Content

Code location

In LCLS software release code of the class RadialBkgd resides in the package pyimgalgos.

Auto-generated documentation for class RadialBkgd

Initialization

    from pyimgalgos.RadialBkgd import RadialBkgd
    rb = RadialBkgd(xarr, yarr, mask=None, radedges=None, nradbins=100, phiedges=(0,360), nphibins=32)

See parameters description in Auto-generated documentation for class RadialBkgd.

Algorithm

Intention

This algorithm is intended to subtract background from images with quasi-symmetric radial distribution of intensities. For example, water ring background:

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Then this averaged intensity is per-pixel subtracted form data n-d array.

Description

Input per-pixel coordinates passed in numpy arrays xarr, yarr are used to evaluate per-pixel radius and polar angle:

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Averaged background intensity for default and non-default binning cases (nphibins=8, nradbins=500):

Results

Background subtracted data for default (nradbins=100, nphibins=32) and non-default binning cases (nradbins=500, nphibins=1), and (nradbins=500, nphibins=8, phiedges=(-20, 240)):

• For good statistical background averaging 2-d bins should contain large number of pixels. Binning artifact in some places are seen in resulting image.
• Photon beam polarization effect is observed in the image with single angular bin (ring-shaped radial bins). One could eliminate this effect by modulation of the background sample using polarization correction.

References

• Auto-generated documentation for class RadialBkgd
• Auto-generated documentation for class HBins

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