Current Optics and Photonics

Optical Society of Korea (한국광학회)
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Analysis and Evaluation of Slanted-edge-based Modulation Transfer Function and Focus Measurements for Optimal Assembly of Imaging Modules in Gastrointestinal Endoscopy

  • Received : 2023.04.27
  • Accepted : 2023.07.05
  • Published : 2023.08.25
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Abstract

We explored a method to evaluate imaging performance for the optimal assembly of an endoscopic miniature lens and a sensor constituting an imaging module at the distal end of gastrointestinal endoscopy. For the assembly of the imaging module, the image sensor was precisely located at the focal plane when collimated light passed through the endoscopic lens. As another method, the distance between the lens and sensor was adjusted to obtain the highest focus index from images measured the star chart of the International Organization for Standardization (ISO) standard at various positions. We analyzed the slanted-edge modulation transfer function (MTF), corresponding depth of field, and number of line pairs for MTF 50% and 20% at each working distance within the range of 5-100 mm for imaging modules assembled in different ways. Assembly conditions of the imaging module with better MTF performance were defined for each working distance range of 5-30 mm and 30-100 mm, respectively. In addition to the MTF performance, the focus index of each assembled module was also compared. In summary, we examined the performance of imaging modules assembled with different methods within the suggested working distance and tried to establish the optimal assembly protocol.

Keywords

Acknowledgement

A Korea Medical Device Development Fund grant funded by the Korean government (the Ministry of Science and ICT, the Ministry of Trade, Industry and Energy, the Ministry of Health & Welfare, the Ministry of Food and Drug Safety) (Project Number: RS-2021-KD000006).

References

  1. A. Boese, C. Wex, R. Croner, U. B. Liehr, J. J. Wendler, J. Weigt, T. Walles, U. Vorwerk, C. H. Lohmann, M. Friebe, and A. Illanes, "Endoscopic imaging technology today," Diagnostics 12, 1262 (2022).
  2. ASGE Technology Committee, S. Varadarajulu, S. Banerjee, B. A. Barth, D. J. Desilets, V. Kaul, S. R. Kethu, M. C. Pedrosa, P. R. Pfau, J. L. Tokar, A. Wang, L.-Michel, W. K. Song, and S. A. Rodriguez, "GI endoscopes," Gastrointest. Endosc. 74, 1-6.e6 (2011). https://doi.org/10.1016/j.gie.2011.01.061
  3. K. Brauniger, D. Stickler, D. Winters, C. Volmer, M. Jahn, and S. Krey, "Automated assembly of camera modules using active alignment with up to six degrees of freedom," Proc. SPIE 8992, 89920F (2014).
  4. G. D. Boreman, Modulation Transfer Function in Optical and Electro-Optical Systems (SPIE Press, USA, 2001).
  5. S. D. Alaruri, "Calculating the modulation transfer function of an optical imaging system incorporating a digital camera from slanted-edge images captured under variable illumination levels: Fourier transforms application using MATLAB," Optik 127, 5820-5824 (2016). https://doi.org/10.1016/j.ijleo.2016.04.018
  6. Z. Qin, P.-J. Wong, W.-C. Chao, F.-C. Lin, Y.-P. Huang, and H.-P. D. Shieh, "Contrast-sensitivity-based evaluation method of a surveillance camera's visual resolution: improvement from the conventional slanted-edge spatial frequency response method," Appl. Opt. 56, 1464-1471 (2017). https://doi.org/10.1364/AO.56.001464
  7. M. Estribeau and P. Magnan, "Fast MTF measurement of CMOS imagers using ISO 12233 slanted-edge methodology," Proc. SPIE 5251, 243 (2004).
  8. H. Li, C. Yan, and J. Shao, "Measurement of the modulation transfer function of infrared imaging system by modified slant edge method," J. Opt. Soc. Korea 20, 381-388 (2016). https://doi.org/10.3807/JOSK.2016.20.3.381
  9. H. Zhang, C. Li, and Y. Duan, "Modified slanted-edge method to measure the modulation transfer function of camera," Optik 157, 635-643 (2018). https://doi.org/10.1016/j.ijleo.2017.11.161
  10. G. Bostan, P. E. Sterian, T. Necsoiu, A. P. Bobei, and C. D. Sarafoleanu, "The slanted-edge method application in testing the optical resolution of a vision system," J. Optoelectron. Adv. M. 21, 22-34 (2019).
  11. P. D. Burn, "Slanted-edge MTF for digital camera and scanner analysis," in Proc. IS&T 2000 PICS Conference (Portland, OR, USA, Mar. 2000), pp. 135-138.
  12. S. Zhang, F. Wang, X. Wu, and K. Gao, "MTF measurement by slanted-edge method based on improved Zernike moments," Sensors 23, 509 (2023).
  13. X. Xie, H. Fan, A. Wang, N. Zou, and Y. Zhang, "Regularized slanted-edge method for measuring the modulation transfer function of imaging systems," Appl. Opt. 57, 6552-6558 (2018). https://doi.org/10.1364/AO.57.006552
  14. E. Guevara, M. Miranda-Morales, K. Hernandez-Vidales, M. Atzori, and F. J. Gonzalez, "Low-cost embedded system for optical imaging of intrinsic signals," Rev. Mex. Fis. 65, 651-657 (2019). https://doi.org/10.31349/RevMexFis.65.651
  15. Y. Du, Y. Ding, Y. Xu, and C. Sun, "Dynamic modulation transfer function analysis of images blurred by sinusoidal vibration," J. Opt. Soc. Korea 20, 762-769 (2016). https://doi.org/10.3807/JOSK.2016.20.6.762
  16. "Photography-electronic still picture cameras-resolution measurements," ISO Standard 12233, ISO (2000).
  17. "Photography-Electronic still picture imaging-resolution and spatial frequency responses," ISO Standard 12233, ISO (2014).
  18. O. van Zwanenberg, S. Triantaphillidou, R. Jenkin, and A. Psarrou, "Edge detection techniques for quantifying spatial imaging system performance and image quality," in Proc. IEEE/CVF Conference on Computer Vision and Pattern Recognition-CVPR Workshops (Long Beach, CA, USA, Jun. 16-20, 2019).
  19. K. Nishi, "Does the slanted-edge method provide the true value of spatial frequency response?," J. Opt. Soc. Am. A 40, 259-269 (2023). https://doi.org/10.1364/JOSAA.478864
  20. Y. -H. Chen, Y.-F. Hsieh, C.-W. Hsu, M. Ou-Yang, C.-C. Lee, C.-H. Hwang, "An image based optical lens eccentric error inspection system," in Proc. IEEE International Instrumentation and Measurement Technology Conference (Graz, Austria, May 13-16, 2012), pp. 1094-1097.
  21. D. Vollath, "Automatic focusing by correlative methods," J. Microsc. 147, 279-288 (1987). https://doi.org/10.1111/j.1365-2818.1987.tb02839.x
  22. M. V. Shirvaikar, "An optimal measure for camera focus and exposure," in Proc. Thirty-Sixth Southeastern Symposium on System Theory (Atlanta, GA, USA, Mar. 16, 2004), pp. 472-475.
  23. A. M. Eskicioglu and P. S. Fisher, "Image quality measures and their performance," IEEE Trans. Commun. 43, 2959-2965 (1995). https://doi.org/10.1109/26.477498
  24. Y. Sun, S. Duthaler, and B. J. Nelson, "Autofocusing in computer microscopy: Selecting the optimal focus algorithm," Microsc. Res. Tech. 65, 139-149 (2004). https://doi.org/10.1002/jemt.20118
  25. W. Huang and Z. Jing, "Evaluation of focus measures in multi-focus image fusion," Patt. Recog. Lett. 28, 493-500 (2007). https://doi.org/10.1016/j.patrec.2006.09.005
  26. D.-C. Chen and C.-C. Lin, "A new inspection method applying to CMOS image sensor bumping," Microw. Opt. Technol. Lett. 49, 2283-2285 (2007). https://doi.org/10.1002/mop.22717
  27. Z. Su and H. Rowlands, "A laser alignment system for boat assembly," Sens. Rev. 20, 206-211 (2000). https://doi.org/10.1108/02602280010372340
  28. D. Vollath, "The influence of the scene parameters and of noise on the behavior of automatic focusing algorithms," J. Microsc. 151, 133-146 (1988). https://doi.org/10.1111/j.1365-2818.1988.tb04620.x
  29. A. R. Cabazos-Marin and J. Alvarez-Borrego, "Automatic focus and fusion image algorithm using nonlinear correlation: Image quality evaluation," Optik 164, 224-242 (2018). https://doi.org/10.1016/j.ijleo.2018.02.101
  30. Y. Yao, B. Abidi, N. Doggaz, and M. Abidi, "Evaluation of sharpness measures and search algorithms for the auto focusing of high-magnification images," Proc. SPIE 6246, 62460G (2006).
  31. O. A. Osibote, R. Dendere, S. Krishnan, and T. S. Douglas, "Automated focusing in bright-field microscopy for tuberculosis detection," J. Microsc. 240, 155-163 (2010). https://doi.org/10.1111/j.1365-2818.2010.03389.x
  32. V. Sukumar., H. L. Hess, K. V. Noren, G. Donohoe, and S. Ay, "Imaging system MTF- modeling with modulation functions," in Proc. Annual Conference of IEEE Industrial Electronics (Orlando, FL, USA, Nov. 10-13, 2008), pp. 1748-1753.
  33. Y. P. Fan, L. Wei, L. Li, L. Yang, Z. Q. Hu, Y. H. Zheng, and Y. H. Wang, "Research on the modulation transfer function detection method of a Bayer filter color camera," Sensors 23, 4446 (2023).
  34. J.-H. Kwon, H.-G. Rhee, Y.-S. Ghim, and Y.-W. Lee, "Performance evaluation of MTF peak detection methods by a statistical analysis for phone camera modules," Curr. Opt. Photonics 20, 150-155 (2016). https://doi.org/10.3807/JOSK.2016.20.1.150
  35. Y. Wu, W. Xu, Y. Piao, and W. Yue, "Analysis of edge method accuracy and practical multidirectional modulation transfer function measurement," Appl. Sci. 12, 12748 (2022).
  36. S. N. Lashansky, S. Mansbach, M. J. Berger, T. Karasik, and M. Bin-Nun, "Edge response revisited," Proc. SPIE 6941, 69410Z (2008).