Digital Ice Function Operation; Digital Ice For Photos Overview; Digital Ice For Film Overview - Epson Perfection V700 Photo Service Manual

EPSON Perfection V700 Photo

2.2 Digital ICE Function Operation

This scanner features Digital ICE, an image correction process that uses
a combination of hardware and software to detect and eliminate physical
flaws, dust or dirt, either on the media or the scanner itself. There are
two modes of Digital ICE, depending on the media being scanned:
photos or film. (Film includes color or monochrome negative, and color
positive.)

2.2.1 Digital ICE for Photos Overview

This scanner has two visible light lamps for reflection. The lamps are
placed symmetrically to produce the same image when a scan is made
twice. One of the properties of visible light is that it reflects irregularly
(scatters) when it illuminates a physical flaw or dust.
By comparing the images obtained with each lamp, an inconsistency in
the light pattern will reveal a physical flaw, dirt or dust. A software
algorithm is employed to interpolate the surrounding image data, and the
flaw or dirt is "removed" and "replaced" by the interpolated image data
— thereby repairing the photo. In this way, tears, creases, thumbtack
holes, etc. can be removed by Digital ICE.
Digital ICE for Photos Process Sequence
1. Energize lamp A and scan the image.
2. Energize lamp B and scan the image.
3. Electronically superimpose the images obtained from each lamp and
detect any inconsistent image data, indicating a physical flaw or
dust.
4. Replace the "flaw" image data with image data interpolated from
adjacent areas.
Operating Principles

2.2.2 Digital ICE for Film Overview

Because of its longer wavelength, infrared light normally passes
completely through film media, such as negatives or slides, during a
scan. Physical flaws or dust, however, do block infrared light. When a
film document with dust or physical flaws is scanned using infrared
light, the light is physically blocked by the flaw or dust, and the resulting
image clearly shows only the dust and/or flaws present. By
superimposing the images scanned with infrared light and visible light,
the Film-ICE software is able to detect the inconsistency in the digitized
data caused by the flaw and automatically remove it using interpolated
image data to overwrite and correct the image.
Because of the difference in wavelength between infrared light and
visible light, a secondary lens ("Glass Plate" in the images below) must
be employed during the Film-ICE visible-light scan to compensate for
the resulting difference in the size of the images so that they can be
superimposed accurately. The Glass Plate is moved into and out of
position by a solenoid.
Infrared Light
Visible Light
Figure 2-9. Refraction of Infrared Light and Visible Light
Digital ICE Function Operation
Lens Glass Plate CCD
Lens Glass Plate CCD
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