Gamma

Noise Reduction

The Gamma option allows you to define the gamma curve setting for normal scanning and computer screen viewing. Choose one of the five gamma curves in the Gamma drop-down list box. There are standard and CRT levels in a gamma curve. If you intend to view the scanned images on a computer screen, select “For CRT.” Otherwise, choose “Normal.”

A gamma setting can be specified only when a Halftone (Dither) pattern, an Error Diffusion pattern for Binary mode, or a Grayscale mode is selected.

Unwanted black speckles or splotches in a scanned document are referred to as noise. Noise Reduction improves image clarity by removing black spots, dust, or voids in white areas. Choose a noise reduction level in the Noise Reduction box. The default is “None.”

The more noise in a scanned image, the larger the compressed file size. Also, if images are being produced for an OCR system (a system that can read text from an image produced by a scanner), too much noise may lessen the reliability and read rate of the OCR system.

While choosing the larger matrix decreases large noise, commas (,) or decimal points (.) may disappear as well. Noise Reduction is valid only in Binary mode. Using Noise Reduction is not recommended when using a Halftone (Dither) setting.

None

Noise Reduction 4 x 4

A-63055 December 1999

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