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Fisheye cameras | Moving towards that perfect view

fisheye-cameras

Having eyes in the back of your head — an attribute relegated to vigilant parents, strict librarians, and more than a few teachers — is a condition that would serve the security industry well. After all, who doesn’t want the ability to have eyes on the action, wherever it’s happening?

Since such forms of sight are a physical impossibility, security personnel have turned to cameras to be their all-seeing counterparts. The problem, however, is that even cameras don’t always capture every movement and moment in a critical scenario. Many cameras have fixed views and pan-tilt-zooms, and even with their wider range, can sometimes be looking in the wrong direction when they really need to be focused elsewhere.

Thus, the industry developed the fisheye technology or 360-degree cameras to provide that all-seeing viewpoint. As camera resolutions increase, the fisheye is turning out to be an especially advantageous choice for situational awareness within the retail industry, not only because these cameras fit their coverage needs, but also because stores can now lower their camera count and save a bit of money as well.

That’s not to say that the fisheye is limited to retail settings. These cameras, with their sweeping views (for example, 360 degrees if ceiling mounted or 180 degrees if wall mounted), are also ideal for university lecture halls, elevator banks, indoor parking areas, hospitals and casinos. As with all camera installations, it is important that camera selection is based on the combination of surveillance system needs and camera capabilities. For 360° cameras, the resolution “sweet-spot” for a 5MP fisheye capturing sufficient details is 20-25 feet. Due to the extreme wide angle lens, objects in the camera’s field of view beyond this distance will become too small to capture details. Thus, other types of cameras would better serve a large, outdoor parking lot application.

As with any component in a surveillance set up, the fisheye is at its best when used in concert with other cameras. For instance HD fixed cameras might be a better choice over the cash drawers, or multiple fisheyes could be used together to surround an HD PTZ unit that can zoom in and closely track events or suspicious individuals identified in the fisheye video. In some cases, however, a single fisheye can cover an entire room, such as classroom, without missing anything.

One challenge with the fisheye is the reality of image distortion at the edges, due to the ultra-wide field of view. Dewarping technology within the camera, as well as within the client, can address this problem and produce a corrected, flat view.

For security personnel, there can also be a learning curve as they become comfortable with navigating around the non-normalized or warped view. However, in an active surveillance situation, officers will want to work with the normalized view that can be produced on the edge by the camera or on the client-side with dewarping completed on the server.

The 360-degree fisheye camera expands the line of vision and takes surveillance into far corners not easily seen before. Over time, working with the views from this latest entrant into the video field will become second nature to surveillance system operators, and security personnel will relish having a new tool in their arsenal as they look to achieve all-seeing status.

  • by tansal
  • posted at 2:43 pm
  • February 17, 2014