Recovering data points from an image
Suppose you have a colored plot of several time series (say, from a paper), but not the raw data. How would you estimate the series, which may intersect, from the plot using the axis labels? Bonus cases to consider:
- Compression artifacts.
- Semilog or log-log plots.
- Textured rather than colored series.
Here is a nice example to show the difficulty presented by overlapping, but without any artifacts: MATLAB example http://www.mathworks.com/help/toolbox/econ/multiple_time_series_cointegration_forecast_path.png
If you can solve the base case, feel free to recompress it to introduce artifacts.