The Influence of Target Properties on the Accuracy of Reflectorless Distance Measurements

Recent years have brought dynamic developments in surveying equipment and techniques. These include reflectorless electromagnetic distance measurement (RL EDM), which is used in a range of devices, especially total stations. Studies concerning the influence of the reflecting surface on the accuracy of RL EDM tend to focus on the colour of the measurement surface, while the influence of the density and thickness of materials is usually neglected. Therefore, this study undertook to examine 53 samples representing various materials of dissimilar features: colour, type of surface and density. The results show that dark and mat surfaces cause higher RL EDM errors than bright, gloss materials. Nonetheless, 76% of the results were in compliance with equipment specifications. Moreover, it was found that the density of the samples had significant impact on the overall accuracy. RL EDM to EPS (expanded polystyrene sheets, low-density material, commonly called Styrofoam) involved a significantly higher error rate. It demonstrates that total station measurements and laser scanning should be performed cautiously, especially with regard to materials of low density (e.g., EPS) and on short distances, where the value of relative error is high.

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AN INSTRUMENTAL BASIS FOR MULTISPECTRAL LIDAR WITH SPECTRALLY-RESOLVED DISTANCE MEASUREMENTS

ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences ◽

10.5194/isprs-archives-xlii-2-w13-1121-2019 ◽

2019 ◽

Vol XLII-2/W13 ◽

pp. 1121-1126

Author(s):

D. Salido-Monzú ◽

A. Wieser

Keyword(s):

Femtosecond Laser ◽

Laser Scanning ◽

Distance Measurement ◽

Distance Measurements ◽

Spectral Bands ◽

Laser Scanners ◽

Propagation Medium ◽

Set Up ◽

Spectrally Resolved ◽

Better Than

<p><strong>Abstract.</strong> Hyperspectral solutions augment laser scanning technology with material probing capabilities by measuring target reflectance along with topography. We propose a novel instrumental basis that enables also spectrally-resolved distance measurement with sufficient sensitivity as to access dispersive phenomena on the reflecting target and along the propagation medium, further enhancing the material analysis capabilities of hyperspectral approaches. To this end we have extended distance metrology using intermode beat notes of a mode-locked femtosecond laser to cover flexibly selected spectral regions. The approach is based on an ultra-broadband source derived from a femtosecond laser via coherent supercontinuum generation. Herein we provide a first demonstration of the successful application of this technique to reflectorless measurements and thus its feasibility for multispectral LiDAR. We use a table-top experimental set-up to assess the approach by measuring distance, spectrally-resolved relative distance and reflectance to 5 different material samples on 5 multiplexed contiguous spectral bands of 50 nm in the range of 600&thinsp;nm to 850&thinsp;nm. We have achieved a distance measurement precision and accuracy better than 100&thinsp;&mu;m using integration times of about 30&thinsp;ms, with promising perspectives regarding scalability to practical distances. The spectrally-resolved distance measurements also show repeatable material-dependent profiles with differences between materials up to several tenths of mm in some spectral bands. Combined with simultaneously acquired reflectance estimations, these profiles enable collecting additional target information, indicating the potential of the approach to enhance the material probing capabilities of prospective multispectral laser scanners.</p>

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Измерение мощности сверхширокополосного хаотического сигнала для решения задач определения расстояния и позиционирования

Письма в журнал технической физики ◽

10.21883/pjtf.2021.10.50970.18524 ◽

2021 ◽

Vol 47 (10) ◽

pp. 30

Author(s):

Е.В. Ефремова ◽

Л.В. Кузьмин

Keyword(s):

Wireless Sensor Networks ◽

Sensor Networks ◽

Relative Error ◽

Experimental Test ◽

Test Bench ◽

Distance Measurement ◽

Ultra Wideband ◽

Wireless Sensor ◽

Distance Measurements ◽

Experimental Test Bench

A method increasing the accuracy of distance measurements using an ultra-wideband chaotic radio pulses, intended for application in wireless sensor networks is proposed. It was shown that the relative error of distance measurement in the experimental test bench is within 5-9%.

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Research on relative error rate analysis method between the earth surface safety monitoring devices of vehicle operation estate

Fifth World Congress on Intelligent Control and Automation (IEEE Cat. No.04EX788) ◽

10.1109/wcica.2004.1343083 ◽

2004 ◽

Author(s):

Guoqiang Cai ◽

Yangdong Ye ◽

Limin Jia

Keyword(s):

Relative Error ◽

Error Rate ◽

Safety Monitoring ◽

Earth Surface ◽

Analysis Method ◽

Rate Analysis ◽

The Earth ◽

Vehicle Operation ◽

Monitoring Devices

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Effect of expanded polystyrene content and press temperature on the properties of low-density wood particleboard

Maderas Ciencia y tecnología ◽

10.4067/s0718-221x2020005000413 ◽

2020 ◽

pp. 0-0

Author(s):

Shupin Luo ◽

Li Gao ◽

Wenjing Guo

Keyword(s):

Expanded Polystyrene ◽

Low Density ◽

Press Temperature

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A Parallel-Phase Demodulation-Based Distance-Measurement Method Using Dual-Frequency Modulation

Applied Sciences ◽

10.3390/app10010293 ◽

2019 ◽

Vol 10 (1) ◽

pp. 293

Author(s):

In-Gyu Jang ◽

Sung-Hyun Lee ◽

Yong-Hwa Park

Keyword(s):

Frequency Modulation ◽

Measurement Method ◽

Continuous Wave ◽

Measurement Range ◽

Distance Measurement ◽

Measurement Technology ◽

Dual Frequency ◽

Distance Measurements ◽

Time Required ◽

Phase Demodulation

Time-of-flight (ToF) measurement technology based on the amplitude-modulated continuous-wave (AMCW) model has emerged as a state-of-the-art distance-measurement method for various engineering applications. However, many of the ToF cameras employing the AMCW process phase demodulation sequentially, which requires time latency for a single distance measurement. This can result in significant distance errors, especially in non-static environments (e.g., robots and vehicles) such as those containing objects moving relatively to the sensors. To reduce the measurement time required for a distance measurement, this paper proposes a novel, parallel-phase demodulation method. The proposed method processes phase demodulation of signal in parallel rather than sequentially. Based on the parallel phase demodulation, 2π ambiguity problem is also solved in this work by adopting dual frequency modulation to increase the maximum range while maintaining the accuracy. The performance of proposed method was verified through distance measurements under various conditions. The improved distance measurement accuracy was demonstrated throughout an extended measurement range (1–10 m).

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Modified TOPSIS Method With Banking Case Study

Multi-Criteria Decision Analysis in Management - Advances in Logistics, Operations, and Management Science ◽

10.4018/978-1-7998-2216-5.ch009 ◽

2020 ◽

pp. 189-224

Author(s):

Semra Erpolat Taşabat ◽

Tuğba Kıral Özkan

Keyword(s):

Banking Sector ◽

Distance Measure ◽

Distance Measurement ◽

Distance Measures ◽

Measurement Unit ◽

Alternative Measure ◽

Topsis Method ◽

Distance Measurements ◽

Modified Topsis

In this chapter, an alternative measure to Euclidean distance measurement is proposed which is used to calculate positive and negative ideal solutions in the traditional TOPSIS method. Lp Minkowski family and L1 family distance measures were used for this purpose. By taking the averages of the distance measurements in the Lq and L1 families, more general and accurate level units were tried to be obtained. Thus, it was shown that TOPSIS method can give different results according to the distance measure used. The importance of the distance measurement unit was emphasized to rank the alternatives correctly. The implementation and evaluation of the proposed method was carried out through the financial performance of the deposit bank operating in the Turkish Banking Sector. It was seen that the rankings of the alternatives changed according to the distance measurements used. By referring to the distance measurements that can be used in the TOPSIS method, it was shown that the rank of the alternatives can vary according to the preferred distance measure.

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