Showing papers on "Visual inspection published in 2010"

An Approach for Condition-Based Maintenance Optimization Applied to Wind Turbine Blades

Abstract: A sound maintenance planning is of crucial importance for wind power systems. There is a large potential in cost savings by optimizing maintenance decisions to make the projects more cost-efficient. This paper presents an approach to optimize condition-based maintenance strategies for components which degradation can be classified according to the severity of the damage. The approach is applicable to inspection-based maintenance as well as maintenance based on online condition-monitoring systems. This enables us to compare the maintenance strategies within a unified framework. First decisions associated with the different maintenance strategies are optimized, then the expected life cycle maintenance costs of the strategies are compared. The model is applied to blades of wind turbine in order to compare three maintenance strategies: visual inspection, inspection with a condition-monitoring technique (e.g., ultrasonic or thermography), and online condition monitoring (e.g., fiber optic). It is shown that online condition monitoring is the optimal maintenance strategy for high failure rate and low crack time to failure. In other cases, inspection with condition-based maintenance is slightly more beneficial.

Consistent visual analyses of intrasubject data

Abstract: Visual inspection of single-case data is the primary method of interpretation of the effects of an independent variable on a dependent variable in applied behavior analysis. The purpose of the current study was to replicate and extend the results of DeProspero and Cohen (1979) by reexamining the consistency of visual analysis across raters. We recruited members of the board of editors and associate editors for the Journal of Applied Behavior Analysis to judge graphs on a 100-point scale of experimental control and by providing a dichotomous response (i.e., "yes" or "no" for experimental control). Results showed high interrater agreement across the three types of graphs, suggesting that visual inspection can lead to consistent interpretation of single-case data among well-trained raters.

X-ray imaging for homeland security

Abstract: Since 9/11, there has been a growing interest to improve the security both of air travel and of cargo shipping. Visual inspection is the simplest tool and is very efficient when single objects of small size are to be checked. The complexity of inspection increases when we have large 'boxes' and/or when several objects are packed into a closed space, as in luggage or even in larger volumes like shipping containers or trucks. This paper gives a brief overview of how different X-ray techniques are used for fast checking of small and large objects.

Visual and nondestructive evaluation inspection of live gas mains using the Explorer™ family of pipe robots

Abstract: Visual inspection and nondestructive evaluation (NDE) of natural gas distribution mains is an important future maintenance cost-planning step for the nation's gas utilities. These data need to be gathered at an affordable cost with the fewest excavations and maximum linear feet inspected for each deployment, with minimal to no disruption in service. Current methods (sniffing, direct assessment) are either postleak reactive or too unreliable to offer a viable and Department of Transportation–acceptable approach as a whole. Toward achieving the above goal, a consortium of federal and commercial sponsors funded the development of Explorer™. Explorer™ is a long-range, untethered, self-powered, and wirelessly controlled modular inspection robot for the visual inspection and NDE of 6- and 8-in. natural gas distribution pipelines-mains. The robot is launched into the pipeline under live (pressurized flow) conditions and can negotiate diameter changes, 45- and 90-deg bends and tees, as well as inclined and vertical sections of the piping network. The modular design of the system allows it to be expanded to include additional inspection and-or repair tools. The range of the robot is an order of magnitude higher (thousands of feet) than present state-of-the-art inspection systems and will improve the way gas utilities maintain and manage their systems. Two prototypes, Explorer-I and -II (X-I and X-II), were developed and field-tested over a 3-year period. X-I is capable of visual inspection only and was field-tested in 2004 and 2005. The next-generation X-II, capable of visual and NDE inspection [remote field eddy current (RFEC) and magnetic flux leakage (MFL)] was developed thereafter and had field trials in 2006 and late 2007. It was successfully deployed into low-pressure ( 500 psig) distribution and transmission natural gas mains, with multi-1,000-ft inspection runs under live conditions from a single excavation. This paper will describe the overall engineering design and functionality of the Explorer™ family of robots, as well as the results of the field trials for both platforms. It will highlight the importance of the various design and safety features of the in-pipe crawler and showcase the value of data types and position-tagged visual∼NDE data collected in working pipelines under live flow conditions. © 2010 Wiley Periodicals, Inc.

Proposal of an Integrated Index for Prioritization of Bridge Maintenance

Abstract: The bridge rating used in bridge management systems commonly uses only a structural condition. Factors such as seismic risk, hydraulic vulnerability, and strategic importance are commonly used in an isolated fashion. However, these factors are relevant when there is no possibility to calibrate deterioration models. This research uses the needs-based framework for developing an integrated bridge index (IBI) as an aid for prioritization and decisions made on maintenance and rehabilitation of bridges. The index weighs the structure distresses, hydraulic vulnerability, seismic risk, and strategic importance of the bridge. The index was calibrated using visual inspection, survey to experts, and regression analysis. After, the index was applied on six bridges placed on a primary road of Chile. To organize visual inspection, bridge inventory, and compute IBI and rank bridges, a software was developed. The calibration of the IBI index shows a correlation of 98% and all the parameters obtained were significant. Further research is needed to integrate cost with the proposed index and allocate maintenance activities.

Using Soft Computing to Analyze Inspection Results for Bridge Evaluation and Management

Abstract: The national bridge inventory (NBI) system, a database of visual inspection records that tallies the condition of bridge elements, is used by transportation agencies to manage the rehabilitation of the aging U.S. highway infrastructure. However, further use of the database to forecast degradation, and thus improve maintenance strategies, is limited due to its complexity, nonlinear relationship, unbalanced inspection records, subjectivity, and missing data. In this study, soft computing methods were applied to develop damage prediction models for bridge abutment walls using the NBI database. The methods were multilayer perceptron network, radial basis function network, support vector machine, supervised self-organizing map, fuzzy neural network, and ensembles of neural networks. An ensemble of neural networks with a novel data organization scheme and voting process was the most efficient model, identifying damage with an accuracy of 86%. Bridge deterioration curves were derived using the prediction models and compared with inspection data. The results show that well developed damage prediction models can be an asset for efficient rehabilitation management of existing bridges as well as for the design of new ones.

Visual and nondestructive evaluation inspection of live gas mains using the Explorer family of pipe robots

Abstract: Visual inspection and nondestructive evaluation (NDE) of natural gas distribution mains is an important future maintenance cost-planning step for the nation's gas utilities. These data need to be g...

Detection of Cracks and Corrosion for Automated Vessels Visual Inspection

Abstract: Vessel maintenance entails periodic visual inspections of internal and external parts of the vessel hull in order to detect cracks and corroded areas. Typically, this is done by trained surveyors at great cost. Clearly, assisting them during the inspection process by means of a fleet of robots capable of defect detection would decrease the inspection cost. In this paper, two algorithms are presented for visual detection of the aforementioned two kinds of defects. On the one hand, the crack detector is based on a percolation process that exploits the morphological properties of cracks in steel surfaces. On the other hand, the corrosion detector follows a supervised classification approach taking profit from the spatial distribution of color in rusty areas. Both algorithms have shown successful rates of detection with close to real-time performance.

Automated visual inspection of surface mounted chip components

Abstract: In order to develop the reliable and fast visual inspection techniques for surface mounted components after they have been placed in wet solder paste on a printed circuit board (PCB). An inspection process based on machine vision is presented. First, with an adaptive segmentation method based on local valley, the binary component electrodes were obtained, at the same, the location of the component was gotten by the sliding location window algorithm, then, the defects such as component missing, component rotation and component shift are detected by analyzing the projection information of the electrodes. Second, the three color features are extracted from the component body and the Bayes classifier is used to inspect whether the components body is wrong. The experiment results have verified the validity of this scheme in terns of recognition rate and speed.

Deep water ROV design for the Mexican oil industry

Abstract: This paper describes both the design and technical integration of a deep water ROV (Remotely Operated Vehicle) that is able to employ visual inspection in deep water, as well as to take samples with an underwater arm. Visual inspection is the essential application for a ROV, which is useful for; underwater structure inspection, underwater oil production systems inspection and underwater pipeline inspection. This paper mainly describes the ROV design, and explains in general manner other elements; such as the SCU, LARS and TMS. It is important to mention that the design phase is complete and it was financed by PEMEX (Federal Mexican Oil Company). The project has stalled, since we are waiting for the financial support from PEMEX for the system construction. A future objective is the design and construction of Work-Class ROVs, which can be used to perform PEMEX specific tasks.

Reliability Safety Assessment of Corroding Reinforced Concrete Structures Based on Visual Inspection Information

Abstract: This paper presents a procedure for adopting visual inspection findings to the update of reliability safety assessments of reinforced concrete (RC) structures. The process involves the application of random field theory by which the structure is divided into many elements to better simulate its temporal and spatial deterioration characteristics. Chloride-induced corrosion and resulting concrete cover cracking can be modeled. The influence of visual inspection finding such as the timing, location and extent of corrosion damage on structural reliability predictions is described. Results show that structural reliabilities have the potential to increase if service-proven performance and inspection findings are used to update the structural reliability analysis. A typical RC beam subject to a marine environment is used to illustrate the role and benefits of inspection data in the safety assessment and service-life prediction of existing structures.

Maintaining Technical Integrity of Petroleum Flowlines on Offshore Installations: A Decision Support System for Inspection Planning

Abstract: Oil and Gas (O&G) platforms in the North Sea are facing aging problems as many of the installations have matured and are approaching their design lifetime. Flowlines are used to transport oil and gas well stream from the wellhead to the production manifold. They are categorised as one of the most critical components on a production facility. Flowline degradation takes place due to corrosion and erosion. The deterioration of a flowline may increase the risk of leakages, ruptures, etc., which shall lead to serious HSE (health, safety and environmental) and financial consequences. Any such risks have a direct impact on the O&G installation’s technical integrity as well as the operator’s sustainability concerns. Conventionally, pipelines are designed with safety provisions to provide a theoretical minimum failure rate over the life span. Furthermore, to reduce the risk of failure various techniques are routinely used to monitor the status of pipelines during the operation phase. The existing methods of flowline health monitoring planning requires one to take into consideration the operator’s plant strategy, flowline degradation mechanisms, historical data, etc. A technical condition report is made based on findings’ reports and degradation trends. This report recommends the inspection of a number of points on the flowlines in a certain year using non-destructive evaluation methods such as visual inspection, ultrasonic testing, radiographic testing, etc. Based on the technical condition report, in general for a certain preventive maintenance shutdown, 10 to 15 flowline inspection openings are accommodated as finance, time and resource availability are taken into consideration. However, it is customary to plan to open more locations in a certain inspection package than can be inspected and minimization of such points is at present done on an ad hoc basis. This paper suggests a formal model and a framework to formally minimize the number of visual inspections by executing the plant strategy as well as HSE concerns. The model is derived using analytic hierarchy process (AHP) framework, which is a multi-criteria decision-making approach. The model is developed based on literature, industrial practice, experience as well as real inspection data from a mature offshore O&G installation located on the Norwegian Continental Shelf.© 2010 ASME

Inspection methods & techniques to determine non-visible corrosion of prestressing strands in concrete bridge components : task 2, assessment of candidate NDT methods.

Abstract: Catastrophic failures of non-composite prestressed precast concrete adjacent-box beam bridges have occurred in several states due to corrosion of the prestressing steel. These failures have highlighted the need to improve methods used to detect corrosion damage and subsequently load rate the damaged members. In light of this, PennDOT initiated a research program aimed at improving inspection techniques through evaluation of off-the-shelf non-destructive testing (NDT) technologies and correlation of surface conditions with non-visible strand corrosion. Currently, inspection of concrete box girder sections relies on visual methods which correlate longitudinal and transverse cracking, spalling, and exposed strands with the rated level of performance of the member. While the visual method provides a qualitative estimate of the amount of damage, the specific location along a strand and the amount of damage to the strands is not clearly defined. As a result, the assessment of the condition of the bridge could in some cases result in an un-conservative or overly-conservative estimate of remaining strength. Furthermore, without a high level of accuracy in locating damage to the strands, remediation and rehabilitation is difficult to accomplish. To improve on the current inspection techniques, the visual inspection requirements are revisited through an extensive destructive evaluation study. In addition, NDT methods are evaluated and compared with actual damage present in a group of 40-50 year old box beams removed from service. The goal of this project is to determine if visual inspection techniques or currently available NDT technologies will allow for accurate identification of non-visible corrosion of prestressing strands. Results of this study indicated that both the Magnetic Flux Leakage and Remnant Magnetism NDT methods are capable of detecting section loss in strands with good accuracy.

Visual inspection system of printed circuit board, and method of the same

Abstract: PROBLEM TO BE SOLVED: To provide a visual inspection system and method of a printed circuit board capable of improving the inspection speed and inspection reliability. SOLUTION: The visual inspection method includes a stage of partitioning the whole inspection region of an object to be inspected with a first region and a second region, a stage of imaging the whole inspection region of the object to be inspected with a first camera and second camera using different illuminations, and a discrimination stage of determining goodness/badness of the first region using a first image acquired from the first camera, and determining goodness/badness of the second region using a second image acquired from the second camera. COPYRIGHT: (C)2010,JPO&INPIT

Automated Visual Inspection of Road Surface Cracks

Abstract: Pavement maintenance requires knowing the state of the road surface. Human inspection is the most common method for evaluating this state. Recently, the automated visual inspection has been addressed, but some important questions remain open concerning the variable ambient lighting, shadows, device synchronisation and the large amount of data. In the present paper, an automated visual inspection system is presented. Images are obtained using laser lighting and linear cameras onboard a vehicle. Longitudinal and transversal cracks are detected and classified using a novel approach based on combining traditional features and Gabor filters. A Differential Global Positioning System (DGPS), a web camera and an Inertial Profiler to measure the International Roughness Index (IRI) are also considered in order to obtain comprehensive information about the road state. Implementation details are given concerning image acquisition and processing, system architecture and data synchronisation. Field results are presented which prove the suitability of the approach.

Visual inspection of glass bottlenecks by multiple-view analysis

Abstract: The narrow structure of bottlenecks poses a very challenging problem for automated visual inspection systems and surprisingly, this issue has received little attention in literature. Bottleneck inspection is highly relevant to the fabrication of glass bottles, e.g., for the wine and beer industry. Defects in glass bottles can arise in various situations such as an incomplete reaction in a batch, batch contaminants and interactions of the melted material among others. This paper presents an inspection approach that utilises geometry of multiple views along with a rich set of feature descriptors to discriminate real flaws from false alarms in uncalibrated images of glass bottlenecks. The proposed method is based on an automatic multiple view inspection AMVI technique for the automatic detection of flaws. This technique involves an initial step that extracts numerous segmented regions from a set of views of the object under inspection. These regions are subsequently classified either as real flaws or as false alarms. The classification process considers that image noise and false alarms occur as random events in different views while real flaws induce geometric and featural relations in the views where they appear. Therefore, by analysing such relations it is possible to successfully localise real flaws and to discard a large number of false alarms. An important characteristic of the proposed methodology is the complete lack of camera calibration which makes our method very suitable for applications where camera calibration is difficult or expensive to carry out. Our inspection system achieves a true positive rate of 99.1% and a false positive rate of 0.9%.

Inspection, Condition Assessment, and Management Decisions for Commercial Roof Systems

Abstract: Regular inspections are common for roof systems. In this paper, we consider the relationships among inspection condition assessment, leaks, and costs for roof systems. We analyze a visual inspection method and consider the use of inspection data, leaks, age, and costs as inputs to roof replacement decision making and argue that using all sources of information is beneficial.

Visual Inspection of Soldering Joints by Neural Network with Multi-angle View and Principal Component Analysis

Abstract: With the development of microelectronics technology, the demands of the automatic inspection system are ever increasing. The current trends toward miniaturization of components, denser packing of boards, surface mounting technology, and highly automated assembly equipment make the task of inspecting these defects more critical and more difficult for humans. In this paper, we achieved 0% of misjudgment by implementing training category intermediate samples. We also achieved cutting down the processing time and an increase of correct judgments by the improvement of inputs using principle component analysis and multi-angle image.

First steps towards a roboticized visual inspection system for vessels

Abstract: Vessel maintenance entails periodic visual inspections of internal and external parts of the vessel hull in order to detect the typical defective situations affecting metallic structures, such as cracks, corrosion, etc. This paper presents the first steps towards a roboticized visual inspection system aiming at automating as much as possible the whole inspection process currently undertaken by human surveyors. Occurrence of defects are first outlined, followed by a brief description of the whole system. Next, details for one of the robotic platforms to be used are given, as well as for the image processing algorithms dealing with the visual detection of defects.

Design of ROVs for the Mexican power and oil industries

Abstract: Underwater robots have had a significant contribution in the inspection, maintenance and repair of underwater structures related to the power and oil industry. Underwater robots have a big potential application in Mexico due to, the two federal Mexican companies related with the power and oil are in constant expansion. CIDESI is working in two projects (Shadow water ROV and Deep water ROV) related to visual inspection ROVs applied to the power and oil industries. Visual inspection is the essential application for a ROV, and it is used into the tasks; underwater structure inspection (dams included), underwater oil production system inspection and underwater pipeline inspection. This applied research paper firstly gives a brief instruction of the two Mexican companies related with the power and oil. Subsequently a description of the objectives and main characteristics of the developed hallow and deep water ROVs are presented and finally a general conclusions and future work is listed.

Ding Inspection Device

Abstract: Visual inspection of an interior bottom of a borehole by means of measuring the sediment thickness at the bottom. An inspection device to be lowered in the borehole and then to be retrieved. The bottom sediment thickness is marked on the piston by a collar attached to the piston.

Visual inspection device and visual inspection method

Abstract: PROBLEM TO BE SOLVED: To acquire a height of an inspection object with a small frequency of imagingSOLUTION: A visual inspection device 10 projects a first stripe pattern whose brightness periodically changes onto an inspection object in multiple different phases and images multiple first projection images The visual inspection device 10 projects a second stripe pattern whose brightness changes at a cycle different from the first stripe pattern onto the inspection object in multiple different phases and images multiple second projection images The visual inspection device 10 calculates a phase of brightness variation corresponding to the second stripe pattern at a measurement point in the inspection object based on brightness at the measurement point in the first projection images and the second projection images, and known relation between the brightness variations corresponding to the respective first and second stripe patterns

Object Inspection System

Abstract: Early techniques for object inspection relied on human inspectors to visually examine objects for defects. However, automated object inspection techniques were subsequently developed due to the labour intensive and subjective nature of human operated inspections. Additionally, object characteristics such as object power and object thickness need to be determined after the objects have been examined for defects. Conventionally, corresponding inspection stations are along the manufacturing lines for determining each of the object characteristics. However, the need for human intervention and time spent to move the objects from one inspection station to another adversely affect the efficiency of the object manufacturing process. An embodiment of the invention disclosed describes a high-resolution object inspection system for performing object inspection.

Image processing system and visual inspection method

Abstract: PROBLEM TO BE SOLVED: To provide an image processing system and a visual inspection method with which an inspection area can be stably identified.SOLUTION: An image processing system has gradation image obtaining means 110 for obtaining gradation images, a distance image generating means 130 for generating distance images, identifying-pattern detection means 150 for detecting identifying-patterns for identifying the inspection region on one of the gradation image and distance image corresponding to the inspection area on the other image, an inspection region identifying means 170 for identifying the inspection region based on at least one of the position and the inclination angle of the identifying- patterns detected by the identifying-pattern detection means on the other image of the gradation image and the distance image, a characteristic amount calculation means 180 for calculating characteristic amount of the inspection region identified and a judgement means 190 for judging whether or not the work is good based on the characteristic amount calculated.

Tire visual inspection method and tire visual inspection device

Abstract: PROBLEM TO BE SOLVED: To provide a visual inspection method and a visual inspection device for inspecting an appearance of a tire by pattern matching without preparing a master image.SOLUTION: The tire visual inspection method includes: a model image setting step which sets a plurality of model images from images imaged a tire surface; a matching image extraction step which repeats pattern matching between the plurality of model images and an imaged image, and extracts an imaged image area having a larger matching rate than a predetermined matching rate as a matching image; a difference image creation step which calculates a difference between the model images and the matching image, and creates a difference image; and a defect image extraction step which compares the difference image with a threshold and extracts a defect image.

Visual lobe shape characteristics of experienced industrial inspectors and inexperienced subjects

Abstract: This article reports research on visual lobe shape differences between experienced industrial inspectors and inexperienced students and the effects of years of inspection experience on lobe-shape characteristics. Comparison of the visual lobes of students and inspectors showed that lobe roundness of the inspectors was higher than that of the students. Also, marked improvement in lobe roundness and regularity for inspectors was evident in those inspectors who had relatively long experience in inspection work, indicating that daily inspection practice did not seem to be an effective way of improving lobe-shape characteristics. The increased lobe roundness level did not change, however, even when the inspectors had not performed an inspection job for a long period of time. This finding suggests that the improved lobe-roundness level could be maintained even without any follow-up inspection practice. It seems that intensive lobe training rather than inspection practice may be required to improve lobe-shape characteristics in a short time. No relationship was found between lobe-shape parameters and the ranked inspection performance of the inspectors, which indicated that, for the inspectors, better search performance may be related more to their better decision making rather than to their higher lobe-roundness level or inspection speed. © 2010 Wiley Periodicals, Inc.

Combination of weak classifiers for metallic corrosion detection and guided crack location

Abstract: Periodic visual inspection of the internal and external parts of vessels hull is typically performed by trained surveyors at great cost. Assisting them during the inspection process by means of mechanisms capable of defect detection would certainly decrease inspection cost. With this aim, this paper presents a corrosion detection algorithm built around a weak classifiers cascade scheme and reports on its performance. As a secondary contribution, a crack detection approach guided by the output of the corrosion detector is also proposed. As a result, false positives rate is reduced as well as the computation time.