1. Introduction to Computational and Biological Vision Keren shemesh
Connect the Dots
Introduction to Computational and Biological Vision
Keren shemesh

2. Introduction The game Motivation & Goal
educative and creational
Motivation & Goal
Kids often play the game alone.
Errors causing false understanding of the numerical system.
Kids can check themselves.
Known topics in computer vision:
OCR
Hough and Circular Hough transform

3. Assumptions Dot Circles All numbers
circle-shaped in range of 5 to 15
approximately the same size and shape
filled black
All numbers
same font size
All digits
can easily be isolated and extracted
horizontal
the intensity of the components is clearly different from the intensity of the background

4. Principles of the Algorithm: stage 1
finds all connected dots in the image
Finding all circles using Circular Hough Transform
Creating bounding box
Filter circles
Ratio of white-pixels/pixels in the bounding box < threshold
The center of the circle is black

5. Principles of the Algorithm: stage 1

6. Principles of the Algorithm: stage 2
finding all numbers in the image
Extracting all connected components

7. Principles of the Algorithm: stage 2
filtering out the potential connected dots while assuming that a connected dot is not ‘in’ a number And vice versa

8. Principles of the Algorithm: stage 2
filtering out components not on the average height
filtering out components not on the average width

9. Principles of the Algorithm: stage 2
Link all digit in the same number

10. Principles of the Algorithm: stage 3
Interpreting each digit using OCR detection
pre-saved database of font templates for every number 0-9
the best fit correspondence between a component and the database is calculated using correlation

11. Principles of the Algorithm: stage 3

12. Principles of the Algorithm: stage 4
matching the dot circles with the numbers by proximity
Match the closest digit of every number to every dot circle
Only the closest circle is matched to each number - removing spare circles
All linked digits are calculated to a number
All connected dots with matched numbers are sorted by the numbers

13. Principles of the Algorithm: stage 4

14. Principles of the Algorithm: stage 5 + 6
Drawing lines between connected dots with sequential numbers using interpolation
Filing the image with random numbers

15. Results

16. Known issues False identification of number
False identification of connected dot
Inaccurate OCR detection due to an unknown font
False identification of connected dot and a number

17. Discussion and Conclusions
Correct identification depends on the components in the image
Size
Proximity to others
Font of the numbers

18. The application

19. Questions?