A numerical analysis scheme has been developed to extract dynamic information from experimental images by the three-dimensional sliced fluorescence imaging method. The present scheme is based on a generalized framework in analyzing fluorescence images from the photo-initiated dynamic process. Specifically, image quality optimization, noise reduction and numerical fitting codes have been implemented in the present scheme to determine differential cross sections of the state-to-state inelastic collisions between CN(A 2£S) and He. These codes are indispensable in extracting state-to-state dynamic information from experimental images in any photo-initiated collision experiment, no matter it is executed in the beam or bulb environment.