Technical Brief

Scanner Technical Brief—Page 5 6/07
3. Processing: Many Epson scanners use a custom ASIC (Application Specifi c Integrated Circuit) for fast
scanning. Key features include:
 Line correction captures and processes full RGB color for every pixel and minimizes color fringing in
subscan direction.
 Zoom capability enables smoothest edges along diagonal or curved lines and achieves higher
interpolated resolution
 On-board memory allows for Auto Area Segmentation (AAS) and Text Enhancement Technology (TET)
processing within the scanner—AAS and TET are independent from PC or Macintosh processing,
allowing the scanner to work with better “raw” data.
Additionally, Epson scanners have a pixel optimization feature
that uses the full resolution of the scanner’s CCD, even scanning
at a lesser resolution. The benefi t of this feature is truer image
quality.
 For example, on one of the Epson 600 dpi Perfection
scanners, when scanning an image at 300 dpi, the scanner
still uses all 600 pixels per inch to scan the image, then
averages the data to yield the lower resolution image.
 Some competitive models lower resolution by turning off
some pixels to capture less image data.
Image Quality—Epson ColorTrue® Imaging System (cont.)
Image Quality—Color CCD
All Epson scanners use a color CCD which uses a single white light source, instead of a monochrome CCD
and three light sources. The color CCD results in faster scanning speeds and the ability to scan three-
dimensional objects without producing color “ghosts.”
Key Differences
Color CCD
Monochrome CCD
How it works
Red, green, and blue are quickly captured
in the color CCD illuminated by a single
light source.
three separate lamps are fi red for eachline
of a scan, slowing the scanning speed.
Result when
scanning three-
dimensional objects
Single light source allows precise
alignment when scanning non-fl at
surfaces
The three lamps can cause misalignment
when refl ected from non-fl at surfaces.
Glass
Monochrome
CCD
Red light
source
Green light
source
Blue light
source
Glass
Color CCD
White light
source
On Off On Off On Off
Epson Method:
Competitive Method:
Average
Average
Average
600 dpi
600 dpi
300 dpi
300 dpi