Robot Builder’s Sourcebook

668
video-imagers
Video Images: Analog or Digital
The vast majority of solid-state video cameras available today provide an analog output
signal (specifically, it is a composite signal that combines synchronization and luminance
signals, and with a color system, chrominance signals as well). Depending on
where in the world you buy your camera, this signal is compatible with your TV and
VCR.
For example, color cameras sold in the United States are compatible with the NTSC
color standard; black-and-white cameras, with the RS-170 standard. Cameras for sale in
many parts of Europe follow the PAL standard. Some cameras are selectable between
NTSC and PAL or are available in either version.
For the most part, cameras with composite signal outputs are only modestly useful in
robotics. The signal must be processed before the electronics (computer, microcontroller)
on the robot can use it. The processing might be in the form of a frame capture
card, or it might be some homemade sync separator and analog-to-digital comparator
circuit. However, a minority of solid-state cameras provides a digital output—usually 8-bit
parallel, but also USB serial. A parallel digital camera can be directly connected to your
robot’s computer or controller; software running on the robot reads the video signal by
processing the digital data.
� (408) 350-5100
� (877) 436-8366
� http://www.foveon.com/
Makers of high-resolution CCD color imagers. Some
technical documents available on the Web site.
�
OmniVision Technologies, Inc. 202281
930 Thompson Place
Sunnyvale, CA 94085
USA
� (408) 733-3030
� (408) 733-3061
� http://www.ovt.com/
Single-chip CMOS black-and-white and color imagers—
”Single-Chip CMOS Image Sensors (Camera-on-a-
Chip).”
The company designs single-chip image sensors for capturing
and converting images for cameras. Their
imagers are used in a number of products and designs,
including the CMUcam (see http://www-
2.cs.cmu.edu/~cmucam/).
x �
�Video-Programming &
APIs
See the description in Video for more information
about this section.
AVR + GameBoy tm Camera = Fun 202277
http://pages.zoom.co.uk/andyc/camera.htm
Detailed information, circuits, and sample programming
(for the Atmel AVR microcontroller) for using
the Gameboy camera for crude machine vision.
�
CMUcam Vision Sensor � 202514
http://www-2.cs.cmu.edu/~cmucam/
See listing under Video-Camera.
�
CORAL Group’s Color Machine Vision
Project 202513
http://www-2.cs.cmu.edu/~jbruce/cmvision/