CMOS active pixel sensors (APS) have performance competitive with charge-coupled device (CCD) technology, and offer advantages in on-chip functionality, system power reduction, cost, and miniaturization. This paper discusses the requirements for CMOS image sensors and their historical development, CMOS devices and circuits for pixels, analog signal chain, and on-chip analog-to-digital conversion are reviewed and discussed.

CMOS image sensors: electronic camera-on-a-chip

A forward-facing vision system for a vehicle includes a forward-facing camera disposed in a windshield electronics module attached at a windshield of the vehicle and viewing through the windshield. A control includes a processor that, responsive to processing of captured image data, detects taillights of leading vehicles during nighttime conditions and, responsive to processing of captured image data, detects lane markers on a road being traveled by the vehicle. The control, responsive to lane marker detection and a determination that the vehicle is drifting out of a traffic lane, may control a steering system of the vehicle to mitigate such drifting, with the steering system manually controllable by a driver of the vehicle irrespective of control by the control. The processor, based at least in part on detection of lane markers via processing of captured image data, determines curvature of the road being traveled by the vehicle.

Vision system for vehicle

An experimental technique is described for observing the effects of switching transients in digital MOS circuits that perturb analog circuits integrated on the same die by means of coupling through the substrate Various approaches to reducing substrate crosstalk (the use of physical separation of analog and digital circuits, guard rings, and a low-inductance substrate bias) are evaluated experimentally for a CMOS technology with a substrate comprising an epitaxial layer grown on a heavily doped bulk wafer Observations indicate that reducing the inductance in the substrate bias is the most effective Device simulations are used to show how crosstalk propagates via the heavily doped bulk and to predict the nature of substrate crosstalk in CMOS technologies integrated in uniform, lightly doped bulk substrates, showing that in such cases the substrate noise is highly dependent on layout geometry A method of including substrate effects in SPICE simulations for circuits fabricated on epitaxial, heavily doped substrates is developed >

Experimental Results and Modeling Techniques for Substrate Noise in Mixed-Signal Integrated Circuits

http://eia.udg.es/%7Eqsalvi/papers/2006-MJ.pdf

Review of CMOS image sensors

A driver assistance system for a vehicle includes an imaging device having a field of view forward of a vehicle and in a direction of travel of the equipped vehicle, an image processor operable to process image data captured by the imaging device, and a global positioning system operable to determine a geographical location of the vehicle. The equipped vehicle includes an adaptive speed control system for controlling the speed of the equipped vehicle. The adaptive speed control system may reduce the speed of the equipped vehicle responsive at least in part to a detection of a curve in the road ahead of the equipped vehicle via processing by the image processor of image data captured by the imaging device.

Driver assistance system for vehicle

A 128/spl times/128-pixel image sensor with a 20 s-10/sup -4/ s electronic shutter has been integrated in a 1.2-/spl mu/m digital CMOS technology. The pixel cell consists of four PMOS transistors and a photodiode with antiblooming suppression. Each pixel measures 24 /spl mu/m by 24 /spl mu/m and has a fill factor of 25%. Current is used to transfer pixel signals to the column readout amplifiers in order to minimize voltage swings on the highly capacitive column lines. Correlated double sampling is used to reduce intracolumn fixed pattern noise. The saturation voltage is 470 mV. The peak output signal to noise ratio is 45 dB, and the optical dynamic range is 56 dB. The frame transfer rate is 1.7 ms per frame.

Chye Huat Aw

Papers

A 128/spl times/128-pixel standard CMOS image sensor with electronic shutter

FA 11.2: A 128x128-Pixel Standard-CMOS Image Sensor with Electronic Shutter