Hierarchical Surface Prediction for 3D Object Reconstruction

Recently, Convolutional Neural Networks have shown promising results for 3D geometry prediction. They can make predictions from very little input data such as a single color image. A major limitation of such approaches is that they only predict a coarse resolution voxel grid, which does not capture the surface of the objects well. We propose a general framework, called hierarchical surface prediction (HSP), which facilitates prediction of high resolution voxel grids. The main insight is that it is sufficient to predict high resolution voxels around the predicted surfaces. The exterior and interior of the objects can be represented with coarse resolution voxels. Our approach is not dependent on a specific input type. We show results for geometry prediction from color images, depth images and shape completion from partial voxel grids. Our analysis shows that our high resolution predictions are more accurate than low resolution predictions.Comment: 3DV 201

Survey of laying hen husbandry in Switzerland

In Switzerland eggs have not been produced in battery cages since January 1992. During the 10 year period from 1981 farmers replaced their battery cages with deep litter, aviary and grid-floor systems and modified cages. However, the cages used to replace the conventional battery cages and most of the grid- floor systems did not fulfil the requirements of the Swiss Welfare Act and they were not permitted to be advertised or sold thereafter. Sixteen years after the ban on battery cages, the Federal Veterinary Office has undertaken a survey to determine how laying hens are kept in Switzerland and how the alternative systems have fared. The survey was carried out on 96 randomly chosen farms with at least 500 hen places to find out more about the housing conditions, management processes, status and performance of hens. The results show that aviaries are very common in Switzerland (65% of the laying hens) and that the laying performance in these systems is significantly higher than that in grid- floor systems and similar to that in battery cages. Provision of a protected outdoor area is a valuable benefit. To be successful with aviary systems it is necessary for pullets to spend the rearing period under similar housing condition

3D Visual Perception for Self-Driving Cars using a Multi-Camera System: Calibration, Mapping, Localization, and Obstacle Detection

Cameras are a crucial exteroceptive sensor for self-driving cars as they are low-cost and small, provide appearance information about the environment, and work in various weather conditions. They can be used for multiple purposes such as visual navigation and obstacle detection. We can use a surround multi-camera system to cover the full 360-degree field-of-view around the car. In this way, we avoid blind spots which can otherwise lead to accidents. To minimize the number of cameras needed for surround perception, we utilize fisheye cameras. Consequently, standard vision pipelines for 3D mapping, visual localization, obstacle detection, etc. need to be adapted to take full advantage of the availability of multiple cameras rather than treat each camera individually. In addition, processing of fisheye images has to be supported. In this paper, we describe the camera calibration and subsequent processing pipeline for multi-fisheye-camera systems developed as part of the V-Charge project. This project seeks to enable automated valet parking for self-driving cars. Our pipeline is able to precisely calibrate multi-camera systems, build sparse 3D maps for visual navigation, visually localize the car with respect to these maps, generate accurate dense maps, as well as detect obstacles based on real-time depth map extraction

Real-World Normal Map Capture for Nearly Flat Reflective Surfaces

Although specular objects have gained interest in recent years, virtually no approaches exist for markerless reconstruction of reflective scenes in the wild. In this work, we present a practical approach to capturing normal maps in real-world scenes using video only. We focus on nearly planar surfaces such as windows, facades from glass or metal, or frames, screens and other indoor objects and show how normal maps of these can be obtained without the use of an artificial calibration object. Rather, we track the reflections of real-world straight lines, while moving with a hand-held or vehicle-mounted camera in front of the object. In contrast to error-prone local edge tracking, we obtain the reflections by a robust, global segmentation technique of an ortho-rectified 3D video cube that also naturally allows efficient user interaction. Then, at each point of the reflective surface, the resulting 2D-curve to 3D-line correspondence provides a novel quadratic constraint on the local surface normal. This allows to globally solve for the shape by integrability and smoothness constraints and easily supports the usage of multiple lines. We demonstrate the technique on several objects and facades

Real-time inline monitoring of zeolite synthesis by Photon Density Wave spectroscopy

The formation process of zeolite A (Linde Type A) was monitored inline at 1.5 L scale by Photon Density Wave (PDW) spectroscopy as novel process analytical technology for highly turbid liquid suspensions. As a result, the reduced scattering coefficient, being a measure for particle number, size, and morphology, provides distinct process information, including the formation of amorphous particles and their transfer into crystalline zeolite structures. The onset and end of the crystallization process can be detected inline and in real-time. Analyses by powder X-ray diffraction and electron microscopy, based on a sampling approach, support the interpretation of the results obtained by PDW spectroscopy. In addition, the influence of the molar water content was investigated, indicating a linear increase of the time needed to reach the end of the zeolite A crystallization with increasing molar water content. Further experiments indicate a strong influence of the silica source on the course of the crystallization. The applicability of PDW spectroscopy under even more demanding chemical and physical conditions was investigated by monitoring the synthesis of zeolite L (Linde Type L)

Switching behaviour in activity based working environments : an exploration of the reasons and influencing factors of switching behaviour in ABW

Purpose: Opposed to underlying assumptions of ABW offices, previous empirical studies ascertained a tendency that employees do not frequently switch between different activity settings. Even though ABW is more and more becoming the default office concept, employees’ switching behaviour has not been investigated in depth. This study aims to understand employees’ switching behaviour by determining reasons to switch and not to switch and various influencing factors of switching behaviour. Theory: Switching behaviour is defined as switching between different places within an office building with work-related, preference-based and/or social purpose, including breaks. Switching behaviour is divided into mandatory and voluntary switching. Mandatory switching is switching due to scheduled activities (meetings) as well as switching due to confidentiality issues. Voluntary switching refers to discretionary switching that may be motivated by a perceived mismatch between either activity or preference, and environment. According to previous research, dissatisfaction with environment can cause switching between different settings in an ABW office. Design/methodology/approach: A questionnaire study was conducted across Switzerland and Belgium, and 124 employees from various organizations and departments participated in the questionnaire. Frequency analyses were conducted to determine reasons (not) to switch, and multinomial logistic regression analyses were performed to identify influencing factors of switching frequency. Findings: Findings show that the majority of the respondents switch multiple times a day, which runs counter to the previous research. In addition, the study revealed clear evidence that mandatory switching frequency is independent of various factors suggested in this study. This indicates that the distinction of mandatory and voluntary switching is valid. Furthermore, privacy, acoustics, distraction, proximity to team/colleagues were ascertained as reasons to switch, and place preference/attachment, proximity to team were determined as reasons not to switch. Originality / Value: Overall, this study contributed to understanding switching behaviour better by defining, distinguishing switching behaviour, and identifying reasons (not) to switch and influencing factors of switching frequency. These findings can provide more knowledge of switching behaviour to workplace or facility management practitioners so that they can understand their employees’ needs and behaviour better and integrate this into workplace concepts and design