Abstract:This study proposes an innovative wide-field time-domain diffuse optical tomography (TD-DOT) approachthat integrates spatial frequency domain (SFD) imaging, single-pixel imaging, and time-correlated single-photon counting techniques to enable wide-field time-resolved measurements in turbid media. Furthermore, a TD-SFD-DOT reconstruction method is developed to achieve three-dimensional reconstruction of the target′s optical parameters. The imaging system is built upon a novel single-pixel SFD architecture, employing two spatial light modulators to respectively realize wide-field structured illumination and wide-field detection via a single-photon avalanche diode detectors. The time-correlated single-photon counting technique is embedded into this architecture to achieve high-cost-effective time-resolved wide-field data acquisition. On the algorithmic side, a time-domain SFD diffusion model incorporating internal source terms is proposed to accurately describe the radiative transfer of spatial modulated light in turbid media. This significantly improves the simulation accuracy of photon propagation in near-surface regions and early-time regimes, addressing the limitations of traditional diffusion equations in modeling highly scattering media near the boundary. To fully harness the rich information embedded in time-resolved signals and improve computational efficiency, a TD-SFD-DOT reconstruction algorithm based on overlapping time-gated data types is developed. This enables the decoupled and depth-resolved reconstruction of both the absorption coefficients and the reduced scattering coefficient. Finally, the proposed system and reconstruction method are validated through a series of agar phantom experiments. Results demonstrate that the method achieves accurate three-dimensional quantitative reconstruction of absorption and reduced scattering coefficients at depths of 3~4 mm beneath the surface of turbid media, providing a novel technical solution for tissue optical tomography.