How to recognize line charts

shape
graph

asked 2014-10-14 06:15:26 -0600

tlearner
1 ●1

First of all I am beginner on this field and hoping to get help from you.

I would like to recognize line chart and get (x,y) values from chart into excel. Charts could look like this. image description

or like this

image description

Charts are in cartesian coordinate. I have checked this. But couldnt understand all the logic fully and feels like it's little outdated. Could you please describe the steps, papers, algorithms and/or specific modules from OpenCV which I should read in order to accomplish my task. Please let me know if I should add specific details.

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answered 2014-10-14 10:59:56 -0600

Haris

3804 ●3 ●28 ●57

You can proceed like,

Convert source to hsv color space using cvtColor().
Now segment each line using inRange(), here you should give appropriate hsv color range each line in your chart.
The inRange() result will give you binary image for each line. You may need to apply morphology as most of the lines in the chart lies on one another.
Finally find contour will give you x-y co-ordinates for each line segment for the input binary.