Half-Period Gray-Level Coding Strategy for Absolute Phase Retrieval
N-ary gray-level (nGL) coding strategy is an effective method for absolute phase retrieval in the fringe projection technique. However, the conventional nGL method contains many unwrapping errors at the boundaries of codewords. In addition, the number of codewords is limited in only one pattern. Con...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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MDPI AG
2022-07-01
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| Series: | Photonics |
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| Online Access: | https://www.mdpi.com/2304-6732/9/7/492 |
| _version_ | 1797416405246672896 |
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| author | Zipeng Ran Bo Tao Liangcai Zeng Xiangcheng Chen |
| author_facet | Zipeng Ran Bo Tao Liangcai Zeng Xiangcheng Chen |
| author_sort | Zipeng Ran |
| collection | DOAJ |
| description | N-ary gray-level (nGL) coding strategy is an effective method for absolute phase retrieval in the fringe projection technique. However, the conventional nGL method contains many unwrapping errors at the boundaries of codewords. In addition, the number of codewords is limited in only one pattern. Consequently, this paper proposes a new gray-level coding method based on half-period coding, which can improve both these two deficiencies. Specifically, we embed every period with a 2-bit codeword, instead of a 1-bit codeword. Then, special correction and decoding methods are proposed to correct the codewords and calculate the fringe orders, respectively. The proposed method can generate n<sup>2</sup> codewords with n gray levels in one pattern. Moreover, this method is insensitive to moderate image blurring. Various experiments demonstrate the robustness and effectiveness of the proposed strategy. |
| first_indexed | 2024-03-09T06:03:45Z |
| format | Article |
| id | doaj.art-d91ef70ddbe34ad7a7b4bd40a58939d7 |
| institution | Directory Open Access Journal |
| issn | 2304-6732 |
| language | English |
| last_indexed | 2024-03-09T06:03:45Z |
| publishDate | 2022-07-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Photonics |
| spelling | doaj.art-d91ef70ddbe34ad7a7b4bd40a58939d72023-12-03T12:06:53ZengMDPI AGPhotonics2304-67322022-07-019749210.3390/photonics9070492Half-Period Gray-Level Coding Strategy for Absolute Phase RetrievalZipeng Ran0Bo Tao1Liangcai Zeng2Xiangcheng Chen3School of Automation, Wuhan University of Technology, Wuhan 430070, ChinaHubei Key Laboratory of Mechanical Transmission and Manufacturing Engineering, Wuhan University of Science and Technology, Wuhan 430081, ChinaKey Laboratory of Metallurgical Equipment and Control Technology of Ministry of Education, Wuhan University of Science and Technology, Wuhan 430081, ChinaKey Laboratory of Icing and Anti/De-Icing, China Aerodynamics Research and Development Center, Mianyang 621000, ChinaN-ary gray-level (nGL) coding strategy is an effective method for absolute phase retrieval in the fringe projection technique. However, the conventional nGL method contains many unwrapping errors at the boundaries of codewords. In addition, the number of codewords is limited in only one pattern. Consequently, this paper proposes a new gray-level coding method based on half-period coding, which can improve both these two deficiencies. Specifically, we embed every period with a 2-bit codeword, instead of a 1-bit codeword. Then, special correction and decoding methods are proposed to correct the codewords and calculate the fringe orders, respectively. The proposed method can generate n<sup>2</sup> codewords with n gray levels in one pattern. Moreover, this method is insensitive to moderate image blurring. Various experiments demonstrate the robustness and effectiveness of the proposed strategy.https://www.mdpi.com/2304-6732/9/7/492fringe projectionabsolute phase retrievalgray-level codinghalf-period coding |
| spellingShingle | Zipeng Ran Bo Tao Liangcai Zeng Xiangcheng Chen Half-Period Gray-Level Coding Strategy for Absolute Phase Retrieval Photonics fringe projection absolute phase retrieval gray-level coding half-period coding |
| title | Half-Period Gray-Level Coding Strategy for Absolute Phase Retrieval |
| title_full | Half-Period Gray-Level Coding Strategy for Absolute Phase Retrieval |
| title_fullStr | Half-Period Gray-Level Coding Strategy for Absolute Phase Retrieval |
| title_full_unstemmed | Half-Period Gray-Level Coding Strategy for Absolute Phase Retrieval |
| title_short | Half-Period Gray-Level Coding Strategy for Absolute Phase Retrieval |
| title_sort | half period gray level coding strategy for absolute phase retrieval |
| topic | fringe projection absolute phase retrieval gray-level coding half-period coding |
| url | https://www.mdpi.com/2304-6732/9/7/492 |
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