3D whole body scanners revisited

An overview of whole body scanners in 1998 (H.A.M. Daanen, G.J. Van De Water. Whole body scanners, Displays 19 (1998) 111–120) shortly after they emerged to the market revealed that the systems were bulky, slow, expensive and low in resolution. This update shows that new developments in sensing and processing technology, in particular in structured light scanners, have produced a new generation of easy to transport, fast, inexpensive, accurate and high resolution scanners. The systems are now moving to the consumer market with high impact for the garment industry. Since the internet sales of garments is rapidly increasing, information on body dimensions become essential to guarantee a good fit, and 3D scanners are expected to play a major role.     

HEVC-based three-layer texture and depth coding for lossless synthesis in 3D video coding

Multimedia Tools and Applications - Efficient lossless coding of a texture image and its corresponding depth map is important to perform accurate view synthesis in 3D applications. In this paper, a...     

3D computational modeling and perceptual analysis of kinetic depth effects

Computational Visual Media - Humans have the ability to perceive kinetic depth effects, i.e., to perceived 3D shapes from 2D projections of rotating 3D objects. This process is based on a variety...     

Helmet accommodation analysis using 3D laser scanning

A method used to determine the probable population accommodation of a helmet sizing system is described. The method involves the use of 3D laser scanning, as a means of measuring helmet standoff distance (distance between the inside of the helmet and the skull), and the selection of a representative sample of test subjects. The laser scanner and the software developed to calculate standoff distance proved to be an excellent tool for the assessment of helmet fit. The main advantages include ease of use and visualization of problem areas. This 3D-analysis method gives designers objective evidence of the need for design changes as well as an idea of what these changes should be. A comparison was made between standoff distance results obtained from the scanner and those obtained using a physical measurement method (a probe). Although discrepancies were found between the two, sources of errors intrinsic to both methods make it difficult to determine which of the two methods yielded the truest standoff distance. Analysis of the comparison data shows laser scanning to be slightly more conservative than the probe method for standoff distance purposes, i.e. erring on the side of safety.     

Development and application of miniaturized scanners for laser beam micro-welding

Nowadays, flexible production systems for laser joining of micro parts require high dynamics and precision, as well as increased flexibility regarding the working space. The combination of miniaturized scanner-based laser joining systems and high-performance assembly systems is a new approach for a high accuracy compact micro assembly system with an increased flexibility. Using highly dynamic oscillation techniques leads to a stabilization of the welding process of difficult-to-weld materials, e.g. of zinc-containing alloys on the one hand, and to an increased process velocity and reduction of the joining geometry, e.g. for the welding of plastic materials on the other. Hence, a miniaturized laser processing optics is being developed featuring an integrated beam deflection for laser beam micro welding of metal as well as plastic materials. The requirements on this laser processing optics, the choice of a suitable beam deflection system and the design and simulation of the miniaturized optics are presented and discussed. Furthermore, results of laser beam micro welding applications are presented. These results directly influence the design of new miniaturized laser processing optics. By means of the integration of highly dynamic scanner devices further process improvements can be achieved for laser beam micro welding.     

Processing and interactive editing of huge point clouds from 3D scanners

This paper describes a new out-of-core multi-resolution data structure for real-time visualization, interactive editing and externally efficient processing of large point clouds. We describe an editing system that makes use of the novel data structure to provide interactive editing and preprocessing tools for large scanner data sets. Using the new data structure, we provide a complete tool chain for 3D scanner data processing, from data preprocessing and filtering to manual touch-up and real-time visualization. In particular, we describe an out-of-core outlier removal and bilateral geometry filtering algorithm, a toolset for interactive selection, painting, transformation, and filtering of huge out-of-core point-cloud data sets and a real-time rendering algorithm, which all use the same data structure as storage backend. The interactive tools work in real-time for small model modifications. For large scale editing operations, we employ a two-resolution approach where editing is planned in real-time and executed in an externally efficient offline computation afterwards. We evaluate our implementation on example data sets of sizes up to 63 GB, demonstrating that the proposed technique can be used effectively in real-world applications.     

3D hierarchical optimization for multi-view depth map coding

Multimedia Tools and Applications - Depth data has a widespread use since the popularity of high resolution 3D sensors. In multi-view sequences, depth information is used to supplement the color...     

A vehicle-borne urban 3-D acquisition system using single-row laser range scanners

In this research, a novel vehicle-borne system of measuring three-dimensional (3-D) urban data using single-row laser range scanners is proposed. Two single-row laser range scanners are mounted on the roof of a vehicle, doing horizontal and vertical profiling respectively. As the vehicle moves ahead, a horizontal and a vertical range profile of the surroundings are captured at each odometer trigger. The freedom of vehicle motion is reduced from six to three by assuming that the ground surface is flat and smooth so resulting in the vehicle moving on almost the same horizontal plane. Horizontal range profiles, which have an overwhelming overlay between successive ones, are registered to trace vehicle location and attitude. Vertical range profiles are aligned to the coordinate system of the horizontal one according to the physical geometry between the pair of laser range scanners, and subsequently to a global coordinate system to make up 3-D data. An experiment is conducted where 3-D data of a real urban scene is obtained by registering and integrating 2412 horizontal and vertical range profiles. Two ground truths are used in examination. They are the outputs of a GPS/INS/Odometer based positioning system and a 1:500 digital map of the testing site. Accuracy and efficiency of the method in measuring 3-D urban scene is demonstrated.     

An overview of depth cameras and range scanners based on time-of-flight technologies

Time-of-flight (TOF) cameras are sensors that can measure the depths of scene points, by illuminating the scene with a controlled laser or LED source and then analyzing the reflected light. In this paper, we will first describe the underlying measurement principles of time-of-flight cameras, including: (1) pulsed-light cameras, which measure directly the time taken for a light pulse to travel from the device to the object and back again, and (2) continuous-wave-modulated light cameras, which measure the phase difference between the emitted and received signals, and hence obtain the travel time indirectly. We review the main existing designs, including prototypes as well as commercially available devices. We also review the relevant camera calibration principles, and how they are applied to TOF devices. Finally, we discuss the benefits and challenges of combined TOF and color camera systems.     

三维激光扫描表面数据区域分割

针对现有三维激光扫描数据区域分割算法受原始碎片表面粗糙度影响较大且只适用于形状较规则、表面较平坦及断裂面较少的物体这一问题,提出了区域膨胀策略的三维扫描表面数据区域分割算法,该算法将三维激光扫描表面数据分割成若干个具有相同法矢方向的区域。首先将三维扫描表面数据转化为三维网格模型;然后利用同一区域中相邻网格具有相似法线方向这一性质,使用区域膨胀策略生成若干获选表面区域;最后通过去除候选区域中的噪声区域得到最终表面区域分割结果。通过实物表面扫描数据对上述算法进行仿真验证,结果表明该算法可对三维表面扫描数据进行有效的区域分割。     

3D depth information extraction with omni-directional camera

This paper presents a novel 3D depth information extraction method without calibration. Firstly, this paper develops an omni-directional 3D camera system, which consists of a CCD camera, hyperbolic mirror, infrared laser diodes and diffractive of element (DOE). Secondly, a depth measurement model is proposed to obtain the 3D depth information. Finally, in order to calculate the speckle shift accurately between the reference image and the object image, a dot matrix pattern and sequence coding algorithm are designed to find the corresponding speckles in the two images. Experimental results show that the reconstructed depth data have a good correlation with the actual distance. The accuracy of the data is also found to be influenced by the distance between the object and the camera.     

动态噪声影响的三维重构几何估计算法

提出针对概率分布参数时变的噪声空间的双目视觉几何估计问题,由于Hartley三维重构几何估计算法是针对双目视觉受到同等噪声影响下所采用的.因此,对于受到不同噪声影响的情况而言,这个方法不能有效、准确地估计实时变化的测量点位置.通过构建动态贝叶斯网,利用先验和后验的知识进行预测和滤波,结合贝叶斯增量式学习方法并充分利用了其学习所获得的噪声样本空间概率模型变化演进的规律,这样可以较准确、平滑地估计出噪声对摄像头的影响,并以此来改进Hartley三维重构几何估计算法.     

Efficient autonomous global localization for service robots using dual laser scanners and rotational motion

This study presents an alternative global localization scheme that uses dual laser scanners and the pure rotational motion of a mobile robot. The proposed method extracts the initial state of the robot’s surroundings to select robot pose candidates, and determines the sample distribution based on the given area map. Localization success is determined by calculating the similarity of the robot’s sensor state compared to that which would be expected at the estimated pose on the given map. In both simulations and experiments, the proposed method shows sufficient efficiency and speed to be considered robust to real-world conditions and applications.