Filtering a photo of a document to look like a proper scan

So there are a couple of iOS apps that "scan" documents and automatically do some processing to make the image look like a quality scan from a real scanner. When I'm trying this on the Mac with pictures from a DSLR manually with Photoshop the results are usually not as good as what these apps achieve. Therefore I'm looking for either a Mac app or instructions for Photoshop on how to achieve this. Or maybe even an Automator script. Just to be clear: I do not need OCR!