1. Things about pattern recognition OGD

2. Pattern recognition ● Simplify the input ● Extract features ● Process ● Learn? ● Output results

3. Binarization ● From 256^3 to 0..1 ● Thresholding ● Otsu ● Adaptive mean ● Many others

4. Simple features ● Runlength → fragile ● Projections → more robust ● Background vs foreground

5. Complex features ● Haar features → face detection in camera ● Wavelengths

6. Knowledge ● The program needs to “know” about things ● Learning ● Or just program it?

7. Machine learning ● Bayes ● SVM's ● Neural networks ● Loads of other things ● Your algorithm here?

8. Just program? ● Often best way to get started ● Understand the problem ● Get to know some of the features

9. The hard part ● Getting data ● Analyzing it ● Extracting features ● Lots of boring code ● Lots of manual labor

10. Wow I'm really smart ● Average brain better than supercomputer ● Massively parallel computer ● Still most of it not understood ● But it is simple for the smallest parts

11. Demo ● Modern dutch license plates ● How to detect and read

12. What do you see?

13. Dutch license plate ● Rectangular ● Mostly yellow ● Fixed ratio height-width ● Contains characters/numbbers ● Little blue thingy ● Usually a car around it

14. OpenCV

15. My IDE

16. Just yellowish pixels

17. Postprocessing Connected components ● Filter out components that are too small ● Calculate ratio of components ● Filter out anything that does not match ratio

18. No more garbage!

19. Working on the plate itself ● We now know where the plate is ● Extract it from original source ● Preprocessing ● Extract coco's ● Resize to 25x25 ● Store coco's

20. Manual processing ● Sort the stored images

21. Simple pixel comparison ● Works great ● Picture is the feature ● Simplest learning by example

22. Possible improvements ● Better plate detection ● Handling dirty plates ● Definitely some refactoring ;)

23. Credits & License ● Content by http:// License: ● OpenOffice.org template by Raphaël Hertzog http://raphaelhertzog.com/go/ooo-template License: GPL-2+ http://raphaelhertzog.com/go/ooo-template ● Background image by Alexis Younes “ayo” http://www.73lab.com License: GPL-2+ http://www.73lab.com