IP CAMERA LEARNING & RESOURCE CENTER

One of many advantages IP cameras have over analogue CCTV is the capability to go beyond optical zoom.

An analog camera may have optical zoom capability, but there’s no scope to go beyond this fixed, mechanical zoom level. Digital zoom provides a solution to this, allowing, in some of the most sophisticated examples, true clarity at massively high zoom. Take, for instance, the Panasonic i-Pro WV-NW964, which has a 30x optical zoom capability. Combine this with its 10x digital zoom function and the camera offers exceptional image quality up to a massive 300x zoom.

Now, even the best digital zoom suffers from a reduction in quality, but in the best examples the perception of clarity and focus remains high.

It works like this: as soon as optical zoom is exceeded the camera begins to digitally extrapolate a zoomed image from the source image at highest optical quality. This work is all done in the processor of the camera and therefore digital zoom should not be confused with optical zoom, but simply seen as an extention of optical to give a higher zoom range, with a progressive loss of quality.

Most, if not all, security camera recording software or NVRs (Network Video Recorder) will these days allow the storage of huge amounts of recorded security footage. It can be a real hassle trawling through weeks of recorded data just to find the interesting event that happened a few days ago, but you can’t remember exactly when.

Of course, all surveillance recording systems have finite storage capacity so you will need some way to extract the footage of any event or security breach for viewing later, for safe keeping and, most importantly, for use as evidence should the matter progress to a court of law.

Any security camera recording system worth its salt will provide the operator or guard with an easy to use, simple mechanism for exporting a segment of footage to a number of different data formats.

Some systems will allow export to completely open formats which can be distributed and played back easily, whilst other systems will export footage to a proprietory format playable only with the player which the system automatically exports with the footage.

Both ways of data export have their advantages and disadvantages, but the key thing is that the data can be extracted and stored separately (and permanently) from the daily recorded footage and used in any criminal proceedings later on. Security camera evidence can be a critical factor in a trial and should be clear, focused and date/timestamped. IP cameras make it easy to achieve security / video surveillance systems which lend themselves extremely well to providing footage to be used as evidence.

Most professional IP cameras come with inputs and outputs designed so that you can connect additional devices in order to receive inputs or trigger outputs depending on camera events.

For instance, connecting the power source for a light to an IP camera can mean that that light can be controlled through the camera on the event that the camera’s motion detection is triggered by an intruder. Or, perhaps a recording of a barking dog.

Similarly, it is possible, through I/O inputs to send triggers to IP cameras. Connect a PIR (Passive Infrared) sensor to a camera and this can be used to trigger events from places the camera can’t see - perhaps in an alleyway up to a doorway overlooked by the camera.

Input/Output event control can massively increase the flexibility of your alarm system, intruder detection and deterrence and the security of your property.

Pinging, with regards to home networks, is a way of locating devices such as IP cameras or computers and is useful for both confirming the IP address of devices and checking to make sure that an IP address is free for use. The program works in a similar way to sonar on a boat, by sending out a signal and waiting for a return.

To ping a device in windows you must open a control window. In windows XP click “Start” then “Run”. Type in “cmd” and press enter. In Windows Vista, click the windows logo and type “cmd” into the white search box. Once done, a black command window will appear.

From here, type in “ping IP_ADDRESS”, for example “ping 192.168.0.1”. If there is a device present on the address specified then you should receive something along the lines of:

Reply from 192.168.0.1: bytes=32 time=1ms TTL=64

If there is no device on the network at that address then you should receive:

Request timed out.

IP cameras, computers and routers use IP addresses to communicate with each other. These however are not easy to read or remember for humans. To solve this problem, DNS servers were developed. DNS stands for Domain Name System and acts like a phone book on the internet. Whenever a network device sees an internet address, such as www.networkwebcams.com, it sends a request to its DNS server. The DNS server then searches through its list of entries until it finds the matching IP address, before passing it back to the device.

There are many different DNS servers out there with each internet service provider having their own. The addresses of these servers are essential to cameras which require access to the internet. Most modern home routers and modems will relay DNS information so their address can be used as a DNS server, otherwise DNS server addresses are available from your internet service provider.

The default gateway of any computer or network camera is the address where information will be sent which is not destined for the local network. Any information being sent will first be checked by the sending device to see if the destination is in the same range as the device. If so the information will be sent locally. If not the information is passed to the default gateway, usually a router or modem, for sending to the internet.

Specifying a default gateway is not necessary for internal camera systems where no remote access is required and is a way of ensuring that no external access is possible. It is however necessary should you wish to gain access from computers external to your home network.

The subnet mask of a network tells network devices such as IP cameras, computers and printers how to understand the IP address it has been given and how it should communicate with other network devices. The subnet mask is split into two sections. The first specifies the network portion of an IP address and the second specifies the device address.

A typical subnet mask is 255.255.255.0. Whenever an IP address is given to a device it compares each number block against the subnet mask. In this example the first three number blocks (255) are the network address and the last (0) is the device address. Since each number block in an IP address can be between 1 and 254 (0 and 255 are reserved) you can have 254 different devices.

Another common subnet mask is 255.255.0.0. This means the first two number blocks of an IP address are the network address while the second two are the device address. Those of you who are numerically minded will know that this allows for 64,516 different devices on the same network.

It does however get tricky when you start looking at subnet masks such as 255.255.255.248 which only allows 6 seperate devices to be used. My advice would be that if you are using less than 250 devices on your network, stick with a subnet of 255.255.255.0.

The subnets of each device on a network have to be the same in order for them to share information. Any information which does not share same network address ( i.e. in the earlier example 192.168.0 ) will be sent to the default gateway rather than the local network.

Every network device needs an IP (Internet Protocol) address. An IP address is a unique number which identifies a device, such as an IP camera or PC, on your network and allows other devices to forward information to it. An analogy of an IP address might be a telephone number. Every telephone number is different and dialling the correct number will allow you to communicate with the right phone. IP addresses can be set dynamically, meaning they are assigned by another device such as a router or modem, or by manually specifying a static address.

An IP address is a set of 4 number clusters with each cluster being a number between 0 and 254 in the form of xxx.xxx.xxx.xxx (e.g. 192.168.0.1). The common range for use on home networks is 192.168.0.1 to 192.168.0.254 which allows you to have 254 different network devices all on the same network.

You may also be interested to know that your internet router will have two IP addresses, one which is seen by the internet (known as a WAN address) and one which is seen by the local network (known as a LAN address). Should you wish to access devices from outwith your local network you will need to know the “outside” address as seen from the internet.