At the most basic level, infrared illumination is light. Although invisible to the human eye -- which would see a completely dark scene -- infrared illumination is a form of light that modern surveillance cameras can use to create images. Providing the IP camera with the right amount of infrared illumination will ensure that nighttime images are high signal, low noise. Under these conditions, AGC becomes unnecessary and compression functions work efficiently. In fact, adding infrared illumination to a system can decrease bitrates by up to 90 percent, resulting in bandwidth requirements that are more similar to day-time levels. Useful for its bitrate reducing effects, infrared illumination is a growing necessity for improving network performance in IP-based security systems.
The use of infrared illumination extends into storage as well. If a camera transmits video at a certain bitrate across a network to be stored, then the video will consume disk space at exactly the same rate. For example, a 1 Mbps video stream will use 1 Mb of space in one second, or about 1/8 = 0.125 Megabytes per second, which equates to 0.125 x 3,600 = 450 Megabytes per hour -- about 11 GB per day or 75 GB per week. Since there is a direct correlation between bitrate and storage requirements, infrared illumination can be an effective strategy for reducing storage demands in IP video applications. This issue is especially important because disk space is one of the most expensive components of a surveillance system.
In summary, infrared illumination not only increases the quality of the images recorded, it also reduces required disk space, improves bandwidth, and enables enhanced nighttime surveillance.
Available options for adding infrared illumination are IP cameras offering integrated infrared or standalone infrared illuminators placed near existing cameras. By adding infrared illumination, achieving improved bandwidth management for existing IP surveillance systems is possible without significant cost. And, for new systems, infrared illumination should be a consideration for any site that requires 24/7 surveillance of areas with challenging lighting conditions.
About the authors: Hamish Dobson is a product manager for Bosch Security Systems. Willem Ryan is the product marketing manager for Bosch’s line of active-infrared, extreme environment and license plate capture cameras and related video devices. They can be reached at firstname.lastname@example.org and email@example.com.