scholarly journals Assessment of the Effect of Cleanliness on the Visual Inspection of Aircraft Engine Blades: An Eye Tracking Study

Sensors ◽  
2021 ◽  
Vol 21 (18) ◽  
pp. 6135
Author(s):  
Jonas Aust ◽  
Antonija Mitrovic ◽  
Dirk Pons

Background—The visual inspection of aircraft parts such as engine blades is crucial to ensure safe aircraft operation. There is a need to understand the reliability of such inspections and the factors that affect the results. In this study, the factor ‘cleanliness’ was analysed among other factors. Method—Fifty industry practitioners of three expertise levels inspected 24 images of parts with a variety of defects in clean and dirty conditions, resulting in a total of N = 1200 observations. The data were analysed statistically to evaluate the relationships between cleanliness and inspection performance. Eye tracking was applied to understand the search strategies of different levels of expertise for various part conditions. Results—The results show an inspection accuracy of 86.8% and 66.8% for clean and dirty blades, respectively. The statistical analysis showed that cleanliness and defect type influenced the inspection accuracy, while expertise was surprisingly not a significant factor. In contrast, inspection time was affected by expertise along with other factors, including cleanliness, defect type and visual acuity. Eye tracking revealed that inspectors (experts) apply a more structured and systematic search with less fixations and revisits compared to other groups. Conclusions—Cleaning prior to inspection leads to better results. Eye tracking revealed that inspectors used an underlying search strategy characterised by edge detection and differentiation between surface deposits and other types of damage, which contributed to better performance.

Aerospace ◽  
2021 ◽  
Vol 8 (11) ◽  
pp. 313
Author(s):  
Jonas Aust ◽  
Antonija Mitrovic ◽  
Dirk Pons

Background—In aircraft engine maintenance, the majority of parts, including engine blades, are inspected visually for any damage to ensure a safe operation. While this process is called visual inspection, there are other human senses encompassed in this process such as tactile perception. Thus, there is a need to better understand the effect of the tactile component on visual inspection performance and whether this effect is consistent for different defect types and expertise groups. Method—This study comprised three experiments, each designed to test different levels of visual and tactile abilities. In each experiment, six industry practitioners of three expertise groups inspected the same sample of N = 26 blades. A two-week interval was allowed between the experiments. Inspection performance was measured in terms of inspection accuracy, inspection time, and defect classification accuracy. Results—The results showed that unrestrained vision and the addition of tactile perception led to higher inspection accuracies of 76.9% and 84.0%, respectively, compared to screen-based inspection with 70.5% accuracy. An improvement was also noted in classification accuracy, as 39.1%, 67.5%, and 79.4% of defects were correctly classified in screen-based, full vision and visual–tactile inspection, respectively. The shortest inspection time was measured for screen-based inspection (18.134 s) followed by visual–tactile (22.140 s) and full vision (25.064 s). Dents benefited the most from the tactile sense, while the false positive rate remained unchanged across all experiments. Nicks and dents were the most difficult to detect and classify and were often confused by operators. Conclusions—Visual inspection in combination with tactile perception led to better performance in inspecting engine blades than visual inspection alone. This has implications for industrial training programmes for fault detection.


Author(s):  
J. Klamklay ◽  
R.R. Bishu

Visual inspection of printed circuit boards was evaluated through a simulated experiment. Photographs of circuit boards were scanned into a PC and the images were manipulated using a Visual Basic program. The visual inspection performance measured reaction time in seconds and accuracy by measuring the number of incorrect responses given. The independent variables studied in this research were age, gender, defect type, board size, inspection pace, and proportion of defects. Forty subjects participated in this experiment. In summary, the study showed that defect proportion, defect type, age and gender do influence both inspection time and inspection accuracy. Perhaps the most interesting result is that rate of false alarm (decision 2) and misses (decision 1) depend on defect type and proportion. This has interesting ramification for quality professionals.


Aerospace ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 18
Author(s):  
Jonas Aust ◽  
Dirk Pons ◽  
Antonija Mitrovic

Background—There are various influence factors that affect visual inspection of aircraft engine blades including type of inspection, defect type, severity level, blade perspective and background colour. The effect of those factors on the inspection performance was assessed. Method—The inspection accuracy of fifty industry practitioners was measured for 137 blade images, leading to N = 6850 observations. The data were statistically analysed to identify the significant factors. Subsequent evaluation of the eye tracking data provided additional insights into the inspection process. Results—Inspection accuracies in borescope inspections were significantly lower compared to piece-part inspection at 63.8% and 82.6%, respectively. Airfoil dents (19.0%), cracks (11.0%), and blockage (8.0%) were the most difficult defects to detect, while nicks (100.0%), tears (95.5%), and tip curls (89.0%) had the highest detection rates. The classification accuracy was lowest for airfoil dents (5.3%), burns (38.4%), and tears (44.9%), while coating loss (98.1%), nicks (90.0%), and blockage (87.5%) were most accurately classified. Defects of severity level S1 (72.0%) were more difficult to detect than increased severity levels S2 (92.8%) and S3 (99.0%). Moreover, visual perspectives perpendicular to the airfoil led to better inspection rates (up to 87.5%) than edge perspectives (51.0% to 66.5%). Background colour was not a significant factor. The eye tracking results of novices showed an unstructured search path, characterised by numerous fixations, leading to longer inspection times. Experts in contrast applied a systematic search strategy with focus on the edges, and showed a better defect discrimination ability. This observation was consistent across all stimuli, thus independent of the influence factors. Conclusions—Eye tracking identified the challenges of the inspection process and errors made. A revised inspection framework was proposed based on insights gained, and support the idea of an underlying mental model.


Author(s):  
P. Mehta ◽  
S. Sadasivan ◽  
J. S. Greenstein ◽  
A. K. Gramopadhye ◽  
A. T. Duchowski

Aircraft inspection is vital to assure safe and reliable air transportation. Search strategy training has been recognized to be effective in improving an inspector's performance in a visual inspection task. Improving the search performance of novice inspectors can be expedited by providing cognitive feedfoward information about the search strategy adopted by an expert inspector. In a collaborative virtual aircraft inspection environment using eye tracking equipment, novice inspectors can observe in real time the point of regard (POR) data of an expert inspector performing an inspection task. This research evaluates the effectiveness of three display techniques —‘dot’, ‘ray casting’ and ‘decaying trace’ – for representing, the gaze slaved visual deictic reference (VDR) of the expert inspector during search strategy training in an aircraft inspection task. Increase in performance of the novices performing an inspection task after training show the ‘decaying trace’ as the most effective form for representing the expert's VDR.


Author(s):  
A. Sivasangari ◽  
G. Sasikumar

Leukemia   disease   is one   of    the   leading   causes   of death   among   human. Its  cure  rate and  prognosis   depends   mainly   on  the  early  detection   and  diagnosis  of   the  disease. At  the  moment, identification  of  blood  disorders  is  through   visual  inspection  of  microscopic  images  by  examining  changes  like  texture, geometry, colour  and   statistical  analysis  of  images . This  project  aims  to  preliminary  of  developing  a  detection  of  leukemia  types  using   microscopic  blood  sample using MATLAB. Images  are  used  as  they  are  cheap  and  do  not  expensive  for testing  and  lab  equipment.


2018 ◽  
Vol 16 (1) ◽  
pp. 112-119
Author(s):  
VLADIMIR GLEB NAYDONOV

The article considers the students’ tolerance as a spectrum of personal manifestations of respect, acceptance and correct understanding of the rich diversity of cultures of the world, values of others’ personality. The purpose of the study is to investgate education and the formation of tolerance among the students. We have compiled a training program to improve the level of tolerance for interethnic differences. Based on the statistical analysis of the data obtained, the most important values that are significant for different levels of tolerance were identified.


Author(s):  
S. Sadasivan ◽  
R. Rele ◽  
J. S. Greenstein ◽  
A. K. Gramopadhye ◽  
J. Masters ◽  
...  

The human inspector performing visual inspection of an aircraft is the backbone of the aircraft inspection process, a vital element in assuring safety and reliability of an air transportation system. Training is an effective strategy for improving their inspection performance. A drawback of present-day on-the-job (OJT) training provided to aircraft inspectors is the limited exposure to different defect types. Previous studies have shown offline feedback training using virtual reality (VR) simulators to be effective in improving visual inspection performance. This research aims at combining the advantages of VR technology that includes exposure to a wide variety of defects and the one-on-one tutoring approach of OJT by implementing a collaborative virtual training environment. In an immersive collaborative virtual environment (CVE), avatars are used to represent the co-participants. In a CVE, information of where the trainer is pointing can be provided to a trainee as visual deictic reference (VDR). This study evaluates the effectiveness of simulating on-the-job training in a CVE for aircraft inspection training, providing VDR slaved to a 3D mouse used by the trainer for pointing. The results of this study show that the training was effective in improving inspection performance.


Author(s):  
Peter McCormick

AbstractGiven the visibility and obvious importance of judicial power in the age of the Charter, it is important to develop the conceptual vocabulary for desribing and assessing this power. One such concept that has been applied to the study of appeal courts in the United States and Great Britain is “party capability”, a theory which suggests that different types of litigant will enjoy different levels of success as both appellant and respondent. Using a data base derived from the reported decisions of the provincial courts of appeal for the second and seventh year of each decade since the 1920s, this article applies party capability theory to the performance of the highest courts of the ten provinces; comparisons are attempted across regions and across time periods, as well as with the findings of similar studies of American and British courts.


Author(s):  
Jiao Ma ◽  
Colin G. Drury ◽  
Ann M. Bisantz

Training has been a consistently effective intervention in improving inspection performance. For example, existing inspection training in the aircraft maintenance domain is mainly a combination of classroom and on-the-job training (OJT). Computer-based training (CBT) has been promoted ever since it was introduced to this domain. In this study we investigate how effectively feedback training can be combined with CBT to improve visual inspection performance. Specifically, we examine the potential positive impacts of performance and process feedback in CBT, given in an on-line manner, on a trainee's performance and process assessment in a visual inspection task. The CBT system for inspection we used was adopted from the ASSIST program (Chen, Gramopadhye and Melloy, 2000). In our computer simulation of a familiar situation, participants were asked to search certain areas inside of a car in order to detect certain targets (dropped coins) with the aid of computerized tools (e.g., a magnifying glass, a flashlight), and fill out an inspection report based upon detection. A significant test effect was found across performance measures. Type of feedback training was found to be significant for search time. Performance measures were significantly correlated with target difficulty level; on-line performance feedback was significantly more efficient in improving performance measures than conventional delayed performance feedback; feedback training did affect process assessment measures.


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