Contour Plot digitizing Software

i need a software that will digitize a scanned iso candela plot and record the data in an excel file. If anyone is interested then please respond to my request and i'll get back to you with the details about this plot. ![][1] ## Deliverables I have attached a sample plot. As you can see, the graph is an aerial view of a hemispherical sky dome with the vertical axis scaled from 0 degree to +90 degree with 10 degree intervals and with 0 degree at the ground level adn 90 degree at the top of the sky dome. This vertical axis is the angle of elevation. The other axis divides the hemispehere into 360 degrees horizontally with 6 degree intervals and with 0 degree at the South 90 degree at the West and so on. Thus the hemisphere has been scaled using a C- Gamma(Y) coordinate system and has been divided into 60 zones at each angle of elevation( see the picture for a better understanding).Thus there are a total of 10x60 zones. Within this hemisphere the iso candela trajectories have been plotted. I need a software to record the candela values at each zone and store them in an excel file. The zones which have not been intercepted by any iso candela lines will have the average value of the last and the next zone that have been intercepted by an iso candela line.