data from JPEG

I have a *.jpeg image of a x-y scatter plot (not monotonic), and I would like to extract the data points. Any ideas? I was going to do it manually by pixels, but I figured that there is a good way to do that with linear algebra.

[Ashish Uthama]

Posting the picture might help get a better answer.

[LALIT PANKAJ GROVER]

How can I extract the data from this jpeg file. Any suggestion are welcomed.

Answer 1

[John Barber]

The File Exchange program GRABIT is a good way to extract data points from an image of a graph. Download it here: http://www.mathworks.com/matlabcentral/fileexchange/7173

[Cameron Frament]

This method is somewhat worse then doing it by pixels.

Is there some sort of FFT type function which can automatically pull the points?

[Cameron Frament]

To clarify, I know that image is not skewed. But the resolution is too low for me to accurately descriminate the points by eye. In additon there are more than 100 data points. That is the main reason that I don't want to do this by eye.

[Image Analyst]

FFT function ?!?!? Do you know what the FFT is?

I suppose you could use image analysis (thresholding, labeling, regionprops) if your points were well isolated and you had already cropped the axes, tick marks, etc. out of your image. I second Ashish's suggestion.

[lakshmi boddu]

Hello sir , can you please help me how to draw a scatter plot for a jpg image