in order to quantify intensity you could try both imageJ or may better open source software CellProfiler, it's not intuitive but few days of practise and it will work.
for CellProfiler you need to set up your ipelne according to your images and in particular to mineralized nodue size.
Rgarding imageJ open your images go to anazlyze set measurements select the variable you need to score, then select the areas to score and back to analyze and click to measure.