A Manager's Checklist for Cameras - part 2

(09/02/2010)

Lighting

Lighting also can impact the type and placement of security video cameras. No doubt, in the out of doors, day/night cameras have a role to play. Still, there are unique lighting issues related to megapixel cameras. For example, when it comes to obtaining full resolution for higher-rated megapixel cameras, without greater levels of lighting than what is naturally in a scene, the camera will not deliver the optimum resolution.

When it comes to lux lighting levels, they usually refer to the light at the sensor, not the ambient lighting in any given scene.

Frame rate also affects low light performance. The longer the exposure, the better the image a sensor can produce in low light. But there is a tradeoff when it comes to moving images.

Frame rate is also an issue with megapixel cameras. Many of these cameras can only deliver 12-15 frames per second. This may prove insufficient for situations involving small, rapid movements such as dealers dealing cards at a casino table or money counting in the backroom at a bank.

Cameras with Intelligence

The degree of intelligence within video surveillance cameras varies. Some IP cameras provide intelligent motion detection, in which motion in certain areas can be noted while motion in other areas can be ignored. Some handle camera tamper alerting and video masking, in which only certain areas of the picture are shown.

Image cropping, people counting, object tracking, tampering detection and exposure
modification of portions of a video picture also are possible. Some surveillance cameras include metadata about what is shown in the video, provide the time and date when the video was recorded, and perform facial and license plate recognition, to name a few.

Of course, how smart a camera has to be is a function of each individual application. Still, having intelligence in the camera – that is, at the edge – enables quick set up without heavy reliance on network resources. Cameras do not need to have expanded intelligence inside, however. Intelligence can also reside in encoders in the case of analogs, in storage devices and through analytics software in video management systems.

In-camera Storage and Command and Control

With the move to more features at the edge, storage has made a leap, too, right into the camera. Some cameras now boast inexpensive and handy SD memory cards. Overall, digital video and network video recorders continue to play an end-of-the-image storage role, of course. In between, there are compression-decompression (codec) choices: MPEG-4 is about 50 percent more efficient than MJEG and H.264 is even more efficient, although H.264 may not work as well with megapixel cameras. By the way, most megapixel cameras employ MJPG, especially at the higher resolutions.

There also is a balancing act between codec used, processing power and storage needed. Overall, H.264 needs more processing power but needs less storage capacity. This is helpful when realizing that megapixel cameras – by their very nature – generate more data than lower resolution cameras.

Network Video Management Systems At the command and control end, there are software-based video management systems (VMS) but, relative to cameras, the VMS must support all the features of the camera selected. Typically, brand leader VMS solutions may support only a sub-set of the features that are common to all megapixel or IP cameras.

Taking the Jump

There are cost implementations when moving from analog to network video as well as cost consequences when moving from IP video to megapixel and HD cameras. But the benefits are also clear. There are
two simple equations.
• Camera Reduction = Cost Savings
• Increasing Resolution = Loss Prevention

While analog is less expensive in small installations with under 30 cameras, for example, a co-existence strategy of analog and digital cameras is a solid one. In addition, use of megapixel cameras can reduce the total number of cameras needed.

Infinova has a stable of technology that emphasizes the co-existence strategy which can gradually and intelligently jump from analog to IP video. There are analog fixed cameras and fixed minidomes, PTZ domes and PTZ cameras, and IR illuminated cameras. There are IP fixed cameras and fixed minidomes as well as PTZ domes and cameras.

Related topics:  CCTV cameras and domes   Knowledgebase   White papers 

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