Wikipedia:Reference desk/Archives/Computing/2015 July 28

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July 28

Simulating scanner distortion

I'm looking for an online service that can simulate the characteristic distortion that a scanner makes. Basically I have a JPEG image of a document, and I want a JPEG image of how said document would look if it were printed out, and then scanned. Currently I'm printing them out and then scanning them, which is A. a waste of time, and B. a waste of trees. Please help me save some trees. Thanks. My other car is a cadr (talk) 13:52, 28 July 2015 (UTC)

What type of "distortion" do you mean ? If it's just a loss of resolution, that's simple enough. Or maybe it goes from a full color image to black and white ? That's easy too. If you could include before and after pics, that would help. StuRat (talk) 14:42, 28 July 2015 (UTC)

You've never seen a scanned document before? Here's a random example I got off the net[1]. Notice how there are random specks of dust here and there and that the edge of the document contrasts with the white scanner bed. The resolution doesn't need to be changed, and it can stay a colored image. My other car is a cadr (talk) 15:02, 28 July 2015 (UTC)

OK, so you are talking about a raw scanned image, not cropped to the document and not cleaned up to remove specks. No OCR either. StuRat (talk) 15:11, 28 July 2015 (UTC)

I have seen thousands of scanned images. Sometimes there are specks. Sometimes there aren't. Sometimes the text looks great. Sometimes it gets some aliasing. Sometimes there are lines cutting horizontally or vertically across the document. Sometimes it is tilted. Sometimes you can see text from the other side of the sheet. Sometimes the scans are in color. Sometimes they are grayscale. Sometimes they are strictly black and white. Sometimes they get darker. Sometimes they get lighter. That is just a few things that COULD happen - and you didn't explain a single one in your question. So, why do you think it is acceptable to ask a belligerent question like "You've never seen a scanned document before?" Try putting some effort into asking a well-formed question. 209.149.113.45 (talk) 15:15, 28 July 2015 (UTC)

Thanks, but I didn't see it as belligerent, they just didn't know that scanning causes a wide variety of "distortions" (defects). StuRat (talk) 16:45, 28 July 2015 (UTC)

For the speck/dust look, try something like this [2]. That might be good for single-page bed scanners, but it won't help with the shearing you get when a document feeder changes speed a little bit, nor things like the crease on the inside of book's spine. See also similar questions and decent answers here [3]. Here's even a way to do it in LaTeX: [4]. The Gimp has a photocopy-effect tool [5], and it looks like ImageMagick does as well [6]. SemanticMantis (talk) 15:22, 28 July 2015 (UTC)

Thank you so much! That ImageMagick command does the trick perfectly! My other car is a cadr (talk) 16:52, 28 July 2015 (UTC)

I liked the one suggestion of rotating it 1-2 degrees (in addition to speckle, downrez, etc). I thought that was a nice touch that really helps sell it :) Also funny that several of the other threads' OPs seemed to have the same motivation as you... SemanticMantis (talk) 18:28, 28 July 2015 (UTC)

BTW, I am curious, why do you want to make images look bad ? StuRat (talk) 16:47, 28 July 2015 (UTC)

Soulless bureaucratic machine expects each document to be printed out, stamped, scanned, and then shredded. Your tax dollars at work, people.My other car is a cadr (talk) 16:52, 28 July 2015 (UTC)

Resolved

So, you are basically cheating the government by pretending that you print, stamp, and scan the digital documents, right? However, how will you explain that there won't be any shredded paper left over? --Yppieyei (talk) 22:01, 28 July 2015 (UTC)

(This is off topic - OP asks questions, we give references if we choose. If you want to question the morality of the scenario, keep in mind you know very little about it. Also I'm reminded of a quote from MLK "One has not only a legal but a moral responsibility to obey just laws. Conversely, one has a moral responsibility to disobey unjust laws." [7] SemanticMantis (talk) 13:18, 29 July 2015 (UTC)

Unjust != Inconvenient SteveBaker (talk) 02:43, 30 July 2015 (UTC)