MITSUBISHI ELECTRIC DV1248ST - Manual (Page 80)

Tips for Improving Recognition Quality
If you have a text document with many unrecognised characters, the reason may
be that the source image is of a poor quality. You should set the correct brightness,
and resolution and use the Diamond View scanner’s Threshold function then rescan
the image. Make sure the page is clean of any pencil marks, dust, etc and clean it
off if necessary.
A poorly recognised text can be due to incorrect recognition parameters, e.g.,
selection of an incorrect language or selecting too many languages. For instance,
recognition errors in each line may be caused with recognition of an English text
with English-Russian language.