Range compensation for accurate 3D imaging system

Chua, Sing Yee; Wang, Xin; Guo, Ningqun; Tan, Ching Seong

doi:10.1364/ao.55.000153

Cited by 13 publications

(7 citation statements)

References 19 publications

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“…The analyzed results are summarized in Fig. 3 where it clearly shows an inverse range-squared relationship of the reflected intensity [10]. Because of the reduced intensity over distance, SNR decreases, and we expect higher range error as deduced from (14).…”

Section: Distancementioning

confidence: 89%

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Theoretical and experimental investigation into the influence factors for range gated reconstruction

et al. 2016

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Range gated is a laser ranging technique that has been applied in various fields due to its good application prospects. In order to improve the effectiveness of this method, influence factors contributing to the system performance should be well understood. Thus this paper performs theoretical and experimental investigation to comprehend the effects caused by multiple factors on range gated reconstruction. Our study focuses on the distance, target reflection, and acquisition time step parameter where their impacts on the quality of range reconstruction are analyzed. The presented experimental results show the expected trends of range error to support the validity of our theoretical model and discussion which can be used in future improvement works.

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Section: Distancementioning

confidence: 89%

“…These parameters could change the characteristics and cause variations in the reflected laser pulse which directly impact the accuracy of range determination. The importance of laser intensity profile [11,12], distance interference [10], sensor [13,14], and scattering effects [16] were discussed in various literatures.…”

Section: Introductionmentioning

confidence: 99%

Theoretical and experimental investigation into the influence factors for range gated reconstruction

et al. 2016

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“…The reflected laser energy

underlies an inverse range-squared dependency that decreases the intensity captured in the range gated imaging system. The relationship between reflected laser intensity and distance factor was studied in previous work [ 28 ]. As a result, SNR decreases with distance and causes a higher range error as deduced from Equation ( 6 ).…”

Section: Accuracy Analysismentioning

confidence: 99%

“…Recovery of the actual target echo pulse is a well known problem in range gated systems. The influence of the laser profile [ 27 ], distance interference [ 28 ], sensor [ 29 , 30 ], and scattering effects [ 31 ] has been discussed in various literatures.…”

Section: Introductionmentioning

confidence: 99%

Improved Range Estimation Model for Three-Dimensional (3D) Range Gated Reconstruction

Chua

Guo

Tan

et al. 2017

Sensors

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Accuracy is an important measure of system performance and remains a challenge in 3D range gated reconstruction despite the advancement in laser and sensor technology. The weighted average model that is commonly used for range estimation is heavily influenced by the intensity variation due to various factors. Accuracy improvement in term of range estimation is therefore important to fully optimise the system performance. In this paper, a 3D range gated reconstruction model is derived based on the operating principles of range gated imaging and time slicing reconstruction, fundamental of radiant energy, Laser Detection And Ranging (LADAR), and Bidirectional Reflection Distribution Function (BRDF). Accordingly, a new range estimation model is proposed to alleviate the effects induced by distance, target reflection, and range distortion. From the experimental results, the proposed model outperforms the conventional weighted average model to improve the range estimation for better 3D reconstruction. The outcome demonstrated is of interest to various laser ranging applications and can be a reference for future works.

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“…In [20], they propose to use the full laser waveform to extract information beyond the first reflection to get richer information in urban settings. The returned intensity has an inverse range-squared dependency, which they model in [21] to improve the range estimates compared to a weighted average method. Some authors have also investigated how to improve the depth resolution below the gating delay step by using superresolution methods.…”

Section: Introductionmentioning

confidence: 99%

Real-time super-resolved 3D in turbid water using a fast range-gated CMOS camera

Risholm¹,

Thorstensen²,

Thielemann³

et al. 2018

Appl. Opt.

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We present a range-gated camera system designed for real-time (10 Hz) 3D estimation underwater. The system uses a fast-shutter CMOS sensor (1280×1024) customized to facilitate gating with 1.67 ns (18.8 cm in water) delay steps relative to the triggering of a solid-state actively Q-switched 532 nm laser. A depth estimation algorithm has been carefully designed to handle the effects of light scattering in water, i.e., forward and backward scattering. The raw range-gated signal is carefully filtered to reduce noise while preserving the signal even in the presence of unwanted backscatter. The resulting signal is proportional to the number of photons that are reflected during a small time unit (range), and objects will show up as peaks in the filtered signal. We present a peak-finding algorithm that is robust to unwanted forward scatter peaks and at the same time can pick out distant peaks that are barely higher than peaks caused by sensor and intensity noise. Super-resolution is achieved by fitting a parabola around the peak, which we show can provide depth precision below 1 cm at high signal levels. We show depth estimation results when scanning a range of 8 m (typically 1-9 m) at 10 Hz. The results are dependent on the water quality. We are capable of estimating depth at distances of over 4.5 attenuation lengths when imaging high albedo targets at low attenuation lengths, and we achieve a depth resolution (σ) ranging from 0.8 to 9 cm, depending on signal level.

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Range compensation for accurate 3D imaging system

Cited by 13 publications

References 19 publications

Theoretical and experimental investigation into the influence factors for range gated reconstruction

Theoretical and experimental investigation into the influence factors for range gated reconstruction

Improved Range Estimation Model for Three-Dimensional (3D) Range Gated Reconstruction

Real-time super-resolved 3D in turbid water using a fast range-gated CMOS camera

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