Estimate PSF size using integrated Gaussian

Based on the image of a single emitter or a fluorescent bead with a size below the diffraction limit the PSF dimensions are estimated by fitting a 2D-Gaussian or -integrated Gaussian function.

Output:

• X0: center position in x in pixels
• Y0: center position in y in pixels
• Sigma: standard deviation in nm
• Amplitude: peak intensity maximum (Gaussian) or total intensity (integrated Gaussian)
• Background: background level