Color BarsTone

color bars are a type of television test pattern, and is most commonly used in countries where the NTSC video standard is dominant, such as those in North America. The Society of Motion Picture and Television Engineers (SMPTE) refers to this test pattern as Engineering Guideline EG 1-1990. The components of this pattern are a known standard, so comparing this pattern as received to that known standard gives video engineers an indication how an NTSC video signal has been altered by recording or transmission, and thus what compensation needs to be applied to that signal to bring it back to original condition. The pattern is also used for setting a television monitor or receiver to reproduce NTSC chrominance and luminance information correctly. Originally conceived in the 1970s by Al Goldberg of CBS Laboratories, and previously categorized by SMPTE as ECR 1-1978, the development of this test pattern was awarded an Engineering Emmy in 2001-2002.[1]
An updated version of SMPTE color bars, developed by the Japanese Association of Radio Industry and Businesses as ARIB STD-B28 and standardized as SMPTE RP 219-2002, is used to test both 4×3 standard definition and 16×9 high-definition video signals.In an SMPTE color bar image, the top two-thirds of the television picture contain seven vertical bars of 75% intensity. In order from left to right, the colors are white, yellow, cyan, green, magenta, red, and blue. This sequence runs through all seven possible combinations that use at least one of the three basic color components of green, red, and blue, with blue cycling on and off between every bar, red cycling on and off every two bars, and green on for the leftmost four bars and off for the rightmost three. Because green contributes the largest share of luminance, followed by red, then blue, this sequence of bars thus appears on a waveform monitor in luminance mode as a downward staircase from left to right. The graticule of a vectorscope is etched with boxes showing the permissible regions where the traces from these seven bars are supposed to fall if the signal is properly adjusted.
Below the main set of seven bars is a strip of blue, magenta, cyan, and white castellations. When a television receiver is set to filter out all colors except for blue, these castellations, combined with the main set of color bars, are used to properly adjust the color controls; they appear as four solid blue bars, with no visible distinction between the bars and the castellations, if the color controls are properly adjusted.

Category:

Entertainment

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• Color
• Bars
• Tone
• Count
• Down
• Clock
• 30
• Seconds
• Total

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