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C Mount

Refer to page C1.  When referring to camera lenses and cameras, they usually refer to way in which the lens is mounted to the camera.  The first standard for CCTV lens screw mounting.  It is defined with the thread of 1" (2.54mm) in diameter and 32- threads/inch, and the back flange-to-CCD imaging sensor distance of 17.526mm (0.69").  The C-mount description applies to both lenses and cameras. C-mount lenses can be put on both C-mount and CS-mount cameras, only in the latter case an adaptor is required.

Closed-circuit television, CCTV

Is the use of video cameras to transmit signal to a specific or limited sets of monitor.  CCTV is often used for surveillance in areas that may need monitoring.

Capacitance

It refers to the ability of a dielectric material between conductors to store energy when a difference of potential exists between the conductors.  The unit of measurement is the farad.  Cable capacitance is usually measured in picofarad (pF).

Capacitive Crosstalk

Cable crosstalk or interference resulting from the coupling of the electrostatic field of one conductor upon one or more others.

CCIR

Committee Consultative International des Radio communique or, in English, Consultative Committee for International Radio, which is the European standardization body that has set the standards for television in Europe.  It was initially monochrome; therefore, today the term CCIR is usually used to refer to monochrome cameras that are used in PAL countries.

Charge Coupled Device, CCD

CCD image sensors are technologies for capturing images digitally.  This type of imager converts light into electric charge and process it into electronic signals. In a CCD sensor, every pixel's charge is transferred through a very limited number of output nodes (often just one) to be converted to voltage, buffered, and sent off-chip as an analog signal. All of the pixel can be devoted to light capture, and the output's uniformity (a key factor in image quality) is high.  CCDs imagers can offer excellent imaging performance when designed properly.  The size of the CCD chip is normally 1/4", 1/3" or 1/2".  As a rule of thumb, the larger the size, the higher the quality of the image produced and the higher the price.  However, higher density 1/4" and 1/3" CCD chips can now produce as good an image as many older 1/3" or 1/2" chips.  Not all CCD chips are equal, even with the same specifications.  Quality varies by manufacturer.  Sony and Panasonic are generally recognized as producers of the best CCD chips.  Most CCTV security cameras supplied in Lotus brand use CCD chips from these two manufacturers.

Class A IP address

A unicast IP address that ranges from 1.0.0.1 through 126.255.255.254. The first octet indicates the network, and the last three octets indicate the host on the network.

Class B IP address

A unicast IP address that ranges from 128.0.0.1 through 191.255.255.254. The first two octets indicate the network, and the last two octets indicate the host on the network.

Class C IP address

A unicast IP address that ranges from 192.0.0.1 to 223.255.255.254. The first three octets indicate the network, and the last octet indicates the host on the network. Network Load Balancing provides optional session support for Class C IP addresses (in addition to support for single IP addresses) to accommodate clients that make use of multiple proxy servers at the client site.

Close-Up

A picture taken with the subject close to the camera-usually less than two or three feet away, but it can be as close as a few inches.

Close-Up Lens

A lens attachment placed in front of a camera lens to permit taking pictures at a closer distance than the camera lens alone will allow.

Coated Lens

A lens covered with a very thin layer of transparent material that reduces the amount of light reflected by the surface of the lens. A coated lens is faster (transmits more light) than an uncoated lens.

Coaxial cable

A cylindrical transmission line composed of a conductor centered inside a metallic tube or shield, separated by a dielectric material, and usually covered by an insulating jacket.  It is commonly used by cable TV companies to distribute signals to homes and businesses.  Also used by telephone companies in some applications and by cellular telephone, radio and television installation.

Coil Effect

The inductive effect exhibited by a spiral wrapped shield, especially above audio frequencies.

Colour Balance

How a colour image reproduces the colors of a scene.  Color images are made to be exposed by light of a certain color quality such as daylight or tungsten.  Colour balance also refers to the reproduction of colors in color prints, which can be altered during the printing process.

Colour Temperature

It is a standard method of describing colours for use in a range of situations and with different equipment.  Colour temperatures are normally expressed in units called kelvins (K).  Note that the "degrees" part of the name was made obsolete in 1967.  However, the "degrees" reference has remained in common use in industries.  For video operations the relevant temperatures range from around 2,000K to 8,000K — these are common lighting conditions. In practical terms this usually means selecting lights, gels and filters which are most appropriate to the prevailing light or to create a particular colour effect. For example, surveillance camera is built to operate at the range "2500K to 9500K", simulating to household light bulbs to blue sky levels of colour temperature.

Common Intermediate Format, CIF

Also known as FCIF (Full Common Intermediate Format), is a format used to standardize the horizontal and vertical resolutions in pixels of YCbCr sequences in video signals, commonly used in video teleconferencing systems. It was first proposed in the H.261 standard. 

CIF was designed to be easy to convert to PAL or NTSC standards. CIF defines a video sequence with a resolution of 352×288 like PAL Source Input Format, a frame rate of 30000/1001 (roughly 29.97) frame/s like NTSC, with colour encoded using YCbCr 4:2:0.  QCIF means "Quarter CIF". To have one fourth of the area as "quarter" implies the height and width of the frame are halved.  

Terms also used are SQCIF (Sub Quarter CIF), 4CIF (4× CIF) and 16CIF (16× CIF).

Compact Disc-Record-able, CD-R

Data can be copied to the CD on more than one occasion; however, data cannot be erased from the CD.

Compact Disc-Rewritable (CD-RW)

Data can be copied to the CD on more than one occasion and can be erased.

Communication Baud Rate

Baud Rate can be roughly defined as the speed of transmission of data between two computers.  All forms of communication using the Serial Port requires the presence of four parameters: the baud rate of the transmission being the very first parameter, then comes the number of data bits encoding a character, the third in line is the optional parity bit, and last one is the number of stop bits.  Each character transmitted using this method uses a character frame that has a single start bit, then data bits, the parity bit which is optional, and lastly the stop bit(s).  For instance, a transmission at a baud rate of 1 kBd or 1 kilo Baud is equivalent to a symbol rate of 1,000 symbols per second. A regular modem operating at this rate would send a thousand tones per second over the serial line.   So Baud rate is actually a measure of how rapidly data is moving between the two computers or other interface instruments using serial communication.  The RS-232 interface uses basically two digital voltages, called MARK which represents some form of data and SPACE to act as a delimiter.  A negative voltage is used to represent the MARK and zero volts often referred to as ground voltage is used to represent the SPACE.  Using the RS-232 standard which basically uses just two voltage levels, referred to as MARK and SPACE the baud rate is the same as the maximum number of bits of data, which includes the "control" bits, the data bits, the optional parity bit and lastly the stop bit(s).
The term baud refers to Emile Baudot, who invented the Baudot code for telegraphy.  Since the unit adheres to the SI standard of units, the first letter denoting the symbol ‘Bd’ should be in upper case but when the whole unit’s name is written (baud), it needs to be written in lowercase except when it is found in the beginning of a sentence.

Complementary Metal Oxide Semiconductor (CMOS)

CMOS image sensors are technologies for capturing images digitally.  This type of imager converts light into electric charge and process it into electronic signals.  In a CMOS sensor, each pixel has its own charge-to-voltage conversion, and the sensor often also includes amplifiers, noise-correction, and digitization circuits, so that the chip outputs digital bits. These other functions increase the design complexity and reduce the area available for light capture.  With each pixel doing its own conversion, uniformity is lower.  But the chip can be built to require less off-chip circuitry for basic operation.  CMOSs imagers can offer excellent imaging performance when designed properly.  CMOS is now a widely used type of semiconductor that uses both negative and positive circuits.  Since only one of the circuit types is on at any given time, CMOS chips require less power than chips using just one type of transistor. CMOS image sensors also allow processing circuits to be included on the same chip, an advantage not possible with CCD sensors, which are also much more expensive to produce.

Component video  

It is the unencoded output of a camera, video tape recorder, etc whereby each red, green, and blue video signal is transmitted down a separate cable (usually coax) to improve picture quality.  It can also refer to video system where the luminance and chrominance video components are kept separate.

Composite video

It is the encoded output of a camera, video tape recorder, etc, whereby the red, green, and blue video signals are combined with the synchronizing, blanking and color burst signals and are transmitted simultaneously down one cable.

Conductor

A substance, usually metal, used to transfer electrically energy from point to point.

Conduit

It is a tube of metal or plastic through which wire or cable can be run.  Used to protect the wire or cable and, in the case of metal conduit, to contain the fire of a burning wire or cable.

Contrast Ratio

It is the difference in brightness between the brightest white and the darkest black within an image.   Video does not cope with extreme contrast and nowhere near as well as the human eye.  The result of over-contrast is that some parts of the picture will be too bright or too dark to see any detail. For this reason you need to ensure that there is not too much contrast in your shot.

Correction of Aberrations at Close Distance Focusing, or CRC

In general, lenses are designed for maximum performance at infinity.  Accordingly, when the lens barrel is fully extended to the shortest focusing distance, resolution is reduced.  Although this is negligible for ordinary lenses, it becomes increasingly important in lens specially designed for close distance shooting.  Lens designers adopted a system where mechanism moves certain lens components as a unit automatically correcting for aberrations.  This assures high lens performance throughout the focusing range.

CRT

Cathode Ray Tube

CS Mount

Refer to page C1, a newer standard for lens mounting.  It uses the same physical thread as the lenses made smaller, more compact and less expensive.  CS-mount lenses can only be used on CS-mount cameras.   So basically, there is an approximate 5mm difference.  Both C and CS mount use the same thread pattern of 1.00/32mm.  CS Mount lenses are approx 5mm closer to the image plane, so to be used with a C-mount camera, a 5mm ring/adaptor can be used to make the gap larger.