This paper presents a technique for multi-channel optical flow estimation. We combine the brightness constancy constraint with the relationship between optical flow fields and disparity fields in estimating optical flow fields by solving systems of linear equations. In this formulation, the so called round-about compatibility constraint is used to ensure the coherence between optical flow fields and to pin down the tangential components of optical flow vectors which are undiscernible from the first order intensity derivatives. Since disparity information is used to assist optical flow estimation here, a reliable disparity field estimator is required. The disparity fields are recovered using a Disparity Space Image (DSI) technique. We also discuss the sensitivity of this technique when the essential parallel-axes camera configuration assumption is violated. Experiments show that the technique is very promising for practical applications.