“…This was one of the first areas of speckle I investigated, in collaboration with Prof. Julian Jones who had recently moved to Heriot-Watt University from the AOG, and the optics research group for Rover cars at Gaydon (UK) [39,40]. Figure 19 shows contour fringes of a gas turbine compressor blade obtained by modulating the laser by 18 GHz170 GHz [38,39,41].…”