Start by looking over the Wikipedia page on JPEG

Start by looking over the wikipedia page on jpeg

This preview shows page 2 - 3 out of 3 pages.

Start by looking over the Wikipedia page on JPEG: Turn in your code for all parts, plots and reconstructed images for a few values of M for part c, and your calculations and reconstructed image for part d. (a) Write a MATLAB function block dct2.m which takes an N × N pixel image, divides it into 8 × 8 pixel blocks (you may assume that N is divisible by 8), and returns the dis- crete cosine transform coefficients for each block. You will find the MATLAB command dct2.m helpful. Write another MATLAB function iblock dct2.m which is the inverse of the above: that takes the blocked DCT coefficients and returns the image. (b) The provided function jpgzzind.m orders the indexes of a block from low frequencies to high frequencies, as shown below: If xb is an 8 × 8 block, then xb(jpgzzind(8,8)) is a 64 × 1 vector containing the same elements, just in the “correct” order. Using this utility, write a MATLAB function block dct2 approx.m that takes an N × N image and a number M , and returns an N × N approximation ˜ x M formed by keeping the first M DCT coefficients in each block.
Image of page 2

Subscribe to view the full document.

Image of page 3
  • Fall '08
  • Staff

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern

Ask Expert Tutors You can ask You can ask ( soon) You can ask (will expire )
Answers in as fast as 15 minutes