DSPI involves the use of a coherent light source, typically a laser, which illuminates the sample surface. The light scattered from the surface forms an interference pattern (speckle pattern) which is recorded by a digital camera. The primary steps include:
1. Illumination: A laser beam is directed at the sample surface. 2. Image Capture: The speckle pattern is captured by a high-resolution camera before and after deformation. 3. Image Processing: Specialized software compares the initial and deformed speckle patterns to calculate the deformation field.
