Terrible B&W Image Quality

Terrible B&W Image Quality

Postby » Fri Apr 22, 2011 8:51 am

Can anyone explain this? I have a program which scans documents using a Canon 4010C scanner, using the Image Controls 3.0 and VRS 4.10.

When I scan from this program, I get some very bad quality on the resulting scan, but the VRS Interactive Viewer seems to come out just fine. I cannot find any settings being applied within the program that might be causing this poor quality. I can try changing it to 300dpi, which looks a bit better. Why does the VRS interactive viewer get a different quality image than my imagecontrols?

Original full-color image (just a test sheet with some various text sizes)
Image

Scanning without changing anything. I think it is defaulting to B&W at 200dpi:
Image

At the same time my program got this bad image, the VRS Interactive Viewer has this image, which is acceptable.
Image
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Re: Terrible B&W Image Quality

Postby » Fri Apr 22, 2011 11:40 am

I'm inclined to think that your application has some clean-up processing that's going on that you need to disable. VRS does all the clean-up. The application should be set to accept the images "as-is" and not try to do anything with them.
Russell
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Re: Terrible B&W Image Quality

Postby » Fri Apr 22, 2011 2:57 pm

Ah.. I think you may have been right! I dug into the code and found this: (VB6--argh)

Code: Select all
If .EdgeEnhancementCap = True Then
   .EdgeEnhancement = True   
   .EdgeEnhancementAlgorithm = KIEDGECHARSMOOTHING Or KIEDGESMOOTHCLEAN Or KIEDGEPRESERVESMOOTHCLEAN Or KIEDGEPRESERVEFILLLINE Or KIEDGELIGHTTHICKEN
End If


Removing that creates a normal looking image. Apparently our past scanners or versions of custom software didn't use this property or supported it differently.

Thanks Russell!
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