|This article does not cite any references or sources. (May 2012)|
A pan–tilt–zoom camera (PTZ camera) is a camera that is capable of remote directional and zoom control.
In television production PTZ controls are used with professional video cameras in television studios and referred to as camera robotics. These systems can be remotely controlled by automation systems. The PTZ controls are generally sold separately without the cameras.
PTZ is an abbreviation for pan, tilt, and zoom and reflects the movement options of the camera. Other types of cameras are ePTZ or Virtual pan-tilt-zoom (VPTZ) where a high resolution camera digitally zooms and pans into portions of the image, with no physical camera movement. Ultra-low bandwidth surveillance streaming technologies, such as TVI from Digital Barriers, utilise VPTZ to stream user-defined areas in higher quality without increasing overall bandwidth usage. Surveillance cameras of this type are often connected to a DVR which records the full field of view in full quality.
An innovation to the PTZ camera is a built-in firmware program that monitors the change of pixels generated by the video clip in the camera. When the pixels change due to movement within the cameras field of view, the camera can actually focus on the pixel variation and move the camera in an attempt to center the pixel fluctuation on the video chip. This process results in the camera following movement. The program allows the camera to estimate the size of the object which is moving and distance of the movement from the camera. With this estimate the camera can adjust the cameras optical lens in and out in an attempt to stabilize the size of pixel fluctuation as a percentage of total viewing area. Once the movement exits the cameras field of view the camera automatically returns to a pre-programmed or "parked" position until it senses pixel variation and the process starts over again.