2011.06.24 23:45 "Re: [Tiff] 16-bit image", by Bob Friesenhahn
On Fri, 24 Jun 2011, Leandro Bugnon wrote:
> Thanks for the quick answer. Here is a test image
> * http://www.filefactory.com/file/cc0b359/n/test1.tif
Another thing that cannot understand is that TIFFTAG_SMINSAMPLEVALUE /
Yes, I see that they are zero.
GraphicsMagick says that you have two image frames:
Type: grayscale
Depth: 15 bits-per-pixel component
Channel Depths:
Gray: 15 bits
Channel Statistics:
Gray:
Minimum: 500.00 (0.0076)
Maximum: 700.00 (0.0107)
Mean: 583.11 (0.0089)
Standard Deviation: 84.91 (0.0013)
and
Type: grayscale
Depth: 14 bits-per-pixel component
Channel Depths:
Gray: 14 bits
Channel Statistics:
Gray:
Minimum: 1000.00 (0.0153)
Maximum: 1400.00 (0.0214)
Mean: 1166.21 (0.0178)
Standard Deviation: 169.82 (0.0026)
From this it is clear that the images are very dark and would appear black on a typical 8-bit display. However, if I normalize the image your test pattern is revealed.
You say that the CCD is 14 bits, but the numeric range is within 11 bits (2^11 = 2048). The values are clearly not scaled up.
Bob
--
Bob Friesenhahn
bfriesen@simple.dallas.tx.us, http://www.simplesystems.org/users/bfriesen/
GraphicsMagick Maintainer, http://www.GraphicsMagick.org/