WebPlotDigitizer

https://automeris.io/WebPlotDigitizer/

Tool

The WebPlotDigitizer is a tool to extract data from plots and images. It guides the user through annotating the image and setting some parameters (such as axis values). This allows the tool to extract the values from the chart. The tools allows many customizations to allow better tuning of the extraction process. WebPlotDigitizer also comes in a desktop version.