The field of robotics has advanced to the point where robots are being developed for use in fire environments to perform firefighting tasks. These environments contain varying levels of fire and smoke, both of which obstruct robotic perception sensors. In order to effectively use robots in fire environments, the issue of perception in the presence of smoke and fire needs to be addressed. The goal of this research was to address the problem of perception, specifically rangefinding, in fire smoke environments. A series of tests were performed in fire smoke filled environments to evaluate the performance of different commercial rangefinders and cameras as well as a long-wavelength infrared (LWIR) stereo vision system developed in this research. The smoke was varied from dense, low temperature smoke to light, high temperature smoke for evaluation in a range of conditions. Through small-scale experiments on eleven different sensors, radar and LWIR cameras outperformed other perception sensors within both smoke environments. A LWIR stereo vision system was developed for rangefinding and compared to radar, LIDAR, and visual stereo vision in large-scale testing, demonstrating the ability of LWIR stereo vision to rangefind in dense smoke when LIDAR and visual stereo vision fail. LWIR stereo vision was further developed for improved rangefinding in fire environments. Intensity misalignment between cameras and stereo image filtering were addressed quantitatively. Tests were performed with approximately isothermal scenes and thermally diverse scenes to select subsystem methods. In addition, the effects of image filtering on feature distortion were assessed. Rangefinding improvements were quantified with comparisons to ground truth data. Improved perception in varying levels of clear and smoke conditions was developed through sensor fusion of LWIR stereo vision and a spinning LIDAR. The data were fused in a multi-resolution 3D voxel domain using evidential theory to model occupied and free space states. A heuristic method was presented to separate significantly attenuated LIDAR returns from low-attenuation returns. Sensor models were developed for both return types and LWIR stereo vision. The fusion system was tested in a range of conditions to demonstrate its ability for improved performance over individual sensor use in fire environments. / Ph. D.

This paper presents a new approach to the feature-matching problem for 3D reconstruction by taking advantage of GPS and IMU data, along with a prior calibrated stereo camera system. It is expected that pose estimates and calibration can be used to increase feature matching speed and accuracy. Given pose estimates of cameras and extracted features from images, the algorithm first enumerates feature matches based on stereo projection constraints in 2D and then backprojects them to 3D. Then, a grid search algorithm over potential camera poses is proposed to match the 3D features and find the largest group of 3D feature matches between pairs of stereo frames. This approach will provide pose accuracy to within the space that each grid region covers. Further refinement of relative camera poses is performed with an iteratively re-weighted least squares (IRLS) method in order to reject outliers in the 3D matches. The algorithm is shown to be capable of running in real-time correctly, where the majority of processing time is taken by feature extraction and description. The method is shown to outperform standard open source software for reconstruction from imagery. / Master of Science

This thesis presents online 3D reconstruction and ground segmentation using unmanned aerial vehicle (UAV) based stereo vision. For this purpose, a long baseline stereo vision system has been designed and built. Application of this system is to work as part of an air and ground based multi-robot autonomous terrain surveying project at Unmanned Systems Lab (USL), Virginia Tech, to act as a first responder robotic system in disaster situations. Areas covered by this thesis are design of long baseline stereo vision system, study of stereo vision raw output, techniques to filter out outliers from raw stereo vision output, a 3D reconstruction method and a study to improve running time by controlling the density of point clouds. Presented work makes use of filtering methods and implementations in Point Cloud Library (PCL) and feature matching on graphics processing unit (GPU) using OpenCV with CUDA. Besides 3D reconstruction, the challenge in the project was speed and several steps and ideas are presented to achieve it. Presented 3D reconstruction algorithm uses feature matching in 2D images, converts keypoints to 3D using disparity images, estimates rigid body transformation between matched 3D keypoints and fits point clouds. To correct and control orientation and localization errors, it fits re-projected UAV positions on GPS recorded UAV positions using iterative closest point (ICP) algorithm as the correction step. A new but computationally intensive process of use of superpixel clustering and plane fitting to increase resolution of disparity images to sub-pixel resolution is also presented. Results section provides accuracy of 3D reconstruction results. The presented process is able to generate application acceptable semi-dense 3D reconstruction and ground segmentation at 8-12 frames per second (fps). In 3D reconstruction of an area of size 25 x 40 m2, with UAV flight altitude of 23 m, average obstacle localization error and average obstacle size/dimension error is found to be of 17 cm and 3 cm, respectively. / MS / This thesis presents near real-time, called online, visual reconstruction in 3-dimensions (3D) using ground facing camera system on an unmanned aerial vehicle. Another result of this thesis is separating ground from obstacles on the ground. To do this the camera system using two cameras, called stereo vision system, with the cameras being positioned comparatively far away from each other at 60 cm was designed as well as an algorithm and software to do the visual 3D reconstruction was developed. Application of this system is to work as part of an air and ground based multi-robot autonomous terrain surveying project at Unmanned Systems Lab, Virginia Tech, to act as a first responder robotic system in disaster situations. Presented work makes use of Point Cloud Library and library functions on graphics processing unit using OpenCV with CUDA, which are popular Computer Vision libraries. Besides 3D reconstruction, the challenge in the project was speed and several steps and ideas are presented to achieve it. Presented 3D reconstruction algorithm is based on feature matching, which is a popular way to mathematically identify unique pixels in an image. Besides using image features in 3D reconstruction, the algorithm also presents a correction step to correct and control orientation and localization errors using iterative closest point algorithm. A new but computationally intensive process to improve resolution of disparity images, which is an output of the developed stereo vision system, from single pixel accuracy to sub-pixel accuracy is also presented. Results section provides accuracy of 3D reconstruction results. The presented process is able to generate application acceptable 3D reconstruction and ground segmentation at 8-12 frames per second. In 3D reconstruction of an area of size 25 x 40 m2 , with UAV flight altitude of 23 m, average obstacle localization error and average obstacle size/dimension error is found to be of 17 cm and 3 cm, respectively.

<p dir="ltr">Consistent intake and feeding behavior records collected on a per-cow basis are useful measures for optimization of feed efficiency, production, and ultimately, resource and economic sustainability of dairy operations. However, current methods for collection are often labor-intensive and impractical to maintain for both individual- and group-housed cows. Across the dairy industry, total mixed rations (TMR) are fed to promote balanced nutrient intake and satisfy evolving energy requirements. TMR intake is an extensively investigated phenotype of dairy cattle and is known to be highly variable due to both intrinsic and extrinsic determinants, which can include composition and palatability of offered TMR, intensity of environmental stressors, and biological aspects of the individual animal. Reductions in TMR intake negatively impact health and production; thus, industry demand has heightened for precise intake monitoring systems. Cyber-physical systems that employ cameras as a sensing device are proposed solutions to ambiguity in existing feeding strategies. Prior studies have demonstrated the efficacy of camera systems to monitor other phenotypes of dairy cattle including body condition, locomotion and gait, social interaction, and early detection of negative health events. In this study, an OAK-D PoE stereo vision camera system was employed to estimate volume of TMR and monitor feeding behavior in a dynamic barn environment. The system leveraged open-source Python software to measure relative depth in near real time and autonomously estimate the amount of TMR present in a feed bunk. Image data were processed to generate a point cloud for which volume of TMR was estimated at a rate of approximately 50 estimates/min. Two experiments were conducted in which mass, volume, and density of TMR, as well as feeding behavior (exclusive to Exp. 2) were manually recorded to be compared to volume estimates of TMR output by the camera system. In Exp. 1, diet type (high-density vs. low-density; HD and LD, respectively), lighting (10,000 Lm vs. existing barn lighting; on vs. off, respectively), and shape of offered TMR (undisturbed vs. simulated post-meal bout; no divot vs. divot, respectively) were assessed for impact on system accuracy across five intervals of known TMR volume. In Exp. 2, system volume estimates were evaluated over time when a cow was present and exhibiting normal feeding behavior. The system accurately estimated volume of TMR across evaluated conditions in Exp. 1, despite significance of the divot condition. As TMR disappeared over time in Exp. 2, system volume estimates decreased with a similar pattern. When the cow was removed and measured TMR volume was unchanged at 2 h collection timepoints in Exp. 2, system volume estimates also remained unchanged and consistent. Post-collection of replicates in Exp. 2, frequency and duration of meal bout events were estimated based on differences in volume when cows were eating. Estimated frequency and durations were similar to manually recorded data and indicated feasibility of behavioral monitoring as an opportunity for further system development. Prior studies have integrated machine learning approaches for refinement of camera monitoring systems and mitigation of reported environmental impact on accurate quantification of TMR volume. Further development of the current system through integration of machine learning applications will improve accuracy and industry applicability as an automated feed bunk management tool for collection of TMR intake and behavioral data on a per-cow basis.</p>

This thesis presents a new method for improved resolution of stereoscopic 3D terrain mapping by local dense bundling of disparity maps. The Unmanned Systems Lab (USL) at Virginia Tech is designing an unmanned aerial vehicle (UAV) first-response system capable of 3D terrain mapping in the wake of a nuclear event. The UAV is a helicopter, and is equipped with a stereo boom imaging system, GPS, and an inertial measurement system (IMU) for low-altitude aerial mapping. Previous 3D reconstruction algorithms on the project used two-frame rectified stereo correspondence to create a local 3D map, which was geo-located by raw GPS and IMU data. The new local dense bundling algo-rithm combines multiple pairs of stereo images by SURF feature point matching, image rectification, matching of dense points with semi-global block matching, and optimization of camera pose and dense 3D point location using a stereo-constrained local bundle adjustment. The performance of the algorithm is evaluated numerically on synthetic im-agery and qualitatively on real aerial flight data. Results indicate the algorithm produces marked improvement in accuracy and vertical resolution, given a proper helicopter flight path and sufficient image overlap. With synthetic imagery and precise pose supplied, the algorithm shows a 1.2x to 6x reduction in vertical error. / Master of Science

Object tracking and object measurement are two well-established and prominent concepts within the field of computer vision. While the two techniques are fairly robust in images and videos where the object of interest(s) is clear, there is a significant decrease in performance when objects appear obscured due to a number of factors including motion blur, far distance from the camera, and blending with the background. Additionally, most established object detection models focus on detecting as many objects as possible, rather than striving for high accuracy on a few, predetermined objects. One application of computer vision tracking and measurement in imprecise and single-object scenarios is programmatically measuring the distance of a shot put throw in the sport of track and field. Shot put throws in competition are currently measured by human officials, which is both time-consuming and often erroneous. In this work, a computer vision system is developed that automatically tracks the path of a shot put throw through combining a custom-trained YOLO model and path predictor with kinematic formulas and then measures its distance traveled by triangulation using binocular stereo vision. The final distance measurements produce directionally accurate results with an average error of 82% after removing one outlier, an average detection time of 2.9 ms per frame and a total average run time of 4.5 minutes from the time the shot put leaves the thrower's hand. Shortcomings of tracking and measurement in imperfect or singular object settings are addressed and potential improvements are suggested, while also providing the opportunity to increase the accuracy and efficiency of the sporting event. / Master of Science / Object tracking and object measurement are two well-established and prominent concepts within the field of computer vision. While the two techniques are fairly robust in images and videos where the object of interest(s) is clear, there is a significant decrease in performance when objects appear obscured due to a number of factors including motion blur, far distance from the camera, and blending with the background. Additionally, most established object detection models focus on detecting as many objects as possible, rather than striving for high accuracy on a few, predetermined objects. One application of computer vision tracking and measurement in imprecise and single-object scenarios is programmatically measuring the distance of a shot put throw in the sport of track and field. Shot put throws in competition are currently measured by human officials, which is both time-consuming and often erroneous. In this work, a computer vision system is developed that automatically tracks the path of a shot put throw through combining a custom-trained YOLO model and path predictor with kinematic formulas and then measures its distance traveled by triangulation using binocular stereo vision. The final distance measurements produce directionally accurate results with an average error of 82% after removing one outlier, an average detection time of 2.9 ms per frame and a total average run time of 4.5 minutes from the time the shot put leaves the thrower's hand. Shortcomings of tracking and measurement in imperfect or singular object settings are addressed and potential improvements are suggested, while also providing the opportunity to increase the accuracy and efficiency of the sporting event.

Im Rahmen dieser Arbeit wurde der Einfluss von passiven und elastischen Rückstromklappen, die auch als Flaps bezeichnet werden, auf einen Tragflügel mit NACA0020 Profil untersucht. Mithilfe einer Kraftwaage erfolgte zunächst die Erfassung der Auswirkungen auf das aerodynamische Verhalten des Tragflügels vor und nach der Strömungsablösung. Für ein detailliertes Verständnis wurde zusätzlich die Umströmung mit der Rauchdrahttechnik visualisiert und die Flapkinematik mit der Stereo Vision Technik aufgenommen. Es konnte festgestellt werden, dass die Vorderkantenflaps mit der geringsten Biegesteifigkeit die Gleitzahl des Tragflügels vor allem in abgelöster Strömung erhöhen. Die festgestellte Auftriebssteigerung resultiert aus der langsamen Aufstellbewegung und beschleunigten Anlegebewegung der Flaps, die eine einhergehende Reduzierung der turbulenten Ablösung verursachen. Die Ergebnisse der Arbeit liefern zahlreiche Erkenntnisse, die eine Übertragung des festgestellten Effekts auf andere technische Anwendungen erleichtern.:Abbildungsverzeichnis....................................................................... VII Tabellenverzeichnis............................................................................ XII Symbol- & Abkürzungsverzeichnis..................................................XVI 1 Einleitung......................................................................................... 1 2 Stand der Forschung........................................................................ 4 2.1 Wesentliche Aspekte von Profilumströmungen ................................. 4 2.2 Zusammenfassung essenzieller Aspekte von Tragflügeln mit Flaps ......7 3 Numerische Untersuchung der Profilumströmung....................... 13 3.1 Numerische Modell ......................................................................13 3.1.1 Grundgleichungen und Turbulenzmodell ..............................13 3.1.2 Randbedingungen und Diskretisierungsschema .....................16 3.2 Ergebnisse für das NACA0018 Profil .............................................18 3.3 Ergebnisse für das NACA0020 Profil .............................................19 3.4 Schlussfolgerung aus den Simulationen ..........................................22 4 Kraftmessungen an einem NACA0020 Tragflügel ....................... 23 4.1 Versuchsvorbereitung ...................................................................23 4.1.1 Windkanal ........................................................................23 4.1.2 Tragflügel und Funktionsweise der Kraftwaage .....................25 4.2 Messunsicherheit und Validierung .................................................27 4.3 Position der Flaps auf dem Tragflügel............................................ 31 4.3.1 Flapgeometrie und Flappositionen....................................... 31 4.3.2 Polardiagramme für variierende Flapposition........................34 4.4 Faserverstärkte Silikonflaps...........................................................36 4.4.1 Verwendeten Materialien ....................................................36 4.4.2 Polardiagramm für faserverstärkte Silikonflaps .....................38 4.5 Flapgeometrie .............................................................................40 4.5.1 Untersuchte Flapformen .....................................................40 4.5.2 Polardiagramm der untersuchten Flapformen ....................... 41 4.6 Wirkung der Flaps bei instationären Anströmung...........................43 4.6.1 Versuchsdurchführung ........................................................43 4.6.2 Ergebnisse der instationären Untersuchung...........................45 4.7 Schlussfolgerung der Auftriebs- und Widerstandsuntersuchungen .....47 5 Strömungsvisualisierung mithilfe der Rauchdrahttechnik........... 49 5.1 Experimenteller Aufbau ...............................................................49 5.2 Vorgehensweise bei der Auswertung...............................................50 5.3 Ergebnisse der Visualisierung........................................................ 51 6 Flapkantenkinematik..................................................................... 58 6.1 Versuchsaufbau und Versuchsdurchführung ....................................58 6.2 Bildauswertung ........................................................................... 61 6.3 Ergebnisse ..................................................................................62 6.3.1 VK Konfiguration - ohne Faserverstärkung...........................62 6.3.2 Bewegungsausführung des Vorderkantenflaps der VK-HK Konfiguration - ohne Faserverstärkung.......................................69 6.3.3 Bewegungsausführung des Vorderkantenflaps der VK-HK Konfiguration - mit Faserverstärkung ........................................75 6.3.4 Auswertung und Interpretation ...........................................82 7 Zusammenfassung.......................................................................... 87 8 Ausblick.......................................................................................... 89 Anhang ................................................................................................ 97 A Anhang 1....................................................................................97 B Anhang 2....................................................................................98 C Anhang 3....................................................................................99 / In the following study the effects of elastic and passive flaps were investigated on an airfoil with a NACA0020 profile. At first the aerodynamic performance of different configurations was measured with a force balance. In order to detect its effects before and after stall the angle of attack was varied during the experiments. For the configurations with increased aerodynamic performance additional experiments were carried out. The smoke wire visualization and stereo vision technique allowed a detailled insight in the flow around the NACA0020 profile and the flap movement. The results show that elastic flaps at the leading and trailing edge of the airfoil improve notably the airfoil performance in deep stall. Furthermore, the highest increase of the lift-to-drag ratio was achieved for the configuration with lowest bending stiffness. It was observed that the highest reduction of the turbulent separation region is caused by the flap movement. The increase of lift-to-drag ratio results from a slow upward and a fast downward motion of the elastic flap. The study delivers helpful information for transfer of the observed effect to other technical applications.:Abbildungsverzeichnis....................................................................... VII Tabellenverzeichnis............................................................................ XII Symbol- & Abkürzungsverzeichnis..................................................XVI 1 Einleitung......................................................................................... 1 2 Stand der Forschung........................................................................ 4 2.1 Wesentliche Aspekte von Profilumströmungen ................................. 4 2.2 Zusammenfassung essenzieller Aspekte von Tragflügeln mit Flaps ......7 3 Numerische Untersuchung der Profilumströmung....................... 13 3.1 Numerische Modell ......................................................................13 3.1.1 Grundgleichungen und Turbulenzmodell ..............................13 3.1.2 Randbedingungen und Diskretisierungsschema .....................16 3.2 Ergebnisse für das NACA0018 Profil .............................................18 3.3 Ergebnisse für das NACA0020 Profil .............................................19 3.4 Schlussfolgerung aus den Simulationen ..........................................22 4 Kraftmessungen an einem NACA0020 Tragflügel ....................... 23 4.1 Versuchsvorbereitung ...................................................................23 4.1.1 Windkanal ........................................................................23 4.1.2 Tragflügel und Funktionsweise der Kraftwaage .....................25 4.2 Messunsicherheit und Validierung .................................................27 4.3 Position der Flaps auf dem Tragflügel............................................ 31 4.3.1 Flapgeometrie und Flappositionen....................................... 31 4.3.2 Polardiagramme für variierende Flapposition........................34 4.4 Faserverstärkte Silikonflaps...........................................................36 4.4.1 Verwendeten Materialien ....................................................36 4.4.2 Polardiagramm für faserverstärkte Silikonflaps .....................38 4.5 Flapgeometrie .............................................................................40 4.5.1 Untersuchte Flapformen .....................................................40 4.5.2 Polardiagramm der untersuchten Flapformen ....................... 41 4.6 Wirkung der Flaps bei instationären Anströmung...........................43 4.6.1 Versuchsdurchführung ........................................................43 4.6.2 Ergebnisse der instationären Untersuchung...........................45 4.7 Schlussfolgerung der Auftriebs- und Widerstandsuntersuchungen .....47 5 Strömungsvisualisierung mithilfe der Rauchdrahttechnik........... 49 5.1 Experimenteller Aufbau ...............................................................49 5.2 Vorgehensweise bei der Auswertung...............................................50 5.3 Ergebnisse der Visualisierung........................................................ 51 6 Flapkantenkinematik..................................................................... 58 6.1 Versuchsaufbau und Versuchsdurchführung ....................................58 6.2 Bildauswertung ........................................................................... 61 6.3 Ergebnisse ..................................................................................62 6.3.1 VK Konfiguration - ohne Faserverstärkung...........................62 6.3.2 Bewegungsausführung des Vorderkantenflaps der VK-HK Konfiguration - ohne Faserverstärkung.......................................69 6.3.3 Bewegungsausführung des Vorderkantenflaps der VK-HK Konfiguration - mit Faserverstärkung ........................................75 6.3.4 Auswertung und Interpretation ...........................................82 7 Zusammenfassung.......................................................................... 87 8 Ausblick.......................................................................................... 89 Anhang ................................................................................................ 97 A Anhang 1....................................................................................97 B Anhang 2....................................................................................98 C Anhang 3....................................................................................99

Dynamic environments pose an open problem for the performance of visual SLAM systems in real-life scenarios. Such environments involve dynamic objects that can cause pose estimation errors. Recently, Deep Learning semantic segmentation networks have been employed to identify potentially moving objects in visual SLAM; however, semantic information is subject to misclassifications and does not yield motion information alone. The thesis presents a hybrid method that employs semantic information and dense optical flow to determine moving objects through a motion likelihood. The proposed approach builds over stereo- inertial ORBSLAM 3, adding the capability of dynamic object detection to allow a more robust performance in dynamic scenarios. The system is evaluated in the OpenLORIS dataset, which considers stereo-inertial information in challenging scenes. The impact of dynamic objects on the system’s performance is studied through the use of ATE, RPE and Correctness Rate metrics. A comparison is made between the original ORBSLAM 3, ORBSLAM 3 considering only semantic information and the hybrid approach. The comparison helps identify the benefits and limitations of the proposed method. Results suggest an improvement in ATE for the hybrid approach with respect to the original ORBSLAM 3 in dynamic scenes. / Dynamiska miljöer utgör ett öppet problem för prestanda för visuella SLAM-system i verkliga scenarier. Sådana miljöer involverar dynamiska objekt som kan orsaka uppskattningsfel vid positionering. Nyligen har djupinlärning med semantiska segmenteringsnätverk använts för att identifiera potentiellt rörliga objekt i visuellt SLAM; emellertid är semantisk information föremål för felklassificeringar och ger inte enskilt rörelseinformation. Avhandlingen presenterar en hybridmetod som använder semantisk information och tätt optiskt flöde för att bestämma rörliga föremål genom en rörlig sannolikhet. Det föreslagna tillvägagångssättet bygger på stereotröghet ORBSLAM 3 och lägger till möjligheten för dynamisk objektdetektering för att möjliggöra en mer robust prestanda i dynamiska scenarier. Systemet utvärderas i OpenLORIS dataset, som tar hänsyn till stereo-inertial information i utmanande scener. Dynamiska objekts inverkan på systemets prestanda studeras med hjälp av medelvärdet av translationsfelet (ATE), relativa positioneringsfelet (RPE) och korrekthetsfördelning (Correctness Rate). En jämförelse görs mellan den ursprungliga ORBSLAM 3, ORBSLAM 3 med endast semantisk information, samt hybridmetoden. Jämförelsen hjälper till att identifiera fördelarna och begränsningarna med den föreslagna metoden. Resultaten tyder på en förbättring av ATE för hybridmetoden i jämförelse med den ursprungliga ORBSLAM 3 i dynamiska scener.

Thesis (MScEng (Mechanical and Mechatronic Engineering))--University of Stellenbosch, 2008. / A rapid measurement system is implemented using two digital video cameras, presenting a faster and less expensive solution to certain metrology problems. The cameras are calibrated from one stereo image-pair of a 3D calibration grid that allows an immediate assessment of the achievable metric accuracy of the system. Three different methods, using either laser tracking or structured light patterns, were developed and employed to solve the coordinate extraction and correspondence matching problems. Different image processing techniques were used to speed up the entire measurement process. All software development was accomplished using only freely distributed software packages. The system achieves calibration in less than a minute and accumulates point correspondences at 12 frames per second. Accuracies of greater than 0.4 mm are achieved for a 235 x 190 x 95 mm measurement volume using a single pair of images with 640 x 480 pixel resolution each.

The subject of this dissertation is the development of three-dimensional (3D) surface profilers for semiconductor back-end inspection. The value of this study is: 1) to provide a new phase-to-height relationship for Fourier Transform Profilometry (FTP) that is universal as it allows alternate FTP system architectures for a micrometer scale object measurement, and 2) to provide a new method for full field substrate warpage and ball grid array (BGA) coplanarity inspection using machine vision. The desire to increase electronic device performance has resulted in denser and smaller IC packaging. As the dimensions of the devices decrease, the requirements for substrate flatness and surface quality become critical in avoiding device failure. For a high yield production, there is an increasing demand in the requirement for the dimensional verification of height, which requires 3D inspection. Based on the current demands from the semiconductor industry, this dissertation addresses the development of fast in-line surface profilers for large volume IC package inspection. Specifically, this dissertation studies two noncontact surface profilers. The first profiler is based on FTP for measuring the IC package front surface, the silicon die and the epoxy underfill profile. The second profiler is based on stereovision and it is intended for inspecting the BGA coplanarity and the substrate warpage. A geometrical shape based matching algorithm is also developed for finding point correspondences between IC package images. The FTP profiler provides a 1 σRMS error of about 4 μm for an IC package sample in an area of 14 mm x 6.5 mm with a 0.13 second data acquisition time. For evaluating the performance of the stereovision system, the linearity between our system and a confocal microscope is studied by measuring a particular IC sample with an area of 38 mm x 28.5 mm. The correlation coefficient is 0.965 and the 2σdifference in the two methods is 26.9 μm for the warpage measurement. For BGA coplanarity inspection the correlation coefficient is 0.952 and the 2difference is 31.2 μm. Data acquisition takes about 0.2 seconds for full field measurements.