Modeling the measurement precision of rough surfaces in multi-wavelength digital holography

Modern industrial production demands high-precision and efficient full-field functional surface measurements. Multi-wavelength digital holography (MWDH) addresses these measurement needs and has been applied in various measurement scenarios. However, the measurement precision of MWDH for rough surfaces is still evaluated experimentally, lacking a comprehensive theoretical model for guidance. In this work, we propose an MWDH precision model focused on rough surfaces, considering both decorrelation noise and acquisition noise. Besides, the model provides a more meaningful assessment of full-field noise under spatial inhomogeneity scattering from rough surfaces. For the first time, we introduce the concept of coherent stray light noise, which is considered a component of acquisition noise in this study. Experiments performed on a rough surface validate the proposed model. Our model not only enables the assessment of measurement precision in MWDH systems, but also allows for a preliminary determination of the measurability of target objects.