DPS Provides New Variable-Light Solution
December, 2003
By:
ST&D
If you have camera surveillance at your facility, chances are, each of
your cameras struggles with capturing quality images in certain
lighting conditions. Even if you've invested in high-dynamic-range
technology, you may still experience some imaging problems in locations
with a high degree of variation in light exposure, or you may have
difficulty seeing images captured in low light. Now, a new, non-CCD
solution to such problems is being integrated into the cameras of
several major manufacturers.
Digital pixel system (DPS) technology from California-based Pixim Inc.
forms the base of this new solution. DPS equips each pixel in an
image-capture array with its own analog-to-digital converter. As Rob
Siegel, executive vice president of Pixim, explained, "What that means
is, every pixel when we capture a video field can act as its own camera
and have a different exposure time. So very bright pixels get short
exposure times because they capture a lot of light quickly, and very
dark pixels get long exposure times because it takes longer to capture
enough light. The benefit of this is that we can extend the dynamic
range, which is basically the ratio between the brightest and darkest
dot in a scene, by two orders of magnitude." This method differs from
that of other technologies, which expose all pixels at the same time,
thus underexposing some and overexposing others.
DPS technology can minimize blooming and artifacts in varying-light
situations and can provide a clearer, more reliable image. In the set
of pictures to the left, a bright lamp sits in a dimly lit room. The
image taken with a DPS-equipped camera includes a clear view of the
lamp base, which is washed out in the other image, and a more accurate
shot of the color chart sitting at the end of the table. Without DPS,
this information would be lost. In low-light applications, Pixim's DPS
is one of the first technologies to compete with the 1 lux-and-below
performance of CCDs. It also works with IR illumination in the same way
a CCD would.
Six Pixim customers are now working to include DPS in their camera
offerings: GE Interlogix, JVC, Pelco, Silent Witness (now a property of
Honeywell), EverFocus in Taiwan, and Baxall in Europe. Lee Hirsch,
Pixim's senior director of marketing, said "The perception I believe
most end users have right now is that high dynamic range is really a
premium product - that they have to go and spend a lot of extra money
and look for very specialized products out in the marketplace. DPS
actually brings that to mainstream cameras. This is going to become
what we hope is a baseline capability."
Contact:
John Monti
Pixim, Inc.
(650) 605-1107
monti@pixim.com
