PSF FWHM Estimator
The most practical way to determine the resolution of an optical system is to measure the Full-Width at Half-Maximum (FWHM) of the Point Spread Function.
Since Huygens version 4.5, we have implemented a PSF FWHM Estimator tool in the PSF distiller option for the Essential and Professional. If you have the PSF distiller option in your license, you can also find this tool in the task bar menu of the Professional under "Analysis" .
The PSF FWHM Estimator can be used to analyze the quality of a PSF. This PSF may have been distilled from images of beads using the PSF Distiller, or may have been generated from the microscopical parameters using the "Theor PSF" function in the Operation Window (in the Professional).
The PSF FWHM Estimator creates a line intensity profile through the center of the PSF in all dimensions, and measures the X value of the peak maximum and the width of each peak at approximately half of the maximum value using a curve fitting procedure. Curve fitters such as Gaussian, Lorentzian, Voight and Pearson, are available for this. This is done for all channels.
The PSF Distiller Wizard has the FWHM measuring tool added. After the distilling process the wizard offers the possibility to measure the FWHM of your newly acquired PSF (see image below).