The scanner is a device which allows you to convert analog graphics e.g. a photograph or a printed page into digital format where it can be stored on the computer and further manipulated by appropriate software. Flat-bed scanners for personal use are quite common nowadays.
Most scanners connect to the computer using the USB, SCSI or parallel ports. To use the scanner, suitable software to control and drive it is required. The SANE backend drivers may be used to drive the scanner hardware while the XSane GUI front-end acts as the end-user interface. To check whether the scanner you have can be used, the SANE website at http://www.sane-project.org should be consulted. You can start the scanning software on the Desktop, from the Main Menu,
Main Menu --> Graphics --> Scanning
This will invoke the XSane program and by default two windows will be displayed, the Main Xsane window and the Preview window.
Click to view screen shot Fig 5.8 XSane Main Window.
There are 5 modes of viewing for this Main window viewer, save, copy, fax, mail:
- viewer mode - an image is scanned and displayed in the viewer
- save mode - an image is scanned and saved to a file
- copy mode - an image is scanned and sent directly to a printer
- fax mode - the scanned image can be sent to a back-end fax software
- mail mode - an image is scanned and sent via email to intended recipients.
The above modes can be selected in the Main window. In addition, the following selections are also available:
Selects the mode of scanning choices including colour, grayscale, lineart.
Selects the source of scanning, e.g.: Flatbed, Transparency, Automatic Document Feeder. This is only displayed if there is more than one possible source of input for scanning.
Selects the scan medium, e.g.: slide, standard negative or full colour range.
Selects the resolution that is to be used for scanning.
Before the actual scanning of an image takes place, the preview operation is usually carried out to preview the scanned image. To perform the preview, place the image to be scanned into the scanner and click on the "Acquire preview" button in the Preview window.
Click to view screen shot Fig 5.9 Preview Window
As the scanner will scan its entire scanner bed by default, if you are scanning an image which occupies only a part of the bed you will want to select only the area which holds the image to be scanned. This can be done from the Preview window in several ways. One way is to manually select the scan area frame by pressing and holding the left mouse button to define one edge, moving the mouse so that the area to scan is completely inside the frame (which is marked by a dashed white line) and then releasing the mouse button. Another way is to select the Autoraise button and then clicking on the image to be scanned. A frame is created to mark the scan area. The mouse may be used to adjust the scan area if it is not fully correct.
After the appropriate scan area has been chosen in the Preview window, the image can be adjusted and/or enhanced for colour correction, contrast, and brightness. The gamma value, brightness and contrast can be adjusted manually in the scan window before performing the scan. In addition, the Autoenhancement button may be used to automatically enhance and sharpen the scanned image for brightness and contrast.
After a satisfactory image is seen in the preview window, perform the actual scan by clicking on the scan button in the main Scan window. The scan will be performed and the scanned image displayed in the Viewer window.
The scanned image that is displayed in the Viewer window can be saved to a file by selecting the operation, File --> Save image. The file name and image format to be saved in can be chosen from the drop down menu selection.
Another way of saving is to select the Save mode, select the filename and format to save the image in and then perform the scan.
More detailed information on how to use the scanner software as well as changing the default configuration can be obtained from the Help menu selection. It also contains useful general information about scanner and scanned image technologies.
1. Perform a scan of an entire photograph containing several people or objects.
2. Using the same photograph as for the previous exercise, this time perform the scan for only the image of one person or object.