采用离焦二值条纹投影技术进行三维面形测量可以克服数字投影仪的非线性响应，同时有利于提高投影速度，实现高速测量.通过理论分析和实验研究了采用数字投影仪时二值条纹的基频、高次谐波能量分布与条纹周期的关系.结合相移算法，以相位测量误差为指标，衡量各种二值条纹的性能.研究结果表明：在周期小时，罗奇光栅和二维误差扩散算法生成的二值条纹离焦后能产生正弦性较好的条纹；在采用满周期等间隔奇数次相移时，罗奇光栅离焦能获得更高的测量准确度；在周期大时，采用优化脉宽调制方法得到的二值光栅离焦测量准确度最高.研究结果为离焦条纹投影三维测量中二值光栅的选择提供了依据.

The non-linear intensity response of digital projector can be eliminated in 3D shape measurement using defocused binary fringe projection technique. The speed of projecting can be increased and it is possible to realize high speed measurement as well. Typical binary fringes used in digital projection were adopted as a study subject. The relation between the fundamental frequency, higher harmonics and fringe period of binary fringe was studied through the theoretical analysis and experiments. According to suitable phase shifting algorithm, the performance of various binary fringes was measured using the measurement error of phase as its target. The results showed that sinusoidal fringe with high performance could be generated by defocusing the Ronchi grating and pattern generated using 2D error diffusion algorithm under the condition that fringe with short period was adopted. The measurement accuracy of defocused Ronchi grating was higher than that of other pattern, when the algorithm of odd step phase-shifting with equal interval in one period was used for 3D measurement; the highest measurement accuracy was obtained by using defocused optimal pulse width modulation fringe, when the period of fringe was long. The research results provide the evidence for selection of binary grating in the 3D measurement based on defocused projection.