1. Image Filtering with GLSL DI1.03 蔡依儒

2. Outline Convolution Convolution Convolution implementation using GLSL Convolution implementation using GLSL Commonly used convolution filter Commonly used convolution filter Mean Filter Mean Filter Gaussian Filter Gaussian Filter Laplacian Filter Laplacian Filter Sharpness Filter Sharpness Filter

3. Convolution 1 Convolution Convolution an operation in which the final pixel is the weighted sum of the neighboring pixels an operation in which the final pixel is the weighted sum of the neighboring pixels Convolution kernel Convolution kernel a matrix which gives some weight to each one of the neighbor pixels a matrix which gives some weight to each one of the neighbor pixels filter, mask, kernel, template, or window filter, mask, kernel, template, or window

4. Convolution 2

5. Convolution implementation using GLSL

6. Mean Filter Most commonly used for the image noise elimination Most commonly used for the image noise elimination eliminating pixel values which are unrepresentative of their surroundings eliminating pixel values which are unrepresentative of their surroundings

7. Gaussian Filter 1 A kind of Lowpass filters A kind of Lowpass filters Used to blur an image and remove detail and noise Used to blur an image and remove detail and noise 1/16 4/16 2/16

8. Gaussian Filter 2

9. Gaussian Filter 3 Results of smoothing with square filter masks of sizes n = 3, 5, 9, 15, and 35, respectively Results of smoothing with square filter masks of sizes n = 3, 5, 9, 15, and 35, respectively The black squares at the top are of sizes 3, 5, 9, 15, 25, 35, 45, and 55 pixels, respectively The black squares at the top are of sizes 3, 5, 9, 15, 25, 35, 45, and 55 pixels, respectively

10. Laplacian Filter 1 Used for the image edges detection Used for the image edges detection 00 00 -4 1 1 1 1

11. Laplacian Filter 2

12. Sharpness Filter Used to increase and to make stand out the details of an image Used to increase and to make stand out the details of an image 00 00 5 9

13. 馬賽克

14. Reference http://www.ozone3d.net/tutorials/image_filtering.php http://www.ozone3d.net/tutorials/image_filtering.php http://www.ozone3d.net/tutorials/image_filtering.php http://www.cee.hw.ac.uk/hipr/html/filtops.html http://www.cee.hw.ac.uk/hipr/html/filtops.html http://www.cee.hw.ac.uk/hipr/html/filtops.html Digital Image Processing 2nd Edition Digital Image Processing 2nd Edition by Gonzalez and Woods by Gonzalez and Woods Prentice Hall Prentice Hall http://big5.yesky.com/b5/www.yesky.com/SoftChann el/72342371928702976/20041028/1869312.shtml http://big5.yesky.com/b5/www.yesky.com/SoftChann el/72342371928702976/20041028/1869312.shtml