# PS2F: Polarized Spiral Point Spread Function for Single-Shot 3D Sensing

arXiv: https://arxiv.org/abs/2207.00945 · HTML: https://mlsanity.com/paper/2207.00945/

## Key facts

- Cited by 4 papers in the map (data through 14 Oct 2026).
- Builds on 5 of its 56 references that are in the map.
- First posted on arXiv 3 Jul 2022.

## Builds on (most cited first, 5 of 5)

- [Adam: A Method for Stochastic Optimization](https://mlsanity.com/paper/1412.6980/) (2014)
- [Deep Optics for Monocular Depth Estimation and 3D Object Detection](https://mlsanity.com/paper/1904.08601/) (2019)
- [Miniscope3D: optimized single-shot miniature 3D fluorescence microscopy](https://mlsanity.com/paper/2010.05382/) (2020)
- [Single-Shot 3D Widefield Fluorescence Imaging with a Computational Miniature Mesoscope](https://mlsanity.com/paper/2003.11994/) (2020)
- [Learning an optimal PSF-pair for ultra-dense 3D localization microscopy](https://mlsanity.com/paper/2009.14303/) (2020)

## Built on by (most cited first, 4 of 4)

- [CodedEvents: Optimal Point-Spread-Function Engineering for 3D-Tracking with Event Cameras](https://mlsanity.com/paper/2406.09409/) (2024)
- [Polarization Multi-Image Synthesis with Birefringent Metasurfaces](https://mlsanity.com/paper/2307.08106/) (2023)
- [Extended monocular 3D imaging](https://mlsanity.com/paper/2502.07403/) (2025)
- [Physically Grounded Monocular Depth via Nanophotonic Wavefront Encoding](https://mlsanity.com/paper/2503.15770/) (2025)

## Abstract (arXiv)

We propose a compact snapshot monocular depth estimation technique that relies on an engineered point spread function (PSF). Traditional approaches used in microscopic super-resolution imaging such as the Double-Helix PSF (DHPSF) are ill-suited for scenes that are more complex than a sparse set of point light sources. We show, using the Cram'er-Rao lower bound, that separating the two lobes of the DHPSF and thereby capturing two separate images leads to a dramatic increase in depth accuracy. A special property of the phase mask used for generating the DHPSF is that a separation of the phase mask into two halves leads to a spatial separation of the two lobes. We leverage this property to build a compact polarization-based optical setup, where we place two orthogonal linear polarizers on each half of the DHPSF phase mask and then capture the resulting image with a polarization-sensitive camera. Results from simulations and a lab prototype demonstrate that our technique achieves up to 50% lower depth error compared to state-of-the-art designs including the DHPSF and the Tetrapod PSF, with little to no loss in spatial resolution.