Extracting data from an image of plots

Hello everyone, We have a pdf page which contains one or more figures which are two-dimensional plots of experimental results. The figures may or may not be embedded in text. Each plot has the x and y axis with their labels and unit measurements marked in the plot. Inside each figure are one or more plots, each with a different color. How can we convert the plot into a table of corresponding x and y values (say for 100 points) ? Looking forward to a solution, Thank you, Himanshu Mishra