A Study of Image Enhancement Processing for Letter Extraction of Image Using Terahertz Signal

테라헤르츠 신호를 이용한 영상의 글자 추출을 위한 화질 개선처리에 대한 연구

  • Kim, Seongyoon (Department of Electronic Engineering, Dankook University) ;
  • Choi, Hyunkeun (Department of Electronic Engineering, Dankook University) ;
  • Park, Inho (Department of Electronic and Electronical Engineering, Dankook University) ;
  • Kim, Youngseop (Department of Electronic and Electronical Engineering, Dankook University) ;
  • Lee, Yonghwan (Department of Digital Contents, Wonkwang University)
  • 김성윤 (단국대학교 전자공학과) ;
  • 최현근 (단국대학교 전자공학과) ;
  • 박인호 (단국대학교 전자전기공학부) ;
  • 김영섭 (단국대학교 전자전기공학부) ;
  • 이용환 (원광대학교 디지털콘텐츠학과)
  • Received : 2017.09.15
  • Accepted : 2017.09.25
  • Published : 2017.09.30

Abstract

Terahertz waves are superior to conventional X-ray or Magnetic Resonance Tomography(MRI), and the amount of information that can be transmitted is as large as thousands of times that conventional X-ray or MRI. In addition, Terahertz waves have great performance in analyzing an object which have some layered structure. By using this advantage, we can extract the letters of a page by analyzing information such as absorption amount and reflection amount by irradiating a closed book with pulses of various frequencies within gap of a terahertz wave. However, in the image of each page using the Terahertz wave might be obtained various kinds of noise and the different character occlusion region. So, to extract letters from the terahertz image, we must take the noise and occlusion region away. We have been working to enhancement the image quality in various ways, and keep on studying de-noising processing for enhancement about the image quality and high resolution. Finally, we also keep on studying about OCR(Optical Character Recognition) technology, which based on pattern matching technique, to read letters.

Keywords

References

  1. Redo-Sanchez,A., Heshmat, B.,Aghasi, A., Naqvi, S., Zhang, M., Romberg. J., Raskar. R., "Terahertz timegated spectral imaging for content extraction through layered structures", Nature Communications, 7, 12665, (2016) https://doi.org/10.1038/ncomms12665
  2. Galvao, R., Hadjiloucas, S., Bowen, J. & Coelho, C. "Optimal discrimination and classification of THz spectra in the wavelet domain". Optics. Express 11, 1462-1473 (2003). https://doi.org/10.1364/OE.11.001462
  3. Yun Sik Jin, "Terahertz wave and application technique," The Korean Institute of Electrical Engineers, Vol. 54, No. 7, pp. 45-53.(2005)
  4. Pratt, William K. Digital Image Processing, 3rd ed. New York: John Wiley & Sons, 2001.
  5. Gonzales, Rafael C. and Richard E. Woods. Digital Image Processing. 2nd ed. Englewood Cliffs, NJ: Prentice-Hall, 2002.
  6. R. Smith. An Overview of the Tesseract OCR Engine, Proceedings of the Ninth International Conference on Document Analysis and Recognition (ICDAR 2007) Vol 2 (2007), pp. 629-633.
  7. Soille, P., Morphological Image Analysis: Principles and Applications, Springer-Verlag, 1999, pp. 173-174.
  8. Chen, Huizhong, et al. "Robust Text Detection in Natural Images with Edge-Enhanced Maximally Stable Extremal Regions." Image Processing (ICIP), 2011 18th IEEE International Conference on. IEEE, 2011.
  9. Lowe, David G. "Distinctive Image Features from Scale-Invariant Keypoints." International Journal of Computer Vision.Volume 60, Number 2, pp. 91-110. https://doi.org/10.1023/B:VISI.0000029664.99615.94
  10. Sobel,I.E. Camera Models and Machine Perception, Ph.D. Thesis, Stanford University (1970). Dissertation