1) Problem 4.19 (Laplacian in the frequency domain, 50%)
2) Problem 4.22 (zero-padding in digital transforms, 50%)
Both problems are from page 218 of G&W. Problem 4.21 is related to 4.22 you may want to take a look, its solution is available at the bookwebsite (http://www.imageprocessingplace.com).
Prepared by Lexing Xie < xlx at ee dot columbia dot edu >, 2007-02-20