How to recognize graphs from image

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I did this a while back. There is no fool-proof solution, but some things can be done quite easily.
Open the image to get rid of the grid, threshold the color channels to get the line and/or use morphology to leave only detect the dots.
Once you have the dots you're mostly done.

In the first use the projection for recognize of table(chart) in the vertical & horizontal direction. In the next step you have to use morph open for recognize spots(remove green lines & remain green spots).