FRAP is an imaging based technique used to measure the diffusion of fluorescently labelled molecules in biological samples. In a FRAP experiment, a small sub region (ROI) of the field of view is irradiated with high power excitation light in order to permanently bleach the fluorophores in that ROI. Timelapse images are then acquired to measure the fluorescence signal recovery in the ROI as fluorophores from adjacent areas diffuse into the ROI and to calculate the diffusion time of the fluorescently labelled molecules.