A novel algorithm is proposed to solve the phase unwrapping problem in three-dimensional(3D) shape measurement.Firstly,the phase was computed by the four-step phase shift method.In each phase-shift fringe,a sinusoidal stripe with the length of a period could be acquired at the same position,so it could get four stripes with 90° phase-shift.Then the interlaced fringe was composed by coding the four stripes.In the measurement,by subtracting the interlaced fringe from the four phase-shift stripes a...