[GSAS-II] GSAS-II image import int vs float

[Von Dreele, Robert B.]

Hi,
I’ll look at this tomorrow.
Bob

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________________________________
From: GSAS-II <gsas-ii-bounces at aps.anl.gov> on behalf of Gallington, Leighanne C. via GSAS-II <gsas-ii at aps.anl.gov>
Sent: Wednesday, March 16, 2022 5:18:24 PM
To: gsas-ii at aps.anl.gov <gsas-ii at aps.anl.gov>
Cc: Chen, Jiahui <jiahuichen at anl.gov>; Weng, James <jweng at anl.gov>
Subject: [GSAS-II] GSAS-II image import int vs float

Hi Bob and Brian,

We've run into some problems when trying to import and apply gain maps, with values ranging from about 0.97 to 1.03, to Jiahui's data.  After doing some digging, I've found that when the PE images are imported, the values are converted from floats to integers.  As far as I can tell, the conversion is happening in the code snippet below, from file G2img_1TIF.py, in function GetTifData.

 elif sizexy == [2048,2048] or sizexy == [1024,1024] or sizexy == [3072,3072]:
        if IFD[273][2][0] == 8:
            if IFD[258][2][0] == 32:
                tifType = 'PE'
                pixy = [200.,200.]
                File.seek(8)
                G2fil.G2Print ('Read APS PE-detector tiff file: '+filename)
                if dataType == 5:
                    image = np.array(np.frombuffer(File.read(4*Npix),dtype=np.float32),dtype=np.int32)  #fastest
                else:
                    image = np.array(np.frombuffer(File.read(4*Npix),dtype=np.int32),dtype=np.int32)

If I change the np.int32 to np.float32, the gain map can be read in, applied to data, and integrated successfully.  I'm not sure what else I might have broken downstream when I do that, and there's still some funkiness with the slider bars for the intensities.  Can you implement a cleaner fix into the G2img code?

Thanks,
Leighanne
--
Leighanne C. Gallington, Ph.D.
Assistant Chemist
Advanced Photon Source (X-ray Science Division)
Argonne National Laboratory
Argonne, IL  60439
gallington at anl.gov
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