How to use the scanner in Ma426

In the Linux laboratory Ma426 there is a scanner connected to the computer switch. The following is a short introduction on how to use these items to scan a picture into the computer. To use the scanner, it is necessary to be logged onto the console of switch.

Single pages / ordinary scanning

If it is desired to scan an image with preprocessing and with the aid of a window-based system, two methods are recommended. The first is with xsane, a program only for scanning images. The second is with Gimp, a more advanced program for image processing, etc. For quick-and-dirty processing, xsane is recommended, while Gimp may be the best choice if the image is to be manipulated afterwards.

xsane

Start xsane by issuing xsane at a command prompt.

When xsane is started for the first time, a license agreement (GPL) is offered. It has no legal effect in Sweden; just click on Accept to start the program.

When the application starts, four windows are displayed: Preview, histogram, xsane och standard options.

Preview

This window is used to obtain a preliminary image of that which lies on the bed of the scanner, in order to select which area will be scanned, etc.

Histogram

This provide a histogram over the use of color in the picture, before and after transformation by the program. The ordinary user can ignore this window.

xsane

In this window, the main configuration parameters for scanning are entered.

standard options

In this window, the basic parameters for scanning, including brightness and contrast, are accessible.

If you are not certain of the function of a button or control, place the mouse cursor over it and after a while a short description will appear.

Scanning in an image

Begin a usual scan by choosing what will be done with the resulting data. Do this by selecting the Xsane mode. Choose Viewer if you want only read it in order to view it in a program, and Save if you want to save it to disk.

Next, select how the image will be read in; color, black-and-white, greyscale, etc. Place the document or picture in the scanner (by lifting the paper feeder) onto the glass; align it with an edge. Next, press the button Acquire preview in the Preview window. This causes a preliminary image to be scanned in the position chosen and displayed in the Preview window.

Now choose the the region of the document or image which is to be read in. To do this, mark the region with the mouse. Press and hold the left mouse button while at one corner, and drag the cursor to the opposite corner. That will create a pane as shown in the example to the right. This is the region which will be scanned in.

Choose the file name under which the image will be saved using the xsane window next to the little diskette icon. Give the entire name or click on the diskette to chose a name. In the menu Type, choose the type of file to be saved, or type the entire file name, including an extension to identify the type (for example, bosse.jpeg will be saved in JPEG-format).

Next, choose the resolution to be used, in dpi (dots per inch), by selecting the uppermost choice (Set scan resolution). This scanner has a maximum resolution of 1200 dpi. Note that after making this selection, the size of the image in the lower part of the window is changed to reflect this choice. The raw size of the data is also given (which may be much larger than the final result if a compressed format such as JPEG will be used). It is best to choose even values, such as 200, 400, or 800 dpi; otherwise the scanner may need to sweep back and forth many times to scan the image properly.

At first, you can ignore the other settings. If the image is too light, too dark, too flat, etc., experiment with the settings Set gamma value, Set brightness, Set contrast and examine the different results.

Press Start to scan in the image.

Gimp

Gimp - GNU Image Manipulation Program is an advanced image-processing program. This information covers only how to scan images using Gimp. For more information on how to use the program, use the built-in help system or consult Gimp's website.

Gimp must install files in your home directory to function well. Read the instructions on the screen and follow them. You will be prompted for a location for the Swapfile. Choose /tmp and not in your home directory as the program suggests. This file can be quite large and is used intensively; therefore it is best to store it locally and not in your home directory, which must accessed over the network. Also, to achieve good results, ask Gimp to read the monitor resolution from the system.

Once in Gimp, enter the File menu and choose Acquire, XSane, plustek:'dev'usb'scanner0. This starts the same scanner interface as in xsane. Follow the instructions under xsane above, with the exception that you cannot choose what to do with the image. After being scanned in, it opens automatically in Gimp and may be processed as you wish.

Good luck!