AS NZS 62676.5 pdf download

AS NZS 62676.5 pdf download.Video surveillance systems for use in security applications
1 Scope
This part of IEC 62676 defines recommendations and requirements for representation and measuring methods of performance values to be described in materials such as instruction manuals, brochures and specifications of video surveillance camera equipment. This document consists of two parts. The first part is requirements for description of video surveillance camera specification items. The second part is requirements for measurement methods of video surveillance camera specification items. A video surveillance camera’s output can be analogue (e.g. composite video such as NTSC or PAL) or digital (e.g. compressed network output, uncompressed SDI (serial digital output), etc.).
3 Terms, definitions and abbreviations
3.1 Terms and definitions 3.1.1 4k image size format with approximately 4 000 horizontal pixels defined as SMPTE 2036 (3 840 × 2 1 60 UHDTV) 3.1.2 aperture opening of lens diaphragm through which light passes 3.1 .3 bit rate amount of digital signal in a second 3.1 .4 C/CS mount lens physical mounting standards (C mount and CS mount) typically used for video surveillance cameras Note 1 to entry: C mount is an older standard defined as one inch (25,4 mm) in diameter with 32 threads per inch and the flange back distance where an image is projected on a sensor is 1 7,526 mm. Note 2 to entry: CS mount is a newer standard which uses the same diameter and thread of C mount, but the flange back distance is 1 2,5 mm. 3.1.5 colour temperature measure of temperature of a heated surface which generates a radiant energy having the same spectral distribution generated from a blackbody of the same temperature Note 1 to entry: Colour temperature is expressed in kelvins (K). [SOURCE: IEC 601 94:201 5, 24.1 355] 3.1.6 compression process of reducing the size of data (image or video) [SOURCE: IEC 62676-1 -1 :201 3, 3.1 .27, modified – In the definition, “data (image or video)” has replaced “a data (image) file”.] 3.1 .7 compression ratio ratio of the uncompressed size of files, images or videos to the compressed size Note 1 to entry: A high compression ratio means smaller image files and lower image quality and vice versa. [SOURCE: IEC 62676-1 -1 :201 3, 3.1 .28, modified – In the definition, “files, images or videos” has replaced “files or images”.] 3.1.8 contrast <related to image> difference in visual luminance properties that makes an object (or its representation in an image) distinguishable from other objects and the background Note 1 to entry: In visual perception of the real world, contrast is determined by the difference in the colour and brightness of the object and other objects within the same field of view.3.1 .9 dome camera camera mounted inside a dome, usually protecting it from outside influences 3.1 .1 0 dynamic range quotient of the signal from the maximum measurable indication of a quantity by the signal from the minimum measurable value of that quantity [SOURCE: IEC 62232:201 1 , 3.1 5] 3.1.1 1 electronic shutter arrangement in the camera changing its sensitivity by electronically controlling the exposure time of the image sensor [SOURCE: IEC 62676-4:201 4, 3.1 .1 4] 3.1.1 2 encoding streams series of consecutive encoded images or video from the same image source which are transmitted from one system component to another [SOURCE: IEC 62676-1 -1 :201 3, 3.1 .77, modified – In the definition, “encoding streams” has replaced “image streams”, “encoded images or video” has replaced “images”.] 3.1.1 3 exposure control electronic control of the time needed to expose image sensor pixels to light Note 1 to entry: For “live” video stream the default exposure is typically 1 /25 s or 1 /30 s. 3.1.1 4 exposure time length of time for which image sensor pixels are exposed to light 3.1.1 5 flare light falling on an image, in an imaging system, which does not emanate from the subject point Note 1 to entry: Flare is also sometimes referred to as veiling glare. Note 2 to entry: See also image flare (3.1 .30).3.1.1 8 F-number iris opening of a lens defined as a ratio between the focal length of the lens and its iris opening Note 1 to entry: It is typically a number larger then 1 (e.g. F1 .4, F2, F2.8) and indicates the amount of light coming through the lens where a lens with lower F-number transmits more light than a lens with higher numbers. 3.1.1 9 gain camera function to amplify the electronic signal 3.1.20 gamma correction correction of the linear response of a camera to compensate for the monitor screen non-linear response Note 1 to entry: It is measured with the exponential value of the curve describing the non-linearity. A typical monochrome monitor’s gamma is 2,2, and a camera needs to be set to the inverse value of 2,2 (which is 0,45) for the overall system to respond linearly (i.e. unity).