Multitemporal and multispectral data fusion for super-resolution of Sentinel-2 images

Multispectral Sentinel-2 images are a valuable source of Earth observation data, however spatial resolution of their spectral bands limited to 10 m, 20 m, and 60 m ground sampling distance remains insufficient in many cases. This problem can be addressed with super-resolution, aimed at reconstructing a high-resolution image from a low-resolution observation. For Sentinel-2, spectral information fusion allows for enhancing the 20 m and 60 m bands to the 10 m resolution. Also, there were attempts to combine multitemporal stacks of individual Sentinel-2 bands, however these two approaches have not been combined so far. In this paper, we introduce DeepSent -- a new deep network for super-resolving multitemporal series of multispectral Sentinel-2 images. It is underpinned with information fusion performed simultaneously in the spectral and temporal dimensions to generate an enlarged multispectral image. In our extensive experimental study, we demonstrate that our solution outperforms other state-of-the-art techniques that realize either multitemporal or multispectral data fusion. Furthermore, we show that the advantage of DeepSent results from how these two fusion types are combined in a single architecture, which is superior to performing such fusion in a sequential manner. Importantly, we have applied our method to super-resolve real-world Sentinel-2 images, enhancing the spatial resolution of all the spectral bands to 3.3 m nominal ground sampling distance, and we compare the outcome with very high-resolution WorldView-2 images. We will publish our implementation upon paper acceptance, and we expect it will increase the possibilities of exploiting super-resolved Sentinel-2 images in real-life applications.Comment: Submitted to IEEE Transactions On Geoscience And Remote Sensin

Historical forest biomass dynamics modelled with Landsat spectral trajectories

Acknowledgements National Forest Inventory data are available online, provided by Ministerio de Agricultura, Alimentación y Medio Ambiente (España). Landsat images are available online, provided by the USGS.Peer reviewedPostprin

Multitemporal Cross-Calibration of the Terra MODIS and Landsat 7 ETM+ Reflective Solar Bands

In recent years, there has been a significant increase in the use of remotely sensed data to address global issues. With the open data policy, the data from the Moderate Resolution Imaging Spectroradiometer (MODIS) and Enhanced Thematic Mapper Plus (ETM+) sensors have become a critical component of numerous applications. These two sensors have been operational for more than a decade, providing a rich archive of multispectral imagery for analysis of mutitemporal remote sensing data. This paper focuses on evaluating the radiometric calibration agreement between MODIS and ETM+ using the near-simultaneous and cloud-free image pairs over an African pseudo-invariant calibration site, Libya 4. To account for the combined uncertainties in the top-of-atmosphere (TOA) reflectance due to surface and atmospheric bidirectional reflectance distribution function (BRDF), a semiempirical BRDF model was adopted to normalize the TOA reflectance to the same illumination and viewing geometry. In addition, the spectra from the Earth Observing-1 (EO-1) Hyperion were used to compute spectral corrections between the corresponding MODIS and ETM+ spectral bands. As EO-1 Hyperion scenes were not available for all MODIS and ETM+ data pairs, MODerate resolution atmospheric TRANsmission (MODTRAN) 5.0 simulations were also used to adjust for differences due to the presence or lack of absorption features in some of the bands. A MODIS split-window algorithm provides the atmospheric water vapor column abundance during the overpasses for the MODTRAN simulations. Additionally, the column atmospheric water vapor content during the overpass was retrieved using the MODIS precipitable water vapor product. After performing these adjustments, the radiometric cross-calibration of the two sensors was consistent to within 7%. Some drifts in the response of the bands are evident, with MODIS band 3 being the largest of about 6% over 10 years, a change that will be corrected in Collection 6 MODIS processing

Symposium franco-chinois de télédétection quantitative en agronomie et environnement. Bilan et perspectives de collaboration. Rapport de mission (26 au 30 mars 2000)

Ce rapport présente les principaux résultats d'un Symposium en Télédétection entre des équipes de chercheurs de l'INRA, du CIRAD, de l'Université de Lille et leurs homologues chinois de l'Institute of Remote Sensing Applications (IRSA) of Chinese Academy of Sciences (CAS), et du National Satellite Meteorological Center (NSMC). Les perspectives d'un programme de collaboration sont présentées avec deux axes majeurs correspondant à deux niveaux d'approche, régional et local en agriculture de précision. (Résumé d'auteur

The role of integrated information acquisition and management in the analysis of coastal ecosystem change

This book chapter represents a synthesis of the work which started in my PhD and which has been the conceptual basis for all of my research since 1993. The chapter presents a method for scientists and managers to use for selecting the type of remotely sensed data to use to meet their information needs associated with a mapping, monitoring or modelling application. The work draws on results from several of my ARC projects, CRC Rainforest and Coastal projects and theses of P.Scarth , K.Joyce and C.Roelfsema

Mapping And Monitoring Wetland Environment By Analysis Different Satellite Images And Field Spectroscopy

Tez (Doktora) -- İstanbul Teknik Üniversitesi, Fen Bilimleri Enstitüsü, 2010Thesis (PhD) -- İstanbul Technical University, Institute of Science and Technology, 2010Bu çalışmada farklı spektral ve mekansal çözünürlükte uydu görüntülerinin “Terkos Havzası Sulak Alanı” örneğinde; arazi örtüsünde meydana gelen değişimleri ve sulak alan bitki türlerinin belirlenmesinde kullanılabilirlikleri için uygulanabilecek uzaktan algılama yöntemleri ele alınmıştır. Kullanılan yöntemler ile elde edilen yeni işlenmiş görüntülerin performanslarının yersel yansıtım değerleri kullanılarak desteklenmesi ile doğal alanların sürdürülebilir korunma ve yönetimi için uzaktan algılama verilerine dayalı bir altlık rehberin oluşturulması imkanı araştırılmıştır. Elde edilen sonuçlara göre heterojen arazi örtüsü yapısına sahip olan çalışma bölgesinde değişim tespiti için Ana Bileşen Dönüşümüne dayalı değişim tespit yöntemi en iyi sonucu vermiştir. Ayrıca bu çalışmada, hiperspektral Hyperion EO-1 görüntüsü ile sulak alan bitki örtüsünün diğer bitki türlerinden doğru olarak ayırt edilebildiği ortaya konmuştur. Sulak alan bitki türlerinin kendi içinde ayırt edilebilmesi ancak yersel spektroskopi ile mümkün olduğu sonucuna ulaşılmıştır.In this study, different satellite data that has different spectral and spatial resolution and in-situ spectroradiometer measurements were used to analyze hydrophytic vegetation and surrounded land cover for sustainable development and conservation of Terkos wetlands. By supporting performances of processed images with field collected reflectance values, the feasibility of structuring a basic guide based on remote sensing data for sustainable preservation and management of natural lands was searched. According to result, land cover changes in the complex natural area were determined more accurately by using PCA based change detection method Therefore, the performance of spaceborne Hyperion EO-1 hyperspectral data was analyzed to determine the capability of the data for wetland vegetation discrimination than the other vegetated areas. At the last stage of the study, field collected reflectance values that have different wetland flora types were compared by statistical ANOVA method and reflectance differences between vegetation types were put forward through calculations.DoktoraPh