CONNECT THE DOTSIntroduction to Computational and Biological VisionKeren shemesh

INTRODUCTION The game

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

ASSUMPTIONS Dot Circles

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

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

PRINCIPLES OF THE ALGORITHM: STAGE 1

PRINCIPLES OF THE ALGORITHM: STAGE 2 finding all numbers in the image

Extracting all connected components

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

PRINCIPLES OF THE ALGORITHM: STAGE 2 filtering out components not on the average

height filtering out components not on the average

width

PRINCIPLES OF THE ALGORITHM: STAGE 2 Link all digit in the same number

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

PRINCIPLES OF THE ALGORITHM: STAGE 3

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

PRINCIPLES OF THE ALGORITHM: STAGE 4

PRINCIPLES OF THE ALGORITHM: STAGE 5 + 6 Drawing lines between connected dots with

sequential numbers using interpolation Filing the image with random numbers

RESULTS

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

DISCUSSION AND CONCLUSIONS Correct identification depends on the

components in the image Size Proximity to others Font of the numbers

THE APPLICATION

QUESTIONS?