CCD and CMOS Sensors Craig Robinson

Definitions CCD CMOS Charge Coupled Device Complementary Metal Oxide Semiconductor

What is CCD and CMOS? Array of Diodes (photosites) that produce a voltage: Linearly Proportional to the AMOUNT incident light. Non-linearly Dependant to the WAVELENGTH Built out of layers of Silicone Silicone is sensitive to light Layers add functionality – different layers perform different functions. (called ‘die’)

CCD History Invented in 1970 by Bell Labs Honeywell developed this into an X-Y scanner and taken further by IBM. Originally for data storage! Taken up by research and astronomy areas. Now used in security cameras, digital cameras and virtually all digital video applications.

CCD and CMOS Uses

CCD vs CMOS More susceptible to noise Light sensitivity is lower Create high-quality, low-noise images. Greater sensitivity and fidelity 100 times more power Require specialized assembly lines Older and more developed technology More susceptible to noise Light sensitivity is lower Consume little power Easy to Manufacture Cheaper Picture quality, sensitivity and cost vs. Cost and battery life.

Types of CCD and CMOS Filter Array Beam Splitters CCD and CMOS Cheap Easy Small Beam Splitters Expensive High Quality One frame required CCD and CMOS Rotational Lens Cheaper Good quality 3 frames req’d – only stationary objects

Properties Resolution: 3.2 Megapixels (2054 x 1056) Frame Rate: 30 ~ 500 Frames/sec Dynamic Range: Signal – noise ratio. Dark Signal Windowing: Enhance Region of Interest Remote Control: Simple serial characters Anti-blooming: Bright object saturation. Interface: Serial, parallel, etc. Power: +5VDC @ 2.5W Size: 4mm and larger Cost: $60 and upwards

Interfacing Many different options: Requires specific power setup Serial Transmission Parallel Transmission VHF/UHF output Requires specific power setup Send Input data to setup: Auto Gain Shutter Speed Power mode, image specs etc Increasing # of onboard calculations

Serial and Parallel Requires MANY Pulses:

Timing

Example Add a CCD / CMOS to the robot in the lab. Robot must wander and clean the your house while you are sleeping. Choose CMOS due to lower power consumption. Need high sensitivity for night vision. Choose the Sharp LZOP3817.

Peripherals: Pulse Pattern Generator Vertical Drivers + DC/DC Converter CDS - AGC – ADC CDS (correlated double sampling) AGC (automatic gain control) ADC (analog-to-digital convertor) DSP

Board Layout DRAM D 0 -7 LZOP3817 CMOS CHIP DSK6711 (Or micro controller) DATA ADRESS GLUE LOGIC Horizontal Timing Vertical timing

Manufacturers Philips Sharp Dalsa Fuji Sony Kodak Polaroid

References HowStuffworks: Digital Cameras www.dalsa.com/markets/Photonics_Spectra_CCDvsCMOS_Litwiller.pdf www.sharpsma.com www.semiconductors.philips.com http://www.ccd.com/ Peter McCullough at The University of Illinois (Astronomy)