Method of confering different signal to noise ratios

CryoSPARC Parameters
1

I’m generating differently oriented simulated maps with various SNRs and defocus values using cryosparc’s simulate data (beta) feature.

I’m curious what method is being used to confer different signal to noise ratios.

Does it follow poisson distribution?
Does it add additive white Gaussian noise?

Can you explain about the method little bit more?

Thank you.

2

Hi @dnamkr,

In Simulate Data job, the noise is Gaussian with zero mean. The variance of the noise is computed using the SNR: first, we take the variance of the projected particle images in real space to compute the power of the signal (this is the overall variance of all pixels in all simulated noiseless images). This is divided by the SNR value to generate the variance of the necessary noise. The noise is generated IID for each pixel and added to the projected particle image.

Hope this helps!

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