Search results
Results from the WOW.Com Content Network
The word was proposed to prevent confusion between luma as implemented in video engineering and relative luminance as used in color science (i.e. as defined by CIE). Relative luminance is formed as a weighted sum of linear RGB components, not gamma-compressed ones. Even so, luma is sometimes erroneously called luminance. [2]
"Luminance" can mean several things even within the context of video and imaging: luminance is the photometric brightness of an object (in units of cd/m 2), taking into account the wavelength-dependent sensitivity of the human eye (the photopic curve); relative luminance is the luminance relative to a white level, used in a color-space encoding ...
A typical computer display emits between 50 and 300 cd/m 2. The sun has a luminance of about 1.6 × 10 9 cd/m 2 at noon. [3] Luminance is invariant in geometric optics. [4] This means that for an ideal optical system, the luminance at the output is the same as the input luminance.
YCbCr, Y′CbCr, or Y Pb/Cb Pr/Cr, also written as YC B C R or Y′C B C R, is a family of color spaces used as a part of the color image pipeline in digital video and photography systems. Y′ is the luma component and C B and C R are the blue-difference and red-difference chroma components.
Video codecs seek to represent a fundamentally analog data set in a digital format. Because of the design of analog video signals, which represent luminance (luma) and color information (chrominance, chroma) separately, a common first step in image compression in codec design is to represent and store the image in a YCbCr color space.
When appearing on light bulb packages, brightness means luminous flux, while in other contexts it means luminance. [5] Luminous flux is the total amount of light coming from a source, such as a lighting device. Luminance, the original meaning of brightness, is the amount of light per solid angle coming from an area, such as the sky.
Luminance only, Chrominance only, and full color image. Chrominance ( chroma or C for short) is the signal used in video systems to convey the color information of the picture (see YUV color model), separately from the accompanying luma signal (or Y' for short).
It is typically used to measure and display the level, or voltage, of a video signal with respect to time. The level of a video signal usually corresponds to the brightness, or luminance, of the part of the image being drawn onto a regular video screen at the same point in time. A waveform monitor can be used to display the overall brightness ...