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PTZ kamerák
Fixed cameras can show selected areas in two ways: as an overall view (using wide-angle lenses) or in detail (the detail increases with the focal length of the lenses). Of course, the detail also increases when the camera is placed closer to the monitored object.
To get the possibility to see the general view and, if necessary, spot details of the observed objects with a single camera, the following solutions can be used:
Motor-zoom cameras
MOTOR-ZOOM kamera: Sunell SN-ZMC6100DN/Z22 (4-88mm, éjjel/nappal, ICR, Sony Super Had II 540 TVL, 0.05 lx, OSD)
Motor-zoom cameras allow the operator to zoom in the central part of the scene. Such a lens can be controlled via RS-485 (from a DVR or keyboard / system control unit), by the voltage applied to the camera connector, or using OSD buttons on the camera.
In the case of the presented camera, there are two auto-focus modes, selectable from its OSD menu:
  • Auto focus with tracking the nearest object - the system automatically selects the nearest object and measures the distance to it,
  • Wide area auto focus - the focus is set not to the object in the center point of the image. It is useful for capturing images of moving objects.
The minimum focusing distance can also be adjusted, beginning with 1 m.
Video recording showing the use the camera in a CCTV system, where after detecting motion a close-up is made. After cessation of the movement the camera returns to the initial state.
PTZ cameras
PTZ cameras can be manually or automatically moved to any direction within the operating range. They differ in functionality:
We distinguish two basic groups of Pan-Tilt devices:
  • Working in one plane, usually horizontal. Each Pan-Tilt device of this type allows the camera to be set in initial vertical position. Horizontal rotation is limited in simple devices to 3500. Professional versions have ability of full rotation. Devices of this type are sometimes called scanners.
  • Working in two planes, vertical and horizontal. Vertical rotation is usually limited to 900. These devices are reasonably called Pan-Tilt mechanisms.
  • Rotation of the device in horizontal plane is commonly called "pan", and in vertical plane - "tilt".
Nowadays, integrated speed dome cameras are increasingly used.
If we decide on that solution we should choose a device of name-brand company. Although camera modules can be comparable, the rotating mechanism is critical for the general performance. Every rotating mechanism consists of mechanical parts which wear out. In cheap devices the cogwheels are made of plastic and - especially when the camera is intensively exploited, its lifetime is considerably reduced. We should be aware that durable mechanism must cost a little and choose proven models of speed dome cameras.
PTZ cameras indicate a large price spread and are generally far more expensive than fixed devices. The reason is the complexity of the PTZ mechanisms, costs of the materials and means used for ensuring adequate IP rating, high speed and repetitiveness of movement. However, not always low price indicates poor quality. Manufacturers supply different categories of PTZ cameras for various applications. An example of a low-cost camera having very good performance is TP-Link TL-SC4171G K1154 designed for monitoring systems in homes and small offices. It is one of the cheapest solutions, allowing for remote control of pan within 354 deg range and tilt within 125 deg range at angular speed of 80 deg./s and 60 deg/s, respectively. The user can easily monitor what's going on in the room.
Wireless Pan-Tilt IP Camera: TP-Link TL-SC4171G (0.5 lx, VGA, IR, 30fps, MPEG-4, 4.3 mm)
Pan-Tilt devices in digital networks.
Increasingly popular use of digital transmission in surveillance systems also requires to employ adequate Pan-Tilt devices. An example of the camera integrated with Pan-Tilt mechanism, adapted for work in these networks is e.g. one of products of ACTi Corporation. The CAM-6621 Video Network Camera is characterized by 23x optical zoom and full remote control through network - thanks to built-in network module. Besides TCP/IP output, it has also standard video signal output and bidirectional audio transmission.
IP High Speed Dome Camera: Sunell 1.3MP SN-IPS54/70DN/Z18W
PTZ IP camera ACTI CAM-6621
Modern PTZ cameras are controlled via:
  • a mouse - by selecting a desirable part of the image or clicking on the suitable OSD buttons from the dedicated application;
  • a USB system control unit (console) - with programmable buttons;
  • an RS-485 system control unit (console) - local control with the use of Pelco P, Pelco D, Dynacolor etc. protocol..
When designing an installation, we should consider the fact that covering the whole monitored area with fixed cameras provides reliable and more efficient observation. Supplement of the system, in the form of high quality Pan-Tilt camera with zoom lens, helps to increase capabilities of the system for observation of small details. However, we have to remember that zooming in on an object, without fixed camera monitoring, means that we can't observe wider area at the same time.
Megapixel cameras with "fish-eye" lenses
Panoráma IP kamera PIXORD PD636E 2Mpix, H.264, 360/180 fokos halszem optika
Cameras of this type have image sensors with minimum 2 MP resolution. Using a wide-angle lens (f = 1.25 mm, FOV = 185°), the image shows a large area but is significantly distorted.
To get a useful picture, the source image has to be appropriately corrected and cut out (selection of interesting fragments). The processing can be performed by the camera or by means of appropriate software on a computer. As the result, the user has a virtual PTZ camera - can select any part of the image and enlarge it. Such a solution has a huge advantage in comparison with typical PTZ cameras - while the operator sees only the selected part, the recording contains the whole image. It can be played back to get information from any other part that may also be enlarged.
Wall-mounted camera covers a whole room:
Source view of the whole room and three independently controlled windows of digital PTZ:

Pixord PD636 K1560 in action
In comparison with VGA cameras, the PD 636E K1560 camera delivers about six times more detail. This means that every part of the scene is much more closely monitored. Additionally, each part of the image can be zoomed, while saving the whole material. The K1560 camera is perfect for monitoring offices, stores, bars, restaurants, hotels, etc.