Video Inspection Research Articles

Sewer pipe defects diagnosis assessment using multivariate analysis on CCTV video imagery

Closed circuit television (CCTV) technology has been commonly used to inspect underground pipe defects, and high CCTV image quality is a prerequisite for accurate defect diagnosis. An acceptance criterion for CCTV inspection videos is critical for ensuring accurate diagnosis and preventing disputes between employers and contractors. This paper used multivariate statistical methods to evaluate the overall quality of CCTV images and to define an acceptance criterion for CCTV videos. Numerous CCTV images from a sewer inspection project were assessed and their quality, consisting of similarity in luminance and contrast distortions, was calculated by comparing a set of ideal images. Principal component analysis (PCA) and redundancy analysis (RDA) grouped the CCTV videos into homogeneous segments with similar image quality and provided a visual acceptance criterion for CCTV inspection videos. Furthermore, RDA triplot indicated that the contrast improvement of CCTV images can effectively enhance image quality and increase the diagnosis efficiency.

Unlocking the Benefits of Long-Term Pipeline-Embedment Processes: Image Analysis–Based Processing of Historic Survey Data

AbstractAn image analysis–based method for retrieving high-resolution bathymetry data from historic pipeline inspection video is detailed. The resulting time-dependant bathymetric datasets are used to inform an improved understanding of pipe-soil and pipe-soil-fluid interaction. This allows better management of existing pipelines and improved design of new pipelines. The pipeline and seabed positions are extracted automatically from the survey video, spurious points removed, the data scaled, and interpolation applied. The data can then be projected in various forms, for different applications. Drawing on field data from Australia’s North West Shelf, applications of the method are described. For pipeline design, it is shown how improvements in on-bottom stability and changes in seabed friction can be quantified for mobile seabeds and through buckling sections of pipeline. This approach unlocks advances in existing design practice by providing quantification of the effects of seabed mobility. The processes ...

Low Fecundity of Red-Headed Woodpeckers (Melanerpes erythrocephalus) at the Northern Edge of the Range

ABSTRACT The Red-headed Woodpecker (Melanerpes erythrocephalus) is a threatened bird species undergoing continued population declines across most of its range. Despite the conservation concern, there are few published studies on the species’ fecundity. We examined the nesting phenology, clutch size, and fledging success of Red-headed Woodpecker nests in southern Ontario and northern New York, where population declines are especially pronounced. We calculated the fecundity of the Red-headed Woodpecker populations from fledgling numbers and nest survival estimates. We found that nest phenology and clutch sizes were similar to those reported in other studies for the species. Red-headed Woodpecker nests monitored using video inspection had an unusually low fledging success (39%), and an average fecundity of 0.43 female fledglings per female per year. The fledgling success and fecundity for the monitored Red-headed Woodpecker population was lower than that reported by other published studies on Melanerpes spp....

Application of alternative methods for determination of rock quality designation (RQD) index: a case study from the Rožná I uranium mine, Strážek Moldanubicum, Bohemian Massif, Czech Republic

A comparison of rock quality designation (RQD) parameters obtained by drill core analysis and the RQD determined using alternative methods is presented using metamorphic rocks such as migmatized gneisses, migmatites, and amphibolites. Methods of borehole–wall imaging using high-resolution acoustic logging, optical televiewer, and simple video inspection as well as the structural analysis of exploration drift walls oriented subparallel to the analysed boreholes are used for alternatively evaluated RQD values. Results show that, in most cases, the RQD index measured directly on a drill core section reaches lower values (about 10%–30%) than the RQD evaluated by alternative methods. Significant differences in determination of the rock mass failure degree using classical and alternative methods may occur, especially in sections with higher frequency of the metamorphic foliation planes created by biotite-rich bands or by dark-coloured melanosome layers. The nature of biotite itself is favourable for the creation of pre-disposed jointing planes, in which the increased drill core disintegration caused by drilling technology or core handling can occur. Results show it is highly appropriate to make these comparisons on a larger scale and thus verify whether the observed differences affect the qualitative classification of the rock mass.

Inversion of a Capsule Impacting Water: Flip by Resurge Jet

A scale-model blunt-cone capsule intended for ocean splashdown was projected into a water pool to evaluate impact loads and postimpact behavior. In a small region of the speed/angle parameter space, the capsule would reproducibly capsize, flipping forward (pitch-down), despite a pitch-up motion induced at impact. Inspection of high-speed video shows that the resurging central jet of the impact cavity is responsible. Capsize occurs when this jet is energetic enough (for which we develop a simple criterion), and is timed to lift the trailing edge of the vehicle. The same phenomenon was observed on the Apollo capsules, and may be relevant for lifeboat deployment from ships and offshore platforms.

Tomographic Inspection of Fiber Coils Using Optical Coherence Tomography

We report the first study of using optical coherence tomography (OCT) to inspect the winding quality of fiber optical gyro coils. We use a swept-source OCT system to scan a quadrupole-wind fiber coil for obtaining its two-dimensional and three-dimensional (3D) tomographic images. The defects beneath the surface of the fiber coil, which otherwise are invisible by video inspection, can be clearly identified with such tomographic images. The winding quality of each layer can also be independently visualized with the reconstructed 3D images from different angles or in different sections. We believe that the proposed method will be useful to ensuring the quality production of each and every fiber gyro coil.

Validation of Bicycle Counts from Pneumatic Tube Counters in Mixed Traffic Flows

FHWA and other public agencies encourage monitoring of nonmotorized traffic volumes and are collaborating with researchers in projects to test monitoring technologies and develop nonmotorized monitoring programs. This paper reports findings from research in Minnesota to validate the use of commercially available pneumatic tube counters to count bicycles in mixed traffic flows on urban roadways. Pneumatic tube counters and video cameras were installed in different configurations at two locations on arterial roadways with different traffic volumes. Bicycle counts from the tube counters were compared with manual counts from video to determine both percentage error and absolute error rates. Researchers matched time stamps from the counters and video and inspected discrepancies to determine causes of error. Calibration equations to adjust for systematic counter error were estimated by regressing hourly manual counts on hourly automated counts. The tube counters generally under-counted bicycles: error rates for the observation periods ranged from 6% to 57% depending on the location, configuration of deployment, type of device, and classification algorithm. Absolute error rates were substantially higher. Inspection of video indicated most false negatives (i.e., undercounts) were caused by occlusion. Calibration equations generally had moderate to very good fit ( R2 values from .82 to .92). Agencies can adapt standard, commercially available pneumatic tube counters to collect bicycle counts in mixed traffic flows; but depending on the site, traffic volumes, configuration, and deployment, error rates may be high. The practicability of using tube counters to count bicycles in mixed traffic flows depends on the applications and the relative need for accuracy in measurement.

Habitat mapping as a tool for conservation and sustainable use of marine resources: Some perspectives from the MAREANO Programme, Norway

One of the main goals of marine spatial management is to promote a sustainable use of marine resources without putting biodiversity and habitats at risk.Environmental status assessments of benthic habitats have traditionally been conducted on soft bottom infauna communities. These communities represent only a limited part of the total diversity of seabed environments. Large and habitat forming organisms that are particularly vulnerable to physical disturbance of the seabed are in general associated with mixed or hard substrates. Together with mobile benthos these large organisms have been poorly mapped with the traditional approach. In accordance with a demand for information on all aspects of benthic habitats there is an increasing interest in a broader mapping approach for assessments of the distribution and status of benthos.This has led to an increased demand for a broader mapping approach for assessments of the distribution and status of benthos to include as many habitats as possible.We present mapping strategies based on literature together with perspectives from Norway's MAREANO Mapping Programme (www.mareano.no). A first and important step is to acquire high resolution topographical information from multibeam echosounder surveys. Building upon this baseline data set, video inspection along transects can provide information about how megafauna and surface sediments relate to local and broad scale topographical features. Classification of habitats/biotopes can be carried out through the analysis of the megafauna composition and its relation to environmental variables such as depth, quantitative terrain descriptors, and substrates. Marine landscapes have several definitions but generally refer to the major features delimiting broad-scale habitats. Each landscape will include different substrates that can be subdivided into smaller biotopes with specific fauna composition, functionality and production. For these habitats and biotopes information from all sampling gears can then be used to describe a more complete community composition.Experience from recent seafloor mapping indicates that a broad approach is required to support evidence-based policy and management of benthic species, communities and habitats. The approach presented can be used to identify biologically valuable areas and assess health status for bottom habitats/biotopes in a broad set of marine

OHL assessment and risk evaluation based on environmental and inspection data

Abstract REN – Rede Electrica Nacional, S.A., Portuguese Transmission System Operator (TSO), has been using LiDAR technology in their aerial inspections. The acquired three-dimensional data in this Power Line Maintenance System are automatically processed, with support of the video inspections and geo-referenced systems. The national transmission grid was fully characterized at span level with urbanization and vegetation growth rate indices. The collection of historical data, together with the knowledge of asset characteristics and system operation conditions, is structured in a generalized relational database, extended with a comprehensive set of different environmental, meteorological and geographic data over the years. A methodology to evaluate operational risk was developed, taking into account the probabilistic nature of contingencies and their severity under specific operating conditions. Risk indices provide an insight to operators of the network state and of the constraints that operators face. Different optimization tools are also being developed.

The impact of the 2011 Tohoku earthquake tsunami disaster and implications to the reconstruction

The authors conducted a comprehensive study to identify the impact of the 2011 Tohoku tsunami disaster and to understand the lessons towards the reconstruction of Tohoku to build tsunami-resilient community. First, the authors identified the extent of tsunami inundation zone by field measurement and satellite remote sensing. A specific index for optical satellite images was applied for the extraction of tsunami inland penetration calibrated with the ground truth data (field survey data). Second, an integrated investigation of field measurement and aerial photo and video inspections with spatial information sciences was performed to understand the hydrodynamic aspect of tsunami inland penetration with a form of tsunami flow velocity and hydrodynamic force, and the preliminary results lead to new understandings of structural vulnerability against the 2011 tsunami with a form of tsunami fragility curve and an implication for land use management and relocation planning to reconstruct resilient coastal communities.

A general framework for wireless capsule endoscopy study synopsis

We present a general framework for analysis of wireless capsule endoscopy (CE) studies. The current available workstations provide a time-consuming and labor-intense work-flow for clinicians which requires the inspection of the full-length video. The development of a computer-aided diagnosis (CAD) CE workstation will have a great potential to reduce the diagnostic time and improve the accuracy of assessment. We propose a general framework based on hidden Markov models (HMMs) for study synopsis that forms the computational engine of our CAD workstation. Color, edge and texture features are first extracted and analyzed by a Support Vector Machine classifier, and then encoded as the observations for the HMM, uniquely combining the temporal information during the assessment. Experiments were performed on 13 full-length CE studies, instead of selected images previously reported. The results (e.g. 0.933 accuracy with 0.933 recall for detection of polyps) show that our framework achieved promising performance for multiple classification. We also report the patient-level CAD assessment of complete CE studies for multiple abnormalities, and the patient-level validation demonstrates the effectiveness and robustness of our methods.

Reach and Grasp reconfigurations reveal that proprioception assists reaching and hapsis assists grasping in peripheral vision.

The dual visuomotor channel theory proposes that prehension consists of a Reach that transports the hand in relation to an object's extrinsic properties (e.g., location) and a Grasp that shapes the hand to an object's intrinsic properties (e.g., size and shape). In central vision, the Reach and the Grasp are integrated but when an object cannot be seen, the movements can decompose with the Reach first used to locate the object and the Grasp postponed until it is assisted by touch. Reaching for an object in a peripheral visual field is an everyday act, and although it is reported that there are changes in Grasp aperture with target eccentricity, it is not known whether the configuration of the Reach and the Grasp also changes. The present study examined this question by asking participants to reach for food items at 0° or 22.5° and 45° from central gaze. Participants made 15 reaches for a larger round donut ball and a smaller blueberry, and hand movements were analyzed using frame-by-frame video inspection and linear kinematics. Perception of targets was degraded as participants could not identify objects in peripheral vision but did recognize their differential size. The Reach to peripheral targets featured a more dorsal trajectory, a more open hand, and less accurate digit placement. The Grasp featured hand adjustments or target manipulations after contact, which were associated with a prolonged Grasp duration. Thus, Grasps to peripheral vision did not consist only of a simple modification of visually guided reaching but included the addition of somatosensory assistance. The kinematic and behavioral changes argue that proprioception assists the Reach and touch assists the Grasp in peripheral vision, supporting the idea that Reach and Grasp movements are used flexibly in relation to sensory guidance depending upon the salience of target properties.

Integrated Vision-Based System for Automated Defect Detection in Sewer Closed Circuit Television Inspection Videos

AbstractThis paper discusses the development of a general framework and software system to support automated analysis of sewer inspection closed-circuit television (CCTV) videos. The proposed system aims primarily to support the off-site review and quality control process of the videos and to enable efficient reevaluation of archived CCTV videos to extract historical sewer condition data. Automated analysis of sewer CCTV videos poses several challenges including the nonuniformity of camera motion and illumination conditions inside the sewer. The paper presents a novel algorithm for optical flow-based camera motion tracking to automatically identify, locate, and extract a limited set of video segments, called regions of interest (ROI), that likely include defects, thus reducing the time and computational requirements needed for video processing. The proposed algorithm attempts to recover the operator actions during the inspection session, which would enable determining the location and relative severity of...

Mapping Cold-Water Coral Habitats at Different Scales within the Northern Ionian Sea (Central Mediterranean): An Assessment of Coral Coverage and Associated Vulnerability

In this study, we mapped the distribution of Cold-Water Coral (CWC) habitats on the northern Ionian Margin (Mediterranean Sea), with an emphasis on assessing coral coverage at various spatial scales over an area of 2,000 km2 between 120 and 1,400 m of water depth. Our work made use of a set of data obtained from ship-based research surveys. Multi-scale seafloor mapping data, video inspections, and previous results from sediment samples were integrated and analyzed using Geographic Information System (GIS)-based tools. Results obtained from the application of spatial and textural analytical techniques to acoustic meso-scale maps (i.e. a Digital Terrain Model (DTM) of the seafloor at a 40 m grid cell size and associated terrain parameters) and large-scale maps (i.e. Side-Scan Sonar (SSS) mosaics of 1 m in resolution ground-truthed using underwater video observations) were integrated and revealed that, at the meso-scale level, the main morphological pattern (i.e. the aggregation of mound-like features) associated with CWC habitat occurrences was widespread over a total area of 600 km2. Single coral mounds were isolated from the DTM and represented the geomorphic proxies used to model coral distributions within the investigated area. Coral mounds spanned a total area of 68 km2 where different coral facies (characterized using video analyses and mapped on SSS mosaics) represent the dominant macro-habitat. We also mapped and classified anthropogenic threats that were identifiable within the examined videos, and, here, discuss their relationship to the mapped distribution of coral habitats and mounds. The combined results (from multi-scale habitat mapping and observations of the distribution of anthropogenic threats) provide the first quantitative assessment of CWC coverage for a Mediterranean province and document the relevant role of seafloor geomorphology in influencing habitat vulnerability to different types of human pressures.

Growth rates, densities, and distribution of Lophelia pertusa on artificial structures in the Gulf of Mexico

Using industry inspection video and ROV imaging, we examined Lophelia pertusa (Linnaeus 1758) on 10 artificial structures of known ages (9 to 100 years) in the northern Gulf of Mexico (GoM). Five different types deep-water energy installations with depths ranging from 320 to 995m, and three shipwrecks with depths ranging from approximately 530 to 615m, were examined. Density, depth ranges, and growth rates of L. pertusa colonies were calculated from video and image analysis. L. pertusa colonies were present on all structures examined. Minimum calculated growth rates for the largest colonies ranged from 0.32 to 3.23cm/yr on the different structures. The shallowest depth at which L. pertusa was observed was 201m and the deepest was 801m, considerably expanding the known depth range of this species in the northern GoM. Colony density varied with structure type, age, and depth, with the highest density between 503 and 518m on the single structure that spanned the entire depth range of occurrence of L. pertusa observed in this study. L. pertusa colonies growing on thinner and deeper installations appear to have higher colonization rates, i.e. to develop higher densities over a shorter time period, compared to those on shallower and more massive types of installations. However, on average, colonies have slower growth rates on these installations than colonies on more massive, shallower installations (compliant and solid installations). In general, the calculated minimum growth rates were higher on the installations than on the shipwrecks, which were substantially older. A continuum of colony sizes was documented on all installations, suggesting multiple settlement events. L. pertusa thickets were observed on the oldest anthropogenic structures, with most of the components of these structures covered by colonies of L. pertusa. Brown, orange, and mottled color-variants were documented for the first time in the GoM. All installations examined for this study were colonized by L. pertusa and it is likely that most artificial surfaces in appropriate depths in the GoM will be as well.

Automated defect detection in sewer closed circuit television images using histograms of oriented gradients and support vector machine

Abstract Condition assessment of municipal sewer pipes using closed circuit television (CCTV) inspections is known to be time consuming, costly, and prone to errors primarily due to operator fatigue or novicity. Automated detection of defects can provide a valuable tool for ensuring the quality, accuracy, and consistency of condition data, while reducing the time and cost of the inspection process. This paper presents an efficient pattern recognition algorithm to support automated detection and classification of pipe defects in images obtained from conventional CCTV inspection videos. The algorithm employs the histograms of oriented gradients (HOG) and support vector machine (SVM) to identify pipe defects. The algorithm involves two main steps: (1) image segmentation to extract suspicious regions of interest (ROI) that represent candidate defect areas; and (2) classification of the ROI using SVM classifier that was trained using sets of HOG features extracted from positive and negative examples of the defect. Proposed algorithm is applied to the problem of detecting tree root intrusions. The performance of linear and radial basis function SVM classifiers evaluated. The algorithm was tested on a set of actual CCTV videos obtained from the cities of Regina and Calgary in Canada. Experimental results demonstrated the viability and robustness of the algorithm.

Optical flow techniques for estimation of camera motion parameters in sewer closed circuit television inspection videos

Abstract This paper discusses a novel approach for automated analysis and tracking of camera motion in sewer inspection closed circuit television (CCTV) videos. This approach represents an important building block for any system that supports automated analysis and defect detection of CCTV videos. The proposed approach employs optical flow techniques to automatically identify, locate, and extract a limited set of video segments, called regions of interest (ROI), which likely include defects, thus reducing the time and computational requirements needed for video processing. Tracking the camera motion parameters is used to recover the operator actions during the inspection session, which would provide important clues about the location and severity of the ROI. Techniques for estimating the camera travelling distance, position inside the sewer, and direction of motion from optical flow vectors are discussed. The proposed techniques were validated using a representative set of sewer CCTV videos obtained from the cities of Regina and Calgary, Canada.

Invited Commentary

After reading the article by Chen and colleagues [1Chen C.-H. Chang H. Lee S.-Y. et al.Video-guided tube thoracostomy with use of an electrical nonfiberoptic endoscope.Ann Thorac Surg. 2013; 96: 1450-1455Abstract Full Text Full Text PDF PubMed Scopus (6) Google Scholar], I had the typical reaction when introduced to a superbly practical and elegant innovation—a “why didn’t I think of that” moment. Given that many patients require drainage of their pleural spaces, it follows that inspecting the organs requiring such therapies could help many patients. Identifying blebs causing spontaneous pneumothoraces, evaluating associated injuries in trauma, and viewing effusion loculations or pleural metastases are just a few examples for which this technology could be useful. Besides optimizing tube placements and preventing lung injury, it follows that direct simple endoscopic procedures like pleural biopsy could be performed by the use of small instruments passed beside the drainage catheter. Greater imaging accessibility brought about by miniaturization and cost reduction is transforming much of what we do. For instance, the similarly constructed Glidescope device improves endotracheal intubation safety. Laparoscopic ports are advanced more carefully through the abdominal wall with camera-tipped trocars. Capsule endoscopy (http://www.givenimaging.com) embodies not only miniaturization and affordability but also the capture of images by wireless transmission. We can expect that this trend will continue for other imaging techniques. Pocket ultrasound probes are now available as smartphone attachments (http://www.mobisante.com/product-overview/) at a fraction of the cost of large systems. Why teach auscultation skills to trainees when they can carry an echocardiography probe in their stethoscope pocket instead? The cost has become so reasonable that disposable transesophageal echocardiography probes for perioperative cardiac monitoring are now available (http://imacorinc.com/). Thus, it is logical to expect that others will build on the work of these authors by using chest tubes as portals for enhanced imaging or monitoring of thoracic organs. Tempering my enthusiasm for the authors' invention is the current trend to reduce the size of pleural drainage tubes. Smaller, more comfortable catheters work well for many problems, but they may be too small for imaging devices. The avoidance of unnecessary healthcare expenses is important; however, the device described in this paper could be reprocessed to save money or even offset costs like radiographic imaging rendered redundant by video inspection. Such concerns aside, improving anatomic exposure is a core desire for all surgeons. I hope that innovations like these continue. If they are practical, we should adopt them readily as a specialty to increase their accessibility, to harness their safety potentials, and to use them to study our patients' diseases. Video-Guided Tube Thoracostomy With Use of an Electrical Nonfiberoptic EndoscopeThe Annals of Thoracic SurgeryVol. 96Issue 4PreviewTube thoracostomy is a common and generally safe procedure. However, potential hazards can occur during placement of the chest tube. Inasmuch as unexpected injuries may arise from tube thoracostomy, we propose a novel video-guided method. Full-Text PDF

Web browsing behavior analysis and interactive hypervideo

Processing data on any sort of user interaction is well known to be cumbersome and mostly time consuming. In order to assist researchers in easily inspecting fine-grained browsing data, current tools usually display user interactions as mouse cursor tracks, a video-like visualization scheme. However, to date, traditional online video inspection has not explored the full capabilities of hypermedia and interactive techniques. In response to this need, we have developed SMT2ϵ, a Web-based tracking system for analyzing browsing behavior using feature-rich hypervideo visualizations. We compare our system to related work in academia and the industry, showing that ours features unprecedented visualization capabilities. We also show that SMT2ϵ efficiently captures browsing data and is perceived by users to be both helpful and usable. A series of prediction experiments illustrate that raw cursor data are accessible and can be easily handled, providing evidence that the data can be used to construct and verify research hypotheses. Considering its limitations, it is our hope that SMT2ϵ will assist researchers, usability practitioners, and other professionals interested in understanding how users browse the Web.

A Need for Processes that Future Proof the Fiber Optic Installation

The tenets of IEC 61300-3-35 have influenced and contributed to numerous standards. These include: a.) the importance of cleaning the fiber optic connection, b.) the concept of diameter of debris or contamination, and, c.) the area of the end face to be cleaned, d.) methods of cleaning. As capacity and bandwidth expand, deployments updated, and new technicians trained, a clear understanding of several other tenets of precision cleaning the connection may also be considered.There are many types of debris and contamination. Some are dry Figure-1 and others are fluidic Figure-2. Debris on an end face may also be present in combination Figure-3. The cleaning procedure should strive to be a first time event. A best practice procedure can be identified that does not require multiple techniques and numerous attempts.Dry, fluidic, or combinations of contaminants also have height Figure-4.(12) Commonly used cleaning techniques can create fluidic contamination outside the field of view of most video inspection and software analysis Figure-5. Another technique can create a static field that attracts additional debris Figure-1.(8)There are well established tenets, present in everyday life, that point the direction to properly cleaning the fiber optic connection. Dry wipers, use of solvents and surfactants, and identification of debris or contamination are every-day choices. These are relevant to precision clean a fiber optic connection.Ineffective cleaning fiber optic cleaning procedures may result in debris being mis-characterized as an artifact. Currently, IEC 61300-3-35 is relative to both production line applications (OEM) and field service (OSP) applications. Various standards are based on IEC. In this work the term OEM refers to Original Equipment Manufacturer or a production line environment. The term OSP refers to Outside Plant/Field Service, or the installation and the post production line maintenance environment.This paper is an effort to define and update inspection and cleaning procedures to facilitate existing operations and anticipate future needs.