![]() So their "dynamic range" is 8 (bit).The ability of wafer scale Complementary Metal Oxide Semiconductor (CMOS) imagers to integrate sensing with analogue to digital conversion at the pixel level has led to their widespread appeal in a variety of imaging applications. We must note that pixels' intensities of both monitors can still be adjusted in 256 different ways only for standard non HDR monitors. However historically happened that they are called contrast ratio or simply contrast. Strictly speaking, these values (or logarithm of these values) should be called dynamic range (without going into details of dynamic contrast of newest LCD monitors). The second monitor has contrast ratio of 500:1. It means that brightest intensity in can display is 1000 times bigger than darkest one. Let's say first monitor has half the base light of the second one and has a contrast ratio of 1000:1. So monitor in never black - there is always some light we see and that light originates from the monitor itself (as opposed to the light reflected or scattered by the monitor). It so happens that even when liquid crystal is 100% opaque there still is some amount of light which reaches the viewer. They differ in one thing thought - light leakage (or base light). They have same electronics, same back light source and both of them are 8 bit devices. The ratio between brightest intensity and darkest intensity that monitor can reliably reproduce is called contrast ratio or simply contrast (in the monitor related industry). What is Contrast Ratio? (confusion about Dynamic Range and Contrast) However dynamic range of such a monitor is just 8 (bit) because it can reproduce only 256 (2^8) shades of gray. ![]() Thus each pixel can have 256*256*256 (16.7M) variations in color. Our darkest intensity (liquid crystal is 100% opaque) will be called black and our brightest (liquid crystal is 100% transparent) is called white. In other words we can display 256 different intensities or 256 shades of gray. It means that transparency of each liquid crystal can be set it 256 different ways (electronics which controls it can apply 2^8=256 different voltages to adjust its transparency). Intensity of the light source is constant so perceived "intensity" of each sub pixel is controlled by transparency of liquid crystal behind it. There is a liquid crystal behind each sub pixel and there is a light source behind all of that. Each pixel we see is actually comprised of three sub pixels each of which is covered with color filter - red, green and blue. Let's consider standard computer LCD monitor as an example. (Note! Foveon X3 ® comes as close as it gets nowadays to a color sensor but it is a very special case which we won't cover here).ĭynamic range is a ratio of brightest to darkest intensity the device can reliably capture or reproduce. This way each pixel has all three color values. In order to get color information we interpolate prime colors from neighboring pixels. It means that each cell sees only part of the light (part of the spectrum) which falls on it. Each individual cell of the CCD or CMOS is covered with Red, Green or Blue filter. How color is obtained then? Very simple actually. So all images obtained with these sensors are actually black and white (grayscale). Both CCD and CMOS can only "see" light as shades of gray. This way each pixel has all three color values.Contrary to popular belief, there is no such thing as a color light sensor. So one byte is eight bits.Ĭontrary to popular belief, there is no such thing as a color light sensor. Those 8 bits are usually combined in a logical block called byte. Notice that 8 digits (or 8 bits) of binary data can code a decimal number from 0 to 255. Number 2 in decimal is 10 in binary (1*2+0). Except instead of 10 numbers there are only 2. The same applies to the binary counting system. So number 1 2 for example tells us that there are 1*10+ 2 objects we have counted (where 10 is the base of the system). There are ten numbers from 0 to 9 which allow us to count up to nine objects (apples, coins, days left till vacation etc.) and if we want to count more than that we will add a digit to the front of the number. ![]() The decimal counting system we use in real word has a base of 10. Binary counting system is a way to store data and process information.
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