Oguz Gungor

Ankara University · Department of Real Estate Development and Management

Erzincan (Cimin) grape, which is an endemic product, makes a significant contribution to the economy of both the region where it is grown and the country's economy. For this reason, the follow-up and dissemination of this product have become increasingly important. The study aims to determine the spatial distribution of vineyards by classifying ver...

In recent years, the pansharpening strategies employing the Generalized Laplacian Pyramid (GLP) based on Gaussian filters that match the Modulation Transfer Function (MTF) of the source multispectral (MS) sensor have attracted attention in remote sensing community. The MTF-GLP-based pansharpening methods differ from each other in the way they obtai...

Soil salinity may occur naturally through pedogenetic processes or may result from abiotic factors resulting from human activities such as irrigation with poor quality water, lack of drainage and land development. The infertility of agricultural lands due to soil salinity brings many economic and social problems on a local and global scale. In this...

Pansharpening fuses the spatial features of a high-resolution panchromatic (PAN) image with the spectral features of a lower-resolution multispectral (MS) image to generate a spatially enriched MS image. Numerous pansharpening strategies have been developed for more than three decades, which forces the analysts who intend to apply pansharpening to...

İnsan beynindeki öğrenme ve analiz mekanizmasını taklit ederek geniş bir veri kümesinden özellikleri otomatik olarak öğrenmeye çalışan derin öğrenme algoritmaları, yüksek hesaplama gerektiren problemleri çözmede bazen insanlardan daha başarılı olabilmektedir. Derin öğrenme tabanlı yöntemlerin çeşitli alanlarda başarı ile kullanımı bu yöntemlerin uz...

The study aims to determine the spatial distribution of vineyards with support vector machines (SVM) and convolutional neural network (CNN) based deep learning model. Multispectral (MS) and Panchromatic (PAN) bands of the high spatial resolution Worldview-2 (WV-2) satellite image were used for the study area located in Erzincan Üzümlü district. MS...

In order to solve insufficient training data problem in remote sensing, a web platform was created so that registered users can generate labeled data for various classes in a dynamic structure. Users were asked to select representative pixel groups for the forest, hazelnut, shadow, soil, tea, and building classes with the polygon tool, and then ass...

Pavement macrotexture contributes greatly to road surface friction, which in turn plays a vital role in reducing road accidents. Conventional methods for macrotexture measurement are either expensive, time-consuming, or of poor repeatability. Based on multi-view smartphone images collected in situ, this paper develops and evaluates an affordable an...

Image fusion aims to spatially enhance a low-resolution multispectral (MS) image by utilizing a high-resolution panchromatic (Pan) band. Various image fusion methodologies have been proposed with the aim to improve the spatial detail quality without deteriorating the colour content of the input MS image. Previous studies revealed the fact that ther...

zet Klasik RGB görüntülerine göre uydu görüntülerinin derin öğrenme amaçlı kullanımlarında önemli problemler bulunmaktadır. Uzaktan algılanmış görüntüler için etiketli eğitim verisi eksikliği bu problemlerden biridir. Uydu görüntüleri için yetersiz etiketli eğitim verisi sorununun çözümünü doğru ve kısa sürede sağlayabilecek en önemli yöntemlerden...

The data obtained with remote sensing sensors are processed to fuel studies related to the Earth’s resources and environment. Sensor technologies being developed are increasing the diversity and capabilities of remote sensing data. However, these advancements are also multiplying the volume of information enormously, straining resources for process...

Research to improve the accuracy of very high-resolution satellite image classification algorithms is still one of the hot topics in the field of remote sensing. Successful results of deep learning methods in areas such as image classification and object detection have led to the application of these methods to remote sensing problems. Recently, Co...

This study proposed a metaheuristic pansharpening (MP) method, which performs in a Synthetic Variable Ratio (SVR)-like manner. The proposed method introduced the Symbiotic Organisms Search (SOS) algorithm, an advanced nature-based optimization algorithm, to estimate a weight for each multispectral (MS) band to achieve the optimum intensity. The SVR...

There is no such thing as ‘the best image fusion method’ in terms of both spectral and spatial fidelity. This fact encourages the researchers to develop more advanced approaches in order to optimally transfer the spatial details without distorting the colour content. Component substitution (CS)-based image fusion methods have been proven to produce...

This study proposed to improve the performance of the conventional Synthetic Variable Ratio (SVR) image fusion algorithm by means of the Genetic Algorithm (GA). The proposed Genetic Algorithm-Based Synthetic Variable Ratio (GA-SVR) method utilizes the GA to estimate the optimum band weights used to generate the intensity component. Performance of t...

Field measurements are the main source of information when determining stand parameters, which are essential to produce an effective forest management plan. However, conducting terrestrial measurements is neither time- nor cost-efficient in most cases. In recent years, the advent of sophisticated remote sensing technologies has enabled the extracti...

“Crowdsourcing” uses masses of people to solve a specific problem, usually focusing on research strategies to reduce time, cost and effort to create data. Crowdsourcing intrinsically claims that groups can make relatively smarter and better decisions than the most intelligent individual among them. We investigated to see if crowdsourcing could be u...

Pansharpening, which is transferring the spatial content of a high-resolution panchromatic (PAN) band into a lower-resolution multispectral (MS) image to produce a spatially enhanced MS image, has always been one of the hottest topics of image processing. Numerous studies have focused on developing approaches to inject the spatial details with mini...

Hyperspectral images offer a good separability among land cover classes, owing to their advantages to provide spectral bands with narrow wavelength intervals. It is also possible to further increase classification accuracy of hyperspectral images by integrating some auxiliary data to classification process. The aim of this study was to increase the...

Ground filtering algorithms mainly focus on filtering LiDAR (Light Detection and Ranging) point clouds owing to their intrinsic characteristics to classify ground and non-ground points. However, the acquisition and processing of LiDAR data is still costly. Compared to LiDAR technology, UAVs (Unmanned Aerial Vehicle) are cheap and easy to use. In th...

In recent years, the advent of unmanned aerial vehicles (UAV)-based photogrammetry has enabled the collection of accurate and comprehensive information from the surface of the Earth. Owing to low-altitude flights, it is possible to generate high-density point clouds, which are useful for accurate representation of topography of the land surface. Gr...

In recent years, remote sensing technologies have been used to collect forest inventory, owing to their ability to provide comprehensive and accurate information about the physical characteristics of forests. Tree crown diameter, which can be defined as the maximum width of the projection of a tree crown, is one of the most significant stand parame...

Tree crown diameter, which is the diameter of the circle enclosing the projection of tree crown, is one of the most important stand parameters that should be identified before the production of forest management plans. This feature is generally obtained with terrestrial measurements, which may not be time- and costefficient in most cases. The use o...

Advancing technology enables the extraction of accurate spatial information relating to the features on the ground. Owing to low-altitude flights, stereo aerial photos taken from digital cameras mounted on unmanned aerial vehicles (UAV) make it possible to generate point clouds as dense as LiDAR (Light Detection and Ranging) point clouds. Contrary...

Digital Terrain Model (DTM) generation is one of the leading applications in photogrammetry. A DTM is generated by the interpolation of ground points retrieved by ground filtering, which is the removal of the points belong to above-ground objects from point cloud. In the literature, a wide variety of ground filtering approaches have been reported f...

Digital Terrain Models (DTMs) as well as Digital Surface Models (DSMs) have been widely used in many forestry applications, especially in locating forest roads, developing transportation planning, and determining the stand parameters. Generally, LiDAR (Light Detection and Ranging) point clouds have been used to generate DTMs, since LiDAR technology...

With the advent of unmanned aerial vehicles (UAVs) for mapping applications, it is possible to generate 3D dense point clouds using stereo images. This technology, however, has some disadvantages when compared to LiDAR (Light Detection and Ranging) system. Unlike LiDAR, digital cameras mounted on UAVs are incapable of viewing beneath the canopy, wh...

Recently, Digital Terrain Models (DTM) have been used by various disciplines. Since LiDAR (Light Detection and Ranging) data results in multiple returns (i.e. first return, last return etc.), LiDAR point clouds are very useful when separating the points belong to the bare earth surface and above ground objects for DTM generation. Despite its wide u...

In Turkey, forest management plans are produced by terrestrial surveying techniques for 10 or 20 year periods, which can be considered quite long to maintain the sustainability of forests. For a successful forest management plan, it is necessary to collect accurate information about the stand parameters and store them in dynamic and robust database...

Digital Elevation Model (DEM) generation is one of the leading application areas in geomatics. Since a DEM represents the bare earth surface, the very first step of generating a DEM is to separate the ground and non-ground points, which is called ground filtering. Once the point cloud is filtered, the ground points are interpolated to generate the...

Turkey is the largest hazelnut producer and exporter in the world with approximately 75% worldwide production and 70-75% of world exports, yet according to FAO; annual yield gain rate is significantly lower than Italy and USA. While Turkey produces 0.94 ton/hectare hazelnut, average yield rates for USA, Italy and Spain are 2.6 ton/hectare, 1.68 ton...

Turkey is the largest hazelnut producer and exporter in the world with approximately 75% worldwide production and 70-75% of world exports, yet according to FAO; annual yield gain rate is significantly lower than Italy and USA. While Turkey produces 0.94 ton/hectare hazelnut, average yield rates for USA, Italy and Spain are 2.6 ton/hectare, 1.68 ton...

Digital Elevation Model (DEM) generation is one of the leading application areas in geomatics. Since a DEM represents the bare earth surface, the very first step of generating a DEM is to separate the ground and non-ground points, which is called ground filtering. Once the point cloud is filtered, the ground points are interpolated to generate the...

Digital Terrain Models (DTM) have been widely used in many forestry applications, especially in determining the stand parameters. Generally, LiDAR (Light Detection and Ranging) point clouds have been used to generate DTMs, since LiDAR technology is able to provide multiple returns, which is very useful to separate the ground surface and non-ground...

Recently, forest resources are planned in the sense of based multiple use forest planning, in which the actual status of forests are needed to be identified accurately to present the products and services offered by forests, except for the wood products. In this regard, precise estimation of stand types and stand parameters affects the accuracy and...

Digital Elevation Model (DEM) generation is one of the leading application areas in geomatics. Since a DEM represents the bare earth surface, the very first step of generating a DEM is to separate the ground and non-ground points, which is called ground filtering. Once the point cloud is filtered, the ground points are interpolated to generate the...

In Turkey, forest management plans are produced by terrestrial surveying techniques for 10 or 20 year periods, which can be considered quite long to maintain the sustainability of forests. For a successful forest management plan, it is necessary to collect accurate information about the stand parameters and store them in dynamic and robust database...

Hyperspectral images can identify minerals better than Multispectral images because of their high spectral resolutions. However, a pixel might include more than one mineral, as hyperspectral images have low spatial resolution. In these situations, the number of minerals can be estimated in mixed pixels but their spatial positions cannot be known. T...

Image fusion is the production of high-resolution images by combining the spatial details of a high-resolution image with the spectral features of a low-resolution one. Reports of various quality metrics to evaluate the spectral and spatial qualities of fused images have been published. However, metrics may lead to misinterpretation due to inherent...

Image fusion is the combination of spectral characteristics of a low-resolution image and spatial features of a higher resolution image to produce the spatially enhanced image. Different fusion techniques have been introduced in the literature. Fusion algorithms tend to yield good results when using single sensor images as input data sets. Fusion p...

Ülkemizde kesin meşcere haritaları üretilirken envanter çalışmalarında ağaç türü karışımı, kapalılık, çap, yaş ve boy gibi çeşitli meşcere parametreleri yersel ölçümlerle toplanmaktadır. Meşcerelerdeki türlerin çap dağılımlarının belirlenebilmesi için, ağaç tepe çapı ile gövde çapı arasında istatistiksel bir ilişkiden yararlanılabilmektedir. Ağaç t...

SUMMARY Turkey is the largest hazelnut producer and exporter in the world with approximately 79% of worldwide production. Turkey also takes the fifth place in production of tea after China, Kenya, India and Sri Lanka. Most of Turkish hazelnut and tea production comes from the eastern Black Sea region of Turkey, which has a mild climate with high pr...

Hazelnuts and tea are two major agricultural crops grown in the eastern Black Sea region in Turkey. Since this part of Turkey is not industrialized, most of the local people work in agriculture, making hazelnuts and tea a part of their lives. For the government side, it is crucial to keep records of the amount of harvested croplands to implement ag...

Hazelnuts and tea are two major agricultural crops grown in the eastern Black Sea region in Turkey. Since this part of Turkey is not industrialized, most of the local people work in agriculture, making hazelnuts and tea a part of their lives. For the government side, it is crucial to keep records of the amount of harvested croplands to implement ag...

ÖZET ArcGIS, ESRI firmasının 1980’'li yıllardan beri geliştirdiği, tüm dünyada hem akademik hem de özel sektör faaliyetlerinde yaygın olarak kullanılan bir CBS yazılımıdır. Vektör ve raster veriler bu yazılım ile işlenebilmekte, sorgulamalar ve analizler yapılabilmektedir. ArcGIS yazılımı ArcMap, ArcCatalog, ArcToolbox, ArcScene, ArcGlobe vb. modül...

Transferring spatial details of a high-resolution image into a low-resolution one is called image fusion. There are some different fusion methods introduced. Due to the nature of fusion process, these methods may damage the spectral quality of the low-resolution multispectral image to a certain extent. In the literature, there are some metrics that...

İnsansız hava araçlarına (İHA) monte edilen kameralar yardımıyla yeryüzünün görüntülenmesi yersel ölçüm tekniklerine göre bazı avantajları beraberinde getirmektedir. İnsansız hava araçlarının kullanılması ile az maliyetle kısa sürede çok yüksek konumsal ve zamansal çözünürlüklü görüntüler elde edilebilmektedir. Elde edilen bu yüksek konumsal çözünü...

Görüntü kaynaştırma konumsal çözünürlüğü yüksek olan bir görüntüdeki konumsal detayların konumsal çözünürlüğü düşük olan görüntülere transfer edilmesidir. Farklı görüntü kaynaştırma yöntemleri farklı kalitede kaynaşmış görüntüler sunmaktadır. Bazı görüntü kaynaştırma yöntemleri yüksek konumsal çözünürlüklü görüntüdeki detayları daha düşük konumsal...

Remotely sensed images are invaluable to acquire geospatial information about earth surface for the assessment of land resources and environment monitoring. In most cases, the information provided by a single sensor is not complete or sufficient. Therefore, images collected by different sensors are combined to obtain complementary information. Each...

This study aims to examine the performance of Random Forest (RF) and Maximum Likelihood Classification (MLC) method to crop classification through pixel-based and parcel-based approaches. Analyses are performed on multispectral SPOT 5 image. First, the SPOT 5 image is classified using the classification methods in pixel-based manner. Next, the prod...

A novel image fusion method using IKONOS satellite images In satellite remote sensing, spatial resolutions of multispectral images over a particular region can be enhanced using better spatial resolution panchromatic images for the same region by a process called image fusion, or more generally data fusion. A fusion method is considered successful,...

When performing post-classification comparison using images of different sensors, change detection is still possible even if images have different resolutions. However, in this case, change pixels are detected in the pixel size of coarser resolution image. This problem can be solved using higher resolution aerial photographs or panchromatic images...

Land Use/Land Cover (LULC) information is crucial in areas such as natural resource management, environmental management, risk management, and the like. Combining LULC data needs common standards in production phase. A common nomenclature and classification system accepted for LULC data does not exist in public institutions in Turkey. In this study...

A low resolution ETM+ and higher resolution IKONOS images obtained in 2000 -2003, respectively, are compared using post-classification comparison algorithm to detect changes due to a new major highway construction initiated in 2000. The spatial resolution difference between the input images, which may lead to wrong registration, thereby, wrong post...

GPS (Global Positioning System) devices can be used in many applications which require accurate point positioning in geosciences. Accuracy of GPS decreases due to outliers resulted from the errors inherent in GPS observations. Several approaches have been developed to detect outliers in geodetic observations. It is important to determine which meth...

Panchromatic and multispectral images are very useful for the acquisition of geospatial information about the Earth surface for the assessment of land resources and environment monitoring. Panchromatic images usually have a better spatial resolution than the multispectral images of the same sensor, while the multispectral images provide spectral pr...

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Image fusion is a process that combines two or more images into one image to make important features more apparent for human or machine perception. In remote sensing, lower resolution multispectral images are often fused with higher resolution panchromatic ones. The objective is to retain both high spectral and high spatial resolutions in the fused...

This paper addresses the principles, implementation and evaluation of wavelet transformation based image fusion. 2-D discrete wavelet transformation is presented concisely to facility the understanding of the wavelet based image fusion method. To best retain the quality of the input images, we propose a strategy that minimizes the necessary resampl...

Panchromatic and multispectral images are useful for the acquisition of geospatial information about the Earth surface for the assessment of land resources and environment monitoring. Panchromatic images usually have a better spatial resolution than the multispectral ones of the same sensor, while the multispectral images provide spectral propertie...

In remote sensing applications, lower spatial resolution multispectral images are fused with higher spatial resolution panchromatic ones. The objective of this fusion process is to enhance the spatial resolution of the multispectral images to make important features more apparent for human or machine perception. This enhancement is performed by inj...