Structured Light in Sunlight

Gupta, Mohit; Yin, Qi; Nayar, Shree K.

doi:10.1109/iccv.2013.73

Cited by 71 publications

(39 citation statements)

References 13 publications

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“…Energy-efficient codes for redistributive projectors: Of course, between the two extremes of ideal impulse projection (minimum redistribution ratio) and conventional mask-based projection (maximum redistribution ratio) lies a whole spectrum of arrangements that redistribute light partially [Hoskinson et al 2010;Mertz et al 2012;Gupta et al 2013;Damberg and Heidrich 2015]. We explore this spectrum briefly through simulations, noting that a rapid "phase transition" seems to occur in our energy-efficient codes, with pure impulses on one end switching to dense codes on the other.…”

Section: Energy-efficient Codes By Homogeneous Factorizationmentioning

confidence: 98%

“…The near end of the range, with σ = 1, represents an idealized projector that is perfectly efficient (Figure 2b). This projector can send all its light through just one pixel for the entire exposure time T but can also distribute it-without any blocking-according to an arbitrary illumination l. Between these two extremes lies a whole spectrum of projection technologies that approach this ideal to a greater or lesser extent [Hoskinson et al 2010;Gupta et al 2013;Damberg et al 2014;Damberg and Heidrich 2015].…”

Section: Redistributive Projection and Sensor Maskingmentioning

confidence: 99%

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Homogeneous codes for energy-efficient illumination and imaging

et al. 2015

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Figure 1: Imagine trying to acquire live video (30fps) of structured-light patterns as they are being projected onto a compact fluorescent bulb that has already been turned on (rated 1600 Lumens), or onto a face in bright sunlight (80 kLux)-with a 5-Lumen projector. One of our two prototypes, shown in (a), achieves this with an off-the-shelf laser projector and a CMOS camera with an ordinary lens. We then used it to capture the video frames in (b) and (c). We also show how to use our prototype to generate a live video feed from the projector's-rather than the camera's-point of view, shown in (d). AbstractProgrammable coding of light between a source and a sensor has led to several important results in computational illumination, imaging and display. Little is known, however, about how to utilize energy most effectively, especially for applications in live imaging. In this paper, we derive a novel framework to maximize energy efficiency by "homogeneous matrix factorization" that respects the physical constraints of many coding mechanisms (DMDs/LCDs, lasers, etc.). We demonstrate energy-efficient imaging using two prototypes based on DMD and laser illumination. For our DMDbased prototype, we use fast local optimization to derive codes that yield brighter images with fewer artifacts in many transport probing tasks. Our second prototype uses a novel combination of a lowpower laser projector and a rolling shutter camera. We use this prototype to demonstrate never-seen-before capabilities such as (1) capturing live structured-light video of very bright scenes-even a light bulb that has been turned on; (2) capturing epipolar-only and indirect-only live video with optimal energy efficiency; (3) using a low-power projector to reconstruct 3D objects in challenging conditions such as strong indirect light, strong ambient light, and smoke; and (4) recording live video from a projector's-rather than the camera's-point of view.

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Section: Energy-efficient Codes By Homogeneous Factorizationmentioning

confidence: 98%

Section: Redistributive Projection and Sensor Maskingmentioning

confidence: 99%

Homogeneous codes for energy-efficient illumination and imaging

et al. 2015

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“…In addition, light transport techniques have been very successful for the challenging problem of 3-D scanning of translucent objects [25,20] and high quality structured light scanning [36,13,37,14].…”

Section: Light Transport Acquisitionmentioning

confidence: 99%

A light transport model for mitigating multipath interference in Time-of-flight sensors

Naik

Kadambi

Rhemann

et al. 2015

2015 IEEE Conference on Computer Vision and Pattern Recognition (CVPR)

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Continuous-wave Time-of-flight (TOF) range imaging has become a commercially viable technology with many applications in computer vision and graphics. However, the depth images obtained from TOF cameras contain scene dependent errors due to multipath interference (MPI). Specifically, MPI occurs when multiple optical reflections return to a single spatial location on the imaging sensor. Many prior approaches to rectifying MPI rely on sparsity in optical reflections, which is an extreme simplification. In this paper, we correct MPI by combining the standard measurements from a TOF camera with information from direct and global light transport. We report results on both simulated experiments and physical experiments (using the Kinect sensor). Our results, evaluated against ground truth, demonstrate a quantitative improvement in depth accuracy.

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“…However, the main drawback of such IR-projector-based sensors is their inability to work outdoors and their power consumption. Authors of [24] also showed the degradation of the 3D reconstruction at different times of the day. The stronger the illuminance, the poorer the quality of the resulting 3D map.…”

Section: Stereo Camerasmentioning

confidence: 99%

“…Our previous study assessed that the scenes illuminance affects the quality of the resulting depth maps [4]. While RGBD cameras are unable to work under bright sunlight [24], passive stereo cameras' performance drastically drops under low or bright illumination unless the sensors have a high dynamic range. Our approach works on depth maps which are not completely dense.…”

Section: Resolution Studymentioning

confidence: 99%

Low-power depth-based descending stair detection for smart assistive devices

Cloix

Bologna

Weiss

et al. 2016

J Image Video Proc.

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Assistive technologies aim at improving personal mobility of individuals with disabilities, increasing their independence and their access to social life. They include mechanical mobility aids that are increasingly employed amongst the older people who rely on them. However, these devices might fail to prevent falls due to the under-estimation of approaching hazards. Stairs and curbs are among these potential dangers present in urban environments and living accommodations, which increase the risk of an accident. We present and evaluate a low-complexity algorithm to detect descending stairs and curbs of any shape, specifically designed for low-power real-time embedded platforms. Based on a passive stereo camera, as opposed to a 3D active sensor, we assessed the detection accuracy, processing time and power consumption. Our goal being to decide on three possible situations (safe, dangerous and potentially unsafe), we achieve to distinguish more than 94 % dangers from safe scenes within a 91 % overall recognition rate at very low resolution. This is accomplished in real-time with robustness to indoor/outdoor lighting conditions. We show that our method can run for a day on a smartphone battery.

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Structured Light in Sunlight

Abstract: Abstract

Cited by 71 publications

References 13 publications

Homogeneous codes for energy-efficient illumination and imaging

Homogeneous codes for energy-efficient illumination and imaging

A light transport model for mitigating multipath interference in Time-of-flight sensors

Low-power depth-based descending stair detection for smart assistive devices

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