Yajun Wang


Ph.D. Student (I have successfully defended my Ph.D. dissertation in Oct. 2013.)
Department of Mechanical Engineering
Iowa State University

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Research Interests

Honors and Awards

Research Projects


My Ph.D. research is about high-speed and high-accuracy 3D shape measurement with binary defocusing techniques and its applications. The conventional digital fringe projection (DFP) method has the potential for high-accuracy 3D measurement. However, there is a speed bottleneck (~120 Hz), caused by the refresh rate of a typical digital projector. The recently proposed binary defocusing technique has the potential for very high-speed measurement. However, it suffers several major limitations. The goal of my Ph.D. research is to achieve superfast 3D measurement by conquering some major challenges associated with the binary defocusing technique and explore some high-speed applications such as biomedical imaging.

Major Progresses

  1. Developed an optimal pulse width modulation (OPWM) method to improve the squared binary technique.
  2. OPWM method
  3. Developed the binary dithering techniques for high-speed 3D measurement & 3D data compression.
  4. Binary dithering
    3-bit compression
  5. Developed a novel phase-coding method for absolute phase retrieval.
  6. Phase-coding
  7. Developed an optimal fringe angle selection method for the DFP systems.
  8. Angle selection
  9. Developed a superfast system and apply it for live rabbit hearts measurement.
  10. Live heart


Book Chapters

  1. Y. Wang, B. Li and S. Zhang, Three-dimensional shape measurement with binary dithering techniques. Recent Advances in Topography Research (2013). (invited)
  2. L. Ekstrand, Y. Wang, N. Karpinsky and S. Zhang. Superfast 3D profilometry with digital fringe projection and phase-shifting techniques. Handbook of 3D machine vision: Optical metrology and imaging (2012). (invited)

Journal Papers

  1. L. Ekstrand, N. Karpinsky, Y. Wang, and S. Zhang, "High-resolution, high-speed three-dimensional video imaging with digital fringe projection techniques," Journal of Visualized Experiments (2013). (in press)
  2. Y. Wang and S. Zhang, "Optimal fringe angle selection for digital fringe projection technique," Appl. Opt. (2013).(with revision)
  3. B. Li, Y. Wang, J. Dai, W. Lohry, and S. Zhang, "Some recent advances on superfast 3D shape measurement with digital binary defocusing techniques," Opt. Laser Eng. (2013). (in press)
  4. Y. Wang, J. I. Laughner, I. R. Efimov, and S. Zhang, "3D absolute shape measurement of live rabbit hearts with a superfast two-frequency phase-shifting technique," Opt. Express 21(5), 5822-5832 (2013). (Cover feature)
  5. P. Ou, B. Li, Y. Wang, and S. Zhang, "Flexible real-time natural 2D color and 3D shape measurement," Opt. Express 21(14), 16736-16741 (2013).
  6. N. Karpinsky, Y. Wang, and S. Zhang, "Three-bit representation of three-dimensional range data," Appl. Opt. 52(11), 2286-2293 (2013).
  7. L. Merner, Y. Wang and S. Zhang, "Accurate calibration for 3D shape measurement system using a binary defocusing technique," Opt. Laser Eng. 51(5), 514-519 (2013).
  8. Y. Wang and S. Zhang, "Three-dimensional shape measurement with binary dithered patterns," Appl. Opt. 51(27), 6631-6636 (2012).
  9. Y. Wang and S. Zhang, "Novel phase-coding method for absolute phase retrieval," Opt. Lett. 37(11), 2067-2069 (2012).
  10. Y. Wang and S. Zhang, "Comparison among square binary, sinusoidal pulse width modulation, and optimal pulse width modulation methods for three-dimensional shape measurement," Appl. Opt. 51(7), 861-872 (2012).
  11. Y. Wang, S. Zhang and J.H. Oliver, "3D shape measurement technique for multiple rapidly moving objects," Opt. Express 19(9), 8539-8545 (2011).
  12. Y. Wang and S. Zhang, "Superfast multifrequency phase-shifting technique with optimal pulse width modulation," Opt. Express 19(6), 5149-5155 (2011).
  13. Y. Wang and S. Zhang, "Optimal pulse width modulation for sinusoidal fringe generation with projector defocusing: Reply to comments," Opt. Lett. 36(6), 809-809 (2011).
  14. Y. Wang and S. Zhang, "Optimal pulse width modulation for sinusoidal fringe generation with projector defocusing," Opt. Lett. 35(24), 4121-4123 (2010).
  15. Y. Wang, S. Yang, X. Gou, "Modified Fourier transform method for 3D profile measurement without phase unwrapping," Opt. Lett. 35(5), 790-792 (2010).
  16. Y. Wang, S. Yang, X. Dai, and H. Li, "The study of seismic signal denoising with the time-frequency analysis method based on smoothing technique," Progress in Geophysics, 24(4), 1473-1482 (2009). (In Chinese)
  17. Y. Wang, D. Xu, X. Chen, and S. Yang, "Fire detection method based on flame dynamic features," Measurement & Control Technology, 26(5), 7-9 (2007). (In Chinese)

Conference Papers

  1. B. Li, J. Gibson, J. Middendorf, Y. Wang, and S. Zhang, "Comparison between LCOS projector and DLP projector in generating digital sinusoidal fringe patterns," in SPIE Optics & Photonics, (San Diego, California) (2013).
  2. S. Zhang, Y. Wang, J. Laughner, and I. R. Efimov, "Measuring dynamic 3D micro-structures using a superfast digital binary phase-shifting technique," in ASME International Manufacturing Science and Engineering Conference (MSEC), (Madison, WI) (2013).
  3. Y. Wang, W. F. Lohry, B. R. halls, T. R. Meyer, and S. Zhang, "Superfast micro-scale 3D optical profilometry using digital binary defocusing techniques," in ASME 2012 International Mechanical Engineering Congress & Exposition, (Houston, TX) (2012). (Poster)
  4. S. Zhang, Y. Wang, L. Ekstrand, Y. Xu, and Y. Gong, "Superfast 3-d shape measurement with binary defocusing techniques," in International Conference on Computational & Experimental Engineering and Sciences (ICCES), (Nanjing, China) (2011). (Invited)
  5. Y. Gong, Y. Wang, and S. Zhang, "High-speed, high-resolution 3-d imaging for biomedical applications," in One Health Symposium: People, Plants & Animals, (Ames, IA) (2010). (Poster)
  6. S. Zhang, Y. Gong, Y. Wang, J. Laughner, and I. R. Efimov, Some recent advance on high-speed, high-resolution 3-d shape measurement using projector defocusing. International Symposium on Optomechatronics Technologies (ISOT2010), (Toronto, Canada) 2010. (Invited)
  7. Y. Wang, S. Yang, and X. Chen, "Single viable cell analysis and feature extraction," in The 1st International Conference on Bioinformatics and Biomedical Engineering (ICBBE2007), (Wuhan, China) (2007).
  8. X. Chen, S. Yang, and Y. Wang, "Research on 3D shape reconstruction using uneven defocusing model," in IEEE International Conference on Mechatronics and Automation (ICMA2007), (Harbin, China) (2007).


  1. S. Zhang, Y. Wang and W. F. Lohry, "3D shape measurement using dithering," Pending U.S. Patent Application No.: 13/732,548 (Filed on January 2, 2013)
  2. S. Zhang, N. Karpinsky and Y. Wang, "Three-dimensional range data compression using computer graphics tools," Pending U.S. Patent Application No.: 61/739,362 (Filed on March 06, 2013)