一种新的双频光栅轮廓术

A Novel Profilometry with Dual-frequency Grating

物体含突变部分时,包裹相位很难准确恢复 若用双频光栅技术分两次测量,测量次数增加,不符合实时要求 提出用软件方法生成含两种不同频率的复合光栅,用液晶投影仪投影 针对不同物体突变情形,生成各种不同灵敏度的复合光栅 只一次采集,就达到过去双频多次采集的效果 两幅不同灵敏度的相位图可同时获取,相位去包裹时高精度光栅相位不确定性由粗光栅对应相位修正 最后,进行了实验测试 结果表明,新方法具有速度快、精度高。

The phase unwrapping is a very difficult problem for profilometry of object containing depth discontinuities .The problem can be resolved with dual-frequency measurement technique. Two measurements with dual different frequencies cannot be contented with real-time demand. The new profilometry is based on compound grating, generated by computer software, projected by liquid crystal projector, so that the grating with different precision is easily created, conveniently changed .The same purpose is attained as capturing two different frequencies′ deforming gratings. Two phase maps are determined simultaneously, whose sensitivity to height variations is correlated with the frequency of pattern gratings. The phase uncertainty of the finest grating can be revised by the phase information coming from the coarse one. Finally, satisfactory experimental results are demonstrated. Meanwhile, it is verified that the new method has high speed, accurate unwrapping and extensive measure range.