Its been a long time since i vanished and not been active on this thread. It was just for the reason i wanted to really navigate away from the ultrasound and look for solution based on optics.
I really wanted to honor and respect the views of the people who wanted to genuinely help me out on this and is the reason for my long silence to come back only after i have done some homework. Now it has come to a point that i have switched to IR. I made an Infrared Meter by reading the tutorial posted here http://elecrom.wordpress.com/2008/02/19/how-to-make-simple-infrared-sensor-modules/#comment-2483
I should say it works fairly good and gives me a lot of hope. Though i am not trying to develop an Imaging solution, but simply wanted to find out the loading time of a grinding wheel. With this module i am able to measure the voltage values generated by the IR receiver based on the reflection from the surface by the IR transmitter. It all costed me very less to make this circuit and also it still satisfies my original goal (Cheaper ways to analyze Grinding Wheel loading). Though the analysis is still left to us, we are monitoring different specimens and are trying to evaluate an average value which will help in deciding about the dressing time of the wheels. Though it is not accurate but it is approximate.
Now is a phase where i have started testing out the unit on different grinding wheel with different loaded conditions. Wish me all the best.
On the other hand i have started looking at the magnetism aspect of testing the loading condition. Since the grinding wheel accumulates a lot of metal particles, was wondering if i can keep a magnet at a minimal constant distance from the grinding wheel and measure the force field between the wheel and magnet if any. Ideally in the starting stages there should not be any force field because of no metallic particles present, as time goes forward a lot of metal particles gets accumulated in the wheel thus should increase the magnetic force between the wheel and the magnet. This would be the theoretical idea, but need to know what are the practical implications of it. Trying to get a hall effect sensor and see if it can cater to this purpose, but am not getting it in my area. Also i need to do some amount of ground work on the IR module and then move on to this solution giving full focus.
I would want to thank every individual in this thread for their time to help me. Once again forgive me for my long absense.