While surveying the vulnerability study to identify physical security requirements, inspect the areas that require video observations. Record information about the location of each camera and the view each camera will have in the camera detail schedule (CDS). This will be the primary identifier when discussing camera views with your systems integrator in future meetings and will serve as the primary reference for communicating equipment locations to vendors during the bid and installation process.
Camera TypeConsider the light level and the view required. It may be required to also view the location at night to determine the amount of available light. In most cases, a standard camera will permit adequate viewing for most well illuminated areas. However, the physical threat assessment may indicate that the area in question is in close proximity to a vulnerable asset or is highly susceptible to intrusion. In these cases, a low light level camera may be needed for night viewing. At this point, it is not important to specify the exact model of camera. Instead, determine the type of camera needed based on the anticipated available light throughout the observation period.
LensesThe lens decision provides the “angle of view.” The width of the scene viewed and the distance of the camera from the subject area determine this. There are formulas to help the security professional make this determination; however, suppliers provide a handy tool for making this decision. It is a handheld lens that assumes a certain size for the camera pickup element, then allows the user to view what the scene would look like for a given lens size. Select the appropriate size lens and record that on the CDS.
In some cases, a single focal length lens may not be adequate for obtaining the views needed to make proper identifications in the subject area. In these cases, a zoom lens is the correct choice. Again, use the lens tool to determine the minimum and maximum focal lengths for the correct lens.
If deciding on an auto versus manual iris lens, it is important to understand what the iris lens does. The lens iris controls the amount of light that enters the lens. In most applications, an auto iris is usually selected because it automatically adjusts to changing light conditions. Exercise caution when placing an auto iris lens on an outdoor camera with a wide range of views.
If the view requires a pan and tilt drive, and the device is set to “auto pan” (the camera pans left and right automatically), consider the light levels of the background throughout the entire pan cycle during a 24-hour period. If the background light shifts significantly, the auto iris will be in constant operation and damage will eventually occur due to excessive use.
Camera SpecsCameras require housings to prevent tampering and to provide protection from the elements. Determine if the camera needs an indoor or outdoor housing and if special devices are needed to counter the effects of weather. An example of such devices would be a sun shield in hot climates or wipers in rainy environments.
Housings are attached to structures by means of mounts. A variety of fixed position mounts are available. Record the surface style needed for your corporate culture or installation on the CDS. The choices are wall, pedestal, parapet or post mounts. There are also movable mounts called pan and tilt drives. Each type of mount is usually associated with a housing type to provide a complete and working system. Use a general description to establish the basis for system design.
For some views with pan tilt zoom (PTZ) features, it may be necessary to auto program the camera to home in on a particular angle of view with a predefined zoom. In these cases, note the need for an alarm input to trigger the auto functions of the camera system and what event will evoke the trigger on the CDS.
Understanding the cameras’ locations and light will allow for the correct decision on which cameras to use. The camera detail schedule will give guidance in determining your ultimate decision.