- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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3D Human Pose Estimation from Range Images with Depth Difference and Geodesic Distance
摘要： Depth difference, as a popularly used feature for characterizing pairwise pixels of range images, fails to precisely capture skeleton joints when human body possesses a wild and complicated articulation. As the geodesic distance of pairwise pixels is able to present a global connected property and adjacent pixels often belong to the same body component, we propose an effective and efficient framework for pose estimation. Firstly, all the pixels of a range image are grouped into superpixels using an improved Simple Linear Iterative Clustering algorithm. Secondly, those superpixels are labelled as the components of a human body using the hybrid feature. Thirdly, component-based cluster feature extraction is undertaken on skeleton joints of body components with K-means clustering algorithm. Finally, the feature points of each component are then stacked as a compact representation of human poses and are mapped to the skeleton joints of a human body. Experimental results demonstrate that the proposed framework outperforms several state-of-the-art pose estimation methods.
关键词： Superpixel,Random decision forest,Geodesic distance,Human pose estimation,Sparse representation
更新于2025-09-23 15:22:29
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Hyperspectral signature analysis using neural network for grade estimation of copper ore
摘要： The ever-increasing demand for the different metal and mineral resources from the earth’s subsurface has brought tremendous pressure on the geochemical laboratory for the growing countries. The success of any mining industry relies on the estimated values of ore grade in the mineral deposit. Hence, rapid assessment of ore grade is critical in daily schedule in mines operations. Commonly the assay value is determined by chemical analysis or X-Ray Fluorescence (XRF), which is one of the constrained by real-time grade estimation, duration of sample preparation and processing. Several researches carried out in exploration and revealed that hyperspectral technique is a promising tool for mineral identification and mapping. The goal of the present study is to determine the effectiveness of narrow band spectroscopy in Cu grade estimation. To achieve this, a multilayer feed-forward neural network model has been developed to establish a functional link between hyperspectral signature derived features with the copper grade. Altogether eight different types of features including absorption depth, band depth center, the area under the absorption curve, full width at half maxima were extracted from continuum removed spectra along with derivative reflectance features, e.g. band depth ratio, 1st and 2nd slopes from the hyperspectral profile. The dimensionality was reduced by applying Principal Component Analysis onto the extracted features. The first seven PCAs are then used as input vector of the ANN model. A five-fold cross-validation exercise is carried out for model performance. The high degree of correlation reveals that the PCA generated feature from hyperspectral data coupled with ANN model could be an alternative approach to predict the copper grade for the copper mine.
关键词： copper grade,ore grade estimation,spectral feature,K-Fold cross validation,principal component analysis,artificial neural network
更新于2025-09-23 15:22:29
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An Efficient and Fast Quantum State Estimator With Sparse Disturbance
摘要： A pure or nearly pure quantum state can be described as a low-rank density matrix, which is a positive semidefinite and unit-trace Hermitian. We consider the problem of recovering such a low-rank density matrix contaminated by sparse components, from a small set of linear measurements. This quantum state estimation task can be formulated as a robust principal component analysis (RPCA) problem subject to positive semidefinite and unit-trace Hermitian constraints. We propose an efficient and fast inexact alternating direction method of multipliers (I-ADMM), in which the subproblems are solved inexactly and hence have closed-form solutions. We prove global convergence of the proposed I-ADMM, and the theoretical result provides a guideline for parameter setting. Numerical experiments show that the proposed I-ADMM can recover state density matrices of 5 qubits on a laptop in 0.69 s, with 6 × 10^{-4} accuracy (99.38% fidelity) using 30% compressive sensing measurements, which outperforms existing algorithms.
关键词： quantum state estimation (QSE),Alternating direction method of multipliers (ADMM),robust principal component analysis (RPCA)
更新于2025-09-23 15:22:29
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Precompensation and System Parameters Estimation for Low-Cost Nonlinear Tera-Hertz Transmitters in the Presence of I/Q Imbalance
摘要： Tera-Hertz (THz) transmission can offer several attractive applications, yet developing low-cost energy-efficient THz devices is at an early stage. The most promising low-cost THz transmitter architecture in the literature is the so-called frequency-multiplier-last architecture. However, it is incapable of transmitting quadrature amplitude modulation (QAM) due to the architecture's inherent nonlinear distortions. We study such nonlinear THz communication systems by incorporating the nonlinearity aspects of the low-cost THz devices and the inphase and quadrature (I/Q) imbalance effect into the signal model. Then, we propose a precompensation scheme to compensate the nonlinearity and I/Q imbalance effects, thus enabling the QAM-capable frequency-multiplier-last architecture for THz systems. The proposed precompensation scheme requires the knowledge of the system parameters. To estimate the system parameters, we propose a maximum-likelihood estimator and its practical implementation via an alternating estimation algorithm. We also derive closed-form expressions for the Cramér–Rao lower bounds (CRLBs) of the system parameters estimation, and design the pilot sequence used in estimating the system parameters. Numerical results show that the proposed precompensation schemes overcome the prominent problems experienced in the existing THz systems, namely severe nonlinear distortions of the modulation symbols as well as spectral spreading and/or large spectrum sidelobes, and mitigate the I/Q imbalance effect.
关键词： precompensation,estimation,QAM,I/Q imbalance,nonlinear distortion,Low-cost,Tera-Hertz
更新于2025-09-23 15:22:29
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[IEEE 2018 25th IEEE International Conference on Image Processing (ICIP) - Athens, Greece (2018.10.7-2018.10.10)] 2018 25th IEEE International Conference on Image Processing (ICIP) - Depth Estimation with Occlusion Handling from a Sparse Set of Light Field Views
摘要： This paper addresses the problem of depth estimation for every viewpoint of a dense light field, exploiting information from only a sparse set of views. This problem is particularly relevant for applications such as light field reconstruction from a subset of views, for view synthesis and for compression. Unlike most existing methods for scene depth estimation from light fields, the proposed algorithm computes disparity (or equivalently depth) for every viewpoint taking into account occlusions. In addition, it preserves the continuity of the depth space and does not require prior knowledge on the depth range. The experiments show that, both for synthetic and real light fields, our algorithm achieves competitive performance to state-of-the-art algorithms which exploit the entire light field and usually generate the depth map for the center viewpoint only.
关键词： light field,stereo matching,optical flow,low rank approximation,depth estimation
更新于2025-09-23 15:22:29
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[IEEE 2018 IEEE 20th International Workshop on Multimedia Signal Processing (MMSP) - Vancouver, BC (2018.8.29-2018.8.31)] 2018 IEEE 20th International Workshop on Multimedia Signal Processing (MMSP) - An Adaptive Bandpass Filter Based on Temporal Spectrogram Analysis for Photoplethysmography Imaging
摘要： Photoplethysmography Imaging (PPGI) in the sense of remote vital sign measurement via camera has attracted high interest in recent years. The non-contact measurement principle allows the use in many health monitoring applications, like monitoring of newborns. Beyond that, there are interesting areas of application in the multimedia sector, such as measuring the reaction to multimedia content or heart rate based liveness detection for multimedia security. The derived signal of a PPGI algorithm is often referred as blood volume pulse signal (BVP). The signal corresponds to the optical signal of blood volume changes in the upper skin layers. Most current approaches use peak detection in frequency spectrum to estimate heart rate from BVP signals. However, we focus on heart rate computation based on beat-to-beat peak detection in time domain. In this paper, we present a method for adaptive bandpass filtering for PPGI based on temporal spectrogram analysis of the BVP signal with a sliding time window. The main goal of this new method is to further improve accuracy of beat-to-beat peak detection in time domain. The approach exploits the analysis of main frequency components of the BVP signal over time, to build a bandpass filter with adaptive cutoff frequencies in order to filter noise and interference. So far, state-of-the-art approaches have usually used fixed cut-off frequencies in the physiologically possible range of heart rate. The novelty of the proposed method lies in its simple but effective solution to reduce the influence of noise and interference in the PPGI signal to improve peak detection for heart rate estimation. We show the improvements applying the adaptive bandpass filter technique to four basic algorithmic approaches of PPGI, namely ICA, Chrominance, POS and 2SR and comparing against current state-of-the-art peak detection approaches. For the evaluation we used a database with videos of 26 subjects in 4 different scenarios, each lasting two minutes.
关键词： Photoplethysmography Imaging,time frequency analysis,signal processing,user reaction,peak detection,remote heart rate estimation,adaptive bandpass filtering
更新于2025-09-23 15:22:29
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[IEEE 2018 IEEE 3rd International Conference on Signal and Image Processing (ICSIP) - Shenzhen, China (2018.7.13-2018.7.15)] 2018 IEEE 3rd International Conference on Signal and Image Processing (ICSIP) - Interferometric SAR Baseline Estimation by Partitioned High Coherence Areas
摘要： In this article, a novel interferometric synthetic aperture radar (InSAR) baseline estimation method based on ground control points (GCPs) and partitioning is proposed. Instead of introducing the existing low-resolution digital elevation model (DEM) to correct the phase jumps between high and low coherence regions in the process of phase unwrapping, we use the high coherence regional block to calibrate the interferometric parameters. In the process of calibration, the GCPs can reference for low resolution DEM, also can be obtained through the filed measurement. Because the interferometric parameters calibration does not change the absolute phase, which avoids the local DEM restriction by low resolution DEM. In addition, the block based on the coherence map avoids DEM inversion error due to overall absolute phase deviation. Gaofen-3 InSAR data of Ningbo area are used to verify the effectiveness of the proposed method.
关键词： baseline estimation,DEM,InSAR
更新于2025-09-23 15:22:29
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[IEEE 2018 IEEE 8th International Conference on Consumer Electronics - Berlin - Berlin, Germany (2018.9.2-2018.9.5)] 2018 IEEE 8th International Conference on Consumer Electronics - Berlin (ICCE-Berlin) - Context-Aware Contrast Enhancement Using Shadow Region Estimation and Bright Channel
摘要： This paper presents a contrast image enhancement method using a shadow region estimation and bright channel. To separate the dark and bright regions, the proposed method estimates the shadow map by selecting the darkest pixels of a low-contrast image. The bright channel represents the brightest pixel among the red, green, and blue pixels and it preserves the bright region of an input image. The resulting image is obtained by synthesizing the input and brightness enhance images using shadow map and bright channel. Experimental results show that the proposed method can provide the enhanced images without undesired artifact brightness saturation and color distortion.
关键词： Contrast enhancement,Shadow estimation,Bright channel prior
更新于2025-09-23 15:22:29
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Partially Asynchronous Distributed Unmixing of Hyperspectral Images
摘要： So far, the problem of unmixing large or multitemporal hyperspectral data sets has been specifically addressed in the remote sensing literature only by a few dedicated strategies. Among them, some attempts have been made within a distributed estimation framework, in particular, relying on the alternating direction method of multipliers. In this paper, we propose to study the interest of a partially asynchronous distributed unmixing procedure based on a recently proposed asynchronous algorithm. Under standard assumptions, the proposed algorithm inherits its convergence properties from recent contributions in nonconvex optimization, while allowing the problem of interest to be efficiently addressed. Comparisons with a distributed synchronous counterpart of the proposed unmixing procedure allow its interest to be assessed on synthetic and real data. Besides, thanks to its genericity and flexibility, the procedure investigated in this paper can be implemented to address various matrix factorization problems.
关键词： partially asynchronous distributed estimation,Hyperspectral (HS) unmixing,nonconvex optimization
更新于2025-09-23 15:22:29
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[IEEE 2017 International Renewable and Sustainable Energy Conference (IRSEC) - Tangier (2017.12.4-2017.12.7)] 2017 International Renewable and Sustainable Energy Conference (IRSEC) - Solar Panels Frames Quality Assessment
摘要： Maintaining solar plant maximum energy production requires a regular inspection of solar panels. Images stitching technique of captured videos is usually used to form panoramic image view of the solar plant. Analyze of those images help supervisors to detect cracks, dust accumulation, …. Often captured videos are done using moveable devices, such as vehicle robots and drones. Usually, motion and shaking of devices provoke some blur captured frames which affect drastically the stitching process. In this paper, we study, experiment, and compare a set of techniques allowing to detect and discard blurred frames. As result, the algorithm based on Fourier Transform allows an efficient (i.e. accuracy of about 98%) and rapid treatment which can be easily integrated into online stitching process.
关键词： Blur estimation,Magnitude Fourier transform,DCT analysis,Image edges,SVD decomposition,Frame quality,Frames stitching
更新于2025-09-23 15:22:29