Difference between revisions of "Improving picture quality"

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(Other tips for translating text characters)
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???? Help !!!
???? Help !!!
=== Other tips for translating text characters ===
Using '''negative''' function on editor, may help us for translating some text characters.
Also, OCR (optical character recognition) may be used on scan but there is some open-sources tools and librairies who allow us to use it on picture.

Revision as of 11:57, 30 March 2007

While researching your family tree, you will come along old sources that need carefull handling. Pictures from these taking in an archive are often not optimal, and need cleaning up to make the text readable. Some pictures are snapshots of microfilm screenreaders.

Here we show how you can work on your picture to make the text come out better, improving readability. All with open source software, off course!

The sample picture 1

Unclean picture example1.jpeg

The sample picture is a raw jpeg picture of 1.5Mb. Light is centered in the middle, getting darker at the edges.


A good application to view these files is Gwenview (KDE).


Step 1

To edit it, The Gimp] comes to the rescue.

  1. Open the file.
  2. Select the relevant portion with the rectangular select tool. Copy and paste into a new canvas: type respectively, CTRL+C, CTRL+N + click OK, CTRL+V
  3. Save the file in the GIMP xcf format

Step 2

In Gimp, the Filters menu has the correctly named 'Enhance' submenu.

  1. Choose 2x2 Contrast Enhance
  2. Select the Destripe option, and set the value to 50.
  3. Now, in the Tools menu, go to the Colour Tools submenu, and choose Curves. You can now play with the curve level to get a better contrast on the picture Adjust colour curve example1.png
  4. As a last edit, select the centre highlighted region of the picture with the elliptic selection tool, and select in Tools menu--> Colour Tools the Brightness-contrast option, and reduce the brightness.

Now, save the result as png with maximum compression level.

The result:
Unclean picture example1 step2.png

What does it say?

The reason of editing the picture is to have a nice picture going with the source. However, in some cases, cleaning up is paramount to be able to read the source. Here this is not really the case, but reading might nevertheless be enhanced by the sharper contrast.

The text of this source says:

???? Help !!!