Development of IP CCTV technology has been relatively slow to date. An important reason was that DVRs with network functions (sometimes more advanced than those of some IP cameras) supported by low-cost analog cameras were an attractive alternative to IP CCTV systems.
But the limit of analog CCTV (PAL, NTSC) is resolution of the images (PAL: 720 x 576). Such restrictions do not exist in the IP CCTV systems equipped with megapixel cameras.
An analysis of the advantages of megapixel cameras can be carried out assuming that the optimum monitoring requires approximately 130 pixels per one meter of the observed object. For a 50-meter wide scene, an analog system (720 pixels) would require to employ 9 cameras. In the case of a camera with 1.3 Mpix resolution (1280 x 1024), the number can be reduced to 5 such cameras, for a 2 Mpix camera - only 4 cameras will do the same job.
A smaller number of cameras has other advantages. First of all, it lowers the cost and time of installation and maintenance. It also lowers operational costs - it is easier to conduct surveillance with a smaller number of points.
Of course, there is another alternative for megapixel cameras - very popular speed dome/ PTZ cameras. With adequate lens, it is even possible to cover the area mentioned above with a single PTZ camera. However, such a solution has many drawbacks. First of all, the camera can be set only in one of two ways. The first one provides an overall view, without possibility of recognition of some important details, e.g. the license number of a car. The second way, using optical zoom, increases the capability of identifying details, but at the expense of losing the rest of the scene.
In addition, PTZ camera has to be controlled by the operator, who must decide what is interesting at the moment and focus on that area. In the case of fixed megapixel cameras, there is always available a complete picture, with all events recorded by the system. Due to a very high resolution of the cameras, the details can be viewed using digital zoom.
But the limit of analog CCTV (PAL, NTSC) is resolution of the images (PAL: 720 x 576). Such restrictions do not exist in the IP CCTV systems equipped with megapixel cameras.
An analysis of the advantages of megapixel cameras can be carried out assuming that the optimum monitoring requires approximately 130 pixels per one meter of the observed object. For a 50-meter wide scene, an analog system (720 pixels) would require to employ 9 cameras. In the case of a camera with 1.3 Mpix resolution (1280 x 1024), the number can be reduced to 5 such cameras, for a 2 Mpix camera - only 4 cameras will do the same job.
A smaller number of cameras has other advantages. First of all, it lowers the cost and time of installation and maintenance. It also lowers operational costs - it is easier to conduct surveillance with a smaller number of points.
Of course, there is another alternative for megapixel cameras - very popular speed dome/ PTZ cameras. With adequate lens, it is even possible to cover the area mentioned above with a single PTZ camera. However, such a solution has many drawbacks. First of all, the camera can be set only in one of two ways. The first one provides an overall view, without possibility of recognition of some important details, e.g. the license number of a car. The second way, using optical zoom, increases the capability of identifying details, but at the expense of losing the rest of the scene.
In addition, PTZ camera has to be controlled by the operator, who must decide what is interesting at the moment and focus on that area. In the case of fixed megapixel cameras, there is always available a complete picture, with all events recorded by the system. Due to a very high resolution of the cameras, the details can be viewed using digital zoom.
