An Efficient Post-processing Using DCT Domain Projections Onto Convex Sets

  • Changhoon Yim
Part of the Lecture Notes in Computer Science book series (LNCS, volume 4141)

Abstract

Post-processing methods using projections onto convex sets (POCS) have shown good performance for blocking artifact reduction. The iterative operations in POCS require infeasible amount of computations for practical real-time applications. In this paper, we propose an efficient non-iterative post-processing method using DCT domain POCS, namely DPOCS. In DPOCS, the inverse DCT and the forward DCT need not be performed by performing the low-pass filtering (LPF) in the DCT domain. Through the investigation of LPF at each iteration in the conventional POCS, the k-th order LPF is defined that is equivalent to the first order LPF with k iterations. By combining DCT domain filtering and the k-th order LPF, we define k-th order DCT domain LPF. The k-th order DCT domain LPF is performed only once to have the equivalent performance to the conventional POCS method with k iterations. Simulation results show that the proposed DPOCS without iteration gives very close PSNR and subjective quality performance compared to the conventional POCS with iterations, while it requires much less computational complexity. If we take into account typical sparseness in DCT coefficients, the DPOCS method gives tremendous complexity reduction compared to the conventional POCS method. Hence the proposed DPOCS is an attractive method for practical real-time post-processing applications.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. 1.
    Paek, H., Kim, R.-C., Lee, S.U.: On the POCS-based postprocessing technique to reduce the blocking artifacts in transform coded images. IEEE Trans. Circuits Syst. Video Technol. 8(3), 358–367 (1998)CrossRefGoogle Scholar
  2. 2.
    Park, S.H., Kim, D.S.: Theory of projection onto narrow quantization constraint set and its applications. IEEE Trans. Image Processing 8(10), 1361–1373 (1999)CrossRefMATHGoogle Scholar
  3. 3.
    Pearson, D., Whybray, M.: Transform coding of images using interleaved blocks. Proc. Inst. Elect. Eng. 131, 466–472 (1984)Google Scholar
  4. 4.
    Malvar, H.S., Staelin, D.H.: The LOT: Transform coding without blocking artifacts. IEEE Trans. Acoust., Speech, Signal Processing 37, 553–559 (1989)CrossRefGoogle Scholar
  5. 5.
    Ramamurthi, B., Gersho, A.: Nonlinear space-variant postprocessing of block coded images. IEEE Trans. Acoust., Speech, Signal Processing 34, 1258–1267 (1986)CrossRefGoogle Scholar
  6. 6.
    Zakhor, A.: Iterative procedure for reduction of blocking effects in transform image coding. IEEE Trans. Circuits Syst. Video Technol. 2(1), 91–95 (1992)CrossRefGoogle Scholar
  7. 7.
    Yang, Y., Galatanos, N.P., Katsaggelos, A.K.: Regularized reconstruction to reduce blocking artifacts of block discrete cosine transform compressed image. IEEE Trans. Circuits Syst. Video Technol. 3(6), 421–432 (1993)CrossRefGoogle Scholar
  8. 8.
    Yang, Y., Galatanos, N.P., Katsaggelos, A.K.: Projection-based spatially adaptive reconstruction of block-transform compressed images. IEEE Trans. Image Processing 4(7), 896–908 (1995)CrossRefGoogle Scholar
  9. 9.
    Jeong, Y., Kim, I., Kang, H.: A practical projection-based postprocessing of block-coded images with fast convergence rate. IEEE Trans. Circuits and Syst. Video Technol. 10(4), 617–623 (2000)CrossRefGoogle Scholar
  10. 10.
    Merhav, N., Kresch, R.: Approximate convolution using DCT coefficient multipliers. IEEE Trans. Circuits Syst. Video Technol. 8, 468–476 (1998)CrossRefGoogle Scholar
  11. 11.
    Madisetti, A., Wilson, J.R., A.N.: A 100 MHz 2-D DCT/IDCT processor for HDTV applications. IEEE Trans. Circuits Syst. Video Technol. 5, 158–165 (1995)Google Scholar
  12. 12.
    Cho, N.I., Lee, S.U.: Fast algorithm and implementation of 2-D discrete cosine transform. IEEE Trans. Circuits and Syst. 38(3), 297–305 (1991)CrossRefGoogle Scholar
  13. 13.
    Kresch, R., Merhav, N.: Fast DCT domain filtering using the DCT and the DST. IEEE Trans. Image Processing 8(6), 378–384 (1999)CrossRefGoogle Scholar
  14. 14.
    Yim, C.: An efficient method for DCT-domain separable symmetric 2-D linear filtering. IEEE Trans. Circuits Syst. Video Technol. 14(4), 517–521 (2004)CrossRefMathSciNetGoogle Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2006

Authors and Affiliations

  • Changhoon Yim
    • 1
  1. 1.Department of Internet and Multimedia EngineeringKonkuk UniversitySeoulKorea

Personalised recommendations