polyTEM.image.fft.ssnr

polyTEM.image.fft.ssnr(img1: ndarray, img2: ndarray, shape: tuple, dx: float, processor: str)

Spectral Signal to Noise Ratio based on Baxter, et al. https://doi.org/10.1016/j.jsb.2009.02.012

SSNR(k) =

rac{FRC(k)}{1 - FRC(k)}

where k is spectral frequency.

This is used in creating the wiener filter for ctf correction So the output will be in u = 1/d spectral frequency and should have matching size as ctf

BUG: These for loops are really slow lol but I can’t bother thinking of making it faster right now

Arguments:

img1: np.ndarray img2: np.ndarray shape: tuple for output shape. dx: A/Pixel resolution of the input images

Returns:

ssnr_array: np array with input shape with signal to noise ratio