Types of machine-readable form
Black-and-white forms with raster background
Black-and-white forms with raster backgrounds place fields as white spaces over fine dot patterns that despeckling removes before recognition.
On these forms, fields are white spaces (usually rectangles) on a raster background made up of individual dots.
The recommended dot size is no more than 0.1 mm, with about 1 mm between dots. Dot size and spacing are crucial, because ABBYY FlexiCapture removes the raster background during despeckling rather than during scanning, treating the dots as garbage. For this reason, the dots must not be glued together on scanned images.