flat_to_qe

romanisim.image.flat_to_qe(flat, gain, area=None)

Convert flat field to relative QE.

The CRDS flat field is area * QE / gain / <(area * QE / gain)>. This function extracts the relative QE component by dividing out the area and gain dependencies and renormalizing.

Parameters:

flatfloat or np.ndarray

Flat field from CRDS

gainfloat or np.ndarray

Gain in electrons/DN (can have astropy units)

areafloat or np.ndarray, optional

Pixel area (collecting area per pixel). If None, assumes area=1. Can be obtained via imwcs.makeSkyImage with sky_level=1.

Returns:

qefloat or np.ndarray

Relative QE normalized so median = 1