Optimize a scanned document for text

[Knocks]

I don't have a scanner so I have to use a digital camera to scan documents. The documents include typed and handwritten text. The jpegs taken by the camera look great on LCD but don't print very well. They come out with a lot of gray tones where the white background is supposed to be, and the clarity of the text is poor.

Does IrfanView have any features that would allow me to optimize these images so I can combine them into a PDF and send to someone else for printing? I appreciate any advice.

P.S. If there is another program or script that I can use in combination with IrfanView to accomplish this, please let me know as well.

[Bhikkhu Pesala]

You could OCR the images and convert them to text — that would be much more useful.

Free OCR will probably give better results than the IrfanView plugin.

[Knocks]

You could OCR the images and convert them to text — that would be much more useful.

Free OCR will probably give better results than the IrfanView plugin.

I don't need OCR, just visible text with a clean background acceptable for printing. Like I said, these documents include handwritten text and are not fit for OCR.

[Frank]

You can use the gamma correction in advanced options of batch conversion!
(See also the german thread: "Schwellenwert für 1Bit Farbtiefe - oder alternatives Vorgehen?")

[Mij]

Try the free Fine threshold 8bf filter.

Just unpack it and put the file finethreshold.8bf into the Plugins\Adobe 8BF folder of your Irfanview installation.

[Knocks]

Try the free Fine threshold 8bf filter.

Just unpack it and put the file finethreshold.8bf into the Plugins\Adobe 8BF folder of your Irfanview installation.

How do I use it after installing?

[Knocks]

You can use the gamma correction in advanced options of batch conversion!
(See also the german thread: "Schwellenwert für 1Bit Farbtiefe - oder alternatives Vorgehen?")

What am I converting to?

[Tomcas]

Try converting it to Black and White using- Image, Decrease Color Depth, choose 2 Colors (black/white).

[Mij]

How do I use it after installing?

To use the 8bf filter open your photographed/scanned image then go to Image> Effects >Adobe 8bf filters (or press Ctrl+K). If you have not used the filters before you will need to press Add 8bf filters and browse to the folder that they are in (in your case Irfanview\Plugins\Adobe 8bf) then press OK. All the filters in that folder should then appear in the list. Highlight Fine threshold and press Start selected filter.

The purpose of Fine Threshold is to produce a Black and White image from a grayscale or colored one but you can adjust the threshold between what will become black and what will become white. To assist you, you have a histogram, and a preview area that you can zoom or click and drag to scroll to the area you want to see. You should be able to adjust the threshold so that all your gray areas become white while still leaving the text black. When you have found the best setting press OK , wait for it to be applied to the whole image then Exit the filter.

This will usually achieve a much better result than just using the fixed threshold conversion to Black and White that Tomcas suggests above.