region-of-interest band-pass-filter statistical-significance-test metrics-evaluation diffraction-limited-spots scale-space-feature-detection total-internal-reflection-fluorescence-micscopy epifluorescence-microscopy fluorescent-speckle-microscopy low-signal-to-noise-ratio subresolution-cluster-of-fluorophores speckle-modulation-analysis imaging-technique-evaluation imaging-quality-metrics gaussian-spatial-frequencies-filtering 2d-convolution-operator image-noise-reduction bessel-function-to-gaussian-fitting vinculin latrunculin