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With An Example Explain Each Type of Dithering and Its Advantage and Disadvantage There Are Three Types of Dithering Methods

There are three main types of dithering: 1) Random dithering introduces high frequency noise and is not suitable for most uses. 2) Ordered dithering uses threshold patterns to convert pixels to black and white in a dispersed pattern to reduce artifacts. Bayer patterns are optimal ordered dithering patterns. 3) Color look-up tables (CLUTs) are matrices that translate source colors to destination colors, such as when converting image colors to a display's color capabilities. CLUTs allow remapping colors between representations.

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216 views3 pages

With An Example Explain Each Type of Dithering and Its Advantage and Disadvantage There Are Three Types of Dithering Methods

There are three main types of dithering: 1) Random dithering introduces high frequency noise and is not suitable for most uses. 2) Ordered dithering uses threshold patterns to convert pixels to black and white in a dispersed pattern to reduce artifacts. Bayer patterns are optimal ordered dithering patterns. 3) Color look-up tables (CLUTs) are matrices that translate source colors to destination colors, such as when converting image colors to a display's color capabilities. CLUTs allow remapping colors between representations.

Uploaded by

Mossey Eliud
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
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Download as DOCX, PDF, TXT or read online on Scribd
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With an example explain each type of dithering and its advantage and disadvantage

There are three types of dithering methods:


 Random dither:
Random Dithering is a method of dithering which can be used for converting color
or gray scale images into monochrome (black and white) images.
Random Dithering works by choosing a different random value for each pixel in the
image. If the pixel is more intense (usually a higher number) than the random value, it
becomes white, if not, it becomes black.
This is the bubble sort of dithering algorithms.  It is not really acceptable as a production
method, but it is very simple to describe and implement.
Random Dithering tends to produce images with a lot of high frequency
noise artifacts(like a badly tuned TV picture), and so is usually not appropriate unless
you actually wish to achieve this type of special effect. 
The picture below shows a gray scale image, and the results of converting it to
monochrome using Random Dithering:

Original Image Image after Random Dithering

 Ordered dither:

We can express the patterns in compact form as the order of dots added:

     8  3  4          and        1  7  4

     6  1  2                         5  8  3
     7  5  9                         6  2  9

Then we can simply use the value in the array as a threshold.  If the value of the pixel
(scaled into the 0-9 range) is less than the number in the corresponding cell of the
matrix, plot that pixel black, otherwise, plot it white.  This process is called ordered
dither.  As before, clustered patterns should be used for devices which blur dots.  In
fact, the clustered pattern ordered dither is the process used by most newspapers, and
the term halftoning refers to this method if not otherwise qualified.

Bayer has shown that for matrices of orders which are powers of two there is an optimal
pattern of dispersed dots which results in the pattern noise being as high-frequency as
possible.  The pattern for a 2x2 and 4x4 matrices are as follows:

        1  3        1  9  3 11        These patterns (and their rotations

        4  2       13  5 15  7        and reflections) are optimal for a

                    4 12  2 10        dispersed-pattern ordered dither.

        16  8 14  6
Explain the concept of Color Look-up Tables (LUTs)
A matrix of color data that is searched in order to change a source set of colors to a destination
set. Color lookup tables (CLUTs) are found in graphics cards (display adapters) in order to
translate the colors in an image to the colors in the hardware. It essential can convert colors and
details in a source file to a new destination state.

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