WebPlotDigitizer - WebPlotDigitizer - Web based tool to extract numerical data from plots, images and maps.
Plot Digitizer - All-in-One Tool to Extract Data from Graphs, Plots & Images
g3data - g3data is used for extracting data from graphs.
DataThief III - DataThief III is a program to extract (reverse engineer) data points from a graph.
Silkscientific UN-SCAN-IT - Digitizing Software converts graph image files to usable (x,y) data automatically
DigitizeIt - Sometimes it is necessary to extract data values from graphs, e.g.