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ABSTRACT:Pleiades images are distributed with 50cm ground sampling distance (GSD) even if the physical resolution for nadir images is just 70cm. By theory this should influence the effective GSD determined by means of point spread function at image edges. Nevertheless by edge enhancement the effective GSD can be improved, but this should cause enlarged image noise. Again image noise can be reduced by image restoration. Finally even optimized image restoration cannot improve the image information from 70cm to 50cm without loss of details, requiring a comparison of Pleiades image details with other very high resolution space images. The image noise has been determined by analysis of the whole images for any sub-area with 5 pixels times 5 pixels. Based on the standard deviation of grey values in the small sub-areas the image noise has been determined by frequency analysis. This leads to realistic results, checked by test targets. On the other hand the visual determination of image noise based on apparently homogenous sub-areas results in too high values because the human eye is not able to identify small grey value differences -it is limited to just approximately 40 grey value steps over the available gray value range, so small difference in grey values cannot be seen, enlarging results of a manual noise determination. A tri-stereo combination of Pleiades 1A in a mountainous, but partially urban, area has been analyzed and compared with images of the same area from WorldView-1, QuickBird and IKONOS. The image restoration of the Pleiades images is very good, so the effective image resolution resulted in a factor 1.0, meaning that the effective resolution corresponds to the nominal resolution of 50cm. This does not correspond to the physical resolution of 70cm, but by edge enhancement the steepness of the grey value profile across the edge can be enlarged, reducing the width of the point spread function. Without additional filtering edge enhancement enlarges the image noise, but the average image noise of approximately 1.0 grey values related to 8bit images is very small, not indicating the edge enhancement and the down sampling of the GSD from 70cm to 50cm. So the direct comparison with the other images has to give the answer if the image quality of Pleiades images is on similar level as corresponding to the nominal resolution. As expected with the image geometry there is no problem. This is the case for all used space images in the test area, where the point identification limits the accuracy of the scene orientation.

ABSTRACT:This paper presents the first experience of georeferencing accuracy analysis of Pléiades 1A mono images. The Pléiades Constellation has been founded by CNES (The Centre National d'Etudes Spatiales -National Centre for Space Studies) consisting of Pléiades 1A&1B, following the previous five sisters of SPOT series. CNES also organized a Pléiades Users Group following a world-wide invitation. The images investigated in this research were received as one of the member of this Group. A stereo-pair was evaluated on Zonguldak test field where the topography is mountainous and undulating overlapping urban, rural and forest landscapes. As a first experience, totally 22 ground control points (GCPs) already existing were marked on the images, and the bias compensated Rational Function Model (RFM) was carried out reaching ±0.8 pixel at the GCPs. The overall georeferencing accuracy was performed by the figure condition analysis (FCA), a new concept successfully applied to IKONOS, OrbView-3 and QuickBird images of the same test field. The range of figure condition is between ±0.3-2.7 pixels. These results were compared with the other images of three sensors mentioned above. Although a special GCP survey by GNSS has not been performed yet, these first results are satisfied for the highly accurate georeferencing of the Pléiades 1A images.

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Optical remote sensing satellites obtain MS and Pan images simultaneously over the same coverage area. Remote sensing and image processing communities are working on different pan-sharpening methods capable of taking advantage of MS and Pan images. Each remote sensing system has its own advantages and disadvantages, leading to the question "Which pan-sharpening method should be used for which type of imagery?"The aim of this research is to investigate the pan-sharpening performance of Pléiades-1Aimages. For this purpose, pan-sharpened images were generated using PCA, HIS and Brovey Transform which are the most popular pan-sharpening methods. Then, the pansharpened images were evaluated quantitatively using Correlation Coefficient, Root Mean Square Error, RASE (Relative Average Spectral Error), SAM (Spectral Angle Mapper) and ERGAS (Erreur Relative Globale Adimensionnelle de Synthése). In addition, pansharpened images were evaluated qualitatively by taking object availability and completeness into consideration.

ABSTRACT:Recently two optical remote sensing satellites, RASAT and GÖKTÜRK-2, launched successfully by the Republic of Turkey. RASAT has 7.5 m panchromatic, and 15 m visible bands whereas GÖKTÜRK-2 has 2.5 m panchromatic and 5 m VNIR (Visible and Near Infrared) bands. These bands with various resolutions can be fused by pan-sharpening methods which is an important application area of optical remote sensing imagery. So that, the high geometric resolution of panchromatic band and the high spectral resolution of VNIR bands can be merged. In the literature there are many pan-sharpening methods. However, there is not a standard framework for quality investigation of pan-sharpened imagery.The aim of this study is to investigate pan-sharpening performance of RASAT and GÖKTÜRK-2 images. For this purpose, pansharpened images are generated using most popular pan-sharpening methods IHS, Brovey and PCA at first. This procedure is followed by quantitative evaluation of pan-sharpened images using Correlation Coefficient (CC), Root Mean Square Error (RMSE), Relative Average Spectral Error (RASE), Spectral Angle Mapper (SAM) and Erreur Relative Globale Adimensionnelle de Synthése (ERGAS) metrics. For generation of pan-sharpened images and computation of metrics SharpQ tool is used which is developed with MATLAB computing language. According to metrics, PCA derived pan-sharpened image is the most similar one to multispectral image for RASAT, and Brovey derived pan-sharpened image is the most similar one to multispectral image for GÖKTÜRK-2. Finally, pansharpened images are evaluated qualitatively in terms of object availability and completeness for various land covers (such as urban, forest and flat areas) by a group of operators who are experienced in remote sensing imagery.

The main objective of this research is to examine child cancer cases in Zonguldak/Turkey descriptively in epidemiological aspect with the help of GIS. Universe of the study is composed of 60 children between 1 and 19 years old who were treated in Children Oncology Clinic with a diagnosis of cancer. Whole universe was reached without selecting a sample in the study. Data were collected by using a form prepared by obtaining expert advice and they were applied to children and their parents at study dates. Results were expressed as percentages. Chi-Square test was used in intergroup comparisons, results were assessed within 95 % confidence interval and p < 0.05 was considered as statistically significant. Variables that were used in the study were assessed, recorded in prepared data collection form and distribution maps were produced. When disease diagnosis of the children participated in the study were evaluated, the most observed three types are ALL with 33.3 % (n = 20), Medullablastoma with 13.3 % (n = 8) and Hodgkin-nonHodgkin Lymphoma with 11.7 % (n = 7). Kdz. Eregli with 31.7 % (n = 19), Center with 31.7 % (n = 19), and Caycuma with 18.3 % (n = 11) are the first-three counties where the cases were mostly observed. Statistically significant difference was found (p = 0.016) comparing disease diagnosis with living place, and distribution maps of the number of cancer cases were produced.

Commission I, WG I/5KEY WORDS: Pléiades, Georeferencing Accuracy, Image Quality, Pansharpening, DSM/DTM ABSTRACT:Pléiades 1A and 1B are twin optical satellites of Optical and Radar Federated Earth Observation (ORFEO) program jointly running by France and Italy. They are the first satellites of Europe with sub-meter resolution. Airbus DS (formerly Astrium Geo) runs a MyGIC (formerly Pléiades Users Group) program to validate Pléiades images worldwide for various application purposes. The authors conduct three projects, one is within this program, the second is supported by BEU Scientific Research Project Program, and the third is supported by TÜBİTAK. Assessment of georeferencing accuracy, image quality, pansharpening performance and Digital Surface Model/Digital Terrain Model (DSM/DTM) quality subjects are investigated in these projects. For these purposes, triplet panchromatic (50 cm Ground Sampling Distance (GSD)) and VNIR (2 m GSD) Pléiades 1A images were investigated over Zonguldak test site (Turkey) which is urbanised, mountainous and covered by dense forest.The georeferencing accuracy was estimated with a standard deviation in X and Y (SX, SY) in the range of 0.45m by bias corrected Rational Polynomial Coefficient (RPC) orientation, using ~170 Ground Control Points (GCPs). 3D standard deviation of ±0.44m in X, ±0.51m in Y, and ±1.82m in Z directions have been reached in spite of the very narrow angle of convergence by bias corrected RPC orientation. The image quality was also investigated with respect to effective resolution, Signal to Noise Ratio (SNR) and blur coefficient. The effective resolution was estimated with factor slightly below 1.0, meaning that the image quality corresponds to the nominal resolution of 50cm. The blur coefficients were achieved between 0.39-0.46 for triplet panchromatic images, indicating a satisfying image quality. SNR is in the range of other comparable space borne images which may be caused by de-noising of Pléiades images. The pansharpened images were generated by various methods, and are validated by most common statistical metrics and also visual interpretation. The generated DSM and DTM were achieved with ±1.6m standard deviation in Z (SZ) in relation to a reference DTM.