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<< Click to Display Table of Contents > Generating a scanner bitmap |
  
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<< Click to Display Table of Contents > Generating a scanner bitmap |
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In the following the parameter setting with SAM for the apple.bmp is shown.
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The apple.bmp consists of a gray scale bitmap with 255 different possible gray scale values G (x,y). After loading the bitmap the user may scale it according to his needs. Depending on the X and Y dimension and Nx, Ny the bitmap will have a specific dx,dy value for each pixel. To prepare the bitmap for the scanner output the user has to generate a so called scanner bitmap out of the original bitmap. This is done with the help of the Bitmap property page.
For an original Gray Scale bitmap there are two possibilities to generate a scanner bitmap:
a) Error diffusion method:
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With this method the gray scale values will be approximated by specific placements of black and white pixels to give the impression of gray values. This is a similar method as with a Black/White LaserJet.
b) GrayScale method:
With this method the gray scale values will be kept when transforming them to the scanner bitmap.
Dither step: For both methods a so called Dither step parameter can be selected which defines the dx and dy value (which are both equal to Dither step) for each pixel inside the scanner bitmap. The original pixel number Nx,Ny will be changed to new ones Nx=DX/Dither Step with DX as the X Dimension of the bitmap, and Ny=DY/Dither Step respectively. With this a gray scale bitmap can be transformed into larger pixel size, for example:
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