[sane-devel] Why is the background of the scanned image not a constant grayscale

[m. allan noah]

1. what mode are you scanning in, grayscale, lineart, color?

2. what do you mean by layer? the fujitsu driver returns only one frame to 
the front end, so there should not be a case where there is multiple pixel 
data available for one physical pixel.

3. does this happen with other front-ends?

4. does this happen with the scsi connection instead of usb?

5. could you send me directly a copy of an image where you see this?

allan

On Fri, 9 May 2003, Peter Chen wrote:

> Hi,
> 
> I set up the tl_x, tl_y, br_x and br_y, scanned one image and found that
> there was another layer between the real image and the dark background. It
> was a rectangle, not of constant grayscale. The scanner is Fujitsu fi-4120c.
> 
> Could somebody pls tell me how to get rid of this layer? Since when I scan
> images using Twain, there is not such a layer.
> 
> The reason that I want to get rid of the layer is I need to do some edge
> detection and deskewing. If the background is a constant black (or white),
> then it would be much easier to implement the algorithm.
> 
> Thanks,
> 
> Peter
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