CMOS IMAGING getting hot.
eetimes.com
CMOS image sensor goes mainstream
By Chappell Brown
EE Times
(11/30/99, 5:54 p.m. EDT)
FREMONT, Calif. ? Logitech Inc.'s recently announced upgrade strategy for its
QuickCam Express digital camera line has pulled CMOS pixel sensor
technology one step closer to the mainstream commercial market. The
company will be replacing charge-coupled device (CCD) sensors in the
cameras with a 352 x 288-pixel CMOS image sensor from Photobit Inc.
(Pasadena, Calif.).
Photobit was formed by engineers from the Jet Propulsion Laboratory, which
had developed the sensor technology for space craft. Only a few years ago,
CMOS "active-pixel" technology was still in the research stage. Photobit began
marketing CMOS image sensors based on the technology last year, and now
has four products. In addition to the QuickCam sensor, Photobit also offers a
VGA-format 640 x 480-pixel sensor, a high-definition television format chip and
a high-speed 500-frame/second megapixel video chip.
NASA was interested in the approach because the imaging chips consume
much less power than CCDs, and since they are CMOS-compatible, it is
possible to integrate image-processing circuitry to simplify camera design.
Those advantages, along with lower cost, also have made the technology
attractive to consumer product vendors. The new sensor, Photobit's PB-0100,
will allow Logitech to enhance the performance of its QuickCam design, which
captures video for low-bandwidth communications over phone lines and the
Internet.
The imager is designed for small-format applications such as video cell phones
or handheld scanners. The chip includes digital signal processing circuitry to
enhance the performance of the sensor. The on-chip circuitry also converts the
output directly into full-frame, 8-bit digital video at 39 frames/second. The chip
can also perform other imaging functions that usually require optical and
mechanical subsystems. Through the use of a digital serial interface, for
example, it can be programmed via digital signal processing for pan, tilt and
zoom functions. |
