scholarly journals Generating a Cylindrical Panorama from a Forward-Looking Borehole Video for Borehole Condition Analysis

2019 ◽  
Vol 9 (16) ◽  
pp. 3437 ◽  
Author(s):  
Zhaopeng Deng ◽  
Maoyong Cao ◽  
Yushui Geng ◽  
Laxmisha Rai
Keyword(s):  
Computational Cost ◽  
Image Sequence ◽  
Qualitative Description ◽  
Borehole Wall ◽  
Absolute Difference ◽  
Geological Condition ◽  
Borehole Data ◽  
Camera System ◽  
Labeling Algorithms ◽  
Forward Looking

Geological exploration plays a fundamental and crucial role in geological engineering. The most frequently used method is to obtain borehole videos using an axial view borehole camera system (AVBCS) in a pre-drilled borehole. This approach to surveying the internal structure of a borehole is based on the video playback and video screenshot analysis. One of the drawbacks of AVBCS is that it provides only a qualitative description of borehole information with a forward-looking borehole video, but quantitative analysis of the borehole data, such as the width and dip angle of fracture, are unavailable. In this paper, we proposed a new approach to create a whole borehole-wall cylindrical panorama from the borehole video acquired by AVBCS, which provides a possibility for further analysis of borehole information. Firstly, based on the Otsu and region labeling algorithms, a borehole center location algorithm is proposed to extract the borehole center of each video image automatically. Afterwards, based on coordinate mapping (CM), a virtual coordinate graph (VCG) is designed in the unwrapping process of the front view borehole-wall image sequence, generating the corresponding unfolded image sequence and reducing the computational cost. Subsequently, based on the sum of absolute difference (SAD), a projection transformation SAD (PTSAD), which considers the gray level similarity of candidate images, is proposed to achieve the matching of the unfolded image sequence. Finally, an image filtering module is introduced to filter the invalid frames and the remaining frames are stitched into a complete cylindrical panorama. Experiments on two real-world borehole videos demonstrate that the proposed method can generate panoramic borehole-wall unfolded images from videos with satisfying visual effect for follow up geological condition analysis. From the resulting image, borehole information, including the rock mechanical properties, distribution and width of fracture, fault distribution and seam thickness, can be further obtained and analyzed.

scholarly journals Design of Robust Infrared Image Sequence (IR-Video) Target Tracking Model

2020 ◽  
Vol 8 (5) ◽  
pp. 5372-5375
Keyword(s):  
Infrared Image ◽  
Infrared Camera ◽  
Image Sequence ◽  
Absolute Difference ◽  
Mapping Technique ◽  
Video Technology ◽  
Mean Absolute Difference ◽  
Tracking Model ◽  
Infrared Cameras ◽  
Do So

As regards protection, monitoring a certain objective has become a primary goal and thus has helped to incorporate the video technology into the industry. However, owing to its zigzag trajectory or shifts of position, it is often difficult to trace the imprevisible existence of the goal. This article therefore proposed the use of infrared cameras as sensors to monitor the object. The infrared camera is effective when the object changes its direction, like its contemporaries. Therefore, a pattern mapping technique was used for infrarouge goal monitoring. Ultimately, there was a distinction among the traditional Mean Absolute Difference (MAD) algorithm and the evolved V-SQ -track model used here. The findings show that the method of V-SQ -track model performs stronger than the MAD algorithm. Even if the modern algorithm is unable to do so, the artifacts can be monitored

scholarly journals The Exoscope versus operating microscope in microvascular surgery: A simulation non-inferiority trial

2020 ◽  
Vol 47 (3) ◽  
pp. 242-249
Author(s):  
Georgios Pafitanis ◽  
Michalis Hadjiandreou ◽  
Alexander Alamri ◽  
Christopher Uff ◽  
Daniel Walsh ◽  
...  
Keyword(s):  
Learning Curve ◽  
Statistical Significance ◽  
Digital Camera ◽  
Suture Line ◽  
Absolute Difference ◽  
Operating Microscope ◽  
Microvascular Anastomosis ◽  
High Definition ◽  
Camera System ◽  
Significant Difference

Background The Exoscope is a novel high-definition digital camera system. There is limited evidence signifying the use of exoscopic devices in microsurgery. This trial objectively assesses the effects of the use of the Exoscope as an alternative to the standard operating microscope (OM) on the performance of experts in a simulated microvascular anastomosis.Methods Modus V Exoscope and OM were used by expert microsurgeons to perform standardized tasks. Hand-motion analyzer measured the total pathlength (TP), total movements (TM), total time (TT), and quality of end-product anastomosis. A clinical margin of TT was performed to prove non-inferiority. An expert performed consecutive microvascular anastomoses to provide the exoscopic learning curve until reached plateau in TT.Results Ten micro sutures and 10 anastomoses were performed. Analysis demonstrated statistically significant differences in performing micro sutures for TP, TM, and TT. There was statistical significance in TM and TT, however, marginal non-significant difference in TP regarding microvascular anastomoses performance. The intimal suture line analysis demonstrated no statistically significant differences. Non-inferiority results based on clinical inferiority margin (Δ) of TT=10 minutes demonstrated an absolute difference of 0.07 minutes between OM and Exoscope cohorts. A 51%, 58%, and 46% improvement or reduction was achieved in TT, TM, TP, respectively, during the exoscopic microvascular anastomosis learning curve.Conclusions This study demonstrated that experts’ Exoscope anastomoses appear non-inferior to the OM anastomoses. Exoscopic microvascular anastomosis was more time consuming but end-product (patency) in not clinically inferior. Experts’ “warm-up” learning curve is steep but swift and may prove to reach clinical equality.

scholarly journals Liquefaction in Palu: The Cause of Massive Mudflows

2021 ◽  
Author(s):  
Abdul Jalil ◽  
Teuku Faisal Fathani ◽  
Iman Satyarno ◽  
Wahyu Wilopo
Keyword(s):  
Shear Strain ◽  
Large Scale ◽  
Flash Flood ◽  
Ground Surface ◽  
Ground Vibration ◽  
Empirical Method ◽  
High Water Content ◽  
Geological Condition ◽  
Borehole Data ◽  
Tectonic Earthquake

Abstract The 7.5 Mw tectonic earthquake that hit Palu City on 28 September 2018 was followed by tsunami and liquefaction that triggered massive mudflows in Balaroa, Petobo, and Jono Oge areas. Extensive damages to infrastructures occurred as the result of these earthquake-triggered disasters. This study explores the causing factors of the massive mudflow in Balaroa, Petobo, and Jono Oge areas as it is a quite rare phenomenon. This study focuses on the causing factors of liquefaction such as the condition of soil lithology, depth of water table, distance to the fo[1]cal mechanism, and the thickness of soft sediment. To carry out the liquefaction analysis, important data, such as microtremor data which included the Horizontal Vertical Spectral Ratio (HVSR), geological condition, and borehole data, were examines. Additional data i.e. ground layers slopes and other factors were also investigated. Normally, these data are not considered when observing common liquefaction. However, for the case of massive mudflows in Balaroa, Petobo, and Jono Oge, they become the key factors. Based on the microtremor data, the analysis results show that the distribution of ground shear strain values in Palu City ranges from 0.75×10-4 to 2.56×10-4. The distribution of the locations of the liquefaction corresponds to the distribution of ground shear strain values. High ground shear strain values were discovered in Palu City valley. Such high value and groundwater level indicate that liquefaction in Palu City will certainly take place. The semi-empirical method confirms that Balaroa, Petobo, and Jono Oge have high potential for large-scale liquefaction to occur at a maximum depth of 16 meters below the ground surface. Having loose soil grain with high water content, the soil will turn into a massive amount of mud during the liquefaction. In addition, ground slopes and ground vibration due to the earthquake will create massive mudflows similar to flash flood. However, the mudflows movement is slow since the slope inclination is slight.

scholarly journals The Accuracy and Reliability of a New Optical Player Tracking System for Measuring Displacement of Soccer Players

2017 ◽  
Vol 16 (3) ◽  
pp. 175-184 ◽  
Author(s):  
J. Mara ◽  
S. Morgan ◽  
K. Pumpa ◽  
K. Thompson
Keyword(s):  
Coefficient Of Variation ◽  
Tracking System ◽  
Intraclass Correlation ◽  
Positional Information ◽  
Absolute Difference ◽  
Camera System ◽  
Actual Distance ◽  
Non Invasive ◽  
Typical Error ◽  
Player Tracking

AbstractRecently, a novel optical player tracking system has been developed to determine positional information of athletes in a non-invasive manner. The aim of this study was to measure the accuracy and reliability of displacement estimates derived from the system. Participants completed five soccer-specific running courses at three different speeds three times each, while being filmed using the multi-camera system. The participant’sx,yfield positions were determined by the optical player tracking system and displacement was estimated using Euclidean distance, and compared with real distance. On average, the difference between actual distance and estimated displacement was 0.25% (mean absolute difference = 0.79 ± 0.56m) with a slightly larger coefficient of variation during 90° turns (4.89%) when compared with straight line running (4.09%). In addition, there were strong correlations between actual distance and measured displacement (r= 0.986 – 0.988). Collectively, the typical error (0.25 – 0.36 m), typical error as a coefficient of variation (1.06 – 1.75%) and intraclass correlation coefficient (0.88 – 0.93) showed high levels of intra-operator reliability. The optical player tracking system provides accurate and reliable estimates of displacement of players on a soccer field. This system provides non-invasive position detections for players and opposition players during soccer matches.

scholarly journals A Stand-Alone Smart Camera System for Online Post-Earthquake Building Safety Assessment

Sensors ◽  
2020 ◽  
Vol 20 (12) ◽  
pp. 3374
Author(s):  
Ting-Yu Hsu ◽  
Xiang-Ju Kuo
Keyword(s):  
Computer Vision ◽  
Safety Assessment ◽  
Large Scale ◽  
Computational Cost ◽  
Video Data ◽  
Shaking Table ◽  
Smart Camera ◽  
Camera System ◽  
Steel Building ◽  
Building Safety

Computer vision-based approaches are very useful for dynamic displacement measurement, damage detection, and structural health monitoring. However, for the application using a large number of existing cameras in buildings, the computational cost of videos from dozens of cameras using a centralized computer becomes a huge burden. Moreover, when a manual process is required for processing the videos, prompt safety assessment of tens of thousands of buildings after a catastrophic earthquake striking a megacity becomes very challenging. Therefore, a decentralized and fully automatic computer vision-based approach for prompt building safety assessment and decision-making is desired for practical applications. In this study, a prototype of a novel stand-alone smart camera system for measuring interstory drifts was developed. The proposed system is composed of a single camera, a single-board computer, and two accelerometers with a microcontroller unit. The system is capable of compensating for rotational effects of the camera during earthquake excitations. Furthermore, by fusing the camera-based interstory drifts with the accelerometer-based ones, the interstory drifts can be measured accurately even when residual interstory drifts exist. Algorithms used to compensate for the camera’s rotational effects, algorithms used to track the movement of three targets within three regions of interest, artificial neural networks used to convert the interstory drifts to engineering units, and some necessary signal processing algorithms, including interpolation, cross-correlation, and filtering algorithms, were embedded in the smart camera system. As a result, online processing of the video data and acceleration data using decentralized computational resources is achieved in each individual smart camera system to obtain interstory drifts. Using the maximum interstory drifts measured during an earthquake, the safety of a building can be assessed right after the earthquake excitation. We validated the feasibility of the prototype of the proposed smart camera system through the use of large-scale shaking table tests of a steel building. The results show that the proposed smart camera system had very promising results in terms of assessing the safety of steel building specimens after earthquake excitations.

scholarly journals Experimental Study on Comprehensive Real-Time Methods to Determine Geological Condition of Rock Mass along the Boreholes while Drilling in Underground Coal Mines

2019 ◽  
Vol 2019 ◽  
pp. 1-17 ◽  
Author(s):  
Ganggang Niu ◽  
Kai Zhang ◽  
Bosong Yu ◽  
Yanlong Chen ◽  
Yu Wu ◽  
...  
Keyword(s):  
Rock Mass ◽  
Real Time ◽  
Coal Mines ◽  
Vibration Measurement ◽  
Geological Condition ◽  
Camera System ◽  
Underground Coal Mines ◽  
Measurement While Drilling ◽  
Borehole Camera ◽  
Rock Mass Condition

The geological condition is essential for mining design and disaster control in underground coal mines. The present research focuses on the real-time assessment method on rock mass condition during drilling boreholes. In situ comprehensive experiments were carried out using three methods, which are measurement while drilling (MWD) system, vibration measurement while drilling (VMWD) system, and borehole camera detecting system. In the MWD system, the operating parameters of the drilling machine were recorded, and a dimensionless index Id based on the collected parameters was adopted to assess the geological condition along the borehole. The results show that the state of rock mass can be well classified using the MWD system for both the cross-layer and in-seam boreholes. In the VMWD system, the vibration of the drilling bit was monitored, and the signal was analyzed in both time domain and frequency domain. The results indicate that the rock mass condition can be quantitatively evaluated using the mean square value of the signal and qualitatively estimated using the energy of the spectrum. In the borehole camera system, the photos of the rock mass along the borehole could be well captured, and the identified rock mass condition was used to verify the results of the MWD and VMWD systems. Comprehensive compassion between the results from the three systems shows that all the methods can give valuable information for the geological condition, and the outcomes of the different methods are generally comparable. For practical purposes, the advantages of the involved three detecting systems are discussed.

REAL-TIME OBJECT DETECTION USING TWO BACKGROUND MODELS UNDER SHAKING CAMERA

2009 ◽  
Vol 06 (01) ◽  
pp. 13-21 ◽  
Author(s):  
TAEHO KIM ◽  
KANG-HYUN JO
Keyword(s):  
Moving Objects ◽  
Displacement Vector ◽  
Motion Vector ◽  
Computational Cost ◽  
Image Sequence ◽  
Background Model ◽  
Experimental Result ◽  
Camera Motion ◽  
Short Period ◽  
Background Models

In this paper, we propose a novel approach to detect moving objects by two background models, multiple background model (MBM) and temporal median background (TMB), from hand-taken image sequence. For this purpose, we record image sequences by hand-held camera without tripod so every frame has variation between consecutive frames. A pixel-based background model is fragile while image sequence has variation. Therefore we calculate the camera movement using correlation between two consecutive images and it helps us to generate MBM under shaking camera. The computational cost of correlation quickly increases if image resolution increases. Hence, we use edge segments to reduce computational cost. These edge segments are gathered by Sobel operator and those are distinctive spatial features to calculate similarity between two regions, belonging to current and previous images, organized by neighbors of edge segments. Based on the similarity result, we obtain a set of best matched regions, centroids of matched regions, and displacement vectors from each pair of previous and current images. Each displacement vector in a set describes the transition of each matched region in the image pair. Using the highest density of displacement vector histogram, we choose the camera motion vector, indicates camera movement between consecutive frames. According to the camera motion vector, every pixel in a current image is related to different position pixels in a previous image. The pixel relation is used to generate MBM in this paper, unlike original MBM [Xiao, M., Han, C. and Kang, K. [2006]. Proc. Int. Conf. Information Fuscon, pp. 1–7.]. The MBM algorithm classifies the variation of pixel values in frame sequence to several clusters. Classification of varying pixel values to several clusters is similar with mixture of gaussian (MOG). Nevertheless, MBM has low cost to calculate because it does not need to estimate parameter. However, MBM is not sensitive to short period changes. Therefore, we use TMB to support MBM. The experimental result shows that proposed algorithm successfully detects moving objects using background subtraction less than 25 ms per frame when camera has 2D translation.

An Efficient Implementation of a Census-Based Stereo Matching and Its Applications in Medical Imaging

2019 ◽  
Vol 9 (6) ◽  
pp. 1152-1159 ◽  
Author(s):  
Xiaobo Lai ◽  
Xiaomei Xu ◽  
Jinyan Zhang ◽  
Ying Fang ◽  
Zihe Huang
Keyword(s):  
Medical Imaging ◽  
Cross Correlation ◽  
Stereo Matching ◽  
Computational Cost ◽  
Implementation Process ◽  
Efficient Implementation ◽  
Absolute Difference ◽  
Image Pairs ◽  
Specific Implementation ◽  
Stereo Algorithm

Compared to most conventional efficient stereo matching algorithms that based on NCC (Normalized Cross-Correlation) or SAD (Sum of Absolute Difference), stereo matching based on census transform is robust to radiometric distortion. Thus, in the paper we propose a census-based efficient implementation stereo algorithm for medical imaging. Firstly, census-based stereo matching is investigated, and its specific implementation process is analyzed in detail. Secondly, in order to simplify the calculation process and improve the efficiency, the moving window and memory organization optimized techniques are used. The program runs on standard PC hardware utilizing various SSE2 instructions. Finally, stereo matching of four standard image pairs on the Middlebury image datasets and a paired cervical images obtained from clinical colposcope are implemented in an efficient way. The experimental results on simulated and real medical images prove the effectiveness of the method for the computational cost.

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