A-63054 February 2004
9A-31
Noise filter
—these options are available to help increase the compression
ratio and improve the appearance of document images.
• Majority Rule—determines central pixel data according to the number of
white and black pixels.
• No Filter—no enhancement is done to the images.
• Remove Lone Pixels—reduces random noise on bitonal images by
converting a black pixel surrounded by white pixels to white and by
converting a white pixel surrounded by black pixels to black.
NOTES: Using the noise filter on documents containing very fine detail (e.g.,
the dot on an “i” in 4-point type) may cause information to be lost. It is
recommended that the noise filter not be used when scanning
documents with text smaller than 7-point type.
Using the noise filter in conjunction with thresholding will optimize the
appearance of document images.
Do not use the noise filter with screening (dithering).
Enhancement
—select None or Halftone removal. Halftone removal is used to
enhance images. containing dot matrix text and/or images with shaded or color
backgrounds using halftone screens. This filter effectively eliminates noise
caused by the halftone screens.