1. Matlab & Image processing toolbox Heejune Ahn SeoulTech Last updated 2015. Jan.

2. Outline Why Matlab? Install Matlab Key concepts of Matlab Basic commands To be an Matlab expert

3. 1.Why Matlab TM ? Nice language  Quicker to Learn than other languages.  Platform-independent  De-facto scientific standard Can focus on algorithm  not low level details  integrated environment (graphics etc)  tool boxes Alternatives  OpenCV

4. Install Matlab Install  Run “setup.exe” as usual License  Individual licenses (use on your Labtop)  Multi-user licenses (at class room, already set-up)

5. Running Matlab and 20 commands workspace (variables) command hisory command windows working directory

6. Key concepts Working directory  pwd  cd Search path  addpath( )  editpath  matlab setup.m file Workspace  whos  clear  save // session.mat file  load

7. Variables Variable  Every thing in Matlab is matrix/array. 1-D, 2-D, & multi-Dim Must be a rectangular  Initialization A = [1 2; 3 4]  implicit vectorization x=1:10, y=sin(pi.*x./2)  Indexing A(rows, columns) first element : “1”, not “0” start:step:end e.g) 0:5:100 All elements: “ : ” 12 34 A(1, 1:2 ) row A(1:2, 2) = A( :, 2) column

8. More on variable Generating  size e.g.) size(A)  zeros, ones, eye modification  repmat e.g.) A=eye(4); B=repmat(A,1,2);  combine: A=[1 2; 3 4], B=[5 6; 7 8], C=[9 10 11 12] ; D= [A B]; E= [A; B]; F = [A B; C] Image  3-D of x, y, & component  A = imread(‘filename’);  imshow(A)

9. Number representation kjkjkjkjkj

10. Operations Mathemetical Operations  scalar operation vs matrix operation scalar: element by element e.g) A=[1:2, 3:4]; B=A; C=A.*B; D=A*B

11. Relational  Element-by-element e.g.

12. Logical

13. Flow control If/else switch

14. Flow control for-loop While-loop Note: implicit vectorization should be prefered in Matlab

15. Matlab Functions Built-in functions  exp, sqrt, log, sin etc M-function files function C=sub_img(A,B); %comments here if size(A) ~= size(B) disp(‘Images are not the same size’) return; else C=imsub(A,B); imshow(C); %Display 8-bit diff image end inputs output

16. Useful in M-script User Interaction  keyboard  type  pause  Input Algorithm  find (indexes) A=1:10; i=find(A>5)

17. Etc 2-D Ploting  Plot  bar  hist Utility  help  quit  print  ; (semi-colon) x = 0:pi/100:2*pi; y = sin(x); figure % opens new figure window plot(x,y)