An integrated optical transient sensor
Author:
- 1 September 2002
- journal article
- Published by Institute of Electrical and Electronics Engineers (IEEE) in IEEE Transactions on Circuits and Systems II: Analog and Digital Signal Processing
- Vol. 49 (9) , 612-628
Abstract
The implementation of a compact continuous-time optical transient sensor with commercial CMOS technology is presented. In its basic version, this sensor consists of a photodiode, five transistors and a capacitor. The proposed circuit produces several output signals in parallel. These include a sustained, logarithmically compressed measure of the incoming irradiance, half-wave rectified and thresholded contrast-encoding measures of positive and negative irradiance transients, and a signal that shows a combination of the sustained and the bidirectional transient response. The particular implementation reported in this work responds to abrupt irradiance changes with contrasts down to less than 1% for positive transients and 25% for negative transients. Circuit modifications leading to more symmetric contrast thresholds around 5% are also described. Due to their compactness these transient sensors are suitable for implementation in monolithic one- or two-dimensional imaging arrays. Such arrays may be used to sense local brightness changes of an image projected onto the circuit plane, which typically correspond to moving contours.Keywords
This publication has 14 references indexed in Scilit:
- A reconfigurable neuromorphic VLSI multi-chip system applied to visual motion computation2003
- A new temporal domain optical flow measurement technique for focal plane VLSI implementation2002
- An analog VLSI velocity sensor2002
- Visual sensor with resolution enhancement by mechanical vibrations2002
- Orientation-selective aVLSI spiking neuronsNeural Networks, 2001
- Active vision using an analog VLSI model of selective attentionIEEE Transactions on Circuits and Systems II: Analog and Digital Signal Processing, 2001
- Pulse-based analog VLSI velocity sensorsIEEE Transactions on Circuits and Systems II: Analog and Digital Signal Processing, 1997
- Image-motion detection using analog VLSIIEEE Journal of Solid-State Circuits, 1992
- Implementing early visual processing in analog VLSI: light adaptation1991
- Silicon retina with adaptive photoreceptors1991