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Chapter 2

50 VirtualReScan (VRS) User’s Guide

Brightness and Contrast

When the Auto Brightness check box is selected, VRS automatically assigns optimal

values for brightness and displays those values in the manual Brightness slider and

numeric text box. The Auto Brightness setting is not applicable when you scan in

color mode.

Moving the Brightness slider, entering a value in the Brightness numeric text box, or

clicking in the Brightness-Contrast custom control turns off Auto Brightness.

Figure 2-35. Auto Brightness Check Box

Edge Detection

Edge detection in VRS is controlled with the Contrast slider. Edge detection, or edge

finding as it is sometimes called, is a technology that can recognize transitions of one

gray level to another level. The larger the difference between the levels of gray, the

more “edgy” the object is. With a low contrast level, only very edgy objects become

black (such as black text on a white background); very faint text and lines would still

not appear because the transition from a white background to light gray is relatively

minor. Faint text and lines are therefore not “edgy.” A background, because it does

not have transitions from one level of gray to another, would not be edgy. A gradient,

because there are no sudden transitions from one level of gray to another, would not

be edgy.

Even something that is technically invisible to the eye, such as a piece of transparent

tape placed on a document, could be detected when contrast is set high enough, since

there is ultimately a transition from the tape to the paper surrounding it.

Manual Image Adjustment

VRS provides the option to manually adjust the settings for an image or images. You

can use the Clarity panel to make the adjustments.

Brightness-Contrast Custom Control

The Clarity panel includes custom controls (visual markers) to assist you in

identifying the optimal range for brightness and contrast.

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Kofax UP-D005-0001 Betriebsanweisung Seite 60