FREQUENTLY ASKED QUESTIONS - C
CCD
CCD stands for charged coupled device. This is a solid-state semiconductor element which uses hundreds of thousands of tiny pixel elements to accept light and translate that information into a vivid, visible picture image. A CCD is one type of camera image sensor. CCDs produce MUCH higher resolution, lower light sensitivity, and better overall video quality than CMOS imagers (also commonly found in CCTV industry cameras).
CCTV
CCTV stands for closed circuit television: a video system which will only be monitored in a closed environment (as opposed to public broadcast). The realm of video security and surveillance is also referred to as CCTV.
CMOS
CMOS stands for charged metal oxide semiconductor. This is one type of camera image sensor which uses a charged metal surface to detect light and create a video image. CMOS technology is often smaller than CCD chips are currently capable of, so these cameras can often be quite miniature. Even the highest resolution CMOS cameras cannot compete with newer CCD imagers in resolution, sharpness, and low light performance.
Coaxial Cable
Coaxial Cable is the most common type of cable used for transmitting a video signal through copper wire. This type of wiring has a coaxial cross-section where an outer shielding protects the actual interior signal conductor from electromagnetic interference. In the CCTV industry, the term "coax" usually refers to RG-59/RG-6/RG-11 cable with BNC-type plug ends.
Codec
Codec refers to an internal computer component which processes analog information (like a video or audio signal) into a digital format such as MJPEG, MPEG-4, etc. for electronic storage on digital recording media. Without a codec in place to compress and digitize video, digital video recording to a hard disk drive would not be possible.
Color Camera
Color Camera - Cameras are available with either color or monochrome image sensors. Color cameras produce video images bearing the entire visible spectrum of colors. And because color CCD cameras have come a long way in recent years, the colors of objects appear vivid, crisp, and distinguished on monitoring and playback of video.
Compression Method
Compression Method refers to the computer software technique the codec in a DVR video recorder (or DVR card) uses to convert the video signal to digital information so it can be compressed and stored on digital media like a hard disk drive, DVD, or CD. Uncompressed video would require massive processing power and nearly unlimited storage capacity and is, therefore, completely out of the question in the real world. MPEG (M-JPEG) is the most common type of compressed digital video, but there are variants of these in addition to other proprietary formats. MPEG-1 and MPEG-2 typically offer the highest quality recording (DVDs use MPEG-2), but smaller file sizes can be obtained by using a lower resolution, more efficient compression method like MPEG-4.
|
