Note: Intensity control of a phase-shift based laser scanner for reducing distance errors caused by varying surface reflectivity

Jang, Junhwan; Hwang, Sungui; Park, Kyihwan

doi:10.1063/1.3665922

Cited by 4 publications

(1 citation statement)

References 11 publications

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“…In general, existing commercial TLS uses two different principles of distance measurement. The first type of laser scanning technology is phase-shift (PS) and the second type is time-of-flight (TOF) [29,30]. The main differences between PS scanners and TOF scanners are the speed of data acquisition, maximum measurement range, and accuracy of distance measurement.…”

Section: Introductionmentioning

confidence: 99%

Down-Sampling of Point Clouds for the Technical Diagnostics of Buildings and Structures

Suchocki

Błaszczak-Bąk

2019

Geosciences

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Terrestrial laser scanning (TLS) is a non-destructive testing method for the technical assessment of existing structures. TLS has been successfully harnessed for monitoring technical surface conditions and morphological characteristics of historical buildings (e.g., the detection of cracks and cavities). TLS measurements with very high resolution should be taken to detect minor defects on the walls of buildings. High-resolution measurements are mostly needed in certain areas of interest, e.g., cracks and cavities. Therefore, reducing redundant information on flat areas without cracks and cavities is very important. In this case, automatic down-sampling of datasets according to the aforementioned criterion is required. This paper presents the use of the Optimum Dataset (OptD) method to optimize TLS dataset. A Leica ScanStation C10 time-of-flight scanner and a Z+F IMAGER 5016 phase-shift scanner were used during the research. The research was conducted on a specially prepared concrete sample and real object, i.e., a brick citadel located on the Kościuszko Mound in Cracow. The reduction of dataset by the OptD method and random method from TLS measurements were compared and discussed. The results prove that the large datasets from TLS diagnostic measurements of buildings and structures can be successfully optimized using the OptD method.

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Section: Introductionmentioning

confidence: 99%

Down-Sampling of Point Clouds for the Technical Diagnostics of Buildings and Structures

Suchocki

Błaszczak-Bąk

2019

Geosciences

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Note: Continuous-wave time-of-flight laser scanner using two laser diodes to avoid 2π ambiguity

Hwang

Jang

Park

2013

Review of Scientific Instruments

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In the continuous-wave time-of-flight method, the distance traveled by light can be obtained by using the phase difference between the reference signal and the measured signal. However, when the phase difference exceeds 2π, the distance cannot be differentiated because the distance variation repeats every 2π period. In this paper, we propose a method in which low- and high-frequency signals are separately applied to two laser diodes simultaneously, and processed using two different signal processing circuits to solve the 2π ambiguity problem and achieve a high distance resolution for a longer distance measurement.

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Note: Optical and electronic design of an amplitude-modulated continuous-wave laser scanner for high-accuracy distance measurement

Jang

Hwang

Park

2015

Review of Scientific Instruments

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To utilize a time-of-flight-based laser scanner as a distance measurement sensor, the measurable distance and accuracy are the most important performance parameters to consider. For these purposes, the optical system and electronic signal processing of the laser scanner should be optimally designed in order to reduce a distance error caused by the optical crosstalk and wide dynamic range input. Optical system design for removing optical crosstalk problem is proposed in this work. Intensity control is also considered to solve the problem of a phase-shift variation in the signal processing circuit caused by object reflectivity. The experimental results for optical system and signal processing design are performed using 3D measurements.

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Note: Intensity control of a phase-shift based laser scanner for reducing distance errors caused by varying surface reflectivity

Cited by 4 publications

References 11 publications

Down-Sampling of Point Clouds for the Technical Diagnostics of Buildings and Structures

Down-Sampling of Point Clouds for the Technical Diagnostics of Buildings and Structures

Note: Continuous-wave time-of-flight laser scanner using two laser diodes to avoid 2π ambiguity

Note: Optical and electronic design of an amplitude-modulated continuous-wave laser scanner for high-accuracy distance measurement

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