The increasing demand for efficient and reliable designs in critical fields such as civil engineering, aerospace, and medical devices necessitates accurate three-dimensional (3D) deformation measurement for structural safety assessment and performance optimization [1], [2]. While traditional measurement techniques often fall short, optical methods have emerged as powerful alternatives, offering non-contact, full-field capabilities with superior precision [3]. Among these, Digital Image Correlation (DIC), Digital Speckle Pattern Interferometry (DSPI), and Digital Shearing Speckle Pattern Interferometry (DSSPI) are extensively utilized [4], [5]. DIC, which operates by tracking surface speckle textures, generally exhibits lower accuracy and is highly sensitive to experimental conditions such as lighting and pattern quality. Furthermore, its application to 3D measurement requires complex stereo-camera calibration, restricting its use in scenarios that demand high precision [6], [7].

Phase-based techniques, such as DSPI and DSSPI, inherently provide greater measurement accuracy. DSPI records speckle patterns before and after an object is loaded, with deformation information extracted through phase calculation and unwrapping [8]. Commercial systems like the Q300 employ three interferometers and temporal phase-shifting to obtain full-field 3D data. However, their reliance on sequential acquisition restricts their use to static or quasi-static scenarios [9].

To address the challenges of dynamic measurement, various approaches have been explored. Hybrid systems combining DSPI with Digital Holographic Interferometry (DHI) or DIC have been proposed [10], [11]; nevertheless, the differing measurement principles often complicate system integration and data fusion. The introduction of spatial carrier frequency methods into DSPI enables single-shot analysis by separating directional phase components in the frequency domain [12], [13]. While this advancement facilitates dynamic measurements, it is typically insufficient for capturing multi-directional deformations simultaneously with a single sensor.

Multi-camera DSPI systems represent a more direct route to 3D dynamic measurements. For instance, Bianco and Bruno et al. [14], [15] developed setups capable of measuring dynamic deformations in three orthogonal directions. Yang et al. [16] utilized a tri-wavelength system with a pyramid prism and a monochrome camera to improve spatial coverage. Although these multi-camera or multi-component systems are effective, they often suffer from bulky setups, intricate alignment procedures, and high hardware costs, which can hinder their robustness and scalability for practical applications.

In contrast to DSPI, DSSPI is a self-referencing interferometric technique. It employs a shearing device to generate two laterally shifted wavefronts from the object beam, which then interfere to form fringes on a single detector. This common-path design enhances stability, particularly under non-isolated environmental conditions, making DSSPI well-suited for applications involving biological materials or complex loading scenarios [17]. However, a fundamental characteristic of DSSPI is that it measures deformation derivatives (gradients) rather than absolute displacements. Furthermore, traditional DSSPI systems cannot perform direct 3D deformation measurement due to the lack of a distinct reference beam for out-of-plane sensitivity and the single sensitivity direction inherent in typical setups. Spectral leakage, caused by shear-induced spatial frequency loss, can further limit measurement accuracy [18], [19]. Previous efforts to combine DSPI and DSSPI principles or to extend DSSPI for 3D capabilities have often involved multi-wavelength sources and discrete optical setups [20]. Such configurations, while demonstrating 3D potential, can suffer from cumulative errors arising from spatial frequency aliasing and misalignment between different optical paths. These persisting limitations underscore the need for a more compact, integrated, and accurate solution for dynamic 3D deformation analysis.

In this study, we propose and experimentally demonstrate a novel tri-wavelength color DSSPI (TC-DSSPI) system designed for single-shot dynamic 3D deformation measurement. The system ingeniously employs three laser sources with distinct red, green, and blue (RGB) wavelengths to establish orthogonal sensitivity directions. These are captured simultaneously using a prism-based color-multiplexed sensor array, allowing for the acquisition of the complete 3D deformation information in a single frame. Phase recovery from the sheared interferograms is accomplished using an advanced unsupervised neural network approach, guided by the physical characteristics of the shearing operation, which we term Adaptive Physics-Informed Gradient (APIG) reconstruction. This method addresses the inherent ill-posedness of shear data inversion and mitigates issues like spectral leakage. The system’s efficacy is validated through dynamic deformation tests on an aluminum plate, with results compared against traditional DSPI measurements and Finite Element Method (FEM) simulations, demonstrating high spatial resolution and robustness.