Whole-field deformation measurement of clear orthodontic aligner using electronic speckle pattern interferometry
To objectively and accurately measure the full-field deformation of clear aligners for improved clinical effectiveness and safety,a comprehensive three-dimensional deformation measurement system based on laser electronic speckle pattern interferometry has been established.The specimen's surface is illu-minated with a tri-wavelength laser,generating a color speckle pattern.A phase-shift device produces a quasi π/2 phase step for all three color channels.Multi-frame images of the color speckle pattern are cap-tured using a 3CCD color camera.Deformation phases are extracted using a 90° step four-frame technique from the separated red,green,and blue channels.A window-deformable filter effectively denoises the phase fringe patterns,allowing six derivative components to be obtained directly from the three deforma-tion components using a digital differential method.Results show that the system achieves a precision of no more than 2.4''for micro-rotation and better than 10 με for strain measurements.Experimental results on clear aligners align closely with expected outcomes.