User:Lovelyraaz1/sandbox

by rajkumar rai CONTRAST RATIO- Contrast is the difference in luminance and/or colour that makes an object (or its representation in an image or display) distinguishable. 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. Because the human visual system is more sensitive to contrast than absolute luminance, we can perceive the world similarly regardless of the huge changes in illumination over the day or from place to place. The maximum contrast of an image is the contrast ratio or dynamic range. Contrast is also the difference between the colour or shading of the printed material on a document and the background on which it is printed, for example in optical character recognition. •	[edit] Biological contrast sensitivity The human contrast sensitivity function shows a typical band-pass filter shape peaking at around 4 cycles per degree with sensitivity dropping off either side of the peak.[1] This tells us that the human visual system is most sensitive in detecting contrast differences occurring at 4 cycles per degree, i.e. at this spatial frequency humans can detect lower contrast differences than at any other spatial frequency. The high-frequency cut-off represents the optical limitations of the visual system's ability to resolve detail and is typically about 60 cycles per degree. The high-frequency cut-off is related to the packing density of the retinal photoreceptor cells: a finer matrix can resolve finer gratings. The low frequency drop-off is due to lateral inhibition within the retinal ganglion cells. A typical retinal ganglion cell presents a centre region with either excitation or inhibition and a surround region with the opposite sign. By using coarse gratings, the bright bands fall on the inhibitory as well as the excitatory region of the ganglion cell resulting in lateral inhibition and account for the low-frequency drop-off of the human contrast sensitivity function. One experimental phenomenon is the inhibition of blue in the periphery if blue light is displayed against white, leading to a yellow surrounding. The yellow is derived from the inhibition of blue on the surroundings by the center. Since white minus blue is red and green, this mixes to become yellow.[2] For example, in the case of graphical computer displays, contrast depends on the properties of the picture source or file and the properties of the computer display, including its variable settings. For some screens the angle between the screen surface and the observer's line of sight is also important. HD READY RESOLUTION- Requirements	HD ready	HD ready 1080p Minimum native resolution	720 horizontal lines (rows) in widescreen ratio	1920×1080 Analogue YPbPr HD input Yes	Yes Digital HDMI or DVI HD input Yes	Yes The HDMI or DVI input supports copy protection (HDCP)	Yes	Yes 720p HD (1280×720 progressive @50 & 60 Hz) Yes	Yes 1080i HD (1920×1080 interlaced @50 & 60 Hz) Yes	Yes 1080p HD (1920×1080 progressive @24, 50 & 60 Hz) No	Yes Accepted video formats are reproduced without distortion	No	Yes Display 1080p and 1080i video without overscan (1:1 pixel mapping) No	Yes Display native video modes at the same, or higher, refresh rate No