How to photograph a huge book on a table so text is level?

Question

I use PENTAX Optio RS1500 Hoya Corp. digital camera with 14 megapixels.

When I photograph a huge book on a table, I can use text mode to capture all the text and lines clearly. But the lines become not straight, because it's hard to press the book to be totally level like just one paper.

How can I photograph the book so that the lines are straight, or how can I use image editors (e.g. gimp, photoshop...) to adjust the image to a straight line table?

Answer

I think you are looking for something like unpaper. The cam scanner app on android works pretty well too.

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