Various embodiments are described herein for an imaging device and associated method for performing fluence compensation on a photoacoustic (PA) image of at least a portion of an object for sets of RF acoustic response signals that are obtained using different illumination wavelengths. A first set of RF acoustic response signals is fluence matched to a second set of RF acoustic response signals by determining relative frequency data for first set of RF acoustic response signals relative to the second set of RF acoustic response signals and using the relative frequency data to filter the first set of RF acoustic response signals.
