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Optimized Optomechanical Anti-Aliasing Filter for Digital Camera Photography

Lee, Sang Won;Chang, Ryungkee;Moon, Sucbei

  • Received : 2015.07.08
  • Accepted : 2015.09.09
  • Published : 2015.10.25

Abstract

We investigated an anti-aliasing (AA) filter for digital camera photography by which the excessively high-frequency components of the image signal are suppressed to avoid the aliasing effect. Our optomechanical AA filter was implemented by applying rapid relative motions to the imaging sensor. By the engineered motion blur of the mechanical dithers, the effective point-spread function (PSF) of the imaging system could be tailored to reject the unwanted high-frequency components of the image. For optimal operations, we developed a spiral filter motion protocol that could produce a Gaussian-like PSF. We experimentally demonstrated that our AA filter provides an improved filtering characteristic with a better compromise of the rejection performance and the signal loss. We also found that the pass band characteristic can be enhanced further by a color-differential acquisition mode. Our filter scheme provides a useful method of digital photography for low-error image measurements as well as for ordinary photographic applications where annoying $moir{\acute{e}}$ patterns must be suppressed efficiently.

Keywords

Aliasing effect;Anti-aliasing filter;AA filter;PSF engineering;Digital imaging system

References

  1. A. J. Jerri, "The Shannon sampling theorem - Its various extensions and applications: A tutorial review," Proc. IEEE 65, 1565-1596 (1977). https://doi.org/10.1109/PROC.1977.10771
  2. K. Ishiga, "Digital camera and digital camera system," US Patent 8259213 (2012).
  3. P. Hao, Y. Li, Z. Lin, and E. Dubois, "A geometric method for optimal design of color filter arrays," IEEE Trans. Image Process. 20, 709-722 (2011). https://doi.org/10.1109/TIP.2010.2077642
  4. J. Couillaud, A. Hore, and D. Ziou, "Nature-inspired color-filter array for enhancing the quality of images," J. Opt. Soc. Am. A 29, 1580-1587 (2012).
  5. B.-J. Jung, "Polarization spectral imaging system for quantitative evaluation of port wine stain blanching following laser treatment," J. Opt. Soc. Korea 7, 234-239 (2003). https://doi.org/10.3807/JOSK.2003.7.4.234
  6. K. K. Patel, A. Kar, S. N. Jha, and M. A. Khan, "Machine vision system: a tool for quality inspection of food and agricultural products," J. Food Sci. Technol. 49, 123-141 (2012). https://doi.org/10.1007/s13197-011-0321-4
  7. M. Keimei, "Light separation unit and imaging unit," Japanese Patent 2013-156379 (2013).
  8. B. H. Pillman, R. J. Palum, and J. N. Border, "Anti-aliasing spatial filter system," US Patent 8228418 (2010).
  9. D. Etchells, "Pentax K-3 review," Imaging Resource, http://www.imaging-resource.com/PRODS/pentax-k3/pentax-k3SELECTIVE_LPF.HTM
  10. J. W. Goodman, Introduction to Fourier Optics (McGraw Hill, 1996), Chapter 6.
  11. B.-S. Lee, "Measurement of spatial resolution in fiber-optic image guides," J. Opt. Soc. Korea 5, 33-36 (2001). https://doi.org/10.3807/JOSK.2001.5.2.033
  12. F. La Rosa, M. C. Virzi, F. Bonaccorso, and M. Branciforte, "Optical Image Stabilization (OIS) - white paper," STMicroelectronics, http://www.st.com/web/en/resource/technical/document/white_paper/ois_white_paper.pdf
  13. G. Agranov, V. Berezin, and R. H. Tsai, "Crosstalk and microlens study in a color CMOS image sensor," IEEE Trans. Electron Devices 50, 4-11 (2003). https://doi.org/10.1109/TED.2002.806473
  14. R. Ramanath, W. E. Snyder, G. L. Bilbro, and W. A. Sander III, "Demosaicking methods for Bayer color arrays," J. Electron. Imaging 11, 306-315 (2002). https://doi.org/10.1117/1.1484495
  15. B. K. Gunturk, J. Glotzbach, Y. Altunbasak, R. W. Schafer, and R. M. Mersereau, "Demosaicking: color filter array interpolation," IEEE Signal Process. Mag. 22, 44-54 (2005). https://doi.org/10.1109/MSP.2005.1407714

Acknowledgement

Supported by : National Research Foundation of Korea