How to extract data from existing JPEG/TiFF graph?

[kelvin490]

Is there any method to extract data from a graph in JPEG/TIFF format, using simple software such as MATLAB? I have a graph as shown below:

I only have this picture but no raw data and I want to plot the black curve in this graph. How to get approximate numerical data of the x and y axis? Thank you.

 

[DrClaude]

I don't know how to do it simply in Matlab. For such tasks, I use DataThief.

 

[Image Analyst]

You can use getframe()

plot(1:10);
structFrame = getframe(); % Get structure
rgbImage = structFrame.cdata;
figure;
imshow(rgbImage);