Placing Surveillance Cameras in Schools
Parking Lot Coverage
Numerous incidents occur in parking lots: fights, vandalism, collisions, etc. First, placing cameras at roof level on most buildings are not recommended, unless the camera will only be used for object detection. High angles provide more of a top-down view of the scene, which may result in more footage of the tops of heads and vehicles and less of faces and license plates. Cameras are typically best located as low as possible while being outside the reach of vandalism, usually 12-15 feet above ground. Second, covering an entire campus from a few locations will do little aside from provide a false sense of coverage. Historically, this notion is one of the most dangerous in the surveillance industry. Driven by a trained operator, pan tilt zoom cameras can provide more detailed recordings of subjects and incidents. However, even under manual control, they are still not seeing the rest of the scene outside of the current frame, which can and will result in missed incidents. Unfortunately, there is no perfect solution for parking lot surveillance in many cases. Oftentimes, they are simply too large of an area to be covered with any sort of pixel density. Multi-megapixel cameras, while still unable to cover the entire scene in detail, will likely provide a better record of incidents than pan tilt zoom cameras on tour. Users should pay attention to where the chokepoints of the lot is, and target these areas, along with providing an overview of the area. In this way, vehicles and subjects can be followed on the overview through the scene to the choke point, where better resolution or a smaller field of view may provide identifying details.
Placing a pan tilt zoom camera at the intersection of hallways is likely to provide nothing more than video that's worthwhile 25% of the time or less. With a pan tilt zoom camera on a pre programmed tour, looking down four hallways, missing incidents is nearly guaranteed. A higher number of fixed cameras are a better option, though it will indeed likely be slightly more expensive, when installation labor, licensing, and the cost of the cameras are taken into account. In some locations, a 360-degree multi-imager camera, may be useful, as long as lighting levels are even, which interior hallways often are.
Clear nighttime video is hardly guaranteed. What's worse is that camera features such as automatic gain control and slow shutter likely will produce brighter video, providing users with a false sense of security. Yes, the image will be brighter, but subjects will appear blurred if the exposure is set too long, and the gain control introduces additional noise into the image, adding up to video that is often useless. Ultimately, there are no tricks or tweaks that can replace decent lighting in exterior areas.
Taking all of the above into account, the biggest mistake in this piece is the assumption that live operators will be on available to control multiple pan tilt zoom cameras. Most schools are eliminating operators, making it unlikely that many small-to-mid-sized school districts would have operators available at all times. For this reason, two trends have developed: higher numbers of fixed cameras are being installed, in order to cover more area, and/or more angles, with no operator intervention required; sales of panoramic and multi-imager cameras have increased, in order to attempt to cover more ground with a single camera, still generally priced below the cost of a pan tilt zoom.