4. (a) JPEG uses the Discrete Cosine Transform (DCT) for image compression. i. What is the value of F(O, 0) if the image f(i, j) is as below? ii. Which AC coefficient |F(u, v)l is the largest for this f (i, j)? Why? Is this F(u, v) positive or negative? Why? 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 80 80 80 80 80 80 80 80 80 80 80 80 80 80 80 80 140 140 140 140 140 140 140 140 140 140 140 140 140 140 140 140 200 200 200 200 200 200 200 200 200 200 200 200 200 200 200 200 314 9 Image Compression Standards (b) Show in detail how a three-level hierarchical JPEG will encode the image above, assuming that i. The encoder and decoder at all three levels use Lossless JPF?G. ii. Reduction simply averages each 2 x 2 block into a single pixel value. iii. Expansion duplicates the single pixel value four times