W-X-Y-Z

WAN (Wide Area Network)

A WAN is a communications network serving a geographically larger area such as cities provinces or countries using satellite communications or telephone lines. The Internet is a WAN. Network IP Cameras are capable of utilizing WAN systems.

Wavelength

The distance over which the wave's shape repeats or how far an electromagnetic wave travels during one cycle. When discussing DVR, the term refers to the colour of light, which every colour having a different wavelength.

Wavelet

This type of image compression is mainly used for single images and not video streams. Because it's superior to JPEG compression, it is however used in some video surveillance codec's, though there isn't a universally adopted standard for usage of this codec.

WDM (Wavelength Division Multiplexing)

This economical procedure enables data from different sources to be simultaneously transmitted over the same fibre optic link. It achieves this by assigning a unique wavelength to each data channel, resulting in many possible wavelengths travelling across one link, which allows one fibre link to do the same work as two or more.

Webcam

Webcams are cameras that connect to the Internet, either via PC or directly, and that allow remote user access. An IP (internet protocol) camera is a popular webcam for video surveillance that does not need a PC connection.

White balance

CCD security cameras feature this adjustment to compensate for ambient light colour. Since there's a colour difference between standard light bulb light and sunlight, white balance adjusts to ensure a more realistic picture. This feature may be set by manual adjustment, or it may have preset settings for the most common situations.

Wide angle lens

This lens enables a wide view of the scene, with a magnification ratio less than 1. A lens that has a shorter focal length and a wider field of view (includes more subject area) than a normal lens

Wireless

Transfer of information over a distance without the use of wires. The distance can vary from a few meters much like a TV remote control to a few kilometres such as a radio.

Y/C

Luminance and Chrominance. Another term for S-Video where the luminance and chrominance are separate from one another so they can be processed more effectively..

YIQ (Luminance In-Phase Quadrature)

The colour space used in NTSC is called the YIQ. Usually used in America and Japan.

YUV (Luminance Chrominance)

YUV is the colour space used in PAL video, television transmissions and is preferred for video signals. YUV and RGB can be converted back and forth.

Zoom lens

A lens that can zoom into a subject from a long distance. A lens with a variable focal length to obtain a wide angle picture to a narrow angle picture to cover a variety of needs.

Zoom ratio

This measures the ratio between the maximum and minimum focal length that a zoom length is capable of. The ratio between the smallest and largest image a lens can projector from a fixed distance