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CPE 631. Image Processing and Computer Vision. Syllabus - Overview. To introduce students to the concepts of computer vision touching on areas of computer graphics image processing artificial intelligence biological vision neural networks pattern recognition robot vision.
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CPE 631 Image Processing and Computer Vision
Syllabus - Overview To introduce students to the concepts of computer vision touching on areas of • computer graphics • image processing • artificial intelligence • biological vision • neural networks • pattern recognition • robot vision
Syllabus - Application • Most applications involve us to use eyes • Good robot should be able to see • Engineering wise control environment • General environment unconstraint • Simulation - Driving on a highway • Millions of Research Topic
Syllabus - Grading • Programming Assignments 25% • Term Project 15% • Best 8 of 10 Quiz 60%
Syllabus – Term Project • The term project will be on a computer vision topic of choice requiring: • Proposal: 1-2 pages and 5-10 min presentation • Project Report: 4-8 pages and 20-25 min presentation
Syllabus – Assignment 1. Simple Thai OCR Competition (10%) 2. Three Dimensional Digitizer Application: Shape from Stereograms (15%)
Syllabus – Reference Books Jain R., R. Kasturi, and B.G. Schunck, Machine Vision, McGraw-Hill.
Syllabus – Topics 1. Overview of Computer Vision Course and Assignments Overview Image Formation and Sensing 3-D Computer Graphics and Visual Realism Digital Images: bw, grayscale, and color 2. Binary Image Processing: Low-level Image Filtering and Edge Detection 3. Regions, Image Segmentation, Texture Segmentation Blob Coloring Contours and Boundary Detection General Hough Technique and Applications
Syllabus – Topics 4. 3-D Computer Graphics Models Revisited Optics, Shading, Curves and Surfaces Energy Minimization and Relaxation Techniques Bayesian Probability, The Pixel Lattice 5. Depth & Shape from X Texture, Shading, and Stereo 6. Calibrations Depth from Binocular Stereo 3-D Volume Rendering from cross-section images
Syllabus – Topics 7. Dynamic Vision Motion Field and Flow: Gradient vs. Matching Methods 8. Structure from Motion, Object Tracking 9. Object Recognition Models
Computer Vision • Divided to 3 Levels: • Low Level • Mid Level • High Level
Low-Level • Edge Detection • Image Processing (Pre-Processing) Image Processing Image Image
Mid-Level (Perception) • Segmentation/Grouping Satellite Images OCR กุ้ง
Mid-Level (Perception) • Finding Depth, Shape, Light, Materials • “Inverse of Computer Graphics” Computer Graphics Computer Vision CG Scence -shape -material – color, shiny, transparency, texture, etc. -light -camera Image CV Image 3D Scence
High-Level (Use Knowledge) • Pattern Recognition • Obstacle Avoidance • Grasping • Object Recognition • Etc.
200 200 200 200 200 200 200 200 200 200 200 200 200 200 200 200 200 200 200 200 Image Formation • Intensity Image (with value 0..255) • 0 – black, 100 – gray, 255 - white • For example, an ideal white paper
222 219 220 200 218 222 220 220 221 200 200 200 220 219 198 198 198 200 210 190 Noise in Sensor • Scanned white papermight not be all 200 • It can be, for example:
222 219 220 200 218 222 220 220 221 200 200 200 220 219 198 198 198 200 210 190 Gaussian Additive Noise G(20,5) • G(m,s)
Salt/Pepper Noise • Random Noise • Black – pepper • White - Salt
To Get Rid of Noise • Gaussian Noise • Use Gaussian Filter • Salt/Pepper Noise • Use Median Filter
Filter F I’ I Filter I x F = I’ Input Image Output Image Convolution
50 45 47 52 54 49 49 50 52 49 52 50 50 51 1/4 1/4 51 51 49 48 1/4 1/4 51 52 51 45 48 50 51 49 48 50 47 54 47 52 Filter- Example (50*1/4)+(45*1/4)+ (49*1/4)+(52*1/4) 2 x 2 Mean Filter Input Image Output Image
50 50 45 47 52 54 50 50 45 47 52 54 1/9 1/9 1/9 49 48 49 51 1/9 1/9 1/9 49 49 52 50 50 51 50 50 49 50 1/9 1/9 1/9 51 51 52 51 45 46 50 50 50 50 50 50 47 54 47 52 Filter- Example (50*1/9)+(50*1/9)+(45*1/9)+ (50*1/9)+(50*1/9)+(45*1/9)+ (49*1/9)+(49*1/9)+(52*1/9) 3 x 3 Mean Filter Input Image Output Image Mirror
1/4 1/4 1/4 1/4 1/9 1/9 1/9 1/9 1/9 1/9 1/9 1/9 1/9 Mean Filter (Average) 2 x 2 Mean Filter 3 x 3 Mean Filter
1 1 2 2 2 1 1 1 2 2 4 2 2 1 2 2 4 8 4 2 2 2 4 8 16 8 4 2 2 2 4 8 4 2 2 1 2 2 4 2 2 1 1 1 2 2 2 1 1 Gaussian Filter
Gaussian Filter • Highest in the middle • Reducing factored by s s high – reduce slow s low – reduce fast
Median Filter • No convolution • Arrange all values, then use the middle one • For example, • 20, 21, 32, 23, 17, 19 , 20 • Order by value • 17 • 19 • 20 • 20 • 21 • 23 • 32 • Use 20 • 20, 22, 32, 23, 17, 19 , 20,24 • Order by value • 17 • 19 • 20 • 20 • 22 • 23 • 24 • 32 • Use 21 Average the middle (20+22)/2 = 21 Use the middle
20 23 22 71 22 22 22 22 24 24 22 21 70 22 24 22 23 22 22 21 24 56 100 21 20 20 20 20 23 20 22 22 21 32 20 20 Median Filter - Example • 2 x 2 Median Filter