Plustek Opticpro A320E Flatbed Scanner - Manual (Page 54)

The TWAIN Interface 19
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2.2.2.4 Filter
Filters help you improve your scans by allowing you to sharpen images as well
as remove excessive dots and distortion.
The following options are available from the drop-down list:
· None -- Applies no filter in the scanned image.
· Average -- Determines the medium depth of an image and averages adjacent
pixels to make images appear softer.
· Blur -- Dulls the edges within an image and decreases the contrast by making
dark edges lighter and light edges darker.
· Blur More -- Adds additional blurring.
· Sharpen -- Allows you to sharpen the edges within an image by making the
edges in an image more distinct. The Sharpen filter also increases contrast
by making dark edges darker and surrounding light edges lighter.
· Sharpen More -- Adds additional sharpening.
· Unsharpen -- Sharpens the edges in an image to remove the blurriness.
This setting is not available when Black & White is selected as Scan Mode .
The application of a filter can greatly reduce the scanning
speed.
2.2.2.5 Gamma
Image Gamma is used to adjust the colors in the image that will be scanned
into the computer. Gamma values follow a smooth curve. By adjusting the
gamma, you can change the tonal range of the selected color channel.
Gamma values are primarily a measure of the brightness of a color. The larger
the gamma value, the brighter the color becomes.