The Case for Digital Recording

By Ed Lawrence | Apr 15, 2007




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Update on technology helps the customer:

Considering the messages electronics manufacturers are delivering, one could wrongly conclude that there is little difference between the video cameras and recorders marketed to memorialize a vacation and those required to protect a business establishment.

A vacationer may be satisfied with a vanilla presentation of the kids cavorting around Disneyland. However, depending on the nature of his business, it is a good bet that your client expects his closed-circuit television surveillance (CCTV) system to assist in preventing shoplifters (or employees) from shrinking an inventory or to alert a security team to the presence of uninvited or unwanted intruders in a lobby area, parking lot or warehouse.

Explore the market, and you will discover that recently introduced digital video recorders (DVRs) have added features and flexibility in operation that may render existing equipment nearly obsolete. These enhancements may present you with an opportunity to introduce your client to improved methods of securing their business.

Products recently unveiled by Mitsubishi Digital Electronics America, Irvine, Calif., and Sanyo Security Systems, a division of Sanyo Fisher Co., Chatsworth, Calif., provide examples of the latest technology. The Mitsubishi DX-TL4509U and DX-TL4516, and Sanyo DSR-2004H MPEG-4 digital video recorders are products against which others may be compared.

The cornerstone of any CCTV system is cameras transmitting images. Prior to the introduction of digital cameras, single lens reflex cameras required properly coordinating shutter speed, aperture opening, film sensitivity and the proper amount of available light. However, the quality of a camera’s lens ultimately determined the quality of the image, a reality that has not changed. Digital cameras used in the surveillance world now have the ability to compensate for varying light levels and movement by objects, but image quality is still a byproduct of lens quality.

Flexibility in operation is an addition to the equation. A static camera may work well to photograph a shoplifter leaving a convenience store. However, many installations require the ability to provide a more fluid view, so cameras with the ability to tilt, pan and rotate may be required.

High-tech cameras also allow a security team to manually manipulate its viewing area or may be programmed to record specific views at predetermined intervals. As a consequence, camera pricing levels vary greatly.

A partial list of criteria generally accepted as important in evaluating any unit includes storage capacity, the ability to network several cameras that may be recording at once, the number of images that may be displayed simultaneously, the rate at which images are recorded, the quality of the recording and flexibility in recording and playback modes.

Perhaps highest on the list of evaluation criteria for manufacturers and consumers is storage capacity. The Mitsubishi recorder, for instance, has a total storage capacity of one terabyte.

To increase storage space, Mitsubishi uses JPEG 2000 video compression, significantly increasing the amount of space available to store images. Recording levels may be adjusted to produce as many as 540 low-resolution pictures per second. Up to 120 high-resolution images may be recorded. The TL4509U, like many others on the market, offers varied recording and monitoring settings, multichannel capability, motion detection and emergency recording.

Many systems also have motion-detection capability and record only one event, which saves precious disk space. Mitsubishi’s recorder is built with a pre-alarm system designed to eliminate unnecessary recording. Imagine a rock hitting a window. In pre-alarm mode, the motion detector and recorder work together to record the event that occurred immediately prior to the arrival of the rock, the impact and subsequent movements.

In addition, the DVR’s hard drive can be partitioned, segregating action recorded when motion detectors are activated from less critical images. As a result, the most pressing information is kept up front.

Sanyo’s recorder, as well as others on the market, adds the ability to search the storage library by time, date or timeline, allowing instant retrieval and output of data based on the timing of specific incidents.

Both companies’ products are compatible with competitors. Sanyo’s 2004-H will operate with cameras offered by other manufacturers; its recorder also supports composite and VGA monitor output.

Considering these developments in the DVR world, this may be an ideal time to review your client’s to-do list with an eye toward updating his knowledge of CCTV systems.             

LAWRENCE is a freelance writer and photographer based in Bozeman, Mont. He can be reached at [email protected].



About The Author

Ed Lawrence is a freelance writer and photographer based in Bozeman, Mont. He can be reached at [email protected].





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