Dome cameras are revolutionary in the history of video surveillance. Their improved technology, higher quality image capture and ability to integrate into the typical LAN at an affordable cost were all significant advances in their own right, but another important advance came in these cameras’ movement capabilities. Pan, tilt and zoom capability became more widespread with the arrival of dome cameras, making a more powerful camera configuration accessible to the professional surveillance product market.
Understanding PTZ Cameras
PTZ is certainly not a new concept in security camera functionality as box style cameras have been able to do it for years. It was something that only institutions with larger budgets could afford to install as fixed mount cameras were more affordable. One of the biggest disadvantages of a box camera with PTZ is that you can easily tell by watching what the camera is aimed at and time any illicit activity with the time interval when the camera was panned away from you.
With dome cameras, it’s harder to tell if the camera is panned towards you, since it is housed within the dome assembly. Using tinted domes makes it even more difficult to determine where the camera is currently aimed. Instead of a long, sweeping predictable pan like previous generations of cameras use, dome cameras can pan at a much faster rate. Many are even programmable, allowing you to set up sophisticated pan movement to over 100 preset locations. Another benefit from the dome housing is that the camera takes up less space than a box camera with PTZ ability and won’t hit items that are stacked too high or on shelves, although such items could block the view of a dome camera.
Key feutures of Dome Cameras
A key feature on many dome cameras is that the pan and tilt speed adjust automatically when zooming. As you zoom in, you want the pan speed to slow down; otherwise the detailed content you are attempting to view up close would disappear out of view more quickly. You can observe this phenomenon while riding in a car going 65 mph. The building that you see from a half mile away stays in view longer, but when you try to look down at the road and look at markings, cracks, rocks, debris and other objects in detail, you can’t focus in on them, because they disappear from view more quickly. You would need the driver of the car to slow down to almost a walking pace to focus on objects only a few feet away on the ground in the same way that you could focus on the building a half mile away when moving at highway speeds.
Another feature that a good indoor or outdoor dome camera has is automatic gain control, a process where images in dimly lit conditions are enhanced to make them easier to see. This is not to be confused with infrared technology, which produces images based on the varying levels heat they give off. AGC while helpful, can be a double edged sword, because it does not discriminate between the content you want to look at and visual noise. Both get amplified equally with this process.
Dome cameras not only made video surveillance more affordable, they also added to the technology of previous generations of video cameras. Now even the smallest businesses can set up a video surveillance system that is technologically sophisticated yet within budget.
Erik Johnson is a industry veteran of the security and surveillance industry. He writes to help educate consumers on the things they need to know to best secure their homes and businesses.