A double threshold correction method for walk error in pulsed laser ranging system

Jinqing, Yang; Gu, Guohua; Qian, Wei; Ren, Kan; Zhang, Jun; Guo, Ping; Gao, Qingsong; Chen, Qian

doi:10.1016/j.infrared.2019.03.023

Cited by 9 publications

(7 citation statements)

References 9 publications

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“…When the uniformly distributed background noise signal is used for endpoint detection using the dual-threshold comparison method in the short period of the beginning of the voice signal, it is required to calculate the zero-crossing rate threshold ZcT, the high-energy threshold ETU, and the low-energy threshold ETL on the initial “silence” segment. Then use them as thresholds to achieve accurate endpoint detection (Yang et al. , 2019).…”

Section: Related Workmentioning

confidence: 99%

“…The realization process of the average zerocrossing rate LHT 41,5 required to calculate the zero-crossing rate threshold Z c T, the high-energy threshold ETU, and the low-energy threshold ETL on the initial "silence" segment. Then use them as thresholds to achieve accurate endpoint detection (Yang et al, 2019). The zero-crossing rate threshold is shown in the following equation:…”

Section: Impact Of Student Learning Aidsmentioning

confidence: 99%

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The impact of student learning aids on deep learning and mobile platform on learning behavior

Fan

Liu

2022

LHT

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PurposeDeep learning (DL) technology is used to design a voice evaluation system to understand the impact of learning aids on DL and mobile platforms on students’ learning behavior.Design/methodology/approachDL technology is used to design a speech evaluation system.FindingsThe experimental results show that the speech evaluation system designed has a high accuracy rate, the highest agreement rate with manual evaluation of pronunciation is 89.5%, and the correct speech recognition rate is 96.64%. The designed voice evaluation system and the manual voice rating system have a maximum error rate of 2%. The experimental results suggest that it is necessary to further optimize the learning aids for mobile platform. The learning aids of the mobile platform need to be further optimized to promote the improvement of student learning efficiency.Originality/valueThe results show that the speech evaluation system designed has good practical application value, and it provides a certain reference value for the future study of learning tools on DL.

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Section: Related Workmentioning

confidence: 99%

Section: Impact Of Student Learning Aidsmentioning

confidence: 99%

The impact of student learning aids on deep learning and mobile platform on learning behavior

Fan

Liu

2022

LHT

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“…Common methods for measurement correction for systems with PIN photodiode or APD receivers are based on the signal's time over threshold (TOT) or rise time. The TOT-based compensation function relies on detected pulse width [25], and the later one is based on signal's rise time, measured by the time it takes for the received signal to rise from first threshold to the next [26]. The ranging device used in this article used TOT-based walk error compensation.…”

Section: Walk Errormentioning

confidence: 99%

Towards a Multi-Perspective Time of Flight Laser Ranging Device Based on Mirrors and Prisms

Pogačnik

Munih

2022

Applied Sciences

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This paper investigates the feasibility of redirecting the field of view (FOV) of a light-based time-of-flight (ToF) ranging device, commonly known as a pulsed lidar, using fixed mirrors and prisms for possible future use in robotics. The emphasis is on configurations where the FOV redirection element is positioned beyond the ranging device’s dead zone. A custom made direct ToF ranging device with time-over-threshold (TOT)-based walk error compensation was used to evaluate the effects of the FOV redirecting optics on range measurement accuracy and precision. The tests include redirecting the FOV with a clean prism with anti-reflective (AR) coating on its legs, as well as with a regular and a first surface mirror in both a clean and dusted state. The study finds the prism to be unsuitable due to parasitic reflections, which ruin the ranging data. The clean mirrors were found to have no noticeable effect on ranging accuracy. When they are dusty, mirrors introduce a negative measurement error. This effect is the most pronounced when a mirror is positioned toward the end of the partial dead zone of the ToF rangefinder, but loses influence as the mirror is moved farther away. The error is attributed to the parasitic reflection off dust on the mirror, which reduces the time of detection of the pulse reflected off the real target, and interferes with the walk error compensation by widening the detected pulse.

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“…The dominant noise in a pulsed TOF laser radar is typically from the receiver electronics [14]. We consider that the influence of the receiver electronics noise in the output waveform is mainly presented as time jitter, and we can reduce the random jitter error by repeating the measurement several times [15]. The statistical plot obtained by 9000 repetitions at a distance of about 5 m is shown in Figure 3.…”

Section: System Performance Analysismentioning

confidence: 99%

A Delay Modulation Method to Improve the Time Resolution for a 32 × 32 Array of MPPC Image Sensor

Huang

2022

IEEE Access

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The array laser detector can achieve three-dimensional (3D) flash imaging via multi-channel parallel ranging, which significantly improves the imaging speed. However, the large number of the array makes it difficult to improve the ranging resolution through circuit evolution and data processing, even the imaging speed will be sacrificed. To overcome the problem, a delay modulation method on the transmitter of the laser is proposed in this study. The method is realized by using a 32×32 Multi-Pixel Photon Counter (MPPC) array and an improved phase-shifted clocks method. We eventually achieve 1024-channel 3D imaging that exceeds the depth resolution of the system. Experimental results show that, the Root Mean Square Error (RMSE) of plane fitting with delay modulation is 2.39-5.03 cm, which has come down to 48.6% than those without delay modulation. Using the delay modulation method, a target with a depth difference of about 4 cm can be clearly distinguished by 3D imaging at a distance of 5 m, even if the minimum resolution of the system is 5 cm. Results also demonstrate that the proposed method can easily and effectively enhance the measurement accuracy of 3D flash imaging.

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A double threshold correction method for walk error in pulsed laser ranging system

Cited by 9 publications

References 9 publications

The impact of student learning aids on deep learning and mobile platform on learning behavior

The impact of student learning aids on deep learning and mobile platform on learning behavior

Towards a Multi-Perspective Time of Flight Laser Ranging Device Based on Mirrors and Prisms

A Delay Modulation Method to Improve the Time Resolution for a 32 × 32 Array of MPPC Image Sensor

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