Scanner software

Scanning and Imaging Software

ScanHelp.com is also a reseller of software with innovative features such as Small Office Scan Tools, Expervison TypeReader and Visioneer PaperPort.


Descreening Images


Why we use descreening


There may come a time when something important is printed, or displayed in a magazine or newspaper that you want to scan into your computer to save or manipulate. This may at first seem to be a simple process when you go about setting up your scan. What could be easier than just putting the document into the scanner, and then scanning it into a computer? Well many people don’t understand that the images that appear so clean and crisp in the magazine or newspapers are printed using a method known as halftoning. Those photos are printed using a series of overlapping dots that fool your eyes into seeing more colors than are actually there. Because of these overlapping dots, scanning these documents or images will produce something known as Moiré pattern (pronounced more-ay).

A Moiré pattern happens when two identical patterns of lines, circles, or array of dots are overlapped with imperfect alignment creating an interference pattern (resembles an optical illusion). Scanning these images into the computer will result in a wavy pattern that garbles the original image leaving you with a useless image. What makes things worse is scanning the image or document slightly off alignment can increase the effects of this wavy pattern, not only that, but the pitch of the scanners sensors will enhances the pattern even more. This will happen with any scanner, so don’t go blame it on the manufacturer just yet for the pitch of the scanner sensors.

To counter this attack on our visual spectrum Art-Scan was designed with two counters to this Moiré pattern. Art-Scan was designed with a descreening function that when used removes the halftone dot pattern from the printed material during scanning by defocusing the image. This effectively eliminates the Moiré pattern and the color shifting patterns. The downside to this process is the image will become slightly less detailed due to the blurring effect caused by the descreening process. This is where Art-Scan’s Sharpen Image setting comes in. By setting the unsharp mask after performing a descreening operation the image can be restored to its original sharpness.

How to perform a descreening


Orginal:
Output:

1) Find the article either from a book or magazine or even a newspaper that you want to save onto your computer. Clip the article from the document, or if it is able to fit underneath the scanner bed lid slide the document onto the scanner bed. For this example we will be using Art-Scan 5.0.

2) Go to your Start Button>click on Programs>click on Art-Scan Pro 5.0>and then click on Art-Scan 5.0 via Jetsoft Viewing Booth Pro 2.0(Acquire Edition) to open Art-Scan. If you are unsure if Art-Scan is using the current scanner you wish to acquire the image from, hold the shift button while you click to open Art-Scan 5.0. This will display the select source dialog, then go ahead and select the current scanner you wish to work with.

3) In order to get an idea of where your document/image is placed on the scanner bed go ahead and click on the ‘Preview’ button in order to get the preview image saved in the image area. Keep repeating this step until the area of the document or image is as squarely lined up parallel with the scanner bed side, which is represented by the edges of the image preview area.


4) Change the scan mode now from RGB (default), to Gray Scale, and perform another ‘Preview’. At this point I would also suggest clicking on the ‘Preferences’ option, then setting the “Target Resolution for Preview Scan:” from its default 50 to 200dpi. That way the image being shown in the preview area is displayed with better clarity to give you a better understanding of what the finished image will look like.

6) After having converted the RGB document into Gray Scale the image still can look very dark, and the outlying pages around the image or text can contrast quite a bit. With Art-Scan’s ‘White Point Selector’ all you need do is select the option, move the selection pointer over the image preview area, and click on the background page. The WPS will then convert whatever color level was selected into the white color. It is also advised that you use the Black Point Selector. Simply pinpoint the darkest area of the image, usually text on the article will provide an excellant choice, and select to set the area to set the black of the image.


White Point Selector:
Black Point Selector:

7) You can now select the descreening option, but when you do make sure click and hold on the button to bring up the advanced descreening options. The first thing you should do is change the ‘Sample Resolution’ from its default 300dpi to 600dpi, and then change ‘Type of Original’ to the type of document you’re working with, anything from a newspaper to lithograph. In our example we chose “Newspaper / Laser (65 – 106 lpi) 9x9”.

8) Since descreening the image will have the unfortunate effect of causing a slight blur, it’s best to apply a sharpen effect to the image as well. By applying the sharpen option the blur from the descreening will be instantly corrected, and the image will again be as crisp and clean as the original was to our naked eye. Since you may make any number of changes with the descreening options, you too can click, and hold on the ‘Sharpen Image’ option to bring up the advanced sharpening menu. From there you can change anything from the percentage of intensity to the percentage of sharpening for shadows in the image. From the menu you can perform a preview to see what the effect of changing the intensity, or any other option will have on your image so you can judge which setting is best for what you’re doing.

9) Finally all that is left is to click the scan button, and let Art-Scan do the rest. The whole process may take a few moments to scan the image at a higher resolution, and then apply both the Descreen and the Sharpening to the image, but in the end we’re sure you’ll be pleased.


Scanner software compatible with the following:
  • Canon
  • Brother
  • Epson
  • HP
  • Lexmark
  • Fujitsu