IsBlankImage function

Questions, comments and suggestions concerning VintaSoft Twain .NET SDK.

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IsBlankImage function

Post by ethosgroup » Tue Dec 02, 2008 9:04 pm

The project I am working on requires the scanner to scan in duplex mode, but there will not always be double sided pages in the scanner. Therefore some blank images will be resulting.

I have been testing a single sided sheet of paper with the IsBlankImage function, yet this function always returns that the image is not blank.

Image 0 (not blank) - has a BPP of 1 and a noise level of 2.34354949
Image 1 (blank) - has a BPP of 1 and a noise level of 0.3512246446

My code is exactly like the example:

If VSTwain1.IsBlankImage(i, 0.01, currentNoise) = False Then '= false since true means blank (or should)
Where i is the index, .01 is the maxNoiseLevel as recommended by tthe documentation, and currentNoise is a variable of type Single.

The image scans in as solid white, perhaps is the software looking for Solid black to indicate blank?

According to the documentation the IsBlankImage function requires a BPP of 1 (and others), which my images have.

Is there something I am not doing that is causing this function to work improperly?

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Re: IsBlankImage function

Post by Alex » Wed Dec 03, 2008 9:17 am


Your code looks correct. Maybe your image contains black border?

Please send your "bad" images to our support team at

Best regards, Alexander

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