离焦投影三维测量的二值光栅生成方法

Method for Binary Grating Generation Using Defocused Projection for Three-Dimensional Measurement

投影仪离焦技术克服了光栅投影三维测量中的投影仪非线性问题,但二值光栅存在的高次谐波会降低生成光栅的正弦性,从而引入相位误差。提出一种二值光栅图像生成方法,基于正弦光栅图像所具有的对称性和周期性,选取了尺寸较小的二值块。然后对所选块进行随机初始化,再采用多像素跳变方法对二值块进行优化,根据优化所得的二值块生成整幅二值光栅图像。最后结合相移算法,在投影仪离焦测量环境下,计算得到三维测量所需的相位信息。相较于传统二值光栅图像生成方法,所提方法能够保证高质量相位信息获取,且适用于不同程度的离焦测量环境。仿真及实验验证了所提方法更加适用于离焦投影三维测量。

Projector defocusing technique can eliminate projector nonlinearity in three-dimensional measurement of grating projection.However,the high frequency harmonics produced by binary grating can weaken the sinusoidal feature of grating and generate phase errors.A new method is proposed to generate binary grating patterns.Based on symmetry and periodicity of sinusoidal grating pattern,this method selects a smaller binary patch.Then the selected patch is randomly initialized,the binary patch is optimized through multi-pixels′mutation,and the binary grating pattern of full size pattern is generated according to the optimized binary patch.Finally,combined with phaseshifting algorithm,required phase information for three-dimensional measurement is retrieved under the environment of defocusing measurement for the projector.Compared with the generation method of traditional binary grating patterns,the proposed method can certify high-quality phase information acquisition and suitable for the measurement environment of different defocusing amounts.Simulations and experiments are carried out to verify that the proposed method is more proper for three-dimensional measurement of defocused projection.