Image Quality Evaluation - Xerox DocuMate 4799 Manual

Xerox® DocuMate® 4799 and 4790
Note
In order to simulate grayscale (8 bits per pixel), the Reference Scanner captures halftone
images at 1 bit per pixel (black and white) and renders them using halftone screening at
different frequencies (lpi – lines per inch) based on the content of the document (fine or course
halftone) versus the Xerox DocuMate 4799, which renders a grayscale image at 8 bits per
pixel. As a result, the Xerox DocuMate 4799 is capable of reproducing images that more
closely approximate the original document
The captured digital images were then compared to equivalent scans (digital images)
obtained from the Reference Scanner, which served as the baseline, or reference for
comparison. The results of this comparison have been documented below. All scans were
captured independent of applying image enhancement software, which might otherwise
improve or enhance the appearance of the images during or post-capture.

Image Quality Evaluation

Black and White
Scans the image bi-
tonal, where everything
on the page is either
black or white
Grayscale
Scans the image using
varying shades of gray
to reproduce the
document
Color
Scans the image in color,
creating a full color copy
of an original document
Overall
  
Fair Good Very Good
1
Compared to equivalent scans from the Reference Scanner
Performance and Image Quality Expectations Guide
1
Xerox DocuMate 4799
 Better reproduction (clarity) of fine text and
 Not suitable for reproducing grayscale or

 Good overall reproduction of shades of

 May experience Moiré (interference pattern
 Acceptable overall reproduction of color
 Acceptable Tonal Reproduction Curve (TRC)

 Good reproduction (color and clarity) of fine
 Light color text on light backgrounds may

Performance and Image Quality
Assessment
line art compared to the Reference Scanner
color graphics
gray – variations from black at the weakest
intensity to white at the strongest, and Tonal
Reproduction Curve (TRC) – luminance, or
brightness of the image, compared to the
Reference Scanner
or artifact) in certain images
(color depth/balance), especially in highlight
areas compared to the Reference Scanner
– graduations of Cyan, Magenta, Yellow or
Black (CMYK) from 0 -100%, compared to
the Reference Scanner
lines and color text compared to the
Reference Scanner
appear fuzzy in certain color combinations
3-5