2026
Iterating the Transient Light Transport Matrix for Non-Line-of-Sight Imaging
Talha Sultan, Eric Brandt, Khadijeh Masumnia-Bisheh, Simone Riccardo, Pavel Polynkin, Alberto Tosi, Andreas Velten
Nature Communications, 17, 8951. 2026
We capture transient light transport with a dense laser scan and a gated SPAD array, then independently focus virtual illumination and detection within a hidden scene. The reconstructed transport matrix reveals time-resolved interactions between hidden surfaces, including indirect shadows, interreflections, and volumetric scattering, and enables direct–indirect separation, relighting, and dual photography.
Iterating the Transient Light Transport Matrix for Non-Line-of-Sight Imaging
Talha Sultan, Eric Brandt, Khadijeh Masumnia-Bisheh, Simone Riccardo, Pavel Polynkin, Alberto Tosi, Andreas Velten
Nature Communications, 17, 8951. 2026
We capture transient light transport with a dense laser scan and a gated SPAD array, then independently focus virtual illumination and detection within a hidden scene. The reconstructed transport matrix reveals time-resolved interactions between hidden surfaces, including indirect shadows, interreflections, and volumetric scattering, and enables direct–indirect separation, relighting, and dual photography.
Trapezoidal Grid Reconstruction for Efficient Non-Line-of-Sight Imaging
Talha Sultan, Chaoying Gu, Alex Bocchieri, Xiaochun Liu, Pavel Polynkin, Andreas Velten
IEEE International Conference on Computational Photography (ICCP), pp. 1–12. 2026
We introduce Scaled Rayleigh–Sommerfeld Diffraction, which reconstructs hidden scenes on a trapezoidal grid that widens with depth. By matching voxel spacing to the system's depth-dependent resolution, the method covers a larger field of view with the same voxel budget while retaining FFT-based efficiency and producing natural perspective views.
Trapezoidal Grid Reconstruction for Efficient Non-Line-of-Sight Imaging
Talha Sultan, Chaoying Gu, Alex Bocchieri, Xiaochun Liu, Pavel Polynkin, Andreas Velten
IEEE International Conference on Computational Photography (ICCP), pp. 1–12. 2026
We introduce Scaled Rayleigh–Sommerfeld Diffraction, which reconstructs hidden scenes on a trapezoidal grid that widens with depth. By matching voxel spacing to the system's depth-dependent resolution, the method covers a larger field of view with the same voxel budget while retaining FFT-based efficiency and producing natural perspective views.
2025
Zero-Phase Phasor Fields for Non-Line-of-Sight Imaging
Pablo Luesia-Lahoz, Talha Sultan, Forrest B. Peterson, Andreas Velten, Diego Gutierrez, Adolfo Muñoz
ICCP 2025
We present Zero-Phase Phasor Fields, a method that improves the depth precision of “seeing around corners” without the usual runtime penalty. Rather than reconstructing hundreds of closely spaced depth slices, we use computational wave cues to refine a coarse reconstruction and locate hidden surfaces between sampled planes. This enables micrometer-scale depth precision while keeping reconstructions fast.
Zero-Phase Phasor Fields for Non-Line-of-Sight Imaging
Pablo Luesia-Lahoz, Talha Sultan, Forrest B. Peterson, Andreas Velten, Diego Gutierrez, Adolfo Muñoz
ICCP 2025
We present Zero-Phase Phasor Fields, a method that improves the depth precision of “seeing around corners” without the usual runtime penalty. Rather than reconstructing hundreds of closely spaced depth slices, we use computational wave cues to refine a coarse reconstruction and locate hidden surfaces between sampled planes. This enables micrometer-scale depth precision while keeping reconstructions fast.
Optimized Sampling for Non-Line-of-Sight Imaging Using Modified Fast Fourier Transforms
Talha Sultan, Alex Bocchieri, Chaoying Gu, Xiaochun Liu, Pavel Polynkin, Andreas Velten
Under review.
We demonstrate that the measurement space for non-line-of-sight imaging can be compressed, enabling the development of novel computational methods for 3D diffraction propagation. These methods allow for flexible measurement schemes and significantly enhance reconstruction speed while maintaining reconstruction quality comparable to state-of-the-art methods.
Optimized Sampling for Non-Line-of-Sight Imaging Using Modified Fast Fourier Transforms
Talha Sultan, Alex Bocchieri, Chaoying Gu, Xiaochun Liu, Pavel Polynkin, Andreas Velten
Under review.
We demonstrate that the measurement space for non-line-of-sight imaging can be compressed, enabling the development of novel computational methods for 3D diffraction propagation. These methods allow for flexible measurement schemes and significantly enhance reconstruction speed while maintaining reconstruction quality comparable to state-of-the-art methods.
2024
Towards a more accurate light transport model for non-line-of-sight imaging
Talha Sultan, Syed Azer Reza, Andreas Velten
Optics Express 2024
We present a graphical representation of the two-frequency spatial Wigner distribution (TFSWD) forward model, which integrates multiple NLOS imaging modalities. Through experimental validation, we demonstrate that the model more accurately captures light transport and wave propagation, paving the way for future improvements in reconstruction
Towards a more accurate light transport model for non-line-of-sight imaging
Talha Sultan, Syed Azer Reza, Andreas Velten
Optics Express 2024
We present a graphical representation of the two-frequency spatial Wigner distribution (TFSWD) forward model, which integrates multiple NLOS imaging modalities. Through experimental validation, we demonstrate that the model more accurately captures light transport and wave propagation, paving the way for future improvements in reconstruction
2023
Virtual Mirrors: Non-Line-of-Sight Imaging Beyond the Third Bounce
Diego Royo, Talha Sultan, Adolfo Muñoz, Khadijeh Masumnia-Bisheh, Eric Brandt, Diego Gutierrez, Andreas Velten, Julio Marco
SIGGRAPH 2023
We show that planar diffuse surfaces can act as virtual mirrors in non-line-of-sight (NLOS) imaging when using structured light modulation at centimeter-scale wavelengths. Leveraging this effect, we extend NLOS imaging beyond the third bounce, enabling the reconstruction of mirror reflections of objects hidden around two corners.
Virtual Mirrors: Non-Line-of-Sight Imaging Beyond the Third Bounce
Diego Royo, Talha Sultan, Adolfo Muñoz, Khadijeh Masumnia-Bisheh, Eric Brandt, Diego Gutierrez, Andreas Velten, Julio Marco
SIGGRAPH 2023
We show that planar diffuse surfaces can act as virtual mirrors in non-line-of-sight (NLOS) imaging when using structured light modulation at centimeter-scale wavelengths. Leveraging this effect, we extend NLOS imaging beyond the third bounce, enabling the reconstruction of mirror reflections of objects hidden around two corners.
Fast Non-Line-of-sight Imaging with Non-planar Relay Surfaces
Chaoying Gu, Talha Sultan, Khadijeh Masumnia-Bisheh, Laura Waller, Andreas Velten
ICCP 2023
We propose a novel computational method for 3D diffraction propagation on arbitrary non-planar surfaces, achieving significantly better complexity than state-of-the-art algorithms while maintaining quality, validated on experimental data.
Fast Non-Line-of-sight Imaging with Non-planar Relay Surfaces
Chaoying Gu, Talha Sultan, Khadijeh Masumnia-Bisheh, Laura Waller, Andreas Velten
ICCP 2023
We propose a novel computational method for 3D diffraction propagation on arbitrary non-planar surfaces, achieving significantly better complexity than state-of-the-art algorithms while maintaining quality, validated on experimental data.