DIGITAL RECORDING SYSTEMS - SPECIAL CAPABILITIES

DIGITAL RECORDING SYSTEMS - SPECIAL CAPABILITIES

Remember, you come to us for a custom video system that adapts a video system to the project, not the project to an off the shelf video system. It's not the equipment you are buying, it's the reliability, quality and quantity of data you need to get the job done right.

Not all digital recording systems have the following capabilities. Proper choices make data collection easier with greater accuracy. We will discuss how appropriate they are for your applications over the phone or in our quotations in greater detail.

Alarms

Alarm recognition is the technology that allows the recorder to respond from a user programmed normal operating mode to a different user programmed mode. Alarms also store in memory and record to the media the time, date and type of alarm received.

Motion Detection

Motion Detection is the technology that allows a user defined area(s) of the viewed image to be monitored for changes in brightness or contrast to indicate that a minimum level of activity has occurred and to output an alarm signal. Sensitivity level adjustment is critical in outdoor environments and empirical testing in conjunction with continuous time lapse is essential if good data is to be collected. We strongly recommend against the use of this technology by itself as the only means of collecting data blocks.

Triggered Response

Triggered Response is the technology that allows various types of external devices to generate an alarm notification to the recording system. The types of triggers are only limited by your imagination and can be wired or wireless. Some examples are infrared beam break, passive infrared detection, sound level triggers, pressure switches, etc. Certain video camera power systems allow alarm triggers to be carried back to the recorder over the video camera cable.

Pre-Alarm Recording

Pre-Alarm Recording is the technology that utilizes a user programmable 10 to 30 second digital loop in memory to capture and download to media alarm activity 5 to 25 seconds before the alarm occurred. Systems with pre-alarm recording can be capturing say 2 images per second which may not have sufficient temporal resolution to capture the data required. Instead the pre-alarm loop at 30 to 60 images per second is recorded to the media for later review. Very useful when short bursts of activity must be recorded over a long period of time.

In addition, the following capabilities are available:

Masking

Masking is the technology that allows you to blank out a user defined portion of the image viewed by the camera so that it is not viewable on the monitor output or recorded on the media. Certain cameras also have masking capability. This is useful for privacy screening of say backyards, windows or to eliminate distracting activity (say cars on a highway) to simplify data analysis.

Massive Hard Drive Capacity

Single hard drive capacities range from 20 to 500 gigabytes. Some recorders can accept three 500 gigabyte hard drives for an internal capacity of 1.5 terabytes! Additional capacity is available through the use of dockable hard drives for trade out. This however, can very quickly become an expensive storage situation because the dockable hard drive can cost from $300.00 to $1000.00 or more and downloading them to DVD's or tape media can be expensive and very time consuming. See our Analog versus Digital Recording sheet for more information.

Network Connectivity

Digital Recording Systems have Network Connectivity either built in or available as an accessory adapter interface. Typical interfaces allow direct connection to a computer, local area networks (LANs), wide area networks (WANs) or the Internet. Transmission speeds vary widely. Off-loading limited segments of data can be done with built in CD-/+ RW on certain recorders but is totally impractical if the entire drive is to be backed up. Network enabled recorders may also have the ability to be remotely reprogrammed. Triplex enabled network recorders allow real time remote monitoring, remote access to previously recorded images while the system continues to record current activity.

Recorded Resolution Levels

Resolution Levels available depend on the recorder chosen. Most have two to four levels with the lowest usually corresponding to that format which is recorded by a VHS field recorder (360 x 240 pixels). Choice of resolution is very important with many digital system as they only allow a format choice of 720 x 240 or 360 x 240 pixels. Remember to also check monitor viewed resolution when recorded versus resolution when played back to make sure you are getting the quality of data required for your project.

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Compression Codecs

Compression Codecs allow much greater quantities of images to be stored in less space on the digital hard drives. Unlike analog system which store each image as a complete and independent data block on a tape, compression codecs recognize and store differences in successive images. Various degrees of compression and formats are designated by the terms: Wavelet, JPEG, MPEG, MPEG2 and MPEG4. MPEG4 is the highest level of compression in general use today.