Auto deskew not working

Technical Support for PaperScan.
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jfcarbel
Posts: 20
Joined: Mon Sep 26, 2011 6:34 am

Auto deskew not working

Post by jfcarbel » Mon Sep 26, 2011 6:38 am

I can get the auto-deskew to work on B/W images in PaperScan, but it will not work on grayscale. I am scanning the same retail receipt. I know deskew technology can work on grayscale images since I am testing other tools and it works with them. The other program I used that deskewed this greyscale image with no issues was using VintaSoftTwain.NET SDK.

I am using latest demo version of PaperScan.

After evalulating many others, I really like yours, but I like to scan receipts in grayscale as the image is better quality then B/W ones.

Loïc
Site Admin
Posts: 96
Joined: Fri Nov 05, 2010 12:38 pm

Re: Auto deskew not working

Post by Loïc » Mon Sep 26, 2011 5:16 pm

Hi,

Could you attach the image for investigation ?

If the image is private you can send it through our help-desk located here: http://support.gdpicture.com

kind regards,

Loïc

jfcarbel
Posts: 20
Joined: Mon Sep 26, 2011 6:34 am

Re: Auto deskew not working

Post by jfcarbel » Mon Sep 26, 2011 9:47 pm

Here are the sample images.

black background, greyscale - does not deskew:
http://www.dvdorganizer.com/pics/receip ... ckback.jpg

same image, but put 8.5/11 white paper behind it before scan, so white background, greyscale - deskews fine:
http://www.dvdorganizer.com/pics/receip ... teback.jpg

black background, B/W image, saved as png - deskews fine:
http://www.dvdorganizer.com/pics/receip ... ckback.png

black background, B/W image, saved as tif lzw - attempts to deskew, but does so incorrectly:
http://www.dvdorganizer.com/pics/receip ... ckback.tif

At first I thought it seemed that a white receipt scanned in greyscale with a black background causes your deskew alogorithmn to be off.
But then I tried a different sample image. In this case the black backgound causes no issues but the white does. I will upload these soon as well.

Ok, here are the other samples. Now in most cases hitting the deskew button does nothing. So perhaps, you can see if the skew angle returned by this function returns zero and perhaps adjust some parms to allow for it to work.
All these samples were also tried within PaperScan with its native aquire with same results. The files here are saved with photoshop without any scanner adjustments applied and when imported into PaperScan provide the same results.

sample1, white background, color image, will not deskew:
http://www.dvdorganizer.com/pics/sample ... teback.jpg

sample1, white background, greyscale image, will not deskew:
http://www.dvdorganizer.com/pics/sample ... teback.jpg

sample1, black background, color image, deskews fine:
http://www.dvdorganizer.com/pics/sample ... ckback.jpg

sample1, black background, greyscale image, deskews fine:
http://www.dvdorganizer.com/pics/sample ... ckback.jpg

BTW, I signed up for your beta testing of your PaperLight beta, perhaps you can put in a good word that I am a user that can provide good feedback as I would love to participate in the private beta.

I am unsure about purchasing the product with these issues since its priced at $150 which is a but high for just an average home user like myself using it for just receipts. But you do have this rotate angle rotation dialog which is a life saver, so I am still giving it some thought as I finish evaluating some other apps.

jfcarbel
Posts: 20
Joined: Mon Sep 26, 2011 6:34 am

Re: Auto deskew not working

Post by jfcarbel » Tue Sep 27, 2011 7:49 pm

The manual deskew can be achieved via angle rotation edit feature, but it would still be nice to have this automatic if possible.

Since manual deskew (i.e. angle rotation) is the fallback it would be great to have some angle rotation dialog improvements in terms of size of image represented in the image window on the right of the dialog.

Sometimes the image in the dialog is too small to determine if rotation changes are correctly lined up. Thus it would be nice to be able to have a dropdown that would allow for 3 sizes of the image in the dialog and thus increase the dialogs image area based on this selection. Or perhaps dynamically size it based on the monitor's resolution.

Unless of course the reason its a smaller image is for rotation display to be live as user moves slider. Perhaps the graphics API would not be able to render the live rotation fast enough if image in dialog window was larger.

Another nice option I have seen apps provide is to allow user to draw guide line across some text in the image and then calculate the skew angle based on this and then rotate it with this skew angle. I still believe the angle rotation dialog you provided is a more user friendly way, but it would be nice to have other options as most times it is not easy to place a small receipt perfectly straight on the scanner flatbed and a straighten image tool is very useful.

Loïc
Site Admin
Posts: 96
Joined: Fri Nov 05, 2010 12:38 pm

Re: Auto deskew not working

Post by Loïc » Wed Sep 28, 2011 10:57 am

Hi,

We fixed an issue with the autodeskew algorithm.
The next version (PaperScan 1.3.5) should be able to deskew almost all images you uploaded.

jfcarbel
Posts: 20
Joined: Mon Sep 26, 2011 6:34 am

Re: Auto deskew not working

Post by jfcarbel » Wed Sep 28, 2011 7:20 pm

We fixed an issue with the autodeskew algorithm.
Does this mean it would be fixed in the GDPicture SDK also?

Loïc
Site Admin
Posts: 96
Joined: Fri Nov 05, 2010 12:38 pm

Re: Auto deskew not working

Post by Loïc » Thu Oct 27, 2011 4:50 pm

Hi,

Sorry for the delay I did not get email confirmation of the answer.

yes this has been also fixed in GdPicture SDK.

Kind regards,

Loïc

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