Double Your Corners, Double Your Fun: The Doorway Camera

Krska, William; Seidel, Sheila W.; Saunders, Charles; Czajkowski, Robinson; Yu, Chang; Murray-Bruce, John; Goyal, Vivek K

doi:10.1109/iccp54855.2022.9887738

Cited by 9 publications

(3 citation statements)

References 17 publications

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“…They can be divided into active and passive methods. Active methods use controlled light sources to illuminate the hidden scene [Cao et al 2022;Katz et al 2014;Luesia et al 2022;Velten et al 2013], while passive methods rely on ambient illumination [Bouman et al 2017;Krska et al 2022] or light emitted by hidden objects themselves [Saunders et al 2019]. In our work, an active laser source emits light pulses to illuminate the hidden scene.…”

Section: Related Workmentioning

confidence: 99%

Virtual Mirrors: Non-Line-of-Sight Imaging Beyond the Third Bounce

et al. 2023

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Non-line-of-sight (NLOS) imaging methods are capable of reconstructing complex scenes that are not visible to an observer using indirect illumination. However, they assume only third-bounce illumination, so they are currently limited to single-corner configurations, and present limited visibility when imaging surfaces at certain orientations. To reason about and tackle these limitations, we make the key observation that planar diffuse surfaces behave specularly at wavelengths used in the computational wave-based NLOS imaging domain. We call such surfaces virtual mirrors. We leverage this observation to expand the capabilities of NLOS imaging using illumination beyond the third bounce, addressing two problems: imaging single-corner objects at limited visibility angles, and imaging objects hidden behind two corners. To image objects at limited visibility angles, we first analyze the reflections of the known illuminated point on surfaces of the scene as an estimator of the position and orientation of objects with limited visibility. We then image those limited visibility objects by computationally building secondary apertures at other surfaces that observe the target object from a direct visibility perspective. Beyond single-corner NLOS imaging, we exploit the specular behavior of virtual mirrors to image objects hidden behind a second corner by imaging the space behind such virtual mirrors, where the mirror image of objects hidden around two corners is formed. No specular surfaces were involved in the making of this paper.

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Section: Related Workmentioning

confidence: 99%

Virtual Mirrors: Non-Line-of-Sight Imaging Beyond the Third Bounce

et al. 2023

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“…However, due to the lack of modulation on the incident light field, these methods are more ill-posed compared to active imaging . They are mainly used for object localization or recognition of motion trajectories. , This work proposes combining CCD/CMOS detectors with active illumination. Under the condition of recovering sufficient information about hidden objects, we aim to explore using standard CCD/CMOS detectors for recovering unknown scattering parameters and expanding the applicable scenarios of our scattering model.…”

Section: Introductionmentioning

confidence: 99%

Speckle Pattern Calculation and Scattering Imaging for General Surface Scattering Problem

Ji,

Zhang,

Wang

et al. 2024

ACS Photonics

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Establishing accurate models for light scattering has attracted widespread attention in optical research. Existing works include the linear system model and the Lambertian model, which achieve imaging small objects through a scattering medium or identifying scenes hidden from the direct line of sight. However, predicting speckle patterns accurately at a specific location after scattering with minimal computational resources remains a challenge. In this work, we introduce a scattering model that considers a scattering surface as a wavefront modulation matrix, which is validated by using the finitedifference time-domain simulation method. The modulating parameters of the scattering surface are retrieved, and the speckle patterns can be accurately calculated by utilizing the retrieved modulating parameters quickly. The results of simulations and experiments demonstrated that the calculated speckles are highly correlated to their corresponding ground truths captured by a charge-coupled device (CCD) sensor. Further experiments show that images of objects hidden from the line of sight can be reconstructed via these calculated speckle patterns. This work provides a general solution to the surface scattering problem and can enhance the utilization of conventional coded imaging techniques in scattering imaging problems.

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“…Different approaches have been proposed to tackle the challenging problem of NLOS imaging [3]- [14]. Active ToFbased methods that utilize a pulsed laser and fast Single Photon Avalanche Diode (SPAD) detectors have been demonstrated to perform robust high quality 3D reconstructions of arbitrary room-sized hidden scenes [15]- [18].…”

Section: Introductionmentioning

confidence: 99%

Fast Non-line-of-sight Imaging with Non-planar Relay Surfaces

Gu,

Sultan,

Masumnia-Bisheh

et al. 2023

2023 IEEE International Conference on Computational Photography (ICCP)

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Non-line-of-sight imaging methods reconstruct images from light captured off a relay surface. In most prior work this relay surface is a diffuse plane. It has been shown that even small deviations from a planar relay wall geometry quickly degrade reconstruction quality. Although existing methods can account for relay surface geometry in a straightforward way, they typically have high computational complexity and take orders of magnitude longer time to compute than state-of-the-art planar methods. In this work, we propose a fast algorithm that can perform non-line-of-sight reconstruction on arbitrary non-planar relay surfaces. Our algorithm has the same computational and memory complexity as the fastest existing algorithms, yet it achieves comparable reconstruction quality to the widely-used slower algorithms.

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Double Your Corners, Double Your Fun: The Doorway Camera

Cited by 9 publications

References 17 publications

Virtual Mirrors: Non-Line-of-Sight Imaging Beyond the Third Bounce

Virtual Mirrors: Non-Line-of-Sight Imaging Beyond the Third Bounce

Speckle Pattern Calculation and Scattering Imaging for General Surface Scattering Problem

Fast Non-line-of-sight Imaging with Non-planar Relay Surfaces

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