1. place dexter in your path, adjust python executable path.
2. have PIL, matplotlib installed under python
3. invoke as dexter imgfile
4. outfile in the Data Extractor window should be the file name that will contain the extracted data points
5. xlim/ylim specifies the data limit in x-axis/y-axis, 3rd parameter is 1 indicates a log scale
6. Plot button shows the plot.
7. Open button opens the outfile
8. Close button closes the outfile
9. Quit button exits the program.
10. after specifying Outfile, xlim (x0 and x1), ylim (y0 and y1), press plot, on the image window, move cursor to the point corresponding to (x0,y0), press "a" key, then move cursor to the point corresponding to (x1,y1), press "b" key, this defines the data scale. then move cursor to the data points, press d key, this will write a line in the Outfile giving the x and y coordinates. if press m key, and move the mouse, a continuous stream of data points is written to Outfile.