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Digital Image Processing Some Special Techniques Dithering 21/11/15 Duong Anh Duc - Digital Image Processing 1 Dithering Dithering, also called Halftoning or Color Reduction, is the process of rendering an image on a display device with fewer colors than are in the image. (Mateus Pins and Hermann Hild) The number of different colors in an image or on a device is used called its Color Resolution. 21/11/15 Duong Anh Duc - Digital Image Processing 2 Dithering If the display device has a higher spatial resolution than the image that you are trying to reproduce, it can show a very good image even if its color resolution is less. This is what we will call `dithering` and is the subject of this work. Dithering is a one-way operation. Once an image has been dithered, although it may look like a good reproduction of the original, information is permanently lost. Many image processing functions fail on dithered images. 21/11/15 Duong Anh Duc - Digital Image Processing 3 Dithering 21/11/15 Duong Anh Duc - Digital Image Processing 4 Dithering Grey-scale and colour simulation Dithering on a screen or printer is analogous to the half-toning techniques used in the print industry. A CRT can be considered to be a complex colour “dithering” device with variable colour intensity. 21/11/15 Duong Anh Duc - Digital Image Processing 5 ... - tailieumienphi.vn
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