# Lecture 38 Blog, ECE438 Fall 2014, Prof. Boutin

Monday November 24, 2014 (Week 14) - See Course Outline.

Jump to Lecture 1, 2, 3 ,4 ,5 ,6 ,7 ,8 ,9 ,10 ,11 ,12 ,13 ,14 ,15 ,16 ,17 ,18 ,19 ,20 ,21 ,22 ,23 ,24 ,25 ,26 ,27 ,28 ,29 ,30 ,31 ,32 ,33 ,34 ,35 ,36 ,37 ,**38** ,39 ,40 ,41 ,42 ,43 ,44

Today we moved to the topic of image processing. We stated from the formula for 2D convolution (in discrete-space) expressing the output of a discrete-space LTI system in terms of the input image f[m,n] and the unit input response h[m,n]. We then proceed to demonstrate how to use the formula using an average filter and a 6x6 digital image. The issue of the boundary conditions was discussed.

We analyzed the frequency response of this average filter. More specifically we computed its discrete-space Fourier transform and looked at its plot. Using the separability of the filter greatly facilitated the computation of its Fourier transform.

## Relevant Rhea Material

- Table of CSFT pairs and properties
- a pdf file of the notes of Hector Santos on 2D signals and CSFT
- 2D signals
- 2D rect signal
- A student summary of spectral analysis of 2D signals
- Signal definitions

## Action Items

- Do HW 11. It is due Monday.

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