Inter-partition phase unwrapping method based on Gray code
-
摘要: 格雷码因具有良好的鲁棒性和抗噪性，被广泛应用到结构光投影三维成像方法中。在三维测量过程中，由于设备以及其他环境噪声的影响，格雷码方法解码条纹级次边沿和截断相位边沿通常无法处于理想的对齐状况，使得展开的相位出现跳变现象。为了更好地避免级次跳变误差，使得边沿跳变区域的容错宽度更大，提出基于格雷码的分区间相位展开方法。在互补格雷码基础上增加一幅格雷码图像，利用所有格雷码解得附加码字，通过对附加码字进行不同位移量的条纹级次映射，得到2个辅助条纹级次。利用所有条纹级次，对截断相位进行分区间相位展开，在边沿跳变区域错误大于半个周期时，仍能获取到无跳变现象的展开相位。实验结果表明，当边沿错误区域宽度小于3/4个条纹周期宽度时，可以有效避免级次跳变产生的误差。Abstract: Gray codes are widely used in structured-light projection three-dimensional (3D) imaging because of good robustness and noise immunity. During the process of 3D measurement, due to the influence of equipment and other environmental noises, the gray-code decoding fringe-order edge and the truncated phase edge usually cannot be in an ideal alignment state, which causes the unwrapped phase to jump. In order to better avoid the level hopping error and make the error tolerance width of the edge hopping region larger, an inter-partition phase unwrapping method based on Gray codes was proposed. A Gray code image was added on the basis of the complementary Gray code, the additional code words were obtained by decoding all the Gray codes, and two auxiliary fringe orders were obtained by performing fringe order mapping with different displacements on the additional code words. Using all the fringe orders, the inter-partition phase unwrapping was performed on the truncated phase. When the error in the edge hopping region was greater than half a period, the unwrapping phase without hopping could still be obtained. The experimental results show that when the width of the edge error region is less than 3/4 of the stripe period width, the error caused by the level hopping can be effectively avoided.
-
Key words:
- three-dimensional measurement /
- Gray code /
- phase unwrapping /
- inter-partition /
- level hopping error
-
图 4 4幅格雷码模式编码获取不同位移的条纹级次
Fig. 4 Four-piece Gray code mode encoding to obtain fringe levels with different displacements
表 1 展开相位准确性分析结果
Table 1 Analysis results of unwrapped phase accuracy
相位展开方法 总点数 错误点个数 错误点占比/% 传统格雷码方法 208 458 73 227 35.13 互补格雷码方法 208 458 42 127 20.21 本文方法 208 658 2 263 1.08 
下载: 导出CSV
-
[1] GORTHI S S, RASTOGI P. Fringe projection techniques: whither we are?[J]. Optics and Lasers in Engineering,2010,48(2):133-140. doi: 10.1016/j.optlaseng.2009.09.001 [2] 刘路, 潘艳娟, 奚冬冬, 等. 相位编码条纹投影轮廓术的相位展开误差校正方法[J]. 应用光学,2020,41(5):978-983. doi: 10.5768/JAO202041.0502007LIU Lu, PAN Yanjuan, XI Dongdong, et al. Phase unwrapping errors correction for phase-encoding based on fringe projection profilometry[J]. Journal of Applied Optics,2020,41(5):978-983. doi: 10.5768/JAO202041.0502007 [3] CHEN F, BROWN G M, SONG M. Overview of 3-D shape measurement using optical methods[J]. Optical Engineering,2000,39(1):10-22. doi: 10.1117/1.602438 [4] 朱勇建, 黄振, 马俊飞, 等. 光栅投影三维测量系统标定技术研究[J]. 应用光学,2020,41(5):938-946. doi: 10.5768/JAO202041.0502002ZHU Yongjian, HUANG Zhen, MA Junfei, et al. Study on calibration method of grating projection 3D measuring system[J]. Journal of Applied Optics,2020,41(5):938-946. doi: 10.5768/JAO202041.0502002 [5] SU X, CHEN W. Reliability-guided phase unwrapping algorithm: a review[J]. Optics and Lasers in Engineering,2004,42(3):245-261. doi: 10.1016/j.optlaseng.2003.11.002 [6] LI B Y, TANG C, ZHOU Q L, et al. Weighted least-squares phase-unwrapping algorithm based on the orientation coherence for discontinuous optical phase patterns[J]. Applied Optics,2019,58(2):219-226. doi: 10.1364/AO.58.000219 [7] 钱晓凡, 张永安, 李新宇, 等. 基于掩膜和最小二乘迭代的相位解包裹方法[J]. 光学学报,2010,30(2):440-444. doi: 10.3788/AOS20103002.0440QIAN Xiaofan, ZHANG Yong'an, LI Xinyu, et al. Phase unwrapping algorithm based on mask and least-squares iteration[J]. Acta Optica Sinica,2010,30(2):440-444. doi: 10.3788/AOS20103002.0440 [8] CHENG Y Y, WYANT J C. Two-wavelength phase shifting interferometry[J]. Applied Optics,1984,23(24):4539. doi: 10.1364/AO.23.004539 [9] WANG Y J, ZHANG S. Novel phase-coding method for absolute phase retrieval[J]. Optics Letters,2012,37(11):2067-2069. doi: 10.1364/OL.37.002067 [10] SANSONI G, CORINI S, LAZZARI S, et al. Three-dimensional imaging based on Gray-code light projection: characterization of the measuring algorithm and development of a measuring system for industrial applications[J]. Applied Optics,1997,36(19):4463-4472. doi: 10.1364/AO.36.004463 [11] LAUGHNER J I, ZHANG S, LI H, et al. Mapping cardiac surface mechanics with structured light imaging[J]. American Journal of Physiology Heart and Circulatory Physiology,2012,303(6):712-720. doi: 10.1152/ajpheart.00269.2012 [12] ZHENG D L, QIAN K M, DA F P, et al. Ternary Gray code-based phase unwrapping for 3D measurement using binary patterns with projector defocusing[J]. Applied Optics,2017,56(13):3660-3665. doi: 10.1364/AO.56.003660 [13] LEI S Y, ZHANG S. Flexible 3-D shape measurement using projector defocusing[J]. Optics Letters,2009,34(20):3080-3082. doi: 10.1364/OL.34.003080 [14] WU Z J, ZUO C, GUO W B, et al. High-speed three-dimensional shape measurement based on cyclic complementary Gray-code light[J]. Optics Express,2019,27(2):1283-1297. doi: 10.1364/OE.27.001283 [15] 孙学真, 苏显渝, 邹小平. 基于互补型光栅编码的相位展开[J]. 光学学报,2008,28(10):1947-1951. doi: 10.3321/j.issn:0253-2239.2008.10.020SUN Xuezhen, SU Xianyu, ZOU Xiaoping. Phase-unwrapping based on complementary structured light binary code[J]. Acta Optica Sinica,2008,28(10):1947-1951. doi: 10.3321/j.issn:0253-2239.2008.10.020 [16] ZHANG Q C, SU X Y, XIANG L Q, et al. 3-D shape measurement based on complementary Gray-code light[J]. Optics and Lasers in Engineering,2012,50(4):574-579. doi: 10.1016/j.optlaseng.2011.06.024 [17] 张启灿, 吴周杰. 基于格雷码图案投影的结构光三维成像技术[J]. 红外与激光工程,2020,49(3):78-90.ZHANG Qican, WU Zhoujie. Three-dimensional imaging technique based on Gray-coded structured illumination[J]. Infrared and Laser Engineering,2020,49(3):78-90. [18] SRINIVASAN V, LIU H C, HALIOUA M. Automated phase-measuring profilometry of 3-D diffuse objects[J]. Applied Optics,1984,23(18):3105. doi: 10.1364/AO.23.003105 -
点击查看大图
图(9) / 表(1)
计量
- 文章访问数: 113
- HTML全文浏览量: 53
- PDF下载量: 26
- 被引次数: 0
陕公网安备 61011302001501号 