What's New At The Edge
How network cameras are reshaping the surveillance landscape
- By Fredrik Nilsson
- Jun 04, 2012
Even though the first product launch of a
network camera happened in 1996, it was
a little more than a decade ago before the
device began appearing in the physical security
arena. Crude by today’s standards,
the pioneering technology boasted the
ability to stream video at a sluggish one
frame per second. Even more, the cameras
required a minimum of 20 lux to deliver any sort of image clarity.
Nowadays, network cameras stream HDTV-quality video at
speeds up to 60 fps, can operate in lighting conditions as low
as 0.008 lux and offer a long list of other features.
So, how did IP-based cameras achieve such a quantum leap in
performance in such a short time frame? Like most other computer
technology, network camera performance follows Moore’s
Law, which describes the trend where digital electronic devices
double in power and speed every 18 months. In the case of network
cameras, this trend specifically encompasses processing
performance, image sensors and pixel count. With so much computing
power now residing in cameras, manufacturers have been
able to push more processing out to the edge of the surveillance
network to provide better image quality, better scalability and
greater functionality at an overall lower system cost.
But how have these performance advances affected surveillance
in the real world? Let’s look at six key features.
Higher Resolution and Frame Rate
Higher resolution means capturing more details in the image area
and therefore increasing the forensic value and usability of video.
True analog systems are limited to the NTSC/PAL standard,
which means their maximum resolution is 720x480—corresponding
to 0.4 megapixels—and often only a quarter of that resolution
is recorded. However, in the IP world, camera resolution has
undergone an exponential evolution to megapixel and HDTVquality
image clarity even faster than Moore’s Law predicted.
Megapixel-resolution cameras first appeared around 2005,
providing more detail for identifying people and objects and covering
a larger field of view. The first megapixel cameras offered
1280x1024-pixel resolution, basically a scaled-up version of VGA
with the same 4:3 aspect ratio. But as the technology improved
from 1.3 to 5.2 megapixels, resolution jumped to a 2560x2048-
pixels format. The drawbacks came in two forms: the aspect ratio
didn’t always match new 16:9 monitors, and the frame rate
for higher megapixel cameras was limited to around 10 fps for 5
megapixels and even lower for higher megapixel cameras, such as
the 8- and 10-megapixel products now on the market.
Like the megapixel cameras, HDTV cameras deliver much
higher resolution than VGA cameras. Unlike megapixel, for a
camera to call itself HDTV it must strictly adhere to SMPTE
standards for resolution, frame rate (30 fps), color fidelity and
16:9 aspect ratio. Like the TVs we buy for our homes, this ensures
that every camera classified as HDTV will deliver consistent performance
no matter who manufactures it.
In addition, HDTV-compatible cameras support advanced
H.264 compression technology, which drastically reduces bandwidth
consumption and storage requirements. HDTV network
cameras come in the same three formats as flatscreen TVs today:
720p (1280x720 pixels), 1080p (progressive, 1920x1080 pixels)
and 1080i (interlaced, 1920x1080 pixels).
Better Video Compression
Advances in compression standards, along with improved processing
power at the edge for real-time compression, have also
evolved to significantly reduce image file size—and therefore
bandwidth consumption and video storage—without adversely
affecting visual quality. In other words, without H.264 compression,
HDTV-quality video wouldn’t be possible in the surveillance
world. The compression standards evolved to focus efforts
on frame consistency for better efficiency, such as reducing color
nuances and color resolution, removing small invisible parts of
the picture, and comparing adjacent images and removing details
that are unchanged between video frames:
Motion JPEG treated each frame as a still JPEG picture. It
prevented dropped frames during transmission, but the compression
ratio was low for video sequences because it made no use of
video compression techniques.
MPEG-1 used a more efficient coding of video sequences, but
the focus was on compression ratio rather than picture quality.
MPEG-2 employed more advanced techniques to enhance
video quality through resolution and frame rate, but it was done
at the expense of higher bandwidth usage. MPEG-2 is used for
standard-definition DVD movies.
MPEG-4 accommodated both ends of the spectrum, streaming
lower-quality video to mobile devices requiring lower bandwidth
consumption and streaming extremely high quality for
applications with almost unlimited bandwidth. The MPEG-4
standard has multiple parts.
H.264, aka MPEG-4 Part 10, is the newest video compression
technology in IP video, representing a huge step forward for video
surveillance applications. Without compromising image quality,
H.264 can reduce the size of a digital video file by more than
80 percent compared with Motion JPEG compression and as
much as 50 percent compared with the MPEG-4 Part 2 standard.
With far less network bandwidth and storage space required for
a video file, users save money and achieve a much higher video
quality for a given bit rate. This advanced compression standard
is being used in the entertainment industry for Blu-ray movies
and online video.
Greater Light Sensitivity
While higher resolution and more effective compression have a
major impact on image quality streaming from the camera, image
processing technology also plays an important role, especially
in difficult lighting conditions. Network camera manufacturers
today have greatly improved a camera’s ability to capture quality
images in fairly complex lighting conditions—from very low light
to wide variations in light throughout the day or within a single
scene—and have surpassed analog in light performance.
Low light. In the past, manufacturers have addressed low-light
problems by integrating more light-sensitive sensors, day/night
filters, IR illuminators and thermal imaging into their cameras.
As new cameras have come on the market with higher processing
power, manufacturers can employ even more advanced filtering
techniques to further improve light sensitivity.
Lightfinder technology is the latest innovation in extremely
low-light surveillance. It works in concert with a network camera’s
sensor and lens to find light in a scene that it can use to
stream color video even at night. Sophisticated image processing
software sets the degree of filtering and sharpening to capture
the best image possible. Highly sensitive to low light, a network
camera enhanced with Lightfinder can maintain tight focus with
minimal noise and lifelike color fidelity from dusk to dawn as well
as in full sunlight.
Wide dynamic range. WDR incorporates techniques for handling
a wide range of lighting conditions within a single scene,
such as extremely bright and darkly shadowed corners or backlit
situations where a person is standing in front of a sunlit window. A
standard surveillance camera would inevitably produce barely visible
images of objects in dark areas. A network camera equipped
with WDR, on the other hand, combines different exposures of
different objects in a scene, depending on the prevailing light to
ensure nearly uniform visibility across the field of view.
With the convergence of improved image quality and sufficient
processing power, manufacturers have started to incorporate intelligent
algorithms in-camera to push video analytics to the edge.
The power of the latest chipsets have made it possible for network
cameras to detect motion, sound and tampering attempts, like
blocking or spray painting the lens; recognize license plates; and
identify objects crossing an imaging line.
Intelligent network cameras also can count people, perform
dwell time analysis for retailers and even track customer flow
through the aisles of a store. This is all being done in the camera
today. Some of the more advanced motion detection analytics
can also filter out the natural rustling of leaves and the swaying
of branches for better success rates.
Because video analytics often require very specific knowledge
about the surveillance application, camera manufacturers typically
partner with expert software companies. The additional processing
power built into the camera makes the edge an attractive and robust
platform for third parties to develop any number of custom analytics
applications—think of it like an App Store for surveillance.
There are several advantages to performing analytics at the
edge. First, raw and uncompressed video contains more information
that can be used in an analysis. Second, analyzing the video
before compressing it and sending it over the network reduces
bandwidth consumption. Third, in-camera analytics provide better
system scalability because they avoid overloading a central
server with too many video streams requiring analysis.
Local Storage Option
Advances in SD memory card technology, formerly found only
in consumer electronics, have created new possibilities for storage
at the edge.
A few short years ago, a 1 GB card could cost upward of $100.
Today, a 32 GB card can be purchased for less than $50. SD cards
with the potential to hold upward of 2 TB of storage are already
on the horizon, which could equate to years’ worth of video storage
at the edge.
Applying H.264 video compression, a customer can now record
15 images per second of high-quality, 1080p HDTV resolution
for days and even weeks on a single card. A network camera
will be able to offer a level of fault tolerance for network outages
by recording locally—even for security applications that require
high resolution and real-time recording rates.
The industry is taking this one step further. While SD cards
traditionally were used for redundant storage in critical surveillance
applications, this year at ISC West we saw manufacturers
and software developers leveraging the IP camera as the recorder.
Individual cameras with a single switch or router can now become
complete security systems unto themselves without the need
for central storage or even a computer running the system. This
camera-as-the-recorder model will be a major trend for moving
IP video into small-camera-count installations by eliminating the
cost for recording hardware.
Smaller Form Factor
The miniaturization of integrated circuit technology has allowed
manufacturers to deliver more processing power in a smaller
chipset. The smaller chips generate less heat, a primary culprit
in picture noise.
But better image quality is only part of the story. Smaller,
more powerful chips allow network camera manufacturers to
downsize their camera form factors while maintaining the same
capabilities as their larger cousins. Today, a palm-sized PTZ IP
camera can discretely monitor a retail store, bank or hotel lobby
without being an obtrusive menace to aesthetics—yet it will deliver
the same HDTV-quality and intelligent benefits as the largest
Where Moore’s Law Will Lead Us
Based on past progress, industry experts foresee network cameras
maintaining the same forward trajectory as other computer
technology. The degree of light sensitivity will become even more
acute while resolution and compression will continue to improve
across an ever-wider dynamic range.
In addition, with advances in chip technology and processing
power, the potential for third-party development of video analytics
applications will become even more prevalent. If we accept
Moore’s Law as an accurate predictor, improvements at the edge
will continue to grow exponentially for the foreseeable future.
This article originally appeared in the June 2012 issue of Security Today.