ITC/USA 2006 Conference Proceedings / The Forty-Second Annual International Telemetering Conference and Technical Exhibition / October 23-26, 2006 / Town and Country Resort & Convention Center, San Diego, California / Drivers’ visibility is an area of automobile safety that has seen very limited improvement over the past several decades. Limited visibility is responsible for many car accidents all across America. Mirrors require constant readjustment, and are easily blocked. There is currently a lot of interest in ways to reduce or eliminate all mirrors on a car, and one such method is through a wide-angle network of cameras mounted on the vehicle’s rear. Using real-time video processing, the data from several cameras can be spliced together, and displayed on a vehicle’s dashboard in an intuitive, easy to understand fashion that a driver can quickly see without having to turn away from the road. This has extensive application to light armored vehicles in the military, as well as to automotive designers today.

This thesis describes a mosaicking system designed to generate image mosaics that facilitate size estimation of 3-dimensional objects by improving data obtained with a multi-sensor video camera. The multi-sensor camera is equipped with a pulse laser-rangefinder and internally mounted inclinometers that measure instrument orientation about three axes. Using orientation data and video data, mosaics are constructed to reduce orientation data errors by augmenting orientation data with image information. Mosaicking is modeled as a 7-step refinement process: 1) an initial mosaic is constructed using orientation information obtained from the camera's inclinometers; 2) mosaics are refined by using coarse-to-fine processing to minimize an energy metric and, consequently, align overlapping video frames; 3) pair-wise mosaicking errors are detected, and removed, using an energy-based confidence metric; 4) mosaic accuracy is refined via color analysis; 5) mosaic accuracy is refined by estimating an affine transformation to align overlapping frames; 6) affine transformation approximations between overlapping video frames are used to reduce image noise through super-resolution; 7) original orientation data are corrected given the refined orientations of images within the mosaic. The mosaicking system has been tested using objects of known size and orientation accuracy has been improved by 86% for these cases. / Master of Science

Made available in DSpace on 2014-06-11T19:23:31Z (GMT). No. of bitstreams: 0 Previous issue date: 2002Bitstream added on 2014-06-13T20:30:18Z : No. of bitstreams: 1 arrudajunior_er_me_prud.pdf: 2916412 bytes, checksum: 6eaa814b2f39dc382f9206c783e274b4 (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Paralelo ao advento da computação e dos equipamentos fotográficos, evoluiu também a Fotogrametria, surgindo assim a Fotogrametria Digital, que realiza os processos fotogramétricos num ambiente de computador. Como as câmaras fotogramétricas digitais ainda possuem um preço bastante elevado, as fotografias obtidas com câmaras digitais de uso doméstico (fotografias de pequeno formato), como alternativa, começaram apoiando as fotografias aéreas convencionais e atualmente estão substituindo-as em inúmeras aplicações. Pelo seu tamanho reduzido, faz-se necessário a fusão (mosaicagem) de um grande número destas fotografias para o recobrimento fotográfico de uma área de interesse. Como os produtos disponíveis, que atendem de maneira satisfatória o processo de produção destes mosaicos, estejam disponíveis em grandes pacotes de softwares, com custo bastante elevado, com necessidade de operadores especializados e necessidade de estações de trabalho específicas, surgiu a necessidade de um produto que realizasse a mosaicagem de imagens digitais. Neste contexto, o trabalho ora proposto, desenvolve um sistema visando solucionar o problema acima mencionado. / As well as the computer science and the photographics advents the photogrammetry has also developed. This development promoted the rise of digital photogrammetry which is responsibles for all the photogrammetry processes in a computer. Once digital photogrammetric cameras still cost a high price, the domestic cameras became an alternative to take usual aero photographics and nowaday domestic cameras are being used in many cases. But by the small size of the pictures is necessary to joint a great member of those pictures (like in a mosaic) to have the photographics recove of the desired area. The disposable products to satisfy the production process of these mosaics are sold only in big packs of software for a high price. The need of specialized operations brought the necessity of a new product to joint digital images. In this context this work develops a system to solve the problem already mentioned.

Orientador: Júlio Kiyoshi Hasegawa / Resumo: Paralelo ao advento da computação e dos equipamentos fotográficos, evoluiu também a Fotogrametria, surgindo assim a Fotogrametria Digital, que realiza os processos fotogramétricos num ambiente de computador. Como as câmaras fotogramétricas digitais ainda possuem um preço bastante elevado, as fotografias obtidas com câmaras digitais de uso doméstico (fotografias de pequeno formato), como alternativa, começaram apoiando as fotografias aéreas convencionais e atualmente estão substituindo-as em inúmeras aplicações. Pelo seu tamanho reduzido, faz-se necessário a fusão (mosaicagem) de um grande número destas fotografias para o recobrimento fotográfico de uma área de interesse. Como os produtos disponíveis, que atendem de maneira satisfatória o processo de produção destes mosaicos, estejam disponíveis em grandes pacotes de softwares, com custo bastante elevado, com necessidade de operadores especializados e necessidade de estações de trabalho específicas, surgiu a necessidade de um produto que realizasse a mosaicagem de imagens digitais. Neste contexto, o trabalho ora proposto, desenvolve um sistema visando solucionar o problema acima mencionado. / Abstract: As well as the computer science and the photographics advents the photogrammetry has also developed. This development promoted the rise of digital photogrammetry which is responsibles for all the photogrammetry processes in a computer. Once digital photogrammetric cameras still cost a high price, the domestic cameras became an alternative to take usual aero photographics and nowaday domestic cameras are being used in many cases. But by the small size of the pictures is necessary to joint a great member of those pictures (like in a mosaic) to have the photographics recove of the desired area. The disposable products to satisfy the production process of these mosaics are sold only in big packs of software for a high price. The need of specialized operations brought the necessity of a new product to joint digital images. In this context this work develops a system to solve the problem already mentioned. / Mestre

The thesis details the development of computer vision and path planning algorithms in order to map an area via UAV aerial imagery and aid a UGV in navigating a roadway when the road conditions are not previously known (i.e. disaster situations). Feature detection was used for transform calculation and image warping to create mosaics. A continuous extension using dynamic cropping based on newly gathered images was used to improve performance and computation time. Road detection using k-means segmentation and binary image morphing was applied to aerial imagery with image shifting tracked by the mosaicking to develop a large road map. Improvements to computation time were developed using k-means for calibration at intervals and nearest neighbor calculating for each image. This showed a greatly reduced computation time for a series of images with only 1-2% error compared to regular k-means segmentation. Path planning for the UAV utilized a traveling wave applied to the traveling salesman genetic algorithm solution to prioritize close targets and facilitate UGV deployment. Based on the large map of road locations and road detection method, the Rapidly-exploring Random Tree (RRT) algorithm was modified for real-time application and efficient data processing. Considerations of incomplete maps and goal adjustments was also incorporated. Finally, aerial imagery from an actual UAV flight was processed using these algorithms to validate and test flight parameters. Testing of different flight parameters showed the desired image overlay of 50% to give accurate mosaics. It also helped to develop a benchmark for the altitude, image resolution and frequency for flights. Vehicle requirements and algorithm limitations for future applications of this system are also discussed. / Master of Science

Algorithms for automatic image registration and mosaicking are developed for a miniature Unmanned Aerial Vehicle (MINI-UAV) platform, assembled by Air-O-Space International (AOSI) L.L.C.. Three cameras onboard this MINI-UAV platform acquire images in a single frame simultaneously at green (550nm), red (650 nm), and near infrared (820nm) wavelengths, but with shifting and rotational misalignment. The area-based method is employed in the developed algorithms for control point detection, which is applicable when no prominent feature details are present in image scenes. Because the three images to be registered have different spectral characteristics, region of interest determination and control point selection are the two key steps that ensure the quality of control points. Affine transformation is adopted for spatial transformation, followed by bilinear interpolation for image resampling. Mosaicking is conducted between adjacent frames after three-band co-registration. Pre-introducing the rotation makes the area-based method feasible when the rotational misalignment cannot be ignored. The algorithms are tested on three image sets collected at Stennis Space Center, Greenwood, and Oswalt in Mississippi. Manual evaluation confirms the effectiveness of the developed algorithms. The codes are converted into a software package, which is executable under the Microsoft Windows environment of personal computer platforms without the requirement of MATLAB or other special software support for commercial-off-the-shelf (COTS) product. The near real-time decision-making support is achievable with final data after its installation into the ground control station. The final products are color-infrared (CIR) composite and normalized difference vegetation index (NDVI) images, which are used in agriculture, forestry, and environmental monitoring.

Unmanned Aerial Vehicles (UAVs) equipped with lightweight, inexpensive cameras have grown in popularity by enabling new uses of UAV technology. However, the video retrieved from small UAVs is often unwatchable due to high frequency jitter. Beginning with an investigation of previous stabilization work, this thesis discusses the challenges of stabilizing UAV based video. It then presents a software based computer vision framework and discusses its use to develop a real-time stabilization solution. A novel approach of estimating intended video motion is then presented. Next, the thesis proceeds to extend previous target localization work by allowing the operator to easily identify targets—rather than relying solely on color segmentation—to improve reliability and applicability in real world scenarios. The resulting approach creates a low cost and easy to use solution for aerial video display and target localization.

Thesis (MA (Geography and Environmental Studies))--University of Stellenbosch, 2005. / Salinisation is a major environmental hazard that reduces agricultural yields and degrades arable land. Two main categories of salinisation are: primary and secondary soil salinisation. While primary soil salinisation is caused by natural processes, secondary soil salinisation is caused by human factors. Incorrect irrigation practices are the major contributor to secondary soil salinisation. Because of low costs and less time that is associated with the use of remote sensing techniques, remote sensing data is used in this study to identify and map salinised irrigated land between Upington and Keimoes, Northern Cape Province, in South Africa. The aim of this study is to evaluate the potential of digital aerial imagery in identifying salinised cultivated land. Two methods were used to realize this aim. The first method involved visually identifying salinised areas on NIR, and NDVI images and then digitizing them onscreen. In the second method, digital RGB mosaicked, stacked, and NDVI images were subjected to unsupervised image classification to identify salinised land. Soil samples randomly selected and analyzed for salinity were used to validate the results obtained from the analysis of aerial photographs. Both techniques had difficulties in identifying salinised land because of their inability to differentiate salt induced stress from other forms of stress. Visual image analysis was relatively successful in identifying salinised land than unsupervised image classification. Visual image analysis correctly identified about 55% of salinised land while only about 25% was identified by unsupervised classification. The two techniques predict that an average of about 10% of irrigated land is affected by salinisation in the study area. This study found that although visual analysis was time consuming and cannot differentiate salt induced stress from other forms; it is fairly possible to identify areas of crop stress using digital aerial imagery. Unsupervised classification was not successful in identifying areas of crop stress.

This thesis analyzes the problem of acquiring stereoscopic images in all gazing directions around a reference viewpoint in space with the purpose of creating stereoscopic panoramas of non-static scenes. The generation of immersive stereoscopic imagery suitable to stimulate human stereopsis requires images from two distinct viewpoints with horizontal parallax in all gazing directions, or to be able to simulate this situation in the generated imagery. The available techniques to produce omnistereoscopic imagery for human viewing are not suitable to capture dynamic scenes stereoscopically. This is a not trivial problem when considering acquiring the entire scene at once while avoiding self-occlusion between multiple cameras. In this thesis, the term omnidirectional refers to all possible gazing directions in azimuth and a limited set of directions in elevation. The acquisition of dynamic scenes restricts the problem to those techniques suitable for collecting in one simultaneous exposure all the necessary visual information to recreate stereoscopic imagery in arbitrary gazing directions. The analysis of the problem starts by defining an omnistereoscopic viewing model for the physical magnitude to be measured by a panoramic image sensor intended to produce stereoscopic imagery for human viewing. Based on this model, a novel acquisition model is proposed, which is suitable to describe the omnistereoscopic techniques based on horizontal stereo. From this acquisition model, an acquisition method based on multiple cameras combined with the rendering by mosaicking of partially overlapped stereoscopic images is identified as a good candidate to produce omnistereoscopic imagery of dynamic scenes. Experimental acquisition and rendering tests were performed for different multiple-camera configurations. Furthermore, a mosaicking criterion between partially overlapped stereoscopic images based on the continuity of the perceived depth and the prediction of the location and magnitude of unwanted vertical disparities in the final stereoscopic panorama are two main contributions of this thesis. In addition, two novel omnistereoscopic acquisition and rendering techniques were introduced. The main contributions to this field are to propose a general model for the acquisition of omnistereoscopic imagery, to devise novel methods to produce omnistereoscopic imagery, and more importantly, to contribute to the awareness of the problem of acquiring dynamic scenes within the scope of omnistereoscopic research.

This thesis analyzes the problem of acquiring stereoscopic images in all gazing directions around a reference viewpoint in space with the purpose of creating stereoscopic panoramas of non-static scenes. The generation of immersive stereoscopic imagery suitable to stimulate human stereopsis requires images from two distinct viewpoints with horizontal parallax in all gazing directions, or to be able to simulate this situation in the generated imagery. The available techniques to produce omnistereoscopic imagery for human viewing are not suitable to capture dynamic scenes stereoscopically. This is a not trivial problem when considering acquiring the entire scene at once while avoiding self-occlusion between multiple cameras. In this thesis, the term omnidirectional refers to all possible gazing directions in azimuth and a limited set of directions in elevation. The acquisition of dynamic scenes restricts the problem to those techniques suitable for collecting in one simultaneous exposure all the necessary visual information to recreate stereoscopic imagery in arbitrary gazing directions. The analysis of the problem starts by defining an omnistereoscopic viewing model for the physical magnitude to be measured by a panoramic image sensor intended to produce stereoscopic imagery for human viewing. Based on this model, a novel acquisition model is proposed, which is suitable to describe the omnistereoscopic techniques based on horizontal stereo. From this acquisition model, an acquisition method based on multiple cameras combined with the rendering by mosaicking of partially overlapped stereoscopic images is identified as a good candidate to produce omnistereoscopic imagery of dynamic scenes. Experimental acquisition and rendering tests were performed for different multiple-camera configurations. Furthermore, a mosaicking criterion between partially overlapped stereoscopic images based on the continuity of the perceived depth and the prediction of the location and magnitude of unwanted vertical disparities in the final stereoscopic panorama are two main contributions of this thesis. In addition, two novel omnistereoscopic acquisition and rendering techniques were introduced. The main contributions to this field are to propose a general model for the acquisition of omnistereoscopic imagery, to devise novel methods to produce omnistereoscopic imagery, and more importantly, to contribute to the awareness of the problem of acquiring dynamic scenes within the scope of omnistereoscopic research.