What’s an IP Camera?
An IP Camera is a normal camera which can be CMOS or CCD with a video server incorporated. This integration allows the camera to directly dialogue with the local Ethernet network or with internet. The use of TCP/IP protocol of communication in the surveillance systems in the internet era is a useful feature because of the growing internet covering and the increasing number of devices that have an internet connection (mobile phones, notebooks, netbooks and so on). These two advantages virtually enable the remote access to IP cameras in every moment allowing, if necessary, to fulfil some checks on the areas controlled with these systems.
How to choose an IP Camera
There are many kinds of IP cameras; the first difference can be made between cabled, i.e. with a direct connection via cable, and RJ45 socket and WI-FI cameras, which wireless connect to normal access point of WI-FI network. Another difference concerning the video quality can be made between CMOS and CCD sensors. The first ones are cheaper and with an amateur video quality and are then good for a domestic or office use, while the second ones are more expensive but have a professional video quality, suitable for an important use such as parking areas, warehouses, storage areas protection, weather stations or other external stations. Moreover there’s a difference between interior cameras (not protected against the bad weather) and exterior cameras, also called Water Proof because of their resistance to rain and bad weather. The network cameras for exterior environment are often provided with an automatic diaphragm objective/lens to regulate the quantity of light to which the image sensor is exposed.
Finally we can distinguish fixed IP cameras and PTZ cameras which allow longitudinal and vertical rotation.
PTZ cameras and PTZ dome cameras
A PTZ (Pan, Tilt, Zoom) camera or a dome PTZ camera can manually or automatically rotate, incline, enlarge or reduce an area or an object. All PTZ commands are sent towards the same network cable of the video transmission; unlike an analogical PTZ camera, you don’t have to install RS-485 cables.
Megapixel technology enable network cameras to supply images with a higher resolution then TVCC analogical cameras, in fact it permits to generate images allowing to see all details and identify people: essential requirement for territorial video surveillance applications, which need to frame very large areas. Network cameras image quality with megapixel resolution is three times better than TVCC analogical cameras.
For applications needing detailed images, such as in case of need of identifying the people’s face, the resolution can reach up to 500 pixels per meter. That means, for example, that you have to install a camera able to guarantee a resolution higher than 1 megapixel (1.050x1.050 pixel), in order to unequivocally identify people passing through a small area of about 2 m2.
Thermal IP cameras
Thermal cameras are the ideal complement for any professional IP video surveillance system designed to protect an area or a perimeter in total darkness. Network thermal cameras create images based on the warmth radiated by any object, vehicle or person.
Thermal cameras, nevertheless, do not produce images allowing a reliable identification; that’s why thermal cameras and conventional cameras complete and support each other in a professional video surveillance installation/system.
Thermal cameras do not need extra, traditional, infrared light sources consuming energy, creating shadows and revealing their location. Moreover, contrary to traditional daily and night cameras whose functioning depends on a certain quantity of infrared light, thermal cameras send reliable surveillance images both in complete obscurity and in some particular weather conditions such as snow, rain, fog and smoke.
Focal calculation IP cameras settings
The right focal choice (lens) is to be fulfilled according to the area you have to record. You have to measure the size of the area to be record and the distance from it and the lens, in order to choose the right lens. The interested area is not meant to be the wall or the gate facing the camera, but it should be the area where you image the events you want to videotape could occur.
You can use the following formulas to calculate the right focal length:
Right focal for 1/4” CCD camera = target distance (m.) x 3.6: target width
Right focal for 1/3” CCD camera = target distance (m.) x 4.8: target width