Exact Algebraic Method of Optical Flow Detection Via Modulated Integral Imaging - Theoretical Formulation and Real-time Implementation using Correlation Image Sensor

A novel mathematical method and a sensing system that detects velocity vector distribution on an optical image with a pixel-wise spatial resolution and a frame-wise temporal resolution is proposed. It is provided by the complex sinusoidally-modulated imaging using the three-phase correlation image sensor (3PCIS) and the exact algebraic inversion method based on the optical flow identity (OFI) satisfied by an intensity image and a complex-sinusoidally modulated image captured by the 3PCIS. Since the OFI is free from time derivatives, any limitations on the object velocity and inaccuracies due to approximated time derivatives is thoroughly avoided. An experimental system was constructed with a 320 × 56 pixel 3PCIS device and a standard PC for inversion operations and display. Several experimental results are shown including the dense motion capture of face and gesture and the particle image velocimetry of water vortices.