Abstract: An efficient algorithm of trinocular epipolar rectification is proposed.The trinocular stereo system involves three cameras in trianglular configuration with known perspective matrices.The common image plane of three images after rectification is calculated under rectification constraints,and three-ranked matrices are then computed under undistorted image constraints.With this the image is resampled in planar affine coordinate to align images either in row or in column.The implementation of trinocular epipolar rectification in real time with a single chip of FPGA is discussed.A performance of 48 frames per second is achieved with an image size of 640×480 pixels and a clock frequency of 60 MHz.