Splitting pages produces miniature page images

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L.Willms
Posts: 134
Joined: 21 Sep 2016, 10:51
E-book readers owned: Tolino Shine
Country: Germany
Location: Frankfurt/Main, Germany

Splitting pages produces miniature page images

Post by L.Willms »

I had submitted a back of fotos of book pages where some picture just one page, others both facing pages. Those do have, of course, less pixels per page.

While the processing of the one-page-pictures went well, ScanTailor produced pages with miniature images of the two facing pages on the top of the white area. I have then aborted the process on seeing this.

My first try with a series of images where each showed only one single page went well.

Might there be a problem with this mixed mode of single-page images with double-page images?
qqmxdpo
Posts: 12
Joined: 24 Sep 2016, 02:13
Number of books owned: 0
Country: china

Re: Splitting pages produces miniature page images

Post by qqmxdpo »

Hi,I m from China .I m sorry to hear that .I also met some problems about Scan Tailor,but it isn t like you 。I think the SCT is too old to fit every situations about Splitting pages. I hope sb can update the SCT to fit somes problem.Ths.
duerig
Posts: 388
Joined: 01 Jun 2014, 17:04
Number of books owned: 1000
Country: United States of America

Re: Splitting pages produces miniature page images

Post by duerig »

I haven't seen this, though all the book projects I've scanned thus far have been either all split or all single.

But, if you aren't already, you might try the latest 'Experimental' version of Scan Tailor.

-D
b0bcat
Posts: 49
Joined: 30 Nov 2012, 21:37
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Country: UK

Re: Splitting pages produces miniature page images

Post by b0bcat »

@L.Willms

I have experienced your problem but only rarely - in fact the only case I recall offhand was I think when I dismantled somebody else's pdf which comprised a single first page and then all subsequent pages were landscape/2 pages side by side like open book. I extracted these pages as tiff format from the pdf and fed them to ScanTailor but when I noticed the similar problem, I removed the first (single page) input tiff from the ST project. I then resized that page in a graphics editor (XnView if I recall right) so its dimensions in pixels were basically equal to one half of a landscape / dual page. I then fed that resized page into ST and processed without further difficulty.

In your case it appears you have more than one different sized input image so my method may be infeasible. Also I suspect there may be a more elegant and practical solution which can be provided by one of the more experienced readers here.
Tulon
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Re: Splitting pages produces miniature page images

Post by Tulon »

If you are trying to output some double-page scans as a single page (let's say a large diagram over two pages), you need to uncheck "Match size with other pages" on the Margins stage for such pages.

If not, it's possible your double-page scans were made with a different DPI compared to single-page ones. If you know those DPIs, use Tools -> Fix DPI to specify them. If you DPIs differ but you don't know them, Scan Tailor Experimental should be used, with "Match size by scaling" option selected on the Margins stage.
Scan Tailor experimental doesn't output 96 DPI images. It's just what your software shows when DPI information is missing. Usually what you get is input DPI times the resolution enhancement factor.
L.Willms
Posts: 134
Joined: 21 Sep 2016, 10:51
E-book readers owned: Tolino Shine
Country: Germany
Location: Frankfurt/Main, Germany

Re: Splitting pages produces miniature page images

Post by L.Willms »

Thanks to b0bcat for the comforting information that I am not alone with the problem, and to Tulon for the tip how to avoid it. I'll try that.

The input is not PDF files, but JPEG images taken by a compact camera in the reading room of a library. Because of the age of the book, photocopying the books is not allowed, but the library now allows taking pictures of the book using one's own camera, but without flash as not to disturb the other readers in their studies.

My photograhing was also done in several sessions, returning to the library to photograph pages where the edges were cut off or having other problems. Then I would also take an image of the affected page only, not of the two facing pages together. Hence the mix and the vastly varying dpi. I put the camera on a little table tripod.

After having learned of ScanTailor, I tried it out with one set of images, which were all single page, and it worked very well. I aborted the second batch with this mix of single and double page images after encountering the problem reported here. I am also very satisfied with ABBYY's ability to split pages.

I normally do scan at home with an Epson V100 Photo flat bed scanner and OCR with ABBYY 11.0, and am very satisfied with that. I can't of course not use that scanner in a public library...
Tulon
Posts: 687
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Re: Splitting pages produces miniature page images

Post by Tulon »

Either use Scan Tailor Experimental with "Match size by scaling" option or classic Scan Tailor with "Match size with other pages" turned off for all pages. The latter option only makes sense if you are only going to OCR the results rather than build a PDF / DJVU file.
Scan Tailor experimental doesn't output 96 DPI images. It's just what your software shows when DPI information is missing. Usually what you get is input DPI times the resolution enhancement factor.
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