Dictionary of video surveillance systems. Terms on the topic — video surveillance.

C

LOCK RECORDING — a function of digital video recording systems that allows you to automatically overwrite old video with new archives.

DIGITAL VIDEO SURVEILLANCE SYSTEMIs a fairly capacious concept that includes a number of security devices, such as a video capture card (video capture card), a video recorder, a video server, a standalone. The basic operating principle is the conversion of an analog signal coming from video cameras into a digital code, with its subsequent processing by a microprocessor.

A modern digital video surveillance system can be implemented using both computer-based systems, using video capture and processing cards, network video cameras and video servers, and non-PC video recorders.

DETECTOR SENSITIVITY is the threshold at which the detector initiates an alarm. For an activity detector, this is, for example, the difference in the brightness of areas in the camera's field of view.

A

ABERRATION(aberration) is an optical term that refers to all the effects that affect the accuracy of image reproduction relative to the original scene.

ACTIVITY DETECTION is a function of detecting movement in the field of view of a connected video camera, available in some video multiplexers, to increase the speed of recording update.

ADVANCED INTELLIGENT TAPE (AIT) is a device for storing digital data on tape.

ALIASING(aliasing) — interference of discrete data. Occurs when an image with high spatial frequencies is projected onto a CCD matrix, also known as the moiré effect. The effect can be minimized using an optical low-pass filter.

ALPHANUMERIC VIDEO GENERATOR (text inserter) — a generator for the formation of symbols in a video signal (text generator), a device for entering additional information, usually superimposed on the reproduced image.

The amount of information can vary from one or two symbols to text occupying the entire screen.

These generators use the video signal sync pulses as a reference signal for inserting text; this means that if the video signal is of low quality, the stability of the text will also be low.

AMPLITUDE (amplitude) is the maximum value of the signal.

ANALOG SIGNAL(analog signal) — a representation of data in the form of continuously changing values. An analog electrical signal is characterized by different values ​​of voltage or current (volts or amperes) and is an electrical representation of the original excitation (sound, light) within the dynamic range of the system.

ANGLE OF VIEW — viewing angle.

ANTI-ALIASING — smoothing, protection against spectral aliasing. The procedure of eliminating or reducing (by smoothing and filtering) distorting effects.

APERTURE(aperture) — the opening of a lens that controls the amount of light reaching the surface of a photodetector. The size of the aperture is controlled by the diaphragm setting. The larger the F-number (F/1.4, F/1.8, R/2.8, etc.), the less light reaches the photodetector.

AMERICAN STANDARD CODE FOR INFORMATION INTERCHANGE(ASCII) is the American Standard Code for Information Interchange. A 128-character set that includes uppercase and lowercase English letters, digits, special symbols, and 32 control codes. Each character is represented by a 7-bit binary number. One character in the ASCII code can be stored in one byte of computer memory.

ASPECT RATIO is the ratio of the width of a television or film image to its height. Currently, the aspect ratio of a television screen is 4:3, i.e. 4 units wide and 3 units high. This aspect ratio was chosen in the early days of television, when most films had this format. The new HDTV (high definition television) format has an aspect ratio of 16:9.

ASTIGMATISM(astigmatism) — blurriness of the image in the foreground and background.

ASYNCHRONOUS (asynchrony) — lack of synchronization. A video signal is unsynchronized if its duration differs from the duration of the system reference signal. An external video signal is unsynchronized until it is processed by the frame synchronizer of the video system.

ASYNCHRONOUS TRANSFER MODE(ATM) — asynchronous transfer mode. A method of transmitting and switching a signal in which the information is non-periodic with respect to some reference signal.

ATTENUATION — a decrease in the amplitude of a signal as it passes through a medium or electrical system. Measured in decibels (dB).

B

BACK PORCH— 1) the part of the video signal corresponding to the blanking period, from the end of the horizontal sync pulse to the beginning of the active part of the video signal; 2) the part of the blanking signal lying between the trailing edge of the horizontal sync pulse and the trailing edge of the corresponding blanking pulse. The color synchronization pulse is located in this area.

BACK- FOCUS is the procedure for setting the position of the CCD matrix/lens to obtain the correct focus at all focal length settings (especially critical for zoom lenses).

BANDWIDTH is the bandwidth.

The full range of frequencies that a circuit or electronic system can operate with minimal signal loss, typically measured at 3 dB. In PAL systems, the maximum bandwidth is 5.5 MHz, in NTSC it is 4.2 MHz.

In PAL and NTSC systems, to ensure accurate digital representation of the video signal without aliasing within the luminance signal bandwidth, the luminance signal sampling frequency was chosen to be 13.5 MHz (ITU 601).

BASEBAND(baseband) — the frequency band occupied by a group of signals used to modulate a carrier before they are combined with the carrier during modulation. In closed-circuit television systems, most of the signals are baseband.

BAUD — a unit of data rate named after Maurice Emile Baude, equal to 1 bit/s. Baud is equivalent to bits per second when each signal element corresponds to exactly 1 bit. If devices communicate, the data rate settings of the two devices must be matched.

BIT ERROR RATE (BER) is the ratio of erroneously received bits to the total number of received bits, used as a measure of distortion caused by noise in a digital data stream. BER is expressed in powers of 10. For example, with 1 erroneous bit per 1 million bits, BER = 10?6.

BINARY(binary) — a base-2 numbering system that uses two digits, 0 and 1 (as opposed to the ten digits [0?9] of the decimal system). In computer systems, binary digits represent two different values ​​of voltage or current, one representing zero and one representing one. All computer programs are executed in binary form.

BROADBAND INTEGRATED SERVICES DIGITAL NETWORK (B-ISDN) — an enhanced version of ISDN that intelligently combines a large number of channels to achieve higher data rates.

BIT RATE— digital flow rate. The digital equivalent of bandwidth. Measured in bits per second. Typically used to express the speed of transmission of a compressed bit stream. The higher the digital flow rate, the more information can be transmitted. Bytes/s (Bps) — byte per second, bits/s (bps) — bits per second.

BIT(bit) — elementary digital information, can take the value 0 or 1. The smallest unit of information in the binary system. A group of bits, such as 8 or 16, makes up a byte. The number of digits in a byte depends on the processing system used. Standard byte sizes are 8-bit, 16-bit, or 32-bit.

BITMAP, BMP (bitmap) — a pixel-by-pixel description of an image. Each pixel is considered a separate element. A standard computer format for graphic files.

BLACK LEVEL(black level) — the portion of the video signal close to the sync level but slightly higher (usually 20-50 mV) to distinguish it from the blanking. Corresponds to the black area of ​​the image, with the white portion equivalent to 0.7 V above the sync level.

BLANKING LEVEL (blanking level) — the beginning of the video information in a video signal. The reference point is taken as 0 V, which is 300 mV above the bottom of the sync pulses. Sometimes called the «pedestal» — the level in the video signal that separates the area containing the image information from the synchronization area.

BLOOMING (image blurring) is the defocusing of parts of the image that have excess brightness.

BAYONET-NEIL-CONCELMAN CONNECTOR (BNC) (bayonet connector) is the most common connector in CCTV systems and in television broadcasting for transmitting baseband video signals over a coaxial cable.

B-PICTURE is a bidirectional predictive-coded image.

BRIGHTNESS— brightness. For NTSC and PAL video signals — information about the image brightness at any given moment is transmitted by the corresponding instantaneous level of constant voltage in the area of ​​the active video signal. Brightness is adjusted by setting the settings (black level, reference black level).

BURST (COLOR BURST)— a color burst signal. Seven to nine (NTSC) or ten (PAL) periods of the subcarrier are placed at the end of the horizontal blanking pulse as a phase (color) reference signal for the modulated color subcarrier.

The color burst signal serves as a standard for a color image.

BUS — a bus. In computer architecture, it is used for internal transmission of information between various components of the system and is available to each of the components.

BYTE (byte) — a digital word consisting of 8 bits (zeros and ones).

С

CANDEIA[cd] — candela [cd]. A unit of luminous intensity. One candela is approximately equal to the amount of light energy emitted by a regular candle. In 1948, a more precise definition of candela appeared: «The luminous intensity emitted by a black body heated to the temperature at which platinum changes from liquid to solid.»

CCD DISCONNECT DETECTION — detection of video signal loss.

CCIR (Committee Consultatif International des Radiocommunique)— television standard: 625 lines, 50 fields per second, line frequency of 15,625 Hz.

CCIR 601 — standard for video signal digitization.

COMPACT DISK READ ONLY MEMORY (CD-ROM) — compact disc for reading only. The total capacity of CD-ROM is 650 MB.

CHIP (chip, IC, microcircuit) — integrated circuit, all components of which are located on a small plate of silicon or similar material.

CHROMA CRAWL(chroma key) is a video encoding artifact also known as dot crawl or luminance crosstalk. It appears in a video image at the edges of highly saturated colors as a continuous sequence of crawling dots due to the mixing of color and luminance information in the decoder circuitry.

CHROMA KEY (chroma key) is a video effect in which one video signal is inserted into the areas of another video signal that has a specific color.

CHROMINANCE(chrominance, chrominance signal) — color information of a color video signal.

CHROMINANCE-TO-LUMINANCE INTERMO-DULATLON (crosstalk, cross-modulation) — intermodulation of color/luminance signals (crosstalk, cross-modulation), an undesirable change in the amplitude of the luminance signal caused by the imposition of color information on the luminance signal.

It appears in a TV image as unjustified variations in luminance associated with changes in color saturation levels.

CMYK—Cyan-Magenta-Yellow-Black. A color coding system used by printers in which colors are expressed as «subtractive primaries» (Cyan-Magenta-Yellow) plus black (K). A layer of black is added to enhance contrast and increase the dynamic range of printing devices.

CODE/DECODE(coder-decoder) is an electronic device that performs compression and decompression of digital signals. Usually performs A/D and D/A conversion.

COLOR BARS is a sample formed by a test TV signal generator, consisting of eight color bars of equal width.

COLOR CARRIER is the carrier frequency of a color video signal (4.43 MHz for PAL), modulated with color information. The frequency of the color carrier is chosen so that its spectrum alternates with the luminance spectrum with minimal overlap.

COLOR DIFFERENCE SIGNAL(color difference signal) is a color video signal created by subtracting the luminance and/or color component from one of the primary color signals (red, green, blue — RGB).

In the Betacam color difference format, for example, the luminance (Y) and color difference components (R-Y and B-Y) are related as follows: Y = 0.3 Red + 0.59 Green + 0.11 Blue R-Y = 0.7 Red — 0.59 Green — 0.11 Blue B-Y = 0.89 Blue -0.59 Green — 0.3 Red

COLOR FIELD(color field) — In NTSC, the color subcarrier is phase-locked to the horizontal sync pulses, so that the phase of the subcarrier changes by 180° with each line. In PAL, the phase of the color subcarrier changes by 90° with each frame. In NTSC, this creates four different field types, and in PAL, there are eight. Alignment of the sequence of color fields from different sources is important for obtaining clean images.

COLOR PHASE(color phase) — the time relationship in a video signal, measured in degrees and responsible for the correctness of the color signal tones.

COLOR SUBCARRIER (color subcarrier) — a signal with a frequency of 3.58 MHz that transmits color information. This signal is superimposed on the luminance signal. The amplitude of the color subcarrier represents the saturation, and the phase angle represents the color tone.

COLOR TEMPERATURE(color temperature) — defines the color tone. Derived from photography, where the color spectrum is based on comparing tones when the color changes when a black body is heated (as in physics) from red to yellow, and then to blue — the hottest. Measured in degrees Kelvin.

COMB FILTER(comb filter) — an electronic circuit that passes a range of frequencies and blocks frequencies in between, producing a jagged frequency response. Uses a composite video signal to separate the chrominance signal from the luminance signal, reducing chrominance crosstalk, or vice versa — to separate the luminance signal from the chrominance signal, reducing luminance crosstalk. Used in S-VHS systems to improve the resolution of the luminance signal.

COMPOSITE SYNC — a signal consisting of horizontal sync pulses, vertical sync pulses, and equalizing pulses (without video signal).

COMPOSITE VIDEO SIGNAL(composite video signal) is a signal in which the brightness and color information are combined according to one of the encoding standards: NTSC, PAL, SECAM, etc.

CONTRAST is a general term used in relation to the dynamic range of a video image, that is, the difference between the darkest and lightest areas of the image.

CENTRAL PROCESSING UNIT (CPU) is a central processor.

D

DARK CURRENT is a dark current. The signal that appears at the output of a CCD matrix in the absence of incident light.

DARK NOISE— dark noise. Noise associated with the quantum nature of dark current.

DIGITAL AUDIO TAPE, DAT (digital audio cassette) — a system with a signal quality equal to CD, originally designed for recording and playing back digitized audio signals. Recent hardware and software developments may lead to the creation of similar low-cost systems for archiving, recording and playing back video signals.

DECIBEL, dB (decibel, dB) is the common logarithm of the ratio of two signals or two values, usually related to power, but can also relate to voltage or current. If power is being considered, the logarithm is multiplied by 10, current or voltage — by 20.

DISCRETE COSINE TRANSFORM(DCT) — discrete cosine transform. A mathematical algorithm used to generate a frequency representation of a block of video pixels. An invertible discrete orthogonal transform between the spatial and temporal domains. There is a forward discrete cosine transform (FDCT) and an inverse discrete cosine transform (IDCT).

DECODER — a device for reconstructing the components of signals coming from a coded signal source.

DIFFERENTIAL PHASE(differential phase) — a change in the phase of a video signal subcarrier caused by a change in the signal brightness level. The color tones of a scene change along with the change in scene brightness.

DIGITAL CAPTURE — digitization.

DIGITAL DISC RECORDER — a hard disk recording device.

DIGITAL SIGNAL (digital signal) — an electronic signal in which each value of real excitation (sound, light) is represented by a combination of binary signals corresponding to an analog signal.

DIGITAL SIGNATURE — a digital signature.

DISK(disk) — a flat, circular plate coated with a magnetic material on which data is recorded by selectively magnetizing parts of the surface. There are flexible and rigid disks, as well as plastic compact discs (CDs) or digital video discs (DVDs).

DISTORTION — a disproportionate representation of the original.

DISK OPERATING SYSTEM, DOS(disk operating system) is a software package that enables a computer to work with such technical devices as a hard disk drive, floppy disk, monitor, keyboard, etc.

DOT PITCH (dot pitch) is the distance in millimeters between individual dots on a video monitor screen. The smaller the pitch, the better, as it displays more dots and increases the resolution.

The dot pitch determines the resolution of the video monitor. A computer monitor or a high-resolution CCTV monitor has a dot pitch of less than 0.3 mm.

DROP-FRAME TIME CODE is an SMPTE time code format that continuously counts 30 frames per second, but drops two frames every minute except every tenth minute (drops 108 frames every hour) to synchronize the time code with the clock.

This is necessary because the actual frame rate of an NTSC video signal is 29.94 frames per second, not 30.

DIGITAL SIGNAL PROCESSING (DSP) — digital signal processing. Usually refers to the part of a device's electronic circuit that performs digital signal processing.

DUBBING — dubbing, rewriting from one medium to another.

DUPLEX(duplex, two-way) — a communication system that carries information in both directions. In CCTV, the term is often used to describe a type of video multiplexer that can perform two functions simultaneously — recording and playback in multiplex mode. It can also refer, for example, to duplex communication between a matrix video switcher and a receiver for remote control signals of a PTZ device.

DVR (Digital Video Recorder) — a digital recording device. Any digital device capable of video recording. It does not matter whether it is PC-based or not.

DYNAMIC RANGE— dynamic range. The difference between the smallest and largest values ​​represented by the system.

E

ELECTRONIC PTZ — the ability to move around an enlarged (digitized) image.

ENCODED — coded (converted into a digital code for recording on a medium).

ENCODER (encoding device) — a device that superimposes information from one electronic signal on other electronic signals.

ENCRYPTION(coding) — a systematic rearrangement of the bit stream of a previously digitized signal, making the information unrecognizable until restored using an authorized access key.

This method is used to protect information transmitted over communication channels to prevent anyone other than authorized users from interpreting the message.

Can be used for voice, video, and other communication signals.

ERASABLE AND PROGRAMMABLE READ ONLY MEMORY, EPROM(Erasable Programmable Read-Only Memory) is an electronic chip used in many security systems that stores program instructions to perform various operations.

EQUALIZER (equalizer, frequency corrector) is a device designed to compensate for frequency losses or delays in a system. A part of a system or circuit that allows you to adjust a signal within a specified frequency band.

ETHERNET— a local area network connecting computers, printers, workstations, terminals, etc., located in the same building.

Uses twisted pair cables and coaxial cables at speeds up to 10 Mbps, as well as the CSMA/CD method (collision detection multiple access) — sharing a common medium (wires, coaxial cables) between different devices.

EVENT LOG — event log.

EVENT RECORDING — event recording.

EXCLUSIVE— video recording of alarm cameras only.

EXTERNAL SYNCHRONIZATION — external synchronization, means of synchronizing equipment from one source.

F

FIELD (frame field) — half of a TV frame, consisting of even or odd lines.

In CCIR systems, each field consists of 625/2 = 312.5 lines, and in EIA systems — of 525/2 = 262.5 lines.

In the CCIR/PAL TV system, 50 fields/second are transmitted, and in EIA/NTSC — 60 fields/second.

FLASH MEMORY(flash memory) is a non-volatile digital memory. Flash memory has lower access times than SRAM or DRAM.

FLICKER — flickering, flicker noise. An annoying interference, mainly associated with frame synchronization and field display. Some flickering is natural, explained by interlaced scanning, and is more noticeable in 50-Hz systems (PAL).

Flickering also occurs when static objects are displayed on the screen, such as computer-generated text converted to video.

Insufficient digital image processing, typical of low-quality converters (when switching from PAL to NTSC and back), creates annoying flickering on the screen.

There are several electronic methods that can minimize flickering.

FOURIER TRANSFORMATION — a mathematical transformation of functions from the time domain to the frequency domain.

FRAME STORE — video memory (frame memory). An electronic device that digitizes a frame (or TV field) of a video signal and places it in memory. Video multiplexers, video quadrators (screen splitters) and some of the latest color video cameras have built-in frame memory.

FRAME SYNCHRONIZER(frame synchronizer) is a digital buffer that stores and compares synchronizing information with the video signal sync pulses, thereby continuously adjusting the signal to avoid synchronization errors.

FRAME— frame (see also TV field). It denotes a set of lines that make up one TV frame. In the CCIR/PAL TV system, one frame consists of 625 lines, and in the EIA/NTSC system, it consists of 525 lines. The CCIR/PAL system transmits 25 frames per second, while the EIA/NTSC system transmits 30 frames per second.

FREEZE (FRZ) — freeze frame.

G

GIGABYTE, GB(gigabyte, GB) is a unit of computer memory, equal to about one thousand million bytes (about one thousand megabytes). The actual value is 1,073,741,824 bytes.

GRAY SCALE is a scale of gradations of brightness.

GRAPHICAL USER INTERFACE (GUI) is a graphical user interface.

H

HARD DISK DRIVE (HDD) is a hard disk drive.

HARD DISK RECORDER (HDR) is a device for recording video on a hard disk.

HERRINGBONE(jaggies) — the formation of a special pattern on an image when displaying a color-modulated composite video signal (PAL or NTSC) on a black-and-white video monitor.

HORIZONTAL RESOLUTION— horizontal resolution. Chromatic and brightness resolution (detail), estimated horizontally of the image on the CRT screen. Usually expressed as the number of transitions from black to white or as the number of distinguishable lines. Limited by the frequency band of the video signal or the bandwidth of the equipment.

HUE (tint, phase, chroma phase) — color tone (hue, phase, phase of the color signal), one of the characteristics of color discrimination. Hue defines a color based on its position in the spectrum, i.e. red, blue, green or yellow, etc. In NTSC and PAL video signals, information about the color tone of each image point is transmitted by the corresponding instantaneous phase of the active video signal subcarrier.

HUM BUG is a synonym for ground loop protection device.

HUM is a background noise, network interference. The term is used to describe unwanted interference caused by the power grid.

HYPER-HAD is a high-sensitivity CCD matrix (based on a HAD matrix with microlenses).

I

INPUT/OUTPUT (I/O) is an input/output.

INTERFACE DEVICE ELECTRONICS (IDE)— device interface. Standard for software and hardware communications when connecting peripheral devices to a computer.

INTERFERENCE— interference, pickup — disturbances of an electrical or electromagnetic nature that cause undesirable consequences in the operation of electronic equipment.

IMAGE PER SECOND (IPS) — the number of images per second.

IP VIDEO CAMERA(see also NETWORK VIDEO CAMERA) — a video camera that has its own network video server connected to any data transmission network.

J

JPEG — a digital image compression format greater than 10:1.

K

KB/S — kilobits per second (kbps), 1024 bits per second.

KILOBAUD — kilobaud, a unit of data transfer rate, equal to 1000 baud.

KILOBYTE — kilobyte, 1024 bytes.

L

LANDING UNIT — a decoder.

LOCAL AREA NETWORK (LAN) — local area network. A communication network for transmitting data over short distances (usually within a single building). It is used to connect computers and peripheral devices (such as printers, CD-ROM drives, modems) into a single system with common control.

LUMEN [Lm] — lumen [lm]. The luminous flux emitted by a source with a luminous intensity of 1 candela within a single solid angle.

LUMINANCE— brightness. Refers to the information contained in a video signal about the illumination of an object. A photometric unit of measurement of light radiation.

LOOK-UP TABLE (LUT) — a lookup table. A cross-reference table in computer memory that converts input information from a scanner or computer and adjusts values ​​to compensate for equipment deficiencies or differences in photo emulsions.

LUX, Lx(lux, lx) is a unit of measurement of illumination. It is defined as the illumination of a surface of 1 m2, on which a luminous flux of 1 lumen falls.

M

MEGABITS PER SECOND, Mb/s (megabits per second (Mbit/s) is a million bits per second.

MEGABYTE, MB (megabytes, Mbytes) is a unit of computer memory, approximately a million bytes. The actual value is 1,048,576 bytes.

MEGABYTES PER SECOND, MB/s (megabytes per second (Mbyte/s) is a million bytes per second, or 8 million bits per second.

MINI DIGITAL VIDEO, DV-Mini (mini digital video) is a new audio and video recording format for small camcorders, adopted by most camcorder manufacturers.

Video and sound are recorded in digital format on a small cassette (66x48x12 mm), surpassing S-VHS and Hi 8 in quality.

M-JPEG (Motion-Joint Picture Expert Group) is a compression in which each frame of a video sequence is “remembered” entirely with JPEG compression.

MOTION PICTURE EXPERTS GROUP (MPEG)— a standard for compressing moving video images (preserving differences only between successive frames).

MOTION TRACKING —

1) motion tracking. This usually refers to the ability of digital systems to control PTZ cameras to track objects in an enlarged view;

2) plotting the path of movement of objects in the camera's field of view.

MULTIPLEXED ANALOG COMPONENTS (MAC)— analog time division multiplexing. A system in which components are time-multiplexed onto a single channel using time-division techniques, i.e. the components are separated as they are transmitted at different times over a single channel. There are many different MAC formats and standards.

N

NON-PC DVR— a digital video recorder based on a unique set of video processing and compression/decompression chips (not based on standard computer — the so-called Wintel platforms). However, in 90% of cases, standard hard disk drives (HDD) and other means of archiving and copying digital data are used for recording.

NOT PC — a characteristic of a hard disk recording device (hardware signal compression).

NTSC (National Television System Committee) — a standard for color video signal.

NVR (Network Video Recording) — video recording over a computer network.

O

OBSERVATION SYSTEM — video surveillance system.

Р

PEAK-TO-PEAK, pp (signal swing) — the difference in amplitude (voltage) between the largest positive and smallest negative peak of an electrical signal.

PEDESTAL — the video signal level corresponding to black.

PIXEL OR PICTURE ELEMENT— pixel, picture element. The smallest visible element transmitted in a bitmap file, usually a single element in a matrix of numbers describing the image.

PREDICTION-CODED PICTURE (P-picture) — predictive-coded picture (coding with motion compensation). MPEG term for describing a picture encoded using a motion compensation method based on a previous reference picture.

PROGRAMMABLE READ ONLY MEMORY (PROM) — programmable read-only memory.

PROTOCOL(protocol) — a specific set of rules, procedures, or agreements concerning the format and timing of data transmission between two devices. A standard procedure by which two devices can «understand» each other. A data transmission protocol covers such aspects as encoding, error handling, user transparency, and control.

PUBLIC SWITCHED TELEPHONE NETWORK (PSTN)— public switched telephone network. This is the usual name for the regular telephone network (or POTS).

R

REDUNDANT ARRAYS OF INDEPENDENT DISKS, RAID (a matrix of independent disk drives with redundancy) is a technology for combining several hard disk drives into a single high-capacity storage device that can be used, among other things, for digital recording of video images.

RANDOM ACCESS MEMORY (RAM)— random access memory. An electronic circuit, commonly called «memory», that stores digital information for as long as voltage is applied to it. Memory capacity is measured in kilobytes. Memory is the working space of a computer.

RECORDING FRAME RATE — the recording speed (number of frames per second).

RESOLUTION— resolution. A measure of the ability of a video camera or television system to reproduce detail. The number of picture elements that can be reproduced with good clarity.

READ ONLY MEMORY (ROM) — read-only memory. An integrated circuit containing digital information that is not erased when the power is removed.

ROUTING SWITCHER — a routing switch. An electronic device that routes a signal (audio, video, etc.) from any input to any output selected by the user.

RS-232— a digital data transmission format that requires only two wires. Also known as «serial data transmission.»

Defines an asynchronous data transmission scheme, but not a bit representation of the data, i.e., it does not define a common message format or protocol.

In CCTV systems, it is often used to transmit data between a keyboard and matrix video switches, or between matrix switches and PTZ units.

The advantages of RS-232 over other standards are its simplicity and the use of only two wires.

RS-422 is an improved digital data transmission format compared to RS-232. The main differences are the use of four wires instead of two, since the connection is not asymmetrical, as in the case of RS-232, but differential.

Simply put, the transmitted signal is read at the receiving end as the difference between two wires without a common ground.

So, if there was noise on the line, it will be eliminated.

RS-422can be used on lines longer than a kilometer and distribute data between several receiving devices, the system can have up to 10 receiving devices.

RS-485 is an improved digital data transmission format compared to RS-422. The main improvement concerns the number of devices controlled by this format — up to 32.

S

SATURATION(in color) — saturation (of color). The intensity of color in the active part of the image. The degree to which the color perceived by the eye differs from the gray or white scale of the same brightness. A 100% saturated color does not contain white; adding white reduces saturation. In the NTSC and PAL systems, the color saturation of the image at any moment is transmitted by the corresponding instantaneous value of the amplitude of the active video signal subcarrier.

SCENE ILLUMINATION— illumination of an object. The average level of light falling into the observation zone. Usually measured within the visible spectrum using an exposure meter (photometer) with a spectral characteristic close to the sensitivity of the human eye, measured in lux.

SMALL COMPUTER SYSTEMS INTERFACE (SCSI) — small computer system interface. A computer standard that defines software and hardware for connecting peripheral devices to a computer bus.

SEQUENTIAL COULEUR AVEC MEMOIRE (SE-CAM) — a color video signal standard.

SERIAL DATA— serially transmitted data. Sequential transmission of data over a single wire. In CCTV systems, the most common method of exchanging data between the control panel and the matrix video switcher and a method of controlling a PTZ camera.

SERIAL INTERFACE(serial interface) is a digital communication interface, the transmission and reception of data is carried out sequentially over one or a pair of wires. Commonly accepted serial interface standards are RS-232 and RS-422.

SERIAL PORT (serial port) is a computer input/output port through which the computer «communicates» with the outside world. A standard serial port is based on the RS-232 interface and allows for bidirectional data transfer over a fairly simple wired connection, since the data is transmitted sequentially.

SERIES RECORDING is a cascade video recording.

SIGNAL-TO-NOISE RATIO(S/N) — signal-to-noise ratio (S/N). S/N can be specified for the luminance signal, color signal, and audio signal. It is expressed in decibels (dB), and the higher the S/N value, the sharper and clearer the image and sound during playback. S/N is equal to the logarithm of the ratio of the normal signal to the root-mean-square value of the noise.

SIMPLEX— simplex. Generally used to describe a communication system that transmits information in only one direction. In closed-circuit television systems, the term is used to describe a method of multiplexing operation in which only one function, such as recording or playback, is performed at a time.

SLOW SCAN — the transmission of a sequence of «frozen» images via analog or digital signals using transmission media with a very limited bandwidth (usually a telephone).

SMEAR(vertical fringing) — an unwanted side effect of charge transfer on a CCD. Bright vertical stripes appear where bright areas of the image should be. In improved video cameras, the effect has been minimized to an almost unnoticeable level.

SNOW — random noise on the screen, often caused by dirty video heads or poor video reception conditions.

SYNC PULSE GENERATOR(SPG) — a sync signal generator, a sync generator. A source of synchronization signals.

STANDALONE (lit. — standing separately) — any digital recording (or video processing) device installed for autonomous operation. Its design does not matter, although more often this term is used to denote video recorders that are not based on standard computer platforms due to their greater reliability.

START BIT(start bit) — a bit preceding a group of bits representing a character. Used to signal the appearance of a character during asynchronous transmission.

SYNC GENERATOR, sync pulse generator, SPG (sync pulse generator, sync generator) — a device that generates synchronizing pulses necessary for normal synchronization of video signal sources.

The sync generator can generate a subcarrier signal, a «flash» pulse (color synchronization signal), a sync mixture, blanking signals, line sync pulses, frame sync pulses, and a color black field signal. Line and frame sync pulses are most often used in CCTV.

T

TDG is a date and time generator.

TIME DIVISION MULTIPLEX (TDM) is a multiplex transmission with time division of channels. Each user is assigned a special segment in each transmission cycle — this way, time division of the transmission channel is achieved.

TEARING— break (line shift). Shifting of video image lines due to synchronization instability. It seems as if the image is broken.

TELEMETRY — telemetry, in security television, remote control. A remote control system based on digital data, used to control pan, tilt, zoom, focus, presets, washer/wiper unit, etc. Since the system is digital, the signal is usually transmitted over a twisted pair or coaxial cable along with the video signal.

THIN-FILM-TRANSISTOR (TFT) is a thin-film transistor. This technology is used mainly in the production of flat computer and video screens (panels), which are superior in quality to classic LCD monitors. The quality of color rendering, fast response time and high resolution are perfect for video.

TRANSPONDER(transponder, repeater) — electronic equipment installed on a satellite; the device receives a signal from Earth, amplifies it, converts it to other frequencies, and transmits it back to Earth.

TRANSISTOR-TRANSISTOR LOGIC (TTL)— transistor-transistor logic (TTL). A term from digital electronics that refers to the ability to directly connect a device or circuit to the input or output of digital equipment. This compatibility eliminates the need for an interface circuit. TTL signals can only have two states — low and high. Thus, they are much more limited than analog signals.

U

UNBALANCED SIGNAL (unbalanced signal) — a type of video signal transmission over a coaxial cable. The signal is called unbalanced because it passes only through the center conductor, while the cable shield is used to equalize the potential difference between the ends of the coaxial cable.

UNSHIELDED TWISTED PAIR (UTP)— unshielded twisted pair. A cable carrier consisting of one or more pairs of twisted insulated copper conductors in a single sheath. Currently, the most common method of connecting a telephone line and transmitting data to a workplace.

V

VARIABLE BIT RATE — variable bit rate. A type of operation in which the bit rate during decoding of a compressed bit stream changes over time.

VERTICAL RESOLUTION— vertical resolution. Color and brightness resolution (detail), expressed along the vertical of the kinescope screen. Limited by the number of scanning lines.

VERTICAL SYNC PULSE — frame sync pulse. Contains part of the frame blanking interval, is at the level of the frame blanking pulse. Synchronizes the frame scan of the TV using a composite video signal. Each frame begins from the same vertical position.

VIDEO BANDWIDTH— video signal bandwidth. The highest frequency in the video signal spectrum that the device passes. The higher the video signal bandwidth, the higher the image quality. A VCR that provides a wide video signal bandwidth produces a well-detailed, high-quality image on the screen. Video signal bandwidths in studio work range from 3 to 12 MHz.

VIDEO EQUALIZATION CORRECTOR(video equalizer) — video equalizer (video corrector). A device that corrects the unevenness of the frequency response and/or phase shifts during video signal transmission.

VIDEO FRAMESTORE — frame video memory. A device for storing one or more digital images and for subsequent stable playback on a video monitor.

VIDEO GAIN(video signal swing) is the range of values ​​from light to dark in an image that is proportional to the difference in voltages corresponding to the black and white levels in a video signal. Displayed on a control oscilloscope as the «whiter than white» voltage level in the active signal. Video signal swing is related to the contrast of the video image.

VIDEO SIGNAL (video signal) is an electrical signal containing all the elements of an image transmitted by a video camera or other source of video information.

VIDEO MOTION DETECTOR (VMD)— video motion detector. A detector that generates an alarm in response to changes in the video signal, usually motion, but it can also be a change in illumination. It is very important in CCTV, since video motion detector precisely controls what the video camera “sees”, i.e. without losses.

VERTICAL SYNC (VS) — frame synchronization.

W

WIDE AREA NETWORK (WAN) — global network.

WAVELET — a special type of video signal compression. Particularly well suited for CCTV. Provides a higher compression ratio with quality equal to or better than JPEG.

WHITE BALANCE — white balance. An electronic process used in video cameras to restore true colors. It is carried out electronically, using the white part of the image object as a basis.

WHITE LEVEL — white level. Part of the video signal that electronically represents the white part of the image. It is 0.7 V away from the blanking level, while the black part is taken to be equal to 0 V.