A Method for Pre-Compensation of Digital Images Based on Total Variation Deconvolution, and Comparing it with Wiener Deconvolution, to Enhance Visual Efficiency In The Presence Of Higher Order Ocular Optical Aberrations

Document Type : Original Article (s)

Authors

1 MSc Student, Department of Biomedical Engineering, School of Medicine AND Student Research Committee, Isfahan University of Medical Sciences, Isfahan, Iran

2 Associate Professor, Department of Biomedical Engineering, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran

Abstract

Background: Normal vision is essential to interact with widespread digital technologies. Higher order aberrations (HOA) are one of the important causes of image degradation in patients suffering from keratoconus, pterygium, or irregular astigmatism. These aberrations cannot be corrected by common ways of refractive errors correction like spectacles. Besides, other methods of HOA correction (e.g. customized contact lenses) are not easily accessible in many regions and photo-refractive surgeries like laser-assisted in situ keratomileusis (LASIK) are expensive. A novel method to correct HOA is pre-compensation of images displayed on computer monitors to provide unaberrated images. We used total variation (TV) deconvolution to pre-compensate images and compared the results with previous methods based on Wiener deconvolution.Methods: MATLAB was used for simulations. Each HOA was reconstructed using single-index scheme for Zernike coefficients. Pupil diameter was assumed to be four millimeters. Root-mean-square error of simulated aberrations was greater than 0.35 micrometers. Point spread functions corresponding to each HOA were created and TV deconvolution was used to pre-compensate the images.Findings: Strehl ratio of TV pre-compensation is very close to the results of Wiener pre-compensation method. Besides, execution time for TV Pre-compensation algorithm is about 20% faster than Wiener.Conclusion: Simulations ascertain that TV based pre-compensation method is a fast and efficient way to pre-compensate the images, and it could improve the patient’s perceived retinal image quality. One more advantage of using TV algorithm is that we could enhance the results just by altering one parameter.

Keywords

References

  1. Gumus K, Erkilic K, Topaktas D, Colin J. Effect of pterygia on refractive indices, corneal topography, and ocular aberrations. Cornea 2011; 30(1): 24-9.
  2. Ryan A, O'Keefe M. Wavefront-guided and aspheric ablation for myopia -- one-year results of the zyoptix personalized treatment advanced algorithm. Am J Ophthalmol 2012; 153(6): 1169-77.
  3. Alonso Jr.M, Barreto A, Cremades G. Image pre-compensation to facilitate computer access for users with refractive errors. Proceedings of the 6th International ACM SIGACCESS Conference on Computers and Accessibility; 2004 Oct 18-20; Atlanta, GA. New York, NY: ACM; 2004. p. 126-32.
  4. Alonso Jr.M. An improved method of pre-deblurring digital images towards the pre-compensation of refractive errors. WSEAS Transactions on Computers 2004; 3(2): 487-92.
  5. Alonso Jr.M, Barreto A, Jacko JA, Adjouadi M, Choudhury M. Improving computer interaction for users with visual acuity deficiencies through inverse point spread function processing. Proceedings of the IEEE SoutheastCon; 2005 Apr 8-10; Lauderdale, Florida. IEEE; 2005. p. 421-7.
  6. Alonso Jr.M, Barreto A, Jacko JA, Adjouadi M. Verification of computer display pre-compensation for visual aberrations in an artificial eye. Proceedings of the 7th International ACM SIGACCESS Conference on Computers and Accessibility; 2005 Oct 9-12; Baltimore, MD. New York, NY: ACM; 2005. p. 210-1.
  7. Alonso Jr.M, Barreto A, Jacko JA, Adjouadi M. A multi-domain approach for enhancing text display for users with visual aberrations. Proceedings of the 8th International ACM SIGACCESS Conference on Computers and Accessibility; 2006 Oct 23-25; Portland, Oregon. New York, NY: ACM; 2006. p. 34-9.
  8. Alonso Jr.M, Barreto A, Adjouadi M, Jacko J. Howard: high-order wavefront aberration regularized deconvolution for enhancing graphic displays for visually impaired computer users. In: Computers helping people with special needs. Miesenberger K, Klaus J, Zagler W, Karshmer A, editors: Berlin, Germany: Springer; 2006. p. 1163-70.
  9. Alonso Jr.M, Armando B, A. JJ, Malek A. Evaluation of onscreen precompensation algorithms for computer users with visual aberrations. Proceedings of the 9th International ACM SIGACCESS Conference on Computers and Accessibility; 2007 Oct 15-17; Tempe, Arizona. New York, NY: ACM; 2007. p. 219-20.
  10. Jonas JB, Nangia V, Matin A, Kulkarni M, Bhojwani K. Prevalence and associations of keratoconus in rural maharashtra in central India: the central India eye and medical study. Am J Ophthalmol 2009; 148(5): 760-5.
  11. Alonso Jr.M, Barreto A, Adjouadi M. Digital image inverse filtering for improving visual acuity for computer users with visual aberrations. Inverse Problems in Science and Engineering 2008; 16(8): 957-66.
  12. Mohammadpour S, Mehridehnavi A, Rabbani H, Lakshminarayanan V, editors. A pre-compensation algorithm for different optical aberrations using an enhanced wiener filter and edge tapering.Proceedings of 11th International Conference on Information Science, Signal Processing and their Applications (ISSPA); 2012 July 2-5; Montreal, QC. IEEE; 2012. P. 935-9.
  13. Chan TF, Mulet P. Iterative methods for total variation image restoration. Los Angeles, CA: Department of Mathematics, University of California; 1996.
  14. Chen DQ, Zhang H, Cheng LZ. A fast fixed point algorithm for total variation deblurring and segmentation. Journal of Mathematical Imaging and Vision 2012; 43(3): 167-79.
  15. Oliveira JP, Bioucas-Dias JM, Figueiredo MAT. Adaptive total variation image deblurring: A majorizationGCominimization approach. Signal Processing 2009; 89(9): 1683-93.
  16. Chan TF, Wong CK. Total variation blind deconvolution. IEEE Transactions on. Image Processing 1998; 7(3): 370–5.
  17. Thibos LN, Applegate RA, Schwiegerling JT, Webb R. Standards for reporting the optical aberrations of eyes. J Refract Surg 2002; 18(5): S652-60.
  18. Krueger RR, MacRae S, Applegate RA. Wavefront customized visual corrections: the quest for super vision II: 2nd ed. Thorofare, NJ: Slack Incorporate; 2003.
Journal of Isfahan Medical School
Volume 31, Issue 223 - Serial Number 223
January and February 2013
Pages 25-31

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History

  • Receive Date: 10 December 2012
  • Revise Date: 29 April 2024
  • Accept Date: 06 April 2022

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