Traditional DPIV (Digital Particle velocimetry) methods mostly are based on area correlation. Though proven to be very time consuming and much error prone

they are widely adopted because of their conceptual simple and easy to be implemented

and also because there is few alternative. This paper provides a non correlation

conceptual new

fast and efficient approach for DPIV which takes the nature of flow into consideration. An Incompressible Affine Flow Model(IAFM) is introduced to describe a flow that incorporates rational constraint directly into the computation. This IAFM

combining with a modified optical flow method named Total Optical Flow Computation(TOFC)

provides a linear system solution to DPIV. Experimental results on real images demonstrate our method to be a very promising approach for DPIV.