Defocusing dither optimization techniques can eliminate the nonlinear error and overcome the limitation of refresh rate of a projector. However, the dithering algorithm is only a simple matrix transform and the dithering fringe after defocusing does not approximate the ideal sinusoidal fringe enough, inducing a measurement phase error. This paper proposes a binary particle swarm optimization (BPSO) method,and the binary defocusing dither technique is optimized. To speed up the BPSO process, binary patches are first optimized; then, the patches are joined together with respect to symmetry and periodicity to generate the full-size pattern. The simulation and experimental results demonstrate that the proposed method can obtain high quality measurement results under various extents of defocusing.