OPTIONS

FRONTEND FUNCTIONS AND OPTIONS:

This backend dynamically enabeles the options that are supported by the scanner in dependence of the scanning-mode and other options. Here is an example of the frontend xsane :

The options Gamma, brightness, contrast and negative in the main window come from xsane that calculates a gamma table using this values. These values are corelated to highlight, midlight and shadow sliders in the Histogram window.

Scan modes:

Mode	Remark
Lineart	1 bit/pixel black/white mode
Halftone	1 bit/pixel dithered black/white mode
Grayscale	8 / 9 / 10 / 12 / 14 / 16 bits/pixel gray mode
Color	24 / 27 / 30 / 36 / 42 / 48 bits/pixel RGB mode

Scan sources:

Scan sources

Flatbed

Transparency adapter (UTA)

Automatic document feeder (ADF)

Standard options:

Standard options	Remark
Analog gamma correction	Define the value for analog gamma correction. * Value between 1.0 and 2.0 . (Analog gamma correction doesn't reduce the number of used colors)
Highlight	Define the intensity that shall be considered white. *
Shadow	Define the intensity that shall be considered black. *
Contrast	Define the contrast of the image - only available in halftone-mode.
Brightness	Define the brightness of the image - only available in halftone-mode.
Threshold	Define the minimum intensity to get a white point- only available in lineart-mode.
Use custom gamma table	Use free definable scanner internal digital gamma table. If you enable this option, the gamma correction is done inside the scanner. If you have a scanner with more than 8/24 bits/pixel, the image is scanned with the maximum available bit depth. The gamma correction does transform the image form the internal bit depth to the selected output *bit depth* (see below). The frontends do handle the usage of the gamma table different. If you use xsane, you should enable this option to use the maximum available bit depth (otherwise xsane does the conversion with the selected output bit depth). (Side-effect: digital gamma correction may reduce the number of used colors -especally if the used bit depth is low.)
Quality calibration	Use quality white calibration. *
Double optical resolution	Use lens 2 on high end scanners, this reduces the scanwidth and increases the maximum scanresolution. *
Negative scan	Inverts color intensity - for scanning negatives.
Bit depth	Image depth in bits/sample the scanner sends to the computer, normally 8 in grayscale and color mode. Some scanners support more than 8bits/sample, but only few file formats support it. If your scanner supports more than 8bis/sample you already get an improvement if you set the bit detpth to 8 and enable the option use custom gamma table (see above) because the scanner internal gamma correction is done with the maximum available bit depth!!! * There is normally no reason to use more than 8 bits/sample! *
Lamp warmup	Enable extended lamp-warmup. *

* only available for some scanners

Advanced Options:

Advanced options	Remark
Set exposure time	Enable selection of exposure time, if not enabled, scanner uses default values. *
Cal. exposure time	Define exposure time for calibration. *
Scan exposure time	Define exposure time for scan. *
Set lamp density	Enable selection of lamp density, if not enabled, scanner automatically selects a value. *
Cal. lamp density	Define lamp density for calibration. *
Set scan lamp density	Enable selection of lamp density for scan, if not enabled scanner uses the value that was used for calibration. *
Scan lamp density	Define lamp density for scan. *
lamp on	Turn on scanner lamp. *
lamp off	Turn off scanner lamp. *
lamp off at exit	Turn off scanner lamp when program exits (when sane_close is called) *

* only available for some scanners

SANE-UMAX index

This page has been changed on 28th. august 2000