/ECE648-HW9

Performance of Image and Video Compression Techniques

ECE648-HW9

Performance of Image and Video Compression Techniques

The purpose of this exercise is to compare the performance of popular image and video compression techniques using VCDemo package.

Image Compression

Open the image Lena256B. Use this image and set the bit-rate to 1 for the entire exercise (except in situations where it is not possible).

  1. Perform image compression using DPCM using all four prediction models. Which is the best prediction model?
  2. Perform image compression using VQ using all the four codebooks with bits per vector set to 12. What is the coded bit-rate? Which is the best codebook? Explain why.
  3. Perform image compression using subband coding (SBC) using all six decompositions, and a 16-tap filter. Use default values for other parameters. What is the effect of increasing the number of subbands on the performance?
  4. Perform image compression using subband coding (SBC) using the second decomposition and default values for other parameters. What is the effect of increasing the number of filter taps from 2 to 32 on the performance?
  5. Comare the performance of the following compression schemes:
  6. JPEG
    Use standard Y quantization and adjust the quality to get a coded bit-rate of 1.
  7. JPEG2000 or JPG2
    Use default values.
  8. SPHIT (Set Partitioning in Hierarchical Trees)
    Use target bit-rate of 1 and no smoothing.
  9. EZW (Embedded Zerotree Wavelet)
    Use resolution levels 2, 4, and 6, with encoder bit-rate set to 1.

Video Compression

Open the video sequence Vectra21Frames from VCDemo. Compress the video sequence using MPEG2 and H.264 compression using default parameters. What are the compression ratios obtained using these schemes? (Hint: look at the size of the original vs the compressed file)

Write-Up

  1. Do not include print outs of the compressed images. Perform subjective evaluation of compressed images by observing them on the computer screen.
  2. Answers to all the questions in the Procedure part.
  3. Table of mse and PSNR values for all the techniques and all the compressed images.
  4. If you were to choose a compression scheme for still images that would yield the best performance for a given bit rate, which one will it be.