Automatic Robot Hand-Eye Calibration Enabled by Learning-Based 3D Vision

Hand-eye calibration, as a fundamental task in vision-based robotic systems, aims to estimate the transformation matrix between the coordinate frame of the camera and the robot flange. Most approaches to hand-eye calibration rely on external markers or human assistance. We proposed Look at Robot Base Once (LRBO), a novel methodology that addresses the hand-eye calibration problem without external calibration objects or human support, but with the robot base. Using point clouds of the robot base, a transformation matrix from the coordinate frame of the camera to the robot base is established as I=AXB. To this end, we exploit learning-based 3D detection and registration algorithms to estimate the location and orientation of the robot base. The robustness and accuracy of the method are quantified by ground-truth-based evaluation, and the accuracy result is compared with other 3D vision-based calibration methods. To assess the feasibility of our methodology, we carried out experiments utilizing a low-cost structured light scanner across varying joint configurations and groups of experiments. The proposed hand-eye calibration method achieved a translation deviation of 0.930 mm and a rotation deviation of 0.265 degrees according to the experimental results. Additionally, the 3D reconstruction experiments demonstrated a rotation error of 0.994 degrees and a position error of 1.697 mm. Moreover, our method offers the potential to be completed in 1 second, which is the fastest compared to other 3D hand-eye calibration methods. Code is released at github.com/leihui6/LRBO.Comment: 17 pages, 19 figures, 6 tables, submitted to MSS

DeltaFS: Pursuing Zero Update Overhead via Metadata-Enabled Delta Compression for Log-structured File System on Mobile Devices

Data compression has been widely adopted to release mobile devices from intensive write pressure. Delta compression is particularly promising for its high compression efficacy over conventional compression methods. However, this method suffers from non-trivial system overheads incurred by delta maintenance and read penalty, which prevents its applicability on mobile devices. To this end, this paper proposes DeltaFS, a metadata-enabled Delta compression on log-structured File System for mobile devices, to achieve utmost compressing efficiency and zero hardware costs. DeltaFS smartly exploits the out-of-place updating ability of Log-structured File System (LFS) to alleviate the problems of write amplification, which is the key bottleneck for delta compression implementation. Specifically, DeltaFS utilizes the inline area in file inodes for delta maintenance with zero hardware cost, and integrates an inline area manage strategy to improve the utilization of constrained inline area. Moreover, a complimentary delta maintenance strategy is incorporated, which selectively maintains delta chunks in the main data area to break through the limitation of constrained inline area. Experimental results show that DeltaFS substantially reduces write traffics by up to 64.8\%, and improves the I/O performance by up to 37.3\%

Lamellar Polypyrene Based on Attapulgite–Sulfur Composite for Lithium–Sulfur Battery

We report on the preparation and characterization of a novel lamellar polypyrrole using an attapulgite–sulfur composite as a hard template. Pretreated attapulgite was utilized as the carrier of elemental sulfur and the attapulgite–sulfur–polypyrrole (AT @400 °C–S–PPy) composite with 50 wt.% sulfur was obtained. The structure and morphology of the composite were characterized with infrared spectroscopy (IR), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). An AT @400 °C–S–PPy composite was further utilized as the cathode material for lithium–sulfur batteries. The first discharge specific capacity of this kind of battery reached 1175 mAh/g at a 0.1 C current rate and remained at 518 mAh/g after 100 cycles with capacity retention close to 44%. In the rate test, compared with the polypyrrole–sulfur (PPy–S) cathode material, the AT @400 °C–S–PPy cathode material showed lower capacity at a high current density, but it showed higher capacity when the current came back to a low current density, which was attributed to the “recycling” of pores and channels of attapulgite. Therefore, the lamellar composite with special pore structure has great value in improving the performance of lithium–sulfur batteries

Different responses of abalone Haliotis discus hannai to waterborne and dietary-borne copper and zincexposure

To investigate the potential influence of the contamination of copper (Cu) or zinc (Zn), the abalone Haliotis discus hannai was exposed to waterborne or macroalgae-borne Cu or Zn over a period of 8weeks. Both Cu and Zn were effectively accumulated by the abalones from water or macroalgae, but their concentration factors and trophic transfer factors were low due to the regulation of Cu and Zn accumulation. Following waterborne or dietary exposure, the abalones exhibited different accumulation patterns of Cu and Zn. The tissue Zn burden decreased quickly after the initial accumulation, and the incoming Zn was mainly deposited in the viscera. In contrast, the tissue Cu burden increased rapidly and gradually reached a steady state. The abalone muscle exhibited a comparable storage capacity of Cu as the viscera and the accumulated Cu in muscle was mainly derived from the dissolved phase instead of trophic transfer. The feeding and growth of the abalone were not influenced in all the exposure regimes. Moreover, the significant induction of metallothionein indicated that the bioaccumulated metals were actively detoxified. In the metal-exposed abalones, more Cu was distributed into the biologically detoxified fractions (metallothionein-like protein and/or metal-rich granule), whereas no significant subcellular redistribution of Zn was observed. Our study suggested that the abalone may have high endurance to the contamination of Cuor Zn. © 2013 Elsevier Inc

Synthesis and Characterization of Benzoxazine Resin Based on Furfurylamine

This paper presents an investigation of the modification of natural oxazines to traditional bisphenol A benzoxazines. Eugenol was reacted with furfurylamine to synthesize a new type of benzoxazine (eugenol–furfurylamine benzoxazine), with a yield of 77.65%; and another new type of benzoxazine (bisphenol A–furfurylamine benzoxazine) was generated from bisphenol A and furfurylamine, with the highest yield of 93.78%. In order to analyze and study the target molecules, IR (infrared radiation) spectroscopy, GPC (gel-permeation chromatograph), mass spectrometry, 1H-NMR (nuclear magnetic resonance), DSC (differential scanning calorimetry), and DMA (dynamic mechanical analysis) tests were conducted. Eugenol-furfurylamine benzoxazine and conventional bisphenol A-aniline benzoxazine (BZ) composite was also analyzed and cured at different mass ratios of 2:98, 5:95, 10:90, 20:80, and 40:60. When the content of eugenol furfurylamine in the blend reached 5%, the strength of the composite was greatly enhanced, while the strength decreased with the increase in eugenol furfurylamine oxazine content. Moreover, octamaleimide phenyl POSS (OMPS, polyhedral oligomeric silsesquioxane) and bisphenol A furamine benzoxazine were mixed at different molar ratios of 1:16, 1:8, 1:4, 1:2, and 1:1. The curing temperature sharply decreased with the increase in OMPS content. When the molar ratio reached 1:1, the curing temperature decreased from 248 to 175℃. A further advantage of using eugenol and furfurylamine is that they are renewable resources, which is important in terms of utilizing resources effectively and developing environmentally friendly products

Synthesis of a Novel Bifunctional Epoxy Double-Decker Silsesquioxane: Improvement of the Thermal Stability and Dielectric Properties of Polybenzoxazine

In this study a new type of bifunctional epoxy compound (DDSQ-EP) based on double-decker silsesquioxane (DDSQ) was synthesized by process of alkaline hydrolysis condensation of phenyltrimethoxysilane and corner capping reaction with dichloromethylvinylsilane, followed by epoxidation reaction of vinyl groups. The resultant structures were confirmed using Fourier transform infrared spectrometry, nuclear magnetic resonance spectrometry and time-of-flight mass spectrometry, respectively. The DDSQ-EP was incorporated into polybenzoxazine to obtain the PBZ/DDSQ-EP nanocomposites. The uniform dispersion of DDSQ-EP in the nanocomposites was verified by X-ray diffraction and scanning electron microscope. The reactions occurred during the curing of the composites and were investigated using infrared spectroscopy of segmented cures. Dynamic mechanical analysis and thermal gravimetric analysis indicated that the storage modulus, glass transition temperature and thermal stability of PBZ/DDSQ-EP were increased in comparison with pure benzoxazine resins. Assessment of dielectric properties demonstrated that the dielectric permittivity and dielectric loss of polybenzoxazine decreased slightly because of the addition of DDSQ-EP

The state-of-the-art research progress on motion segmentation

Conference Name:6th International Conference on Internet Multimedia Computing and Service, ICIMCS 2014. Conference Address: Xiamen, China. Time:July 10, 2014 - July 12, 2014.National Natural Foundation of China; SIGMM China Chapter; Xiamen UniversityMotion segmentation is currently one of the most active research topics in the areas of computer vision and multimedia. It has a wide spectrum of potential applications, including action recogn-ition, visual surveillance, video indexing, video compression, and many other applications. In this paper, we review the recent deve-lopments (especially for those in recent five years) of motion seg-mentation methods and analyze their respective pros and cons. Several valuable research directions are discussed and some sugg-estions are put forward in the end. Categories and Subject Descriptors I.2.10 [Vision and Scene Understanding]: Motion; I.4.8 [Scene Analysis]: Motion General Terms Algorithms, Performance. Copyright 2014 ACM

Comparative study: Face recognition via the correlation filter technique

Conference Name:6th International Conference on Internet Multimedia Computing and Service, ICIMCS 2014. Conference Address: Xiamen, China. Time:July 10, 2014 - July 12, 2014.National Natural Foundation of China; SIGMM China Chapter; Xiamen UniversityFace recognition attracts much attention in various applications due to its non-intrusive nature and the widespread availability of digital cameras. Recently, the benefits of using spatial frequency domain representations for face recognition have drawn great interests from the computer vision and pattern recognition community. In this paper, we present a comparative study by using the correlation filter (CF) technique in the application of face recognition. We overview some representative correlation filters (CFs) proposed recently and analyze their respective pros and cons. Experiments using different types of CFs with different training parameters are conducted on public face databases to investigate the overall performance of the CF-based face recognition methods. The observations based on these experiments are expected to provide widely applicable guidelines for designing the face recognition systems via the CF technique. Categories and Subject Descriptors I.4.8 [Image Processing and Computer Vision]: Scene Analysis - object recognition General Terms Algorithms, Performance, Experimentation, Verification. Copyright 2014 ACM

Different responses of abalone Haliotis discus hannai to waterborne and dietary-borne copper and zinc exposure

973 Program of China [2011CB409800]; Natural Science Foundation of China [40976067]; Program for Changjiang ScholarsTo investigate the potential influence of the contamination of copper (Cu) or zinc (Zn), the abalone Haliotis discus hannai was exposed to waterborne or macroalgae-borne Cu or Zn over a period of 8 weeks. Both Cu and Zn were effectively accumulated by the abalones from water or macroalgae, but their concentration factors and trophic transfer factors were low due to the regulation of Cu and Zn accumulation. Following waterborne or dietary exposure, the abalones exhibited different accumulation patterns of Cu and Zn. The tissue Zn burden decreased quickly after the initial accumulation, and the incoming Zn was mainly deposited in the viscera. In contrast, the tissue Cu burden increased rapidly and gradually reached a steady state. The abalone muscle exhibited a comparable storage capacity of Cu as the viscera and the accumulated Cu in muscle was mainly derived from the dissolved phase instead of trophic transfer. The feeding and growth of the abalone were not influenced in all the exposure regimes. Moreover, the significant induction of metallothionein indicated that the bioaccumulated metals were actively detoxified. In the metal-exposed abalones, more Cu was distributed into the biologically detoxified fractions (metallothionein-like protein and/or metal-rich granule), whereas no significant subcellular redistribution of Zn was observed. Our study suggested that the abalone may have high endurance to the contamination of Cu or Zn. (c) 2013 Elsevier Inc. All rights reserved