Originally posted by kirbic:
Moire is really not that hard to define, but it is hard to conceptualize. The best example from everyday life that I can think of is two screens one just in front of the other. If you rotate one screen slightly, you'll see a pattern of broad dark and light bands appear. That's because of the way the wires of one screen overlay the wires and openings of the other.
Moire in a camera is just like that. If a light-dark repeating pattern is projected (by the lens) onto the sensor, and the pattern repeats at almost, but not quite the same frequency as the pixels, you'll get moire. The funky color effects happen because not all colors are sensed at all pixel positions (because of the color filter array). The order of color filters in any given row is GRGR... the next row alternates GBGB.. every other pixel senses green, but only every fourth senses red or blue. The pattern is offset in each row, and the resulting two-dimensional filter patern is called a Bayer Pattern.
In most cameras, a filter is used over the top of the sensor that limits the resolution of the resulting image, and is referred to as an "AA" or anti-aliasing filter. This filter helps to eliminate "jaggies" on diagonal lines, and also greatly reduces Moire. |
You know i got jus about everything in the first sentence or to and then everything you said went straight about my head i wondered if you might be able to rephrase that into a dummy version thanks
Leon
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