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Trunk detection based on laser radar and vision data fusion

International Journal of Agricultural and Biological Engineering 2018年第6期11卷 20-26页

作者： Jinlin Xue Bowen Fan Jia Yan Shuxian Dong Qishuo Ding College of Engineering Nanjing Agricultural UniversityNanjing 210095China

Tree trunks detection and their location information are needed to perform effective production and management in forestry and fruit farming.A novel algorithm based on data fusion with a vision camera and a 2D laser scanner was developed to detect tree trunks *** transformation was built from a laser coordinate system to an image coordinate system,and the model of a rectangle calibration plate with two inward concave regions was established to implement data alignment between two sensors ***,data fusion and decision with Dempster-Shafer theory were achieved through integration of decision level after designing and determining basic probability assignments of regions of interesting(RoIs)for laser and vision data *** trunk width was calculated by using laser data to determine basic probability assignments of RoIs of laser *** a stripping segmentation algorithm was presented to determine basic probability assignments of RoIs of vision data,by calculating the matching level of RoIs like tree trunks.A robot platform was used to acquire data from sensors and to perform the developed tree trunk detection *** calibration tests were conducted to calculate a conversion matrix transforming from the laser coordinate system to the image coordinate system,and then field experiments were carried out in a real pear orchard under sunny and cloudy conditions,with trunk width measurement of 120 trees and 40 images processed by the presented stripping segmentation *** showed the algorithm was successful to detect tree trunks and data fusion improved the ability for tree trunk *** algorithm could provide a new method for tree trunk detection and accurate production and management in orchards.

关键词： trunk detection data fusion evidence theory calibration laser radar vision camera

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Path Planning Approach Based on Dual laser radar Fusion

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Journal of Donghua University(English Edition) 2012年第1期29卷 9-13页

作者：褚涛孙富春孟丽霞 State Key Laboratory of Intelligent Technology and Systems Department of Computer Science and TechnologyTsinghua University

A dual laser radar based path planning method for mobile robot in general outdoor road environment is proposed. Firstly, the point-wise sequence and target library of the global optimal path are generated based on algorithm A*. Secondly, the local target information and the perceptive information from dual laser radar are combined, and the different field information from both horizontal and aslant fixed laser radars is fused. Finally, the optimal driving angle is computed by the improved angle potential field(APF)algorithm. The practical experiment results validate the robustness and timeliness of the proposed approach.

关键词： mobile robot laser radar path planning

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A high sensitive 66 dB linear dynamic range receiver for 3-D laser radar

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Journal of Semiconductors 2017年第8期38卷 81-86页

作者： Rui Ma Hao Zheng Zhangming Zhu School of Microelectronics Xidian University

This study presents a CMOS receiver chip realized in 0.18μm standard CMOS technology and in- tended for high precision 3-D laser radar. The chip includes an adjustable gain transimpedance pre-amplifier, a post-amplifier and two timing comparators. An additional feedback is employed in the regulated cascode tran- simpedance amplifier to decrease the input impedance, and a variable gain transimpedance amplifier controlled by digital switches and analog multiplexer is utilized to realize four gain modes, extending the input dynamic range. The measurement shows that the highest transimpedance of the channel is 50 kΩ, the uncompensated walk error is 1.44 ns in a wide linear dynamic range of 66 dB （1 ： 2000）, and the input referred noise current is 2.3 pA/√ （rms）, resulting in a very low detectable input current of 1μA with SNR = 5.

关键词： laser radar linear dynamic range transimpedance amplifier timing comparator walk error

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Wavelet Filter and Noise Rejection for the Pulse laser radar

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Chinese Journal of lasers 2000年第4期9卷 26-31页

作者： CAI Xiping ZHAO Yuan QIAO Lijie LIU Jianbo (Department of Applied Physics, Harbin Institute of Technology, Harbin 150001, China) 哈尔滨工业大学黑龙江哈尔滨

The stochastic noise can be expanded on the basis of Fourier progression. It can be divided into two components, one is called ac noise which obeys the normal distribution statistically, on the other hand, the other is called dc noise which can decrease the detection SNR. Generally, a matched filter is used to reject noise, but it is only suitable for the rejection of white noise. In this paper, a wavelet filter is introduced to reject the dc noise for the signal detection of the pulse laser radar. The bubble function is selected as the mother function. The simulation results indicated that the SNR can be improved by wavelet filter when the dc noise is existing. It is indicated that the SNR is higher with matched filter than that with wavelet filter in the absence of the dc noise, while the SNR is greatly higher with wavelet filter than that with matched filter when dc noise is in existence.

关键词： wavelet transform noise rejection laser radar

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Design of laser radar Fiber Optic Liquid Level Sensor System

引用

Semiconductor Photonics and Technology 1998年第4期 52-56页

作者： QI Bing (Dept. of Computer,Tsinghua University, Beijing 100084, CHN) QI Fei (Dept. of Physics,Dalian University, Dalian 116001, CHN) PENG Wei (Dalian University of Technology, Dalian 116023, CHN)

１ＩｎｔｒｏｄｕｃｔｉｏｎＡｓｔｈｅｒａｐｉｄｄｅｖｅｌｏｐｍｅｎｔｏｆｆｉｂｅｒｏｐｔｉｃｓｅｎｓｏｒ［１］，ｌａｓｅｒｒａｄａｒｈａｓｔｒａｄｉｔｉｏｎａｌｙｂｅｎｕｓｅｄｆｏｒｌｏｎｇｒａｎｇｅｄｉｓｔａｎｃｅ... 详细信息

１ＩｎｔｒｏｄｕｃｔｉｏｎＡｓｔｈｅｒａｐｉｄｄｅｖｅｌｏｐｍｅｎｔｏｆｆｉｂｅｒｏｐｔｉｃｓｅｎｓｏｒ［１］，ｌａｓｅｒｒａｄａｒｈａｓｔｒａｄｉｔｉｏｎａｌｙｂｅｎｕｓｅｄｆｏｒｌｏｎｇｒａｎｇｅｄｉｓｔａｎｃｅｍｅａｓｕｒｅｍｅｎｔ．Ｕｓｉｎｇ...

关键词： Fiber Optic Sensor laser radar Liquid Level

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A Combined System of Redundant MEMS and laser radar

A Combined System of Redundant MEMS and Laser Radar

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第36届中国控制会议

作者： Zhanqing Wang Dong Li Yun Lei Yanshun Zhang School of Automation Beijing Institute of Technology School of Instrumentation Science and Opto-electronics Engineering Beihang University

ISBN: (纸本)9781538629185

In this paper,we adopt a combination optimization algorithm of multi-Micro Electro Mechanical System(MEMS),according to the differences of different single independent MEMS,which are combined to achieve the optimal *** scheme we proposed is to integrate two MEMS gyroscopes and four MEMS ***,this algorithm is effective in situations of multi MEMS *** the same time,we use the laser radar to measure environmental information to match the position where the object arrives just the prior *** allows a closed-loop trajectory acquired by combining MEMS and radar *** on the closed-loop trajectory,we build the graph model,and then use the graph optimization algorithm to optimize the trajectory and get more accurate pose information.

关键词： Redundant MEMS Closed loop Graph optimization laser radar

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Signal properties and the optical parameter design of a laser radar

Signal properties and the optical parameter design of a lase...

引用

2000 25～(th) International Conference on Infrared and Millimeter Waves Conference Digest

作者： He Yi Wu Jian Peng RenjunInstitute of Applied Physics University of Electronic Science & Technology of China Chengdu 610054 PRC

＜正＞ The 3dB-contrast criterion is suggested based on the statistical properties of the back-scattered signal *** case of heterodynedetection,the signal light speckle size is considered to be a key parameter in the matching between the signal light and the local oscillator（LO）***,the angular discrimination of a scanning imaging laser radar（lidar）is concluded to be 0.75θ for heterodyne detection and0.67θ for direct detection,where θ is the probe beam divergence angle Based on these analyses,the relationship among the optical parametersof a lidar is *** may help us to design the optical system properly.

关键词： laser radar discrimination heterodyne detection

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Doppler shift of a laser pulse beam scattered by a rotating cone and cylinder

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Chinese Physics B 2014年第5期23卷 60-65页

作者：王保平王明军吴振森李应乐向宁静 National Key Laboratory of Sciences and Technology on UAV Northwestern Polytechnical University School of Physics and Electronic Engineering Xianyang Normal College School of Science Xidian University

Based on laser radar equations, a Doppler shift model of a laser pulse beam scattered by a rotating arbitrary convex target is reported in this paper. The boundary relations between an incident pulse beam and the detected area elements are analyzed by geometric methods. The Doppler shift characteristics of the rotating cone and cylinder are discussed and the difference between the laser pulse beam and the plane wave scattered from the same rotating target is compared accordingly. Numerical simulations show that the Doppler shift is tightly relevant to their dimensions, speeds, and so on. In the same incidence conditions, the pulse beam and plane wave have difference peak values and the same Doppler shift bandwidth. If the waist radius of the pulse beam is larger, the peak value is higher, and the Doppler shifts are proportional to the speed of the rotating target. By virtue of our theoretical model, we probe into the scattered characteristics of the Doppler shifts of a laser pulse beam, which would benefit target identification in national defense.

关键词： scattered characteristics of laser pulse beams Doppler shift laser radar target identification

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Lidar Measurements of Aerosols in the Tropical Atmosphere

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Advances in Atmospheric Sciences 1993年第3期10卷 365-378页

作者： P.C.S.Devara P.Ernest Raj Indian Institute of Tropical Meteorology Pune 411008 IndiaIndian Institute of Tropical Meteorology Pune 411008 India

Measurements of atmospheric aerosols and trace gases using the laser radar (lidar) techniques, have been in progress since 1985 at the Indian Institute of Tropical Meteorology, Pune (18°32'N, 73°51'E, 559 m AMSL), India. These observations carried out during nighttime in the lower atmosphere (up to 5.5 km AGL), employing an Argon ion / Helium-Neon lidar provided information on the nature, size, concentration and other characteristics of the constituents present in the tropical atmosphere. The time-height variations in aerosol concentration and associated layer structure exhibit marked differences between the post-sunset and pre-sunrise periods besides their seasonal variation with maximum concentration during pre-monsoon / winter and minimum concentration during monsoon months. These observations also revealed the influence of the terrain of the experimental site and some selected meteorological parameters on the aerosol vertical distributions. The special observations of aerosol vertical profiles obtained in the nighttime atmospheric boundary layer during October 1986 through September 1989 showed that the most probable occurrence of mixing depth lies between 450 and 550 m, and the multiple stably stratified aerosol layers present above the mixing depth with maximum frequency of occurrence at around 750 m. This information on nighttime mixing depth / stable layer derived from lidar aerosol observations showed good agreement with the height of the ground-based shear layer / elevated layer observed by the simultaneously operated sodar at the lidar site.

关键词： laser radar Atmospheric aerosols Aerosol layer Nocturnal boundary layer Tropics

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Gravity Wave Activity and Spectra in the Upper Mesosphere at Wuhan,China During Early March 1996

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Wuhan University Journal of Natural Sciences 1998年第1期3卷 49-52页

作者： Ai Yong Lu Su Zhang Xunjie Gong Shunsen

Sodium layers (75–105 km) were measured by Na lidar on three nights from 1 to 3 of March 1996. The lidar data were used to calculate the relative atmospheric density perturbations and their spectra. The average r. m. s. density perturbations for early March at Wuhan are 5%. The Vertical wave number spectra exhibit power-law shapes with an average slpoes of ?2. 12 in the upper mesosphere when the associated density mean quantity of the day was used.

关键词： gravity wave laser radar sodium layer spectrum

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