Probabilistic Evaluation of 3D Surfaces Using Statistical Shape Models (SSM)

Inspecting a 3D object which shape has elastic manufacturing tolerances in order to find defects is a challenging and time-consuming task. This task usually involves humans, either in the specification stage followed by some automatic measurements, or in other points along the process. Even when a detailed inspection is performed, the measurements are limited to a few dimensions instead of a complete examination of the object. In this work, a probabilistic method to evaluate 3D surfaces is presented. This algorithm relies on a training stage to learn the shape of the object building a statistical shape model. Making use of this model, any inspected object can be evaluated obtaining a probability that the whole object or any of its dimensions are compatible with the model, thus allowing to easily find defective objects. Results in simulated and real environments are presented and compared to two different alternatives.

Ultrasonic Flaw Recognition by Multi-Angle Phased Array Data Integration

This study presents a method of ultrasonic flaw identification using phased array ultrasonic inspection data. Raw data from each individual channel of the phased array ultrasonic inspection are obtained. The data trimming and de-noising are employed to retain the data within the boundary of the inspected object and remove the speckle noise components from the raw data, respectively. The resulting data are passed into a sequence of signal processing operations to identify embedded flaws. A shape-based filtering method is proposed to reduce the intensity of geometric noise components due to the non-uniform microstructures introduced in the manufacturing process. The resulting data matrices are integrated to obtain the intensity matrix of the possible flaw regions. Thresholding is applied to the intensity matrix to obtain the potential flaw regions, followed by a connected component analysis to identify the flaws. The overall method is demonstrated and validated using realistic phased array experimental data.

Simulation of Translational Data Acquisition Scheme of X-Ray Computed Tomography for Application in NDT

The invention of computed tomography some few decades ago, coupled with its applications in the field of non-destructive testing for industrial objects inspection has revolutionized the way inspections were formerly done. Despite the conventional data acquisition scheme which is integrated with a rotational stage in between the source and the detector works perfectly for small and lighter objects, hence, it seems impossible to investigate complicated, bulky objects with interconnected unbalanced composites. Moreover, it will be very expensive to harnessed technologies into the rotational stage which can be incorporated into this conventional technique with an optimum degree of accuracy. Therefore, this paper will consider the translational data acquisition scheme which is proven mathematically as an alternative method to the conventional technique [1]. This translational scheme takes into account the variations and the magnification of both the source x-ray and the detector around the object and then proceeded by scans from different focal distances. Python packages with necessary plugins were used in implementing the reconstructive algorithm generated in simulating and modelling a suitable image of inspected object.

Assessment of Sensor Technologies for Aircraft SHM Systems

SHM is a monitoring system which uses sensors, actuators and data transmission, acquisition and analysis, permanently integrated with the inspected object. The objective of SHM is to detect, localize, identify and predict development of fatigue fractures, increasing safety and reliability. This paper presents an assessment of sensor technologies used in aircraft SHM system. Due to the fact that most of these measurement methods are relatively new and still under development the present appraisal focuses on a number of parameters with reference to each method, including a sensor’s installation issues, reliability, power consumption, sensor infrastructure, sensitivity and cost and availability. The work is predominantly focused on the assessment ofpermanently bonded sensors, such as foil strain gages, Comparative Vacuum Monitoring (CVM), Piezo sensors (PZT), Eddy-Current Transducers (ECT). Finally, all these methods are briefly discussed.