PyDDM.ddm_calc.determining_A_and_B
PyDDM.ddm_calc.determining_A_and_B¶
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determining_A_and_B(im, use_BH_filter=False, centralAngle=None, angRange=None)¶ Used to assist in determining the parameters \(A\) and \(B\) in the expression for the DDM matrix \(D(q,\Delta t) = A(q) [1 - f(q, \Delta t)] + B(q)\). We take the Fourier transforms of each image and average those together. Those are then radially averaged (or average over a select range of angles if centralAngle and angRange are not None). This (now 1D) function should approach the value \(\frac{1}{2} \times (A(q) + B(q))\) as \(q\) gets large.
- Parameters
im (array) – Images used for DDM analysis. Should be 3D array with the first dimension being time.
use_BH_filter (bool, optional) – Whether or not BLackman-Harris windowing is applied in the DDM analysis. The default is False.
centralAngle (float, optional) – Use if you do not want to radially average the full DDM matrix. Otherwise, set to None (the default).
angRange (float, optional) – Use if you do not want to radially average the full DDM matrix. Otherwise, set to None (the default).
- Returns
rad_av_av_fftsq – Radial average of the average of all Fourier transforms of the images
- Return type
array