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| Understanding Scanners/Monochrome images and Optical Character Recognition (OCR) | Index | Home |
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Images imported in color cannot be reproduced neatly with facsimiles or monochrome printers |
Binarized image; the gradations are not displayed |
Facsimiles, monochrome printers and monochrome page printers print by using two kinds of dots; one represents white and one represents black. This method works well for printing letters and other symbols but turns subtle color gradation found in images into solid black. |
Original image |
To make a scanned image more attractive when printed, its overall surface must be processed with a simulated gradation; the original photo must be processed with a monochrome net-like dither before being imported. Dithering serves to simulate gradation by rearranging the dots. |
Choosing dither |
Image corrected with dithering |
When the data of an image is transmitted directly from a computer through a facsimile modem, the recipient must ascertain whether the image has already been dithered prior to the transmission. This precaution is necessary to avoid a repeated dithering of the image by the receiver. |
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