Method for the time-resolved measurement of the size and position of a moving particle using an image sensor

A new method for the continuous measurement of both the size and position of a moving particle using a two-dimensional metal-oxide-semiconductor-type image sensor is described. With this method the particle position is determined precisely by the number of the scanning line and the pixel number within one frame image in place of the frame number used in ordinary video camera methods. This simple and novel sizing method, associated with the image storage property of the image sensor over one field interval, was first described and applied by König et al. [J. Aerosol. Sci. 17, 157 (1986)]. The numerical analysis and the experiment to verify the sizing method are performed. Details of the system and its application for a freely falling small glass sphere are presented.