Camera Resolution
Camera resolution is a measurement of the cameras clarity. A cameras resolution is determined by the number of horizontal video lines (like 400 or Hi-Res 600 lines) that the camera needs in order to reproduce the desired image. The higher the resolution number, the sharper the image will be.
LUX
Lux (1/10 of a foot candle) is a standardized method by which to measure a camera's sensitivity to light. The lower the number, the less light it will take to reproduce a clear image. For example: A camera that sees down to 1 LUX, means it generally has the ability to see an image during early evening hours or just before dusk. A camera that's down to .1 has the ability to see an image in let's say, a well lit parking lot. A rating of .05, the ability to clearly view an image in a dimly lit area at night. A .05 image can usually enable a camera to actually see better than the human eye at night
What is the wireless security camera?
Each wireless security camera system has a transmitter and a receiver. Generally speaking, each camera has a built in transmitter, which sends information over a specific frequency to a video receiver – usually this is a monitor or is connected to a monitor. Keep in mind that with wireless systems you still need power to each camera. This means you will need access to a power outlet or look for a system that can be battery operated.
WHAT IS OFDM AND COFDM?
Orthogonal Frequency Division Multiplexing (OFDM) is a multicarrier transmission technique, which divides the available spectrum into many carriers, each one being modulated by a low rate data stream. OFDM is similar to FDMA in that the multiple user access is achieved by subdividing the available bandwidth into multiple channels, which are then allocated to users. However, OFDM uses the spectrum much more efficiently by spacing the channels much closer together. This is achieved by making all the carriers orthogonal to one another, preventing interference between the closely spaced carriers. Coded Orthogonal Frequency Division Multiplexing (COFDM) is the same as OFDM
Except that forward error correction is applied to the signal before transmission. This is to overcome errors in the transmission due to lost carriers from frequency selective fading, channel noise and other propagation effects. For this discussion the terms OFDM and COFDM are used interchangeably, as the main focus of this thesis is on OFDM, but it is assumed that any practical system will use forward error correction, thus would be COFDM.
WHAT IS WIRELESS MESH NETWORK?
A wireless mesh network (WMN) is a communications network made up of radio nodes organized in a mesh topology. It is also a form of wireless ad hoc network. Wireless mesh networks often consist of mesh clients, mesh routers and gateways. The mesh clients are often laptops, cell phones and other wireless devices while the mesh routers forward traffic to and from the gateways which may, but need not, be connected to the Internet. The coverage area of the radio nodes working as a single network is sometimes called a mesh cloud. Access to this mesh cloud is dependent on the radio nodes working in harmony with each other to create a radio network. A mesh network is reliable and offers redundancy. When one node can no longer operate, the rest of the nodes can still communicate with each other, directly or through one or more intermediate nodes. Wireless mesh networks can self form and self heal. Wireless mesh networks can be implemented with various wireless technologies including 802.11, 802.15, 802.16, cellular technologies and need not be restricted to any one technology or protocol
What is a hidden camera ?
We take ordinary, everyday looking objects and integrate a small "board level" video camera and video transmitter so that it is impossible or very hard for anyone to detect the presence of the camera
What is COFDM
COFDM is a modulation scheme that divides a single digital signal across 1,000 or more signal carriers simultaneously. The signals are sent at right angles to each other (hence, orthogonal) so they do not interfere with each other. COFDM is used predominately in Europe and is supported by the Digital Video Broadcasting (DVB) set of standards. In the U.S., the Advanced Television Standards Committee (ATSC) has chosen 8-VSB (8-level Vestigial Sideband) as its equivalent modulation standard.
What is the difference between Auto Iris and Direct Drive Lenses?
An Auto Iris lens is one that automatically adjusts its iris for changes in the scene lighting levels. The motor that opens and closes the iris is driven by an Amplifier that processes a small electronic signal changing with the light level.
Do I need an infrared security camera?
If your surveillance camera is inside, it depends on whether or not you want to be able to see at night, and if you routinely leave any lights on after you close. The security cameras inside are only used to watch employees or processes, and after hours surveillance isn’t needed at all. In this case a regular hi-resolution color security camera is more suitable. No point in paying for something you don’t need.
When can I use a manual iris lens?
A general rule of thumb is only to use a MI lens in an internal application. This is because you are reliant on the electronic circuitry of the camera compensating for light changes in the scene and this is not able to compensate to the same degree as that of an Auto Iris lens.
What size monitor should I be using?
The correct size monitor is dependent on its use e.g. the number of images to be displayed at any given time, the viewing distance and the available space.
