Abstract
This section will explain how to install and use scanners by means of ScannerDrake (the scanner wizard), SANE and XSane (scanner interface software). It will also give a list of other scanner interface software working under GNU/Linux.
Using scanners under Mandrake Linux has never been easier. If your scanner is supported by SANE, which is very likely if it is a USB one, you only have to connect it to the computer, turn it on and launch your favorite image-acquisition application.
If this does not happen, don't worry: thanks to the ScannerDrake wizard you will have your scanner identified, configured and ready to work in just a few minutes.
Note that, while support is now very good for these kind of devices, not all scanners are supported under GNU/Linux: before buying new hardware, it's always a good idea to visit MandrakeSoft's Hardware Database, the Linux Hardware Database web site, and the SANE home page, to check for compatibility issues.
If your computer is connected to a LAN, you might be interested in running the ScannerDrake wizard to take advantage of its scanner sharing feature.
Most modern scanners need no configuration at all: it should be possible to just connect a scanner to the computer, turn it on, and launch the image acquisition software. The scanner will be automatically recognized and you will be able to use it at once.
If you use GNOME or KDE, when a scanner is plugged in and turned on you will see an icon similar to the one shown in Figure 13.3 appearing on your desktop. This icon will give you instant access to the scanning software and will disappear when the scanner is turned off or disconnected.
If the icon fails to show up, or the scanning software (XSane) does not seem to work, the reason could be any of the following:
The dynamic icons feature is not working properly on your system: make sure that you installed the hotplug and dynamic packages.
The SANE software is not installed on your system. Please start ScannerDrake to get it installed automatically or refer to the section called “The SANE software”, to learn how to install all of the required packages.
XSane cannot be used because your scanner has not been automatically recognized. Please read the section called “ScannerDrake”, to learn how to configure your scanner with ScannerDrake.
Your scanner is not a USB one. The dynamic icons only work for USB scanners. In this case launch XSane by choosing + -> in the main menu.
You can be confident that SANE will automatically recognize USB scanners. If you have a SCSI or parallel port scanner, you probably must set it up using ScannerDrake.
SANE, which stands for “Scanner Access Now Easy”, is an interface for scanners and other image-acquisition devices like digital cameras and framebuffers. SANE sits in the middle between the device and the acquisition/image processing software, in order to allow developers to write application software without worrying about device drivers.
The SANE software consists of three packages: the SANE library (libsane1), the SANE back-ends (sane-backends, the modules for the scanner devices) and the SANE front-ends (sane-frontends, basic programs for scanning images). If you have not installed the SANE packages during the system installation, please run ScannerDrake: it will install all required packages automatically.
ScannerDrake is the Mandrake Linux scanner detection and configuration tool. This wizard will help you install your scanner if the automatic detection fails and, as of Mandrake Linux 9.1, it has some interesting new features.
At the moment of writing this manual, ScannerDrake supports practically all USB scanners and the majority of SCSI and parallel port scanners. Once again, refer to the SANE home page for more information.
Before launching ScannerDrake, the connection interface (USB, SCSI or parallel port) must be working properly, the scanner itself must be connected to your computer and the power turned on. Refer to the manufacturer's manual to learn how to install and test your hardware.
When everything is ready, you can launch
ScannerDrake clicking on this icon in the Mandrake Control Center under
the Hardware section. Remember that all
hardware configuration must be done as root.
The program will try to detect the manufacturer and model of your scanner, if it finds one which is ready to use it will show some information about it in the upper part of the wizard's main window. If, on the other hand, detection failed and no scanners were identified, you will be shown this window:
You can try to perform a new search clicking on , useful if you have just plugged in a scanner. If the automatic detections fails in any case, click on and look for the specific model you own by first expanding the manufacturer's section, then browsing through the list of available models.
After choosing the appropriate model, you will be asked to select the device your scanner is attached to. Unless it is a parallel port scanner, you can leave the default Auto-detect available ports option and click on Ok, as shown below. If you have a parallel port scanner, please specify the port it is connected to. Usually there is only one parallel port in a computer, so selecting /dev/parport0 in the pull-down list should be the right choice.
Now your scanner is installed and you are ready to use the programs that come with SANE, XSane or other acquisition software.
Note that HP multi-function devices, like the OfficeJet or PSC printers, must be configured through PrinterDrake. Please refer to the section called “PrinterDrake: Configuring Printers” for more information. The scanning part of non-HP multi-function devices can be set up with ScannerDrake as a stand-alone scanner.
To test that everything works correctly, launch xscanimage from a shell and try to acquire a picture with your scanner. You can first acquire a preview of the scanned image clicking on the Preview window button, as shown in Figure 13.7.
Note that xscanimage can also be invoked directly from GIMP, choosing + + -> from the menu, or choosing directly the [name_of_your_scanner]:[port_of_your_scanner] entry, where [name_of_your_scanner] will be the manufacturer's name of your scanner; and [port_of_your_scanner] will be the port your scanner is connected to, e.g. epson:/dev/usb/scanner0 for an Epson USB scanner.
Starting from the version included in Mandrake Linux 9.1, ScannerDrake allows for scanner sharing among users connected via a LAN. Installation is very easy just click on and put a mark in the checkbox if you want to share a local scanner with other users connected on the same LAN; or on the checkbox if you want to connect to a scanner connected to some other computer on the network. With these buttons you can define which machines are allowed to use your scanners and to which machines the remote scanners you want to use are connected to.
While xscanimage is more than enough for your basic scanning needs, more experienced and/or graphic-oriented users will be glad to know that Mandrake Linux includes a more sophisticated program, XSane, which offers more options and a more informative display as regards the image acquisition process.
You can launch XSane by clicking on the desktop icon, or choosing + -> from the main menu. You will see several windows pop up on the screen, as shown in Figure 13.9.
If the package xsane-gimp is installed, you will have a GIMP plug-in at your disposal. This will allow you to import your images directly into GIMP for image retouching tasks (see the Graphic Art and Image Manipulation chapter from our on-line documentation). To do this, simply choose -> -> from the menu to launch XSane. You can now scan your image and have it sent directly to GIMP.
Most modern scanners boast high resolutions, typically 600 DPI (Dot Per Inch) or even more, which can increase to higher values through interpolation. But it would be a mistake to perform all of your scanning at the maximum available resolution. It could happen that there is very little, if any, quality difference between a 300 and a 600 DPI image scan, but the file size will grow exponentially at higher values, up to many MBs of disk space for a single image file.
The resolution value should be chosen according to the device on which the image will be reproduced. For images that will be shown on computer monitors, e.g. web site images, the resolution will have to be as close as possible to the monitor's one, about 80 DPI (for a 1024x768 display, could be less for 800x600); higher values will result not only in “heavier” images, but the dimensions will also increase, so that an image scanned at 160 DPI instead of 80 will be about twice as large[15].
If you intend to print your images, a resolution of 150-200 DPI should be enough for most home printers; increase this value if you have a very high quality ink jet printer or a dye-sublimation one. Keep in mind that the value commonly used in printed magazines is 300 DPI.
Higher values should be chosen only for specific uses, such as enlarged images on very high quality printers, or scans of black and white originals. You will have to experiment a little until you are satisfied with the results.
Unfortunately, OCR (Optical Character Recognition) software is not as common or sophisticated as the image acquisition counterpart. There is at least two programs, however, that are mature enough: Clara OCR and GOCR/JOCR . You will find all the necessary packages in the contrib CD.
Clara's graphic interface is very simple and does not require a specific desktop environment, but it will be necessary to train the program on the scan of a sample page. The training process can be quite tedious, and not very intuitive for the newbie [16], so be sure to read the tutorial file. More experienced users should also refer to the Advanced User's Manual.
GOCR/JOCR is another project which has reached an usable status, but bear in mind that it's still beta software (latest release at the moment of writing was 0.37). GOCR/JOCR can read images in many formats, while its output is a simple text file. It is a command-line tool, so if you want to use a graphical front-end you will need to install the gocr-gtk package.
Here is a list of other scanner interface software which is known to work under GNU/Linux:
if you installed the kdegraphics-kooka package, you will be able to use Kooka, a simple graphical front-end to SANE which is also able to perform OCR tasks; to launch it, choose + -> from the main menu;
users of the FLTK (“Fast Light Tool Kit”) graphic user interface can try FlScan, a FLTK front-end for SANE;
for EPSON scanners, you can download Image Scan! for Linux, a scanner utility provided free of charge to GNU/Linux users by EPSON KOWA Corporation. It aims at achieving the same level of user friendliness and image quality as the Windows/MacOS software bundled with the Epson scanners;
while multi-functional HP devices are configured using PrinterDrake, owners of these devices should have a look at the HP OfficeJet Linux driver project. The developers involved in the project aim at providing GNU/Linux support for most Hewlett-Packard OfficeJet, PSC, LaserJet, and PhotoSmart printer multi-function peripherals (MFPs).
[15] This, however, is a quick way to enlarge images taken from small originals. You could also scan at a higher resolution and then save it at half size, using graphic manipulation software like GIMP, to improve image quality if you are not satisfied with the result obtained at 80-90 DPI.
[16] To quote the authors: “Clara OCR is not simple to use. A basic knowledge about how it works is required for using it”.