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 TImageEnProc.WhiteBalance_WhiteAt() question
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chuckm

2 Posts

Posted - May 29 2013 :  16:20:29  Show Profile  Reply
Searched the forum and sample programs but didn't see any info on using WhiteBalance_WhiteAt(). I use Autowhite() to correct images but would like to have a bit more control over defining the white balance. I implemented the procedure, passing the X,Y returned from XScr2Bmp(), but calling the method seems to have no impact on the image.

Am I missing some part of making it work beyond calling the method with the X/Y of a white pixel? When I use just the autowhite() it sometimes makes no difference to the image and sometimes overexposes. I was expecting it to perform like AutoWhite() but with me picking the baseline white pixel for the adjustment.

I've tried multiple images, locations, etc. and get no change in the image with any of them. I'm using V3 of the components with this app. Would appreciate any insights or workarounds. Thanks.

fab

1310 Posts

Posted - Jun 05 2013 :  06:43:12  Show Profile  Reply
WhiteBalance_WhiteAt extends the range from black to the white value read from the specified coordinate. You should Not specify a pure White (255,255,255) pixel, otherwise WhiteBalance_WhiteAt leave the image unchanged.
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chuckm

2 Posts

Posted - Jun 07 2013 :  23:17:39  Show Profile  Reply
Thanks fab. I've tried various pixels across the color range and no matter what I submit I don't see any effect on the image. Is there an additional procedure to call? The .Autowhite() call will immediately change the image except in a few where it seems to not be able to make any adjustment. I'm wondering if the WhiteAt() is having that same problem or if I'm missing a step somewhere. I've fed it mouse selected coordinates as well as various random ones for a series of images.

Appreciate the help. Getting some more direct control over the white balance would be really useful but I haven't had any luck with it.
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fab

1310 Posts

Posted - Jun 15 2013 :  00:22:30  Show Profile  Reply
Depends by the image and by the chosen point.
For example, this is the original:



After applying ImageEnView1.Proc.WhiteBalance_WhiteAt(346, 251):

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