get_source_psf

pysaber.get_source_psf(pix_wid, src_pars, sod=1.0, odd=1.0)

Function to compute the point spread function (PSF) of X-ray source blur in the plane of the X-ray source or the detector.

If source to object distance (SOD) is equal to object to detector distance (ODD), then the PSF on the detector plane is same as that on the plane of the X-ray source. If PSF on detector plane is desired, it is required to specify the SOD and ODD. If PSF on source plane is desired, use the default values for SOD and ODD.

Parameters

  • pix_wid (float) – Effective width of each detector pixel. Note that this is the effective pixel size given by dividing the physical width of each detector pixel by the zoom factor of the optical lens.

  • src_pars (dict) – Dictionary containing the estimated parameters of X-ray source PSF. It consists of several key-value pairs. The value for key source_FWHM_x_axis is the full width half maximum (FWHM) of the source PSF along the x-axis (i.e., second numpy.ndarray dimension). The value for key source_FWHM_y_axis is the FWHM of source PSF along the y-axis (i.e., first numpy.ndarray dimension). All FWHMs are for the source PSF in the plane of the X-ray source (and not the plane of the detector). The value for key cutoff_FWHM_multiplier decides the non-zero spatial extent of the source PSF. The PSF is clipped to zero beginning at a distance, as measured from the PSF’s origin, equal to the maximum of src_pars['cutoff_FWHM_multiplier'] times src_pars['source_FWHM_x_axis']/2 and src_pars['cutoff_FWHM_multiplier'] times src_pars['source_FWHM_y_axis']/2.

  • sod (float) – Source to object distance (SOD).

  • odd (float) – Object to detector distance (ODD).

Returns

PSF of X-ray source blur.

Return type

numpy.ndarray