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

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

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

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?