Unlike digital TV applications, however,
digital video processors for surveillance
applications don’t need to deal with compression
algorithms. Instead, developers look
for processing power to add functionality such as face recognition, enhanced lowlight
visibility, and ease of use.
For example, Vimicro’s VC0706 enables
the implementation of “motorless” electronic
pan, tilt, and zoom functions by
operating on the camera signal. This helps
to eliminate the need for mechanical maintenance
in the system.
As with television, though, there’s pressure
among users to move to HD video
resolution. This demand places a heavier
burden on both image sensors and the video
processors, according to Yu. But because
sensor sizes tend to remain constant, pixels
become smaller fractions of the chip area.
“The higher the pixel count, the faster
the processor must run to handle more
input data,” says Yu. “But the smaller the
pixel area, the less sensitive a pixel will
become, leading to image degradation
under low light conditions. This requires
the chip to increase performance even further
to provide image enhancements.” Yet
programmability remains key to handling
innovation in application software.
The innovation in surveillance-type
applications also manifests itself in the
form of new uses for processor-enhanced
cameras. Yu pointed out that surveillance
cameras are being applied to vehicle
rear-view monitoring, video door phones,
industrial inspection, and the like. This
type of application spillover is also showing
up in other areas as digital video processing
evolves.
TI’s Andrews noted that there’s a growing
desire among developers to utilize HD
video in non-traditional applications as
well. “We’re seeing video showing up in
a lot of different products not known for
their video needs,” says Andrews, “such as
vending machines and exercise bikes.”
Lowe of Sigma Designs pointed out that
all sorts of industries are connecting their
product to the Internet and getting a screen,
making video capability an easy add-on that
they are finding ways to utilize. Andrews
agreed, saying, “Even if they have a different
primary function, video is becoming a
checkbox for many applications.”
NEW ARCHITECTURES ARISE
Recent architectural advances in digital
video processing may further accelerate
this trend of bringing digital video to new
applications. Toshiba’s SpursEngine video
co-processor promises a significant jump in
performance by clearing an I/O bottleneck
that chokes many co-processor designs.
The choke arises because image processing
and enhancement must take place on fully
decoded video.
With video moving toward full HD
resolution of 1080p at 120 frames/s as the
preferred resolution, the need to manipulate
fully decoded video creates a tremendous
I/O burden on the system bus just to move
data into and out of the video co-processor.
The Toshiba SpursEngine addresses this
bottleneck by allowing its I/O to handle
compressed data formats. In addition to
four programmable Synergistic Processing
Element (SPE) cores, the chip has dedicated
MPEG-2 and H.264 encoders and
decoders and an interface to high-speed
XDR memory (Fig. 3).
The device does an on-chip expansion
of compressed video, uses the four SPEs to
process the video, and then recompresses
it before sending it back out. According
to Deepak Mithani, director of business
development for the digital multimedia
group at Toshiba America Electronic
Components (TAEC), this drops bus
loading by nearly 70%.
The bus bandwidth reduction along with
the expanded processing power of dedicated
codec hardware and multiple processing
cores has the potential to enable an explosion
of new applications for digital video
processing. The device initially targets use
with a PC add-in card, but could be utilized
as part of a dedicated system, as well.
Mithani indicated that TAEC is already
looking at applications such as image
recognition for automatic indexing of
disk-archived video content, faster than
real-time transcoding, picture resolution
upscaling for HDTV, and real-time 3D
face tracking for video communications.
There’s even an application that monitors a
PC’s built-in camera to let consumers control
the PC using only hand gestures.
A host of even more exotic digital video
applications will undoubtedly arise as a
result of this and other architectural innovations
among processor vendors. Experimental
work is already under way, for
instance, to enhance surveillance by automatically
recognizing faces in a crowd.
Work is also being done to improve
automobile safety by identifying unsafe pedestrian movements, recognizing driver
drowsiness, or locating the car’s position
relative to road paint stripes and alert the
driver of hazards. Combining 3D face
tracking with an ability to superimpose
graphics on images may enable the development
of video “mirrors” that allow retail
customers to “try on” virtual clothing.
Applications will additionally arise simply
because the solutions for other applications
have put new capabilities in place.
“By eliminating the flicker associated with
interlaced display, HD will allow text and
graphics to be mixed with the video and
remain readable. This provides opportunities
to deliver features not available
before,” says Sigma Designs’ Lowe, “essentially
for free.” A variety of new markets
may thus be created simply by asking what
has become possible each time the performance
bar is raised.
Whatever the function, the many
options available for digital video processors
along with their continued growth in
resolution and performance will ensure the
continual expansion of digital video’s application
base. The key for developers will be
to understand the requirements of the
application in terms of resolution, performance,
power, latency, and cost. That there
will be a processor available to match their
needs is becoming ever more certain.