Depth Fields: Extending Light Field Techniques to Time-of-Flight Imaging

A variety of techniques such as light field, structured illumination, and time-of-flight (TOF) are commonly used for depth acquisition in consumer imaging, robotics and many other applications. Unfortunately, each technique suffers from its individual limitations preventing robust depth sensing. In this paper, we explore the strengths and weaknesses of combining light field and time-of-flight imaging, particularly the feasibility of an on-chip implementation as a single hybrid depth sensor. We refer to this combination as depth field imaging. Depth fields combine light field advantages such as synthetic aperture refocusing with TOF imaging advantages such as high depth resolution and coded signal processing to resolve multipath interference. We show applications including synthesizing virtual apertures for TOF imaging, improved depth mapping through partial and scattering occluders, and single frequency TOF phase unwrapping. Utilizing space, angle, and temporal coding, depth fields can improve depth sensing in the wild and generate new insights into the dimensions of light's plenoptic function.Comment: 9 pages, 8 figures, Accepted to 3DV 201

Extrinsic Parameter Calibration for Line Scanning Cameras on Ground Vehicles with Navigation Systems Using a Calibration Pattern

Line scanning cameras, which capture only a single line of pixels, have been increasingly used in ground based mobile or robotic platforms. In applications where it is advantageous to directly georeference the camera data to world coordinates, an accurate estimate of the camera's 6D pose is required. This paper focuses on the common case where a mobile platform is equipped with a rigidly mounted line scanning camera, whose pose is unknown, and a navigation system providing vehicle body pose estimates. We propose a novel method that estimates the camera's pose relative to the navigation system. The approach involves imaging and manually labelling a calibration pattern with distinctly identifiable points, triangulating these points from camera and navigation system data and reprojecting them in order to compute a likelihood, which is maximised to estimate the 6D camera pose. Additionally, a Markov Chain Monte Carlo (MCMC) algorithm is used to estimate the uncertainty of the offset. Tested on two different platforms, the method was able to estimate the pose to within 0.06 m / 1.05$^{\circ}$ and 0.18 m / 2.39$^{\circ}$. We also propose several approaches to displaying and interpreting the 6D results in a human readable way.Comment: Published in MDPI Sensors, 30 October 201

Fully Reversed Engineering: streamlining 3D component digitization, modification, and reproduction

The availability of rapid prototyping enhances a designer’s creativity and speed, enabling quicker development of new products. However, because this process relies heavily on CAD models it can often be time costly and inefficient when a component is needed urgently in the field. This paper proposes a method to seamlessly integrate the digitization of existing objects with the rapid prototyping process. Our technique makes use of multiple structured-light techniques in conjunction with photogrammetry to build a more efficient means of product development. This combination of methods allows our developed application to rapidly scan an entire object using inexpensive hardware

SSTRED: A data-processing and metadata-generating pipeline for CHROMIS and CRISP

We present a data pipeline for the newly installed SST/CHROMIS imaging spectrometer, as well as for the older SST/CRISP spectropolarimeter. The aim is to provide observers with a user-friendly data pipeline, that delivers science-ready data with the metadata needed for archival. We generalized the CRISPRED data pipeline for multiple instruments and added metadata according to recommendations worked out as part of the SOLARNET project. We made improvements to several steps in the pipeline, including the MOMFBD image restoration. A part of that is a new fork of the MOMFBD program called REDUX, with several new features that are needed in the new pipeline. The CRISPEX data viewer has been updated to accommodate data cubes stored in this format. The pipeline code, as well as REDUX and CRISPEX are all freely available through git repositories or web download. We derive expressions for combining statistics of individual frames into statistics for a set of frames. We define a new extension to the World Coordinate System, that allow us to specify cavity errors as distortions to the spectral coordinate.Comment: Draf

Efficient completeness inspection using real-time 3D color reconstruction with a dual-laser triangulation system

In this chapter, we present the final system resulting from the European Project \u201d3DComplete\u201d aimed at creating a low-cost and flexible quality inspection system capable of capturing 2.5D color data for completeness inspection. The system uses a single color camera to capture at the same time 3D data with laser triangulation and color texture with a special projector of a narrow line of white light, which are then combined into a color 2.5D model in real-time. Many examples of completeness inspection tasks are reported which are extremely difficult to analyze with state-of-the-art 2D-based methods. Our system has been integrated into a real production environment, showing that completeness inspection incorporating 3D technology can be readily achieved in a short time at low costs