frequencies, while the oscillator core consumes at most 10 mW. The AlN resonators are currently wirebonded to the integrated circuit realized in the AMIS 0.5 μm 5 V CMOS process. This work constitutes a substantial step forward towards the demonstration of a single-chip multi-frequency reconfigurable timing solution that could be used in wireless communications and sensing applications.Publication A CMOS image processing sensor for the detection of image features(2005-12-01) Nishimura, Masatoshi; Van der Spiegel, JanA compact CMOS vision sensor for the detection of higher level image features, such as corners, junctions (T-, X-, Y-type) and linestops, is presented. The on-chip detection of these features significantly reduces the data amount and hence facilitates the subsequent processing of pattern recognition. The sensor performs a series of template matching operations in an analog/digital mixed mode for various kinds of image filtering operations including thinning, orientation decomposition, error correction, set operations, and others. The analog operations are done in the current domain. A design procedure, based on the formulation of the transistor mismatch, is applied to fulfill both accuracy and speed requirements. The architecture resembles a CNN-UM that can be programmed by a 30-bit word. The results of an experimental 16x16 pixel chip demonstrate that the sensor is able to detect features at high speed due to the pixel-parallel operation. Over 270 individual processing operations are performed in about 54 µsec.