Advanced Imaging


Advanced Imaging Magazine

Updated: January 12th, 2011 10:01 AM CDT

Component Integration: CCD vs. CMOS

CCD has been around longer, but CMOS is closing the gap
image of a star
© NASA, ESA and Keith Noll Space Telescope Science Institute.
This image of a star, similar to our sun, 3,600 light years way ending its life was taken by Feb. 6, 2007, by the Wide Field and Planetary Camera 2 (WFPC2) on the Hubble telescope. It is actually a composite of many separate exposures made by the CCD instrument.
CMOS sensor
© Sarnoff Corp.
There are fundamental differences in architecture and operations between this CMOS sensor and a CCD sensor.

By Barry Hochfelder

It's in the field of scientific imaging that the battle is really engaged—NASA and space exploration, spy satellites and weather-related work.

"They have common denominators," Janesick says. "Pretty pictures help get the public to support the programs, but our main objective is images that measure things. Cost is more important for our work. There's no research money around.

That's part of the emotional fight between CCD and CMOS. For the first dozen years, the science types and analog types developed the technology. Then the commercial people followed."

Sarnoff currently is introducing NASA's solar group, which monitors the sun for solar flares, to CMOS. "Their work essentially has been CCD," Janesick says. "They want to make the transition. We have to overcome some noise problems."

CMOS can measure very quickly at very high speeds, he explains. "CCD has a serial port. CMOS is parallel, so you have many ports and electronics on a chip can multiplex all of them to one channel. Plus, computers are faster and telemetry is faster."

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