Fig. 1. Schematic of the common-path illumination speckle interferometry for specular object deformation measurement. M, mirror; BE, beam expander; PH, pinhole; BS, beam splitter; HWP, half-wave plate; PL, projector lens; FPL, focal point of the projection lens; PPBS, polarizing plate beam splitter; IL, imaging lens; CL, collimating lens; LP, linear polarizer; NDF, neutral density filter; IS, image sensor.

Fig. 2. (a) Schematic of the light path for a point on the specular object before and after deformation in the measurement system. (b) Schematic of the illumination beam being reflected by a specular object. (c) Schematic of the observation beam being reflected by a specular object.

Fig. 3. (a) Comparison of experimental results with theoretical values. Speckle interferogram collected at a rotation stage reading of (b) 17° and (c) 47°.

Fig. 4. (a) Phase fringe maps obtained by off-axis and common-path illumination. (b) Measurement sensitivity of two illumination methods.

Fig. 5. Phase fringe maps obtained by ejector loading at the (a) lower right, (b) middle, and (c) upper left of the microcrystalline glass.