Automatic Main Road Extraction from High Resolution Satellite Imagery

Road information is essential for automatic GIS (geographical information system) data acquisition, transportation and urban planning. Automatic road (network) detection from high resolution satellite imagery will hold great potential for significant reduction of database development/updating cost and turnaround time. From so called low level feature detection to high level context supported grouping, so many algorithms and methodologies have been presented for this purpose. There is not any practical system that can fully automatically extract road network from space imagery for the purpose of automatic mapping. This paper presents the methodology of automatic main road detection from high resolution satellite IKONOS imagery. The strategies include multiresolution or image pyramid method, Gaussian blurring and the line finder using 1-dimemsional template correlation filter, line segment grouping and multi-layer result integration. Multi-layer or multi-resolution method for road extraction is a very effective strategy to save processing time and improve robustness. To realize the strategy, the original IKONOS image is compressed into different corresponding image resolution so that an image pyramid is generated; after that the line finder of 1-dimemsional template correlation filter after Gaussian blurring filtering is applied to detect the road centerline. Extracted centerline segments belong to or do not belong to roads. There are two ways to identify the attributes of the segments, the one is using segment grouping to form longer line segments and assign a possibility to the segment depending on the length and other geometric and photometric attribute of the segment, for example the longer segment means bigger possibility of being road. Perceptual-grouping based method is used for road segment linking by a possibility model that takes multi-information into account; here the clues existing in the gaps are considered. Another way to identify the segments is feature detection back-to-higher resolution layer from the image pyramid

Automated classification of retinopathy of prematurity in newborns

La Retinopatia de l'Prematur (ROP) és una malaltia que afecta els nadons prematurs mostrant-se com un subdesenvolupament dels vasos retinians. El diagnòstic precoç d'aquesta malaltia és un tot un repte ja que requereix de professionals altament qualificats amb coneixements molt específics. Actualment a Espanya, només uns pocs hospitals compten amb els equipaments especialitzats per al tractament i diagnòstic d'aquesta patologia. Aquest projecte final de màster, té com a objectiu final desenvolupar una eina preliminar per a la classificació de l'extensió aquesta malaltia. Aquesta applicació, ha estat disenyada per a ser integrada en una plataforma de suport a la diagnosi de la Retinopatia i poder evaluar la malaltia, proporcionant informació detallada sobre les imatge analitzades. Aquest projecte, també estableix les bases per a la comparació entre l'enfocament clínic, que utilitzen els metges, i la naturalesa "Black-Box" natural de la Xarxa Neuronal Artificial per classificar l'extensió de la malaltia. L'algoritme desenvolupat és capaç de: segmentar els vasos oculars utilitzant una xarxa neuronal convolucional U-Net; extreure les característiques representatives de la malaltia a partir de la segmentació; i classificar aquestes característiques en casos ROP i casos ROP Plus, mitjançant l'ús d'una gamma de classificadors. Les principals característiques analitzades són la tortuositat i el gruix dels vasos, indicadors de la malaltia emprats pels patolegs experts. La xarxa de segmentació ha obtingut una precisió global de l'96,15%. Els resultats dels diferents classificadors indiquen un trade-off entre la precisió i el volum d'imatges analitzades. S'ha obtingut una precisió de l'100% emprant un classificador de doble threshold en el analisis de l'12,5% de les imatges. En canvi, mitjançant l'ús d'un classificador "decision tree", s'ha obtingut una precisió del 70,8% analitzant el 100% de les imatges.La Retinopatía del Prematuro (ROP) es una enfermedad que afecta a los bebés prematuros mostrándose como el subdesarrollo de los vasos retinianos. El diagnóstico precoz de dicha enfermedad es un desafío ya que requiere de profesionales altamente capacitados con conocimientos muy específicos. Actualmente en España, solo unos pocos hospitales están dotados con los equipamientos especializados para el tratamiento y diagnóstico de esta patología Este proyecto final de master, tiene como objetivo final desarrollar una herramienta preliminar para la clasificación de la extensión dicha enfermedad. Esta aplicación, ha sido diseñada para ser integrada en una plataforma de soporte al diagnóstico de la Retinopatía y evaluar la enfermedad, proporcionando información detallada sobre las imágenes analizadas. Este proyecto también sienta las bases para la comparación entre el enfoque clínico, que utilizan los médicos, y la naturaleza "Black-Box" natural de la Red Neuronal Artificial para clasificar la extensión de la enfermedad. El algoritmo desarrollado es capaz de: segmentar los vasos oculares utilizando una red neuronal convolucional U-Net; extraer las características representativas de la enfermedad a partir de la segmentación; y clasificar estas características en casos ROP y casos ROP Plus, mediante el empleo de una gama de clasificadores. Las principales características analizadas son la tortuosidad y el grosor de los vasos, indicadores cauterizantes de la enfermedad empleados por los patólogos expertos. La red de segmentación ha logrado una precisión global del 96,15%. Los resultados de los diferentes clasificadores indican un trade-off entre la precisión y el volumen de imágenes analizadas. Se ha obtenido una precisión del 100% empleando un clasificador de doble threshold en el análisis del 12,5% de las imágenes. En cambio, mediante el uso de un clasificador “decision tree”, se ha obtenido una precisión del 70,8% analizando el 100% de las imágenes.Retinopathy of Prematurity (ROP) is a disease in preterm babies with underdevelopment in retinal vessels. Early diagnosis of the disease is challenging and requires skilled professionals with very specific knowledge. Currently, in Spain, only a few hospitals have departments specialized in this pathology and, therefore, are able to diagnose and treat it accordingly. This master project aims to develop the first preliminary instrument for the classification of the extent of Retinopathy disease. This tool has been built to be integrated into a diagnostic support platform to detect the presence of retinopathy and evaluate the sickness, providing insightful information regarding the specific image. This project also lays the base for the comparison between the clinical approach that the doctors use and the “black box” approach the Artificial Neural Network uses to predict the extent of the disease. The developed algorithm is able to: segment ocular vessels using a U-Net Convolutional Neural Network; extract the critical features from the segmentation; and classify those features into ROP cases and ROP Plus cases by employing a range of different classifiers. The main features analyzed by the related specialists and thus selected are tortuosity and thickness of the vessels. The segmentation Network achieved a global accuracy of 96.15%. The results of the different classifiers indicate a trade-off between accuracy and the volume of computed images. An accuracy of 100% was achieved with a Double Threshold classifier on 12.5% of the images. Instead, by using a Decision tree classifier, an accuracy of 70.8% was achieved when computing 100% of the images

Modelling Neuron Morphology: Automated Reconstruction from Microscopy Images

Understanding how the brain works is, beyond a shadow of doubt, one of the greatest challenges for modern science. Achieving a deep knowledge about the structure, function and development of the nervous system at the molecular, cellular and network levels is crucial in this attempt, as processes at all these scales are intrinsically linked with higher-order cognitive functions. The research in the various areas of neuroscience deals with advanced imaging techniques, collecting an increasing amounts of heterogeneous and complex data at different scales. Then, computational tools and neuroinformatics solutions are required in order to integrate and analyze the massive quantity of acquired information. Within this context, the development of automaticmethods and tools for the study of neuronal anatomy has a central role. The morphological properties of the soma and of the axonal and dendritic arborizations constitute a key discriminant for the neuronal phenotype and play a determinant role in network connectivity. A quantitative analysis allows the study of possible factors influencing neuronal development, the neuropathological abnormalities related to specific syndromes, the relationships between neuronal shape and function, the signal transmission and the network connectivity. Therefore, three-dimensional digital reconstructions of soma, axons and dendrites are indispensable for exploring neural networks. This thesis proposes a novel and completely automatic pipeline for neuron reconstruction with operations ranging from the detection and segmentation of the soma to the dendritic arborization tracing. The pipeline can deal with different datasets and acquisitions both at the network and at the single scale level without any user interventions or manual adjustment. We developed an ad hoc approach for the localization and segmentation of neuron bodies. Then, various methods and research lines have been investigated for the reconstruction of the whole dendritic arborization of each neuron, which is solved both in 2D and in 3D images

Genetic algorithm and tabu search approaches to quantization for DCT-based image compression

Today there are several formal and experimental methods for image compression, some of which have grown to be incorporated into the Joint Photographers Experts Group (JPEG) standard. Of course, many compression algorithms are still used only for experimentation mainly due to various performance issues. Lack of speed while compressing or expanding an image, poor compression rate, and poor image quality after expansion are a few of the most popular reasons for skepticism about a particular compression algorithm. This paper discusses current methods used for image compression. It also gives a detailed explanation of the discrete cosine transform (DCT), used by JPEG, and the efforts that have recently been made to optimize related algorithms. Some interesting articles regarding possible compression enhancements will be noted, and in association with these methods a new implementation of a JPEG-like image coding algorithm will be outlined. This new technique involves adapting between one and sixteen quantization tables for a specific image using either a genetic algorithm (GA) or tabu search (TS) approach. First, a few schemes including pixel neighborhood and Kohonen self-organizing map (SOM) algorithms will be examined to find their effectiveness at classifying blocks of edge-detected image data. Next, the GA and TS algorithms will be tested to determine their effectiveness at finding the optimum quantization table(s) for a whole image. A comparison of the techniques utilized will be thoroughly explored

A Methodology for Extracting Human Bodies from Still Images

Monitoring and surveillance of humans is one of the most prominent applications of today and it is expected to be part of many future aspects of our life, for safety reasons, assisted living and many others. Many efforts have been made towards automatic and robust solutions, but the general problem is very challenging and remains still open. In this PhD dissertation we examine the problem from many perspectives. First, we study the performance of a hardware architecture designed for large-scale surveillance systems. Then, we focus on the general problem of human activity recognition, present an extensive survey of methodologies that deal with this subject and propose a maturity metric to evaluate them. One of the numerous and most popular algorithms for image processing found in the field is image segmentation and we propose a blind metric to evaluate their results regarding the activity at local regions. Finally, we propose a fully automatic system for segmenting and extracting human bodies from challenging single images, which is the main contribution of the dissertation. Our methodology is a novel bottom-up approach relying mostly on anthropometric constraints and is facilitated by our research in the fields of face, skin and hands detection. Experimental results and comparison with state-of-the-art methodologies demonstrate the success of our approach

Human-Centered Content-Based Image Retrieval

Retrieval of images that lack a (suitable) annotations cannot be achieved through (traditional) Information Retrieval (IR) techniques. Access through such collections can be achieved through the application of computer vision techniques on the IR problem, which is baptized Content-Based Image Retrieval (CBIR). In contrast with most purely technological approaches, the thesis Human-Centered Content-Based Image Retrieval approaches the problem from a human/user centered perspective. Psychophysical experiments were conducted in which people were asked to categorize colors. The data gathered from these experiments was fed to a Fast Exact Euclidean Distance (FEED) transform (Schouten & Van den Broek, 2004), which enabled the segmentation of color space based on human perception (Van den Broek et al., 2008). This unique color space segementation was exploited for texture analysis and image segmentation, and subsequently for full-featured CBIR. In addition, a unique CBIR-benchmark was developed (Van den Broek et al., 2004, 2005). This benchmark was used to explore what and how several parameters (e.g., color and distance measures) of the CBIR process influence retrieval results. In contrast with other research, users judgements were assigned as metric. The online IR and CBIR system Multimedia for Art Retrieval (M4ART) (URL: http://www.m4art.org) has been (partly) founded on the techniques discussed in this thesis. References: - Broek, E.L. van den, Kisters, P.M.F., and Vuurpijl, L.G. (2004). The utilization of human color categorization for content-based image retrieval. Proceedings of SPIE (Human Vision and Electronic Imaging), 5292, 351-362. [see also Chapter 7] - Broek, E.L. van den, Kisters, P.M.F., and Vuurpijl, L.G. (2005). Content-Based Image Retrieval Benchmarking: Utilizing Color Categories and Color Distributions. Journal of Imaging Science and Technology, 49(3), 293-301. [see also Chapter 8] - Broek, E.L. van den, Schouten, Th.E., and Kisters, P.M.F. (2008). Modeling Human Color Categorization. Pattern Recognition Letters, 29(8), 1136-1144. [see also Chapter 5] - Schouten, Th.E. and Broek, E.L. van den (2004). Fast Exact Euclidean Distance (FEED) transformation. In J. Kittler, M. Petrou, and M. Nixon (Eds.), Proceedings of the 17th IEEE International Conference on Pattern Recognition (ICPR 2004), Vol 3, p. 594-597. August 23-26, Cambridge - United Kingdom. [see also Appendix C

An algorithm for multiple object tracking

Background for multiple object tracking -- Data association -- The model of object

Generalizable automated pixel-level structural segmentation of medical and biological data

Over the years, the rapid expansion in imaging techniques and equipments has driven the demand for more automation in handling large medical and biological data sets. A wealth of approaches have been suggested as optimal solutions for their respective imaging types. These solutions span various image resolutions, modalities and contrast (staining) mechanisms. Few approaches generalise well across multiple image types, contrasts or resolution. This thesis proposes an automated pixel-level framework that addresses 2D, 2D+t and 3D structural segmentation in a more generalizable manner, yet has enough adaptability to address a number of specific image modalities, spanning retinal funduscopy, sequential fluorescein angiography and two-photon microscopy. The pixel-level segmentation scheme involves: i ) constructing a phase-invariant orientation field of the local spatial neighbourhood; ii ) combining local feature maps with intensity-based measures in a structural patch context; iii ) using a complex supervised learning process to interpret the combination of all the elements in the patch in order to reach a classification decision. This has the advantage of transferability from retinal blood vessels in 2D to neural structures in 3D. To process the temporal components in non-standard 2D+t retinal angiography sequences, we first introduce a co-registration procedure: at the pairwise level, we combine projective RANSAC with a quadratic homography transformation to map the coordinate systems between any two frames. At the joint level, we construct a hierarchical approach in order for each individual frame to be registered to the global reference intra- and inter- sequence(s). We then take a non-training approach that searches in both the spatial neighbourhood of each pixel and the filter output across varying scales to locate and link microvascular centrelines to (sub-) pixel accuracy. In essence, this \link while extract" piece-wise segmentation approach combines the local phase-invariant orientation field information with additional local phase estimates to obtain a soft classification of the centreline (sub-) pixel locations. Unlike retinal segmentation problems where vasculature is the main focus, 3D neural segmentation requires additional exibility, allowing a variety of structures of anatomical importance yet with different geometric properties to be differentiated both from the background and against other structures. Notably, cellular structures, such as Purkinje cells, neural dendrites and interneurons, all display certain elongation along their medial axes, yet each class has a characteristic shape captured by an orientation field that distinguishes it from other structures. To take this into consideration, we introduce a 5D orientation mapping to capture these orientation properties. This mapping is incorporated into the local feature map description prior to a learning machine. Extensive performance evaluations and validation of each of the techniques presented in this thesis is carried out. For retinal fundus images, we compute Receiver Operating Characteristic (ROC) curves on existing public databases (DRIVE & STARE) to assess and compare our algorithms with other benchmark methods. For 2D+t retinal angiography sequences, we compute the error metrics ("Centreline Error") of our scheme with other benchmark methods. For microscopic cortical data stacks, we present segmentation results on both surrogate data with known ground-truth and experimental rat cerebellar cortex two-photon microscopic tissue stacks.Open Acces