So that the roof micro-deformed monitoring can be equipped on the roof bolt conveniently and which is more prior in terms of detecting density, cycle and precision in comparison with others'.

Then, every frame is mapped from spatial domain to statistical domain incorporating the factors such as the difference image from the consecutive frames and the prior distribution of a pixel density.

Compared with prior art, the process is simple, and the obtained SiC sintered compact has high density, no residue of free silicon and high strength and toughness.