Cracking is a major pavement distress that jeopardizes road serviceability and traffic safety. Automated pavement distress survey (APDS) systems have been developed using digital imaging technology to replace human surveys for more timely and accurate inspections. Most APDS systems require special lighting devices to illuminate pavements and prevent shadows of roadside objects that distort cracks in the image. Most of the artificial lighting devices are laser based, which are either hazardous to unprotected people, or require dedicated power supplies on the vehicle. This study is aimed to develop a new imaging system that can scan pavement surface at highway speed and determine the severity level of pavement cracking without using any artificial lighting. The new system consists of dual line-scan cameras that are installed side by side to scan the same pavement area as the vehicle moves. Cameras are controlled with different exposure settings so that both sunlit and shadowed areas can be visible in two separate images. The paired images contain complementary details useful for reconstructing an image in which the shadows are eliminated. This paper intends to presents (1) the design of the dual line-scan camera system for a high-speed pavement imaging system that does not require artificial lighting, (2) a new calibration method for line-scan cameras to rectify and register paired images, which does not need mechanical assistance for dynamical scan, (3) a customized image-fusion algorithm that merges the multi-exposure images into one shadow-free image for crack detection, and (4) the results of the field tests on a selected road over a long period. / text

<p>We present a geometrical and mathematical solution to a problem faced in the glass industry in this work. Volume measurement of the glass gob is vital in making glassware. Geometric models were used to represent the glass gob.</p><p>A line scan camera system takes the images of the glass gob and the volume information of the glass gob is obtained by the image processing in the industry. This work is carried out to implement a simulator which estimates the change in the volume measurement of glass gob through line scan when it is rotated or when its shape is changed. A mixture of graphical and mathematical approaches is used to carry out this study. Geometric models have been used to represent the different gob models. Geometric models facilitate the manipulation of volumetric data.A simple and effective technique is used in this work. The problem is divided into steps. Volume measurement through a line scan technique is simulated. An easy to use graphical user interface (GUI) is designed to interact with the gob model and check the results of volume measurements.We present a geometrical and mathematical solution to a problem faced in the glass industry in this work. Volume measurement of the glass gob is vital in making glassware. Geometric models were used to represent the glass gob.A line scan camera system takes the images of the glass gob and the volume information of the glass gob is obtained by the image processing in the industry.This work is carried out to implement a simulator which estimates the change in the volume measurement of glass gob through line scan when it is rotated or when its shape is changed. A mixture of graphical and mathematical approaches is used to carry out this study. Geometric models have been used to represent the different gob models. Geometric models facilitate the manipulation of volumetric data.</p><p>A simple and effective technique is used in this work. The problem is divided into steps. Volume measurement through a line scan technique is simulated. An easy to use graphical user interface (GUI) is designed to interact with the gob model and check the results of volume measurements.</p>

This thesis presents a collection of photogrammetry techniques aimed at the analysis of short-lived events. The small time scale on which these phenomena happen makes them difficult to capture not only from the point of view of hardware but also because one can not obtain several measurements of events that are not repeatable. Three subjects are presented in ascending order of complexity. We first detail a new approach that uses a simple unidimensional image sensor for traffic monitoring in order to obtain a large number of accurate measurements like speed, acceleration or inter-vehicle distances. This is followed by a discussion on the reconstruction of the surface of an evanescent liquid flow using stereovision on floating tracers. Finally, a new spectral model is used for the three-dimensional detection of aircraft wake vortices from IR LIDAR measurements. The approach was successfully tested during flight tests and proved to be invaluable to detect the wakes under these specific conditions.

We present a geometrical and mathematical solution to a problem faced in the glass industry in this work. Volume measurement of the glass gob is vital in making glassware. Geometric models were used to represent the glass gob. A line scan camera system takes the images of the glass gob and the volume information of the glass gob is obtained by the image processing in the industry. This work is carried out to implement a simulator which estimates the change in the volume measurement of glass gob through line scan when it is rotated or when its shape is changed. A mixture of graphical and mathematical approaches is used to carry out this study. Geometric models have been used to represent the different gob models. Geometric models facilitate the manipulation of volumetric data.A simple and effective technique is used in this work. The problem is divided into steps. Volume measurement through a line scan technique is simulated. An easy to use graphical user interface (GUI) is designed to interact with the gob model and check the results of volume measurements.We present a geometrical and mathematical solution to a problem faced in the glass industry in this work. Volume measurement of the glass gob is vital in making glassware. Geometric models were used to represent the glass gob.A line scan camera system takes the images of the glass gob and the volume information of the glass gob is obtained by the image processing in the industry.This work is carried out to implement a simulator which estimates the change in the volume measurement of glass gob through line scan when it is rotated or when its shape is changed. A mixture of graphical and mathematical approaches is used to carry out this study. Geometric models have been used to represent the different gob models. Geometric models facilitate the manipulation of volumetric data. A simple and effective technique is used in this work. The problem is divided into steps. Volume measurement through a line scan technique is simulated. An easy to use graphical user interface (GUI) is designed to interact with the gob model and check the results of volume measurements.

This MEng (Master of Engineering) research thesis evaluates the capabilities and limitations of line-scan thermography for the non-destructive evaluation of composite structures containing hidden defects. In simple terms, line-scan thermography is a state-of-the-art technique in which a focused line of thermal energy is transmitted into a material. Line-scan thermography has great potential for the rapid and low cost non-destructive inspection of composite structures for aircraft, automobiles and ships. In this project, theoretical research exploring the heat transfer physics was undertaken in conjunction with experimental studies to develop an optimum inspection regime for line-scan thermography. The capability of line-scan thermography to detect impact damage in carbon/epoxy laminates was experimentally investigated in Chapter 3. From the impact side, in all materials, line-scan thermography overestimated the size of the impact damage whereas flash thermography underestimated the size. There was a close relationship between the ultrasonic profile and the line-scan thermographic thermal response curve. New experimental data has been produced and analysed for the ability of line-scan thermography to determine the defect as well as the defect size. It was found that line-scan thermography was able to distinguish back drilled holes, but it was not possible to determine accurate defect sizing due to the depth of the holes from the inspected surface and the limitations associated with the line-scan thermographic apparatus itself. There was excellent correlation between the C-scan ultrasonics intensity curves and the line-scan thermographs as well as excellent correlation with the theoretical results. The relationship between line-scan thermography and foreign body objects were experimentally investigated for carbon/epoxy composites. A major limitation found with line-scan thermography is its limited depth penetration, which is highlighted in the foreign object study using 6 mm and 13 mm diameter Teflon® discs and 13 mm Teflon® strips embedded in carbon/epoxy laminates. Depth penetration allowed only 2 mm resolution for the 13 mm diameter discs and 1.5 mm resolution for the 6 mm discs in a composite panel. The results of the investigation of stainless steel shim objects in carbon/epoxy laminates reveal that line-scan thermography is capable of determining their presence and size close to the surface. There was also excellent correlation between the ultrasonic response curve and the line-scan thermographic intensity curve. The results of the investigation of thermoplastic film foreign body objects in carbon/epoxy laminates show that at present line-scan thermography does not have the capability to determin e such defects. Experimental results show that line-scan thermography is capable of detecting large voids, back drilled holes, some foreign body objects, and impact damage. However, the ability of line-scan thermography to measure the defect dimensions is dependent on the size and type of damage, the distance from the line source, the depth of the defect, and the type of composite material.

The railroad industry is pivotal in the United States to ensure that the supply chain does not shut down for the American people. Non-Destruction Evaluation (NDE) approaches are preferred and performed on the railways to ensure the safety of the population that is exposed to the railway industry. When damage occurs on the rail base, there is an increased risk derailment of the train cars. Due to the nature of the railroad industry, there are challenges with developing a quick and reliable inspection method, along with the improvement of current NDE methods. The load, speed, and cycles of trains have increased the load that track sections endure over time. Some railways that were originally built in the early 20th century are still utilized today, designed for trains that are not nearly as heavy or fast as used today. Defects and damage on the railways lead to the need of development of an NDE approach utilizing Line Scan Thermography approaches. One of the most common defects that are formed are on the rail base is known as “base nicks” and “half-moon cracks”, these types of defects can occur over time. This research aims to study the feasibility of applying this NDE technique to detect defects that can occur on a rail base, both internal and external. For this research, a heat source up to 6000 W and tested velocities up to 447.1 mm/s (1.0 mph) are used to study the effects of line scanning thermography on various samples. In total, 10 samples are employed to test for feasibility: each one having a unique set of defects. Some defects fabricated on these samples are internal, such as bottom drilled holes (BDH) and side drilled holes (SDH); some of these samples are fabricated from actual rail samples. From tests conducted for internal defects, it can be concluded that defects with diameters of 6.35 mm (0.25”) can be detected at a remaining thickness from the observation surface of 6.35 mm. Along with internal defects, there are also external defects employed on the samples; these defects include simulated base nicks, fractures, and half-moon cracks. For surface defects tests from this research, it is found that the anomalies can be detected visually. The results from the experimental studies provide insight and limitations of LST for the possibility of a future commercial application.

This thesis deals with the design and subsequent implementation of a unit inspecting a printed logos on the pen surface. A line-scan camera is used to capture the object. Whole the unit including acquited data processing is controlled by Raspberry Pi 4 platform extended by perifery board. The control of the hardware parts is implemented in C++, the detection algorithms in Python using OpenCV and TensorFlow libraries. The unit has a graphical user interface for control of the inspection process. In the end of the thesis test of the unit reliability is shown.

The great social and economic impact of earthquakes has made necessary the development of novel structural health monitoring (SHM) solutions for increasing the level of structural safety and assessment. SHM is the process of comparing the current state of a structure’s condition relative to a healthy baseline state to detect the existence, location, and degree of likely damage during or after a damaging input, such as an earthquake. Many SHM algorithms have been proposed in the literature. However, a large majority of these algorithms cannot be implemented in real time. Therefore, their results would not be available during or immediately after a major event for urgent post-event response and decision making. Further, these off-line techniques are not capable of providing the input information required for structural control systems for damage mitigation. The small number of real-time SHM (RT-SHM) methods proposed in the past, resolve these issues. However, these approaches have significant computational complexity and typically do not manage nonlinear cases directly associated with relevant damage metrics. Finally, many available SHM methods require full structural response measurement, including velocities and displacements, which are typically difficult to measure. All these issues make implementation of many existing SHM algorithms very difficult if not impossible. This thesis proposes simpler, more suitable algorithms utilising a nonlinear Bouc-Wen hysteretic baseline model for RT-SHM of a large class of nonlinear hysteretic structures. The RT-SHM algorithms are devised so that they can accommodate different levels of the availability of design data or measured structural responses, and therefore, are applicable to both existing and new structures. The second focus of the thesis is on developing a high-speed, high-resolution, seismic structural displacement measurement sensor to enable these methods and many other SHM approaches by using line-scan cameras as a low-cost and powerful means of measuring structural displacements at high sampling rates and high resolution. Overall, the results presented are thus significant steps towards developing smart, damage-free structures and providing more reliable information for post-event decision making.

The Doctoral thesis demonstrates the design of reliable industrial visual systems. The special emphasis is dedicated to the detection of defects on webs in industrial applications based on line-scan cameras. This system makes possible detection and classification of defects originating during the real production conditions. This work covers a theoretical study of a visual system for the defect detection on endless bands as well as of appropriate lighting and the scene arrangement. Further to that have been selected, adjusted and designed key components of hardware. Following the design and optimization of algorithms a system prototype had been installed on non-woven textiles production line. Eight visual systems implemented into real-life industrial conditions based on this prototype

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