Dither

Technique for producing halftone images by representing the entire grayscale with only two pixel levels, black and white.

Double feed detection

A scanner function which detects the accidental feeding of multiple sheets by the ADF unit. Can be turned on or off by the operator.

Double Letter Size

A standard paper size used in the U.S.A. and other countries. Paper size is 11 x 17 inches.

dpi

Dots per inch.

Dropout color

A color which is used in the document but does not appear in the read image.

Duplex reading mode

A reading mode in which both sides of the document are read.

Equipment Error

An error that cannot be corrected by the operator. Call CE.

Error diffusion

High-quality halftone (pseudo-grayscale) image production based on black-and-white pixel binarization. A pixel’s optical density and that of adjacent pixels are summed, with black pixels relocated in their order of density as they relate to adjacent pixels.

The purpose of this technique is to minimize the average error between read and printed densities. Density data for adjacent pixels is modified by diffusing errors on the objective pixel into several pixels, which are then binarized. This maintains high grayscale levels and resolution during reading, while suppressing more patterns by dotted halftone images such as newspaper photographs.

GL-2