Motion blur in digital images - analys, detection and correction of motion blur in photogrammetry

Unmanned aerial vehicles (UAV) have become an interesting and active research topic for photogrammetry. Current research is based on images acquired by an UAV, which have a high ground resolution and good spectral and radiometrical resolution, due to the low flight altitudes combined with a high resolution camera. UAV image flights are also cost effective and have become attractive for many applications including, change detection in small scale areas. One of the main problems preventing full automation of data processing of UAV imagery is the degradation effect of blur caused by camera movement during image acquisition. This can be caused by the normal flight movement of the UAV as well as strong winds, turbulence or sudden operator inputs. This blur disturbs the visual analysis and interpretation of the data, causes errors and can degrade the accuracy in automatic photogrammetric processing algorithms. The detection and removal of these images is currently achieved manually, which is both time consuming and prone to error, particularly for large image-sets. To increase the quality of data processing an automated process is necessary, which must be both reliable and quick. This thesis proves the negative affect that blurred images have on photogrammetric processing. It shows that small amounts of blur do have serious impacts on target detection and that it slows down processing speed due to the requirement of human intervention. Larger blur can make an image completely unusable and needs to be excluded from processing. To exclude images out of large image datasets an algorithm was developed. The newly developed method makes it possible to detect blur caused by linear camera displacement. The method is based on human detection of blur. Humans detect blurred images best by comparing it to other images in order to establish whether an image is blurred or not. The developed algorithm simulates this procedure by creating an image for comparison using image processing. Creating internally a comparable image makes the method independent of additional images. However, the calculated blur value named SIEDS (saturation image edge difference standard-deviation) on its own does not provide an absolute number to judge if an image is blurred or not. To achieve a reliable judgement of image sharpness the SIEDS value has to be compared to other SIEDS values of the same dataset. This algorithm enables the exclusion of blurred images and subsequently allows photogrammetric processing without them. However, it is also possible to use deblurring techniques to restor blurred images. Deblurring of images is a widely researched topic and often based on the Wiener or Richardson-Lucy deconvolution, which require precise knowledge of both the blur path and extent. Even with knowledge about the blur kernel, the correction causes errors such as ringing, and the deblurred image appears muddy and not completely sharp. In the study reported in this paper, overlapping images are used to support the deblurring process. An algorithm based on the Fourier transformation is presented. This works well in flat areas, but the need for geometrically correct sharp images for deblurring may limit the application. Another method to enhance the image is the unsharp mask method, which improves images significantly and makes photogrammetric processing more successful. However, deblurring of images needs to focus on geometric correct deblurring to assure geometric correct measurements. Furthermore, a novel edge shifting approach was developed which aims to do geometrically correct deblurring. The idea of edge shifting appears to be promising but requires more advanced programming

The potential of flexible micro pillars to investigate near wall flow

The potential of flexible micro pillars for measuring near wall flow phenom- ena was theoretically and experimentally investigated. The bending of the micro pillars is a measure for the local wall shear stress (WSS) or a visualisa- tion of near wall flow phenomena. Polydimethylsiloxane (PDMS) was chosen as material for the sensor. Within the thesis the experimental work with the shear stress sensor mainly has the focus on the transition to turbulence. Closely connected are improvements of the measurement techniques. The transition is thereby investigated qualitatively and quantitatively. Another huge part of the thesis was the improvement of the reliability of the manu- facturing process of the micro pillars. For this purpose new manufacturing methods for single pillars and pillar arrays have been tested. Further on, dif- ferent detection methods for capturing the bending of the pillar were tested, too. The measurements of the transitional flow were performed at flat plate boundary layer in an oil channel. Ondina 913 was used as test fluid. The physical properties of the PDMS changed dramatically while longer exposed to Ondina 913. Hence, it was unfeasible to receive reproducible quantita- tive results. Better results were achieved if the pillars are used as flexible micro tufts revealing the flow and WSS topology directly at the wall quali- tatively. With the pillar sensor it was possible to detect turbulent spots in the transitional state of the flat plate boundary layer. Furthermore, coherent structures and their typical sign in the viscous sublayer could be identified and the occurrence of critical points and back flow could be experimentally verified

Advanced scanners and imaging systems for earth observations

Assessments of present and future sensors and sensor related technology are reported along with a description of user needs and applications. Five areas are outlined: (1) electromechanical scanners, (2) self-scanned solid state sensors, (3) electron beam imagers, (4) sensor related technology, and (5) user applications. Recommendations, charts, system designs, technical approaches, and bibliographies are included for each area

NASA Tech Briefs, April 1991

Topics: New Product Ideas; NASA TU Services; Electronic Components and Circuits; Electronic Systems; Physical Sciences; Materials; Computer Programs; Mechanics; Machinery; Fabrication Technology; Mathematics and Information Sciences; Life Sciences

Research and Technology, 1994

This report selectively summarizes the NASA Lewis Research Center's research and technology accomplishments for the fiscal year 1994. It comprises approximately 200 short articles submitted by the staff members of the technical directorates. The report is organized into six major sections: Aeronautics, Aerospace Technology, Space Flight Systems, Engineering and Computational Support, Lewis Research Academy, and Technology Transfer. A table of contents and author index have been developed to assist the reader in finding articles of special interest. This report is not intended to be a comprehensive summary of all research and technology work done over the past fiscal year. Most of the work is reported in Lewis-published technical reports, journal articles, and presentations prepared by Lewis staff members and contractors. In addition, university grants have enabled faculty members and graduate students to engage in sponsored research that is reported at technical meetings or in journal articles. For each article in this report a Lewis contact person has been identified, and where possible, reference documents are listed so that additional information can be easily obtained. The diversity of topics attests to the breadth of research and technology being pursued and to the skill mix of the staff that makes it possible

Holography: A survey

The development of holography and the state of the art in recording and displaying information, microscopy, motion, pictures, and television applications are discussed. In addition to optical holography, information is presented on microwave, acoustic, ultrasonic, and seismic holography. Other subjects include data processing, data storage, pattern recognition, and computer-generated holography. Diagrams of holographic installations are provided. Photographs of typical holographic applications are used to support the theoretical aspects

Foundations, Inference, and Deconvolution in Image Restoration

Image restoration is a critical preprocessing step in computer vision, producing images with reduced noise, blur, and pixel defects. This enables precise higher-level reasoning as to the scene content in later stages of the vision pipeline (e.g., object segmentation, detection, recognition, and tracking). Restoration techniques have found extensive usage in a broad range of applications from industry, medicine, astronomy, biology, and photography. The recovery of high-grade results requires models of the image degradation process, giving rise to a class of often heavily underconstrained, inverse problems. A further challenge specific to the problem of blur removal is noise amplification, which may cause strong distortion by ringing artifacts. This dissertation presents new insights and problem solving procedures for three areas of image restoration, namely (1) model foundations, (2) Bayesian inference for high-order Markov random fields (MRFs), and (3) blind image deblurring (deconvolution). As basic research on model foundations, we contribute to reconciling the perceived differences between probabilistic MRFs on the one hand, and deterministic variational models on the other. To do so, we restrict the variational functional to locally supported finite elements (FE) and integrate over the domain. This yields a sum of terms depending locally on FE basis coefficients, and by identifying the latter with pixels, the terms resolve to MRF potential functions. In contrast with previous literature, we place special emphasis on robust regularizers used commonly in contemporary computer vision. Moreover, we draw samples from the derived models to further demonstrate the probabilistic connection. Another focal issue is a class of high-order Field of Experts MRFs which are learned generatively from natural image data and yield best quantitative results under Bayesian estimation. This involves minimizing an integral expression, which has no closed form solution in general. However, the MRF class under study has Gaussian mixture potentials, permitting expansion by indicator variables as a technical measure. As approximate inference method, we study Gibbs sampling in the context of non-blind deblurring and obtain excellent results, yet at the cost of high computing effort. In reaction to this, we turn to the mean field algorithm, and show that it scales quadratically in the clique size for a standard restoration setting with linear degradation model. An empirical study of mean field over several restoration scenarios confirms advantageous properties with regard to both image quality and computational runtime. This dissertation further examines the problem of blind deconvolution, beginning with localized blur from fast moving objects in the scene, or from camera defocus. Forgoing dedicated hardware or user labels, we rely only on the image as input and introduce a latent variable model to explain the non-uniform blur. The inference procedure estimates freely varying kernels and we demonstrate its generality by extensive experiments. We further present a discriminative method for blind removal of camera shake. In particular, we interleave discriminative non-blind deconvolution steps with kernel estimation and leverage the error cancellation effects of the Regression Tree Field model to attain a deblurring process with tightly linked sequential stages

Renaissance Fun

Renaissance Fun is about the technology of Renaissance entertainments in stage machinery and theatrical special effects; in gardens and fountains; and in the automata and self-playing musical instruments that were installed in garden grottoes. How did the machines behind these shows work? How exactly were chariots filled with singers let down onto the stage? How were flaming dragons made to fly across the sky? How were seas created on stage? How did mechanical birds imitate real birdsong? What was ‘artificial music’, three centuries before Edison and the phonograph? How could pipe organs be driven and made to play themselves by waterpower alone? And who were the architects, engineers, and craftsmen who created these wonders? All these questions are answered. At the end of the book we visit the lost ‘garden of marvels’ at Pratolino with its many grottoes, automata and water jokes; and we attend the performance of Mercury and Mars in Parma in 1628, with its spectacular stage effects and its music by Claudio Monteverdi – one of the places where opera was born. Renaissance Fun is offered as an entertainment in itself. But behind the show is a more serious scholarly argument, centred on the enormous influence of two ancient writers on these subjects, Vitruvius and Hero. Vitruvius’s Ten Books on Architecture were widely studied by Renaissance theatre designers. Hero of Alexandria wrote the Pneumatics, a collection of designs for surprising and entertaining devices that were the models for sixteenth and seventeenth century automata. A second book by Hero On Automata-Making – much less well known, then and now – describes two miniature theatres that presented plays without human intervention. One of these, it is argued, provided the model for the type of proscenium theatre introduced from the mid-sixteenth century, the generic design which is still built today. As the influence of Vitruvius waned, the influence of Hero grew

Renaissance Fun: The machines behind the scenes

Renaissance Fun is about the technology of Renaissance entertainments in stage machinery and theatrical special effects; in gardens and fountains; and in the automata and self-playing musical instruments that were installed in garden grottoes. How did the machines behind these shows work? How exactly were chariots filled with singers let down onto the stage? How were flaming dragons made to fly across the sky? How were seas created on stage? How did mechanical birds imitate real birdsong? What was ‘artificial music’, three centuries before Edison and the phonograph? How could pipe organs be driven and made to play themselves by waterpower alone? And who were the architects, engineers, and craftsmen who created these wonders? All these questions are answered. At the end of the book we visit the lost ‘garden of marvels’ at Pratolino with its many grottoes, automata and water jokes; and we attend the performance of Mercury and Mars in Parma in 1628, with its spectacular stage effects and its music by Claudio Monteverdi – one of the places where opera was born. Renaissance Fun is offered as an entertainment in itself. But behind the show is a more serious scholarly argument, centred on the enormous influence of two ancient writers on these subjects, Vitruvius and Hero. Vitruvius’s Ten Books on Architecture were widely studied by Renaissance theatre designers. Hero of Alexandria wrote the Pneumatics, a collection of designs for surprising and entertaining devices that were the models for sixteenth and seventeenth century automata. A second book by Hero On Automata-Making – much less well known, then and now – describes two miniature theatres that presented plays without human intervention. One of these, it is argued, provided the model for the type of proscenium theatre introduced from the mid-sixteenth century, the generic design which is still built today. As the influence of Vitruvius waned, the influence of Hero grew

Cumulative index to NASA Tech Briefs, 1986-1990, volumes 10-14

Tech Briefs are short announcements of new technology derived from the R&D activities of the National Aeronautics and Space Administration. These briefs emphasize information considered likely to be transferrable across industrial, regional, or disciplinary lines and are issued to encourage commercial application. This cumulative index of Tech Briefs contains abstracts and four indexes (subject, personal author, originating center, and Tech Brief number) and covers the period 1986 to 1990. The abstract section is organized by the following subject categories: electronic components and circuits, electronic systems, physical sciences, materials, computer programs, life sciences, mechanics, machinery, fabrication technology, and mathematics and information sciences