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Background Filtering and Object Detection With a Stationary LiDAR Using a layer-based method

IEEE ACCESS 2020年 8卷 184426-184436页

作者： Song, Yanjie Zhang, Han Liu, Yuanqiang Liu, Jinzhang Zhang, Hongbo Song, Xiuguang Shandong Univ Sch Qilu Transportat Jinan 250061 Peoples R China Shandong Univ Suzhou Res Inst Suzhou 215123 Peoples R China Shandong Hispeed Construct Management Grp Co Ltd Jinan 250001 Peoples R China Yantai Water Bldg Conservancy Invest & Design Aca Yantai 264003 Peoples R China Yantai Water Ind Grp Co Ltd Yantai 264003 Peoples R China

The connected vehicle environment is significant for the future road network. For constructing the connected vehicle environment, real-time data acquirement is always the prerequisite. Recently, using Light Detection and Ranging (LiDAR)-based roadside infrastructures are becoming a prevalent method of obtaining real-time traffic data. However, the collected raw data from LiDAR cannot usually be used directly. The steps of data processing, like background filtering and object detection, are necessary. The processed data can then be employed in different applications. This paper proposed a novel layer-based searching method that is established with the help of the point distribution features to distinguish moving objects from the point cloud. It aimed to address the unexpected influence of factors such as congested situations and package loss. The new approach was also evaluated compared with the state-of-the-art methods by applying field data. The results showed that the proposed method is more effective than other methods. This method may be applicable to other types of rotating LiDAR for improving the background filtering performance.

关键词： Laser radar Filtering Laser beams Clustering algorithms Object detection Packet loss Background filtering object detection stationary LiDAR layer-based method

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Parallel computing method for generating hologram of 3D objects using layer-based method 7

Parallel computing method for generating hologram of 3D obje...

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7th International Conference on Optical and Photonic Engineering (icOPEN)

作者： Huang, Jia Xiao, Bo Zheng, Huadong Gao, Zhifang Li, Fei Yu, Yingjie Shanghai Univ Dept Precis Mech Engn Shanghai 200072 Peoples R China Chinese Minist Educ Key Lab Adv Display & Syst Applicat Shanghai 200072 Peoples R China

ISBN: (数字)9781510631601

ISBN: (纸本)9781510631601

Parallel computing of layer-based method for generating hologram of 3D objects is introduced. 3D MAX is used to model 3D object. The hologram of 3D model with depth information is calculated by Fresnel diffraction algorithm. The computational hologram generated by computer is reconstructed photoelectric to verify the correctness of the algorithm. This paper expounds the hardware architecture of GPU and CPU, briefly introduces the bottleneck and solution of CPU and GPU acceleration, and describes the optimization of thread and storage bandwidth in parallel processing. We use GPU hardware parallel computing and optimize the calculation process of 3D object hologram by using MKL and CUDA computing environment to improve the efficiency of computing. After analysis, the results show that the parallel computing speed of GPU hardware is 63 times faster than CPU alone. The parallel acceleration method can greatly shorten the computing time of generating hologram with layer-based method.

关键词： holography computational holography,3D object layer-based method acceleration GPU CUDA

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Digital Volume Reflection Holography using 3D Point Cloud and layer method 18

Digital Volume Reflection Holography using 3D Point Cloud an...

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Conference on Photonic Fiber and Crystal Devices - Advances in Materials and Innovations in Device Applications XVIII

作者： Qissi, Saleha Banerjee, Partha P. Univ Dayton Electroopt & Photon 300 Coll Pk Dayton OH 45469 USA

ISBN: (纸本)9781510679405;9781510679412

The performance of a combination the point cloud and layer-based method numerically to obtain a composite digital volume reflection hologram from digital transmission holograms is investigated. The 3D point cloud is reclassified into parallel two-dimensional layers. The digital transmission hologram is obtained from each layer. These layers can be at a specific wavelength or combination of wavelengths. This is followed by obtaining digital volume reflection holograms from digital transmission holograms using reflection grating theory, and then reading out the composite digital volume reflection hologram using coupled wave theory. Readout information from the digital volume reflection hologram with high wavelength selectivity is investigated.

关键词： volume reflection hologram digital holography point cloud method layer-based method wavelength selectivity

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Performance evaluation of Python and MATLAB for CGH generation using layer-based approach

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JOURNAL OF OPTICS-INDIA 2024年第5期53卷 4762-4771页

作者： Gupta, Anuj Das, Bhargab Kumar, Raj CSIR Cent Sci Instruments Org Chandigarh 160030 India

In the field of computational holography, creating intricate holographic patterns is a fundamental yet computationally intensive endeavor, posing substantial challenges in obtaining large space-bandwidth product. The computational burden for calculating computer generated hologram (CGH) is notably affected by various factors, with object and CGH sizes being the prominent ones. As such, the task of optimizing CGH generation algorithms for larger matrix dimensions is paramount, especially in practical applications such as holographic dynamic displays. This work presents a comprehensive comparative analysis of two widely used programming languages, Python and MATLAB, for CGH calculation. The study tends to provide valuable insights to predict the suitability of these languages for CGH calculation in terms of efficiency and performance. The large matrix dimensions up to 8192 x 8192 are used as test cases to ensure the relevance and practicality of the findings. Our findings reveal that MATLAB and Python perform comparably in terms of the quality of reconstruction objects and also the execution time disparity diminishes, particularly for higher matrix dimensions. As a result, users can choose either language based on their requirement and personal comfort with the programming environment.

关键词： Computer-generated hologram Holographic displays layer-based method Python MATLAB

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Optical tomography in coherent off-axis scanning holography 12

Optical tomography in coherent off-axis scanning holography

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Conference on Holography, Diffractive Optics, and Applications XII Part of SPIE/COS Photonics Asia Conference

作者： Yao, Yongwei Zhang, Yaping Poon, Ting-Chung Kunming Univ Sci & Technol Yunnan Prov Key Lab Modern Informat Opt Kunming 650500 Yunnan Peoples R China Virginia Tech Bradley Dept Elect & Comp Engn Blacksburg VA 24061 USA

ISBN: (纸本)9781510657038;9781510657021

Off-axis optical scanning holography (OSH) has been recently proposed to perform scanning holography without the use of heterodyning. In the present work, we combine the principle of off-axis scanning holography operating in the coherent mode with the idea of a layer-based method to achieve a new computational imaging technique for optical tomography. The point cloud data of a complex three-dimensional (3D) scene is layered along the depth direction as the 3D object is divided into a series of planar layers parallel to the hologram along the optical axis direction. The data of each layer generates a single-layer hologram under coherent off-axis scanning holography. Finally, the hologram of a complex three-dimensional object is obtained by superimposing all the single-layer holograms. We use a single-sideband filter to extract the hologram spectrum to obtain a positive first-order reconstruction and demonstrate numerical reconstruction with different diffraction distances. Also, optically reconstructed images are displayed by a spatial light modulator. The results indicate that the proposed method can realize the holographic recording and reconstruction of a complex three-dimensional object without the zeroth-order beam and the twin image, providing a new computational method for the generation of holograms of large-scale and long-depth 3D objects.

关键词： Off-axis optical scanning holography layer-based method computational holography optical tomography

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Optimized layered method for real-time interactive holographic display based on ray-tracing technique

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OPTICAL ENGINEERING 2020年第10期59卷

作者： Li, Hui Sang, Xinzhu Zhao, Linmin Chen, Duo Chen, Zhidong Wang, Yuan Zhao, Xin Peng, Cheng Yan, Binbin Wang, Kuiru Yu, Chongxiu Beijing Univ Posts & Telecommun State Key Lab Informat Photon & Opt Commun Beijing Peoples R China

The extreme computational complexity in generating a hologram makes the interactive holographic display very difficult. An optimized layered rendering method for real-time interactive holographic display based on ray-tracing technique is presented in order to overcome this challenge and realize real-time interaction of three-dimensional scenes. Ray tracing is able to render more complex and photorealistic images for different illuminations and circumstances. Rays are launched in parallel and traced to obtain ray-object intersections, and then the complex wave field of the effective pixels in different layers is determined. The occlusions between different layers are also considered to effectively reduce the overall computation. A computer-generated hologram is fused with the multilayer-hologram-diffraction results using the layered fast Fourier transform algorithm. The experimental results demonstrate the effectiveness of the proposed method. The reconstructed holographic image with real depth cues is demonstrated by the experiments, and the optical reconstruction images can be interacted in real-time. (C) 2020 Society of Photo-Optical Instrumentation Engineers (SPIE)

关键词： computer-generated hologram holographic display layer-based method ray-tracing technique real time

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Three-dimensional hologram generation method based on space-division

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OPTIK 2020年 200卷

作者： Su, Ping Gao, Qi-xiang He, Ze-hao Ma, Jian-she Tsinghua Univ Grad Sch Shenzhen Shenzhen 518055 Peoples R China

The layer-based method for three-dimensional (3D) hologram generation suffers from reconstruction quality decreasing. On the basis of the layer-based method, a new method based on the idea of "space-division" is proposed. The method divides the object into small pieces, named spaces;for spaces with small number of points, the point-based method is used for hologram generation, to ensure the reconstruction quality;for spaces with large number of points, the fast Fourier transform method is used to ensure the computation efficiency. An index named "qualitytime ratio" Q is defined, to synthetically evaluate the influence effect of the number of portions, the number of layers and the number of points to the effect of the algorithm. The simulation results show that, the increment of the number of portions improves Q the most effectively, which proves the validity of our method. The method is further tested by computer and optical reconstructions using different objects, and it is proved that the space partitioning method can obtain reconstructed images with the same quality in about 30% fewer time.

关键词： Computer-generated holograms Hologram generation algorithm Space-division layer-based method

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Bengali Printed Character Recognition - A New Approach 1

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12th IFIP TC8 International Conference on Computer Information Systems and Industrial Management Applications (CISIM)

作者： Shaikh, Soharab Hossain Tabedzki, Marek Chaki, Nabendu Saeed, Khalid Univ Calcutta AK Choudhury Sch Informat Technol Kolkata 700073 W Bengal India Bialystok Tech Univ Fac Comp Sci Bialystok Poland Univ Calcutta Dept Comp Sci & Engn Kolkata 700073 W Bengal India AGH Univ Sci & Technol Fac Phys & Appl Comp Sci Krakow Poland

ISBN: (数字)9783642409257

ISBN: (纸本)9783642409257;9783642409240

This paper presents a new method for Bengali character recognition based on view-based approach. Both the top-bottom and the lateral view-based approaches have been considered. A layer-based methodology in modification of the basic view-based processing has been proposed. This facilitates handling of unequal logical partitions. The document image is acquired and segmented to extract out the text lines, words, and letters. The whole image of the individual characters is taken as the input to the system. The character image is put into a bounding box and resized whenever necessary. The view-based approach is applied on the resultant image and the characteristic points are extracted from the views after some preprocessing. These points are then used to form a feature vector that represents the given character as a descriptor. The feature vectors have been classified with the aid of k-NN classifier using Dynamic Time Warping (DTW) as a distance measure. A small dataset of some of the compound characters has also been considered for recognition. The promising results obtained so far encourage the authors for further work on handwritten Bengali scripts.

关键词： Bengali character view-based algorithm layer-based method bounding box unequal partition

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