A study about size measurements of cavitation nuclei is performed, by comparing results from different techniques as Holography, Phases Doppler and Centerbody Venturi. These systems are installed in line along a new installation, specially designed to guarantee optimal optical and flow conditions. First, to calibrate the different systems, pressure distribution inside the Centerbody Venturi is determined, using Laser velocimetry measurements. Response of the optical techniques is analyzed by injecting size calibrated latex particles. Then, the comparative measurements arc performed for different cavitation nuclei conditions.