Automatic Coastline Extraction Using Edge Detection and Optimization Procedures

Coastal areas are quite fragile landscapes as they are among the most vulnerable to climate change and natural hazards. Coastline mapping and change detection are essential for safe navigation, resource management, environmental protection, and sustainable coastal development and planning. In this paper, we proposed a new methodology for the automatic extraction of coastline, using aerial images. This method is based on edge detection and active contours (snake method). Initially the noise of the image is reduced which is followed by an image segmentation. The output images are further processed to remove all small spatial objects and to concentrate on the spatial objects of interests. Then, the morphological operators are applied. We used aerial images taken from an aircraft and high-resolution satellite images from a coastal area in Crete, Greece, and we compared the results with geodetic measurements, to validate the methodology

COASTLINE EXTRACTION FROM AERIAL IMAGES BASED ON EDGE DETECTION

Nowadays coastline extraction and tracking of its changes become of high importance because of the climate change, global warming and rapid growth of human population. Coastal areas play a significant role for the economy of the entire region. In this paper we propose a new methodology for automatic extraction of the coastline using aerial images. A combination of a four step algorithm is used to extract the coastline in a robust and generalizable way. First, noise distortion is reduced in order to ameliorate the input data for the next processing steps. Then, the image is segmented into two regions, land and sea, through the application of a local threshold to create the binary image. The result is further processed by morphological operators with the aim that small objects are being eliminated and only the objects of interest are preserved. Finally, we perform edge detection and active contours fitting in order to extract and model the coastline. These algorithmic steps are illustrated through examples, which demonstrate the efficacy of the proposed methodology

Fusing Georeferenced and Stereoscopic Image Data for 3D Building Façade Reconstruction

3D building façade reconstruction has become a very popular topic in various applications related to restoration and preservation of architectural structures as well as urban planning. This paper deals with the reconstruction of realistic 3D models of buildings façades, in the urban environment for cultural heritage. We present an approach that enables the relation of stereoscopic images with tacheometry data. The proposed multimodal fusing scheme results in an accurate 3D realistic façade reconstruction and provides a fast and low cost solution. In the first stage of the proposed approach a 2D skeleton of the building is extracted from the viewed scene using Active Contour and Hough line extraction. The next stage of our method utilizes depth information, extracted from a stereoscopic layout, to infer the structural details of inner façade structures, such as windows or doors. In the final stage, the structural information extracted from the image data is integrated with georeferenced point datasets. The final output of our method is a georeferenced 3D model of the structure’s façade, which can be further refined with the use of image-driven texture information

Automatic coastline extraction from aerial images using edge detection and optimization procedures

Summarization: Nowadays, coastline detection and formation monitoring has become of high importance due to the increasing effects of climate change, global warming and rapid growth of human population on the morphological characteristics of coasts. Coastal areas play a significant role on the economy of an entire region especially in major tourist destinations, where tourist infrastructure has been developed in the last decades. This thesis addresses the problem of coastline extraction and morphological change monitoring/tracking in the course of decades. The proposed methodology presents an automatic coastline extraction algorithm, which utilizes grayscale aerial images. Our method is summarized in a four-step algorithm that enables robust extraction of the coastline. Specifically, the first step of our approach is a noise distortion reduction stage with the goal of ameliorating its impact on the input data. The subsequent step involves the application of a local threshold in the input image to segment it into a binary class image, land and sea. The result is then passed to the third stage of our approach, which applies morphological operators on the binary image, with the aim of removing small objects and preserving only the objects of interest. Finally in the last stage of our method, we perform edge detection and active contours fitting, in order to extract and model the coastline. The aforementioned algorithmic steps are illustrated through examples, which demonstrate the efficacy of the proposed methodology. The algorithm is also applicable to one band satellite imagery due to the fact they have same characteristics with grayscale aerial images

Impact of space weather on human heart rate during the years 2011–2013

During the last years a possible link between different levels of solar and geomagnetic disturbances and human physiological parameters is suggested by several published studies. In this work the examination of the potential association between heart rate variations and specific space weather activities was performed. A total of 482 individuals treated at Hippocratio General Hospital in Athens, the Cardiology clinics of Nikaia General Hospital in Piraeus and the Heraklion University Hospital in Crete, Greece, were assessed from July 2011 to April 2013. The heart rate of the individuals was recorded by a Holter monitor on a n hourly basis, while the hourly variations of the cosmic ray intensity measured by the Neutron Monitor Station of the Athens University and of the geomagnetic index Dst provided by the Kyoto Observatory were used. The ANalysis Of VAriance (ANOVA) and the Multiple Linear Regression analysis were used for analysis of these data. A statistically significant effect of both cosmic rays and geomagnetic activity on heart rate was observed, which may indicate that changes in space weather could be linked to heart rate variations. © 2017, Springer Science+Business Media B.V