1. A Brief Introduction to MATLAB Digital Image Processing 2014 Fall NTU

2. Outline MATLAB overview Matrix 2-D plotting 3-D plotting Image Processing more about MATLAB Reference

3. Outline MATLAB overview Matrix 2-D plotting 3-D plotting Image Processing more about MATLAB Reference

4. MATLAB NTU AppShare ( 臺大雲端軟體運算銀行 ) – Windows & IE https://app.ntu.edu.tw/vdiportal/

5. MATLAB interface

6. basic operation

7. variables English alphabet, number, underline – first word must be English alphabet – variable length <= 32 characters variables need not be previously declared (default double) comments – %

8. operators arithmetic operators – +, -, *, /, ^ relational operators – ==, ~=, >, >=, <, <= logical operators – &, |, ~ bitwise operators – bitand, bitor, bitxor

9. flow control conditional control – if-else – switch loop control – for – while – continue

10. script or type “edit filename.m” to create a script from command window Click to create a new script

11. Outline MATLAB overview Matrix 2-D plotting 3-D plotting Image Processing more about MATLAB Reference

12. matrix creation row vector – R = [7 8 9 10]; – R = [7, 8, 9, 10]; column vector – C = [7; 8; 9; 10]; build vector fast – start:step:end – linspace(start, end, num);

13. extract sub-matrix A = [1 2 3 4; 5 6 7 8; 9 10 11 12]; B = A(1, 2:4); C = A(2:3, 2:3); D = A([1 3], [1 2 3]); 1 2 3 4 5 6 7 8 9 10 11 12 1 2 3 4 123123

14. Matrix operations add Scalar

15. Matrix operation(Cont’d) matrix multiplication array multiplication

16. Outline MATLAB overview Matrix 2-D plotting 3-D plotting Image Processing more about MATLAB Reference

17. 2-D plotting

18. subplot Example 2 ： create figure with multiple graphs

19. Axis control Axis control example ：

20. histogram hist(data) ： histogram plot – data = randn(1000, 3); – hist(data, 20);

21. Outline MATLAB overview Matrix 2-D plotting 3-D plotting Image Processing more about MATLAB Reference

22. 3-D plotting Example 1 ： mesh graph

23. 3-D plotting (Cont’d) Example 2 ： surface graph

24. 3-D plotting (Cont’d) Example 3 ： 3-d curve

25. Outline MATLAB overview Matrix 2-D plotting 3-D plotting Image Processing more about MATLAB Reference

26. overview Basic commands ： – img = imread(‘lena.jpg’, ‘jpg’); – imwrite(img, ‘my_lena.jpg’, ‘jpg’); – imfinfo(‘lena.jpg’) – image(img);

27. Image load and display

28. image scale imresize(img, scale) – resize image

29. image rotation I2 = imrotate(I, 60, ‘nearest’); I3 = imrotate(I, 60, ‘bilinear’); Nearest interpolationBilinear interpolation Original image

30. filter h1 = fspecial(‘laplacian’); f1 = filter2(h1, double(f)/255); h2 = fspecial(‘sobel’); f2 = filter2(h2, double(f)/255); laplacian filtersobel filter original image

31. edge detection f3 = egde(f, ‘sobel’); f4 = edge(f, ‘canny’); edge detection by sobel method edge detection by canny method original image

32. Outline MATLAB overview Matrix 2-D plotting 3-D plotting Image Processing more about MATLAB Reference

33. more about MATLAB more on, more off ： control paged output for command window help function_name ： help for functions in command window lookfor keyword ： search for keyword in all help entries

34. Outline MATLAB overview Matrix 2-D plotting 3-D plotting Image Processing more about MATLAB Reference

35. reference Mathworks document Mathworks forum Tutorial from Jyh-Shing Roger Jang