Phase unwrapping and denoising for time-of-flight imaging using generalized approximate message passing

Mei, Jonathan; Kirmani, Ahmed; Colaço, Andrea; Goyal, Vivek K

doi:10.1109/icip.2013.6738075

Cited by 9 publications

(8 citation statements)

References 26 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As alluded to above, one of the main challenges with the log transform is the question of how to handle the phase and possible wrapping. This is generally not an issue for OCT since they use transport equations for the light propagation modeling and artificially introduce the phase by way of a low frequency modulation-for breast imaging they typically use 100 MHz [34–36]. In this situation, the wavelength is sufficiently long that the phase never exceeds + /− π.…”

Section: Design Trade-offsmentioning

confidence: 99%

Addressing Multipath Signal Corruption in Microwave Tomography and the Influence on System Design and Algorithm Development

Meaney

Paulsen

2018

OAJBEB

View full text Add to dashboard Cite

In developing a microwave tomography system, we started by examining the fundamental signal measurement challenges-i.e., how to interrogate the target while suppressing unwanted multi-path signals. Beginning with a lossy coupling bath to suppress unwanted surface waves, we have developed a robust and reliable system that is both simple and low profile. However, beyond the basic measurement configuration, the lossy coupling medium concept has also informed our choice of array antenna and imaging algorithms. The synergism of these concepts has produced a novel concept which is embodied in a system that has been successfully translated to the clinic.

show abstract

Section: Design Trade-offsmentioning

confidence: 99%

Addressing Multipath Signal Corruption in Microwave Tomography and the Influence on System Design and Algorithm Development

Meaney

Paulsen

2018

OAJBEB

View full text Add to dashboard Cite

show abstract

“…This produces ambiguities in the relation between phase and depth. For example, frequency ω1 = 100 MHz only encodes depth for a maximum unambiguous range of c 2ω 1 ≈ 1.5 m. For a greater depth range, we acquire direct/retro-reflective PMD photos for two frequencies ω1 and ω2 = ω1/2 and use phase-unwrapping [Mei et al 2013] to calculate depth. Specifically, given photos i ω 1 and i ω 2 , the phase-unwrapped depth is…”

Section: Depth Acquisition From Direct/retro-reflective Pmd Photosmentioning

confidence: 99%

Temporal frequency probing for 5D transient analysis of global light transport

et al. 2014

View full text Add to dashboard Cite

a) scene (b) transient frame (t = 1.9 ns) (c) transient frame (t = 3.2 ns) (d) mesh Figure 1: (a) We use a photonic mixer device (PMD) coupled with a 2D projector to acquire "light-in-flight" images and depth maps for scenes with complex indirect transport. (b)-(c) The sharp, evolving wavefronts of light travelling along direct and caustic light paths can be seen clearly. (d) We also recover time-of-flight depth maps in a way that is not affected by strong indirect light. This indirect light mainly consists of diffuse inter-reflections for the scene in (a) but we also show experimental results where caustic light paths dominate. AbstractWe analyze light propagation in an unknown scene using projectors and cameras that operate at transient timescales. In this new photography regime, the projector emits a spatio-temporal 3D signal and the camera receives a transformed version of it, determined by the set of all light transport paths through the scene and the time delays they induce. The underlying 3D-to-3D transformation encodes scene geometry and global transport in great detail, but individual transport components (e.g., direct reflections, inter-reflections, caustics, etc.) are coupled nontrivially in both space and time.To overcome this complexity, we observe that transient light transport is always separable in the temporal frequency domain. This makes it possible to analyze transient transport one temporal frequency at a time by trivially adapting techniques from conventional projector-to-camera transport. We use this idea in a prototype that offers three never-seen-before abilities: (1) acquiring time-of-flight depth images that are robust to general indirect transport, such as interreflections and caustics; (2) distinguishing between direct views of objects and their mirror reflection; and (3) using a photonic mixer device to capture sharp, evolving wavefronts of "light-in-flight".

show abstract

“…In [12] a simulator for ToF measurements is developed and used to evaulate performance of a MRF that does simultaneous unwrapping and denoising using a wavelet basis. The performance on real data is however not shown.…”

Section: Related Workmentioning

confidence: 99%

Efficient Multi-Frequency Phase Unwrapping using Kernel Density Estimation

Lawin¹,

Forssén²,

Ovrén³

2016

Preprint

View full text Add to dashboard Cite

In this paper we introduce an efficient method to unwrap multi-frequency phase estimates for time-of-flight ranging. The algorithm generates multiple depth hypotheses and uses a spatial kernel density estimate (KDE) to rank them. The confidence produced by the KDE is also an effective means to detect outliers. We also introduce a new closed-form expression for phase noise prediction, that better fits real data. The method is applied to depth decoding for the Kinect v2 sensor, and compared to the Microsoft Kinect SDK and to the open source driver libfreenect2. The intended Kinect v2 use case is scenes with less than 8m range, and for such cases we observe consistent improvements, while maintaining real-time performance. When extending the depth range to the maximal value of 18.75m, we get about 52% more valid measurements than libfreenect2. The effect is that the sensor can now be used in large depth scenes, where it was previously not a good choice. Code and supplementary material are available at http://www.cvl.isy.liu.se/research/datasets/kinect2-dataset/.

show abstract

Phase unwrapping and denoising for time-of-flight imaging using generalized approximate message passing

Cited by 9 publications

References 26 publications

Addressing Multipath Signal Corruption in Microwave Tomography and the Influence on System Design and Algorithm Development

Addressing Multipath Signal Corruption in Microwave Tomography and the Influence on System Design and Algorithm Development

Temporal frequency probing for 5D transient analysis of global light transport

Efficient Multi-Frequency Phase Unwrapping using Kernel Density Estimation

Contact Info

Product

Resources

About