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Satellite crop detection technologies are focused on the detection of different types of crops in fields. The information of crop-type area is more useful for food security than the earlier phenology stage is. Currently, data obtained from remote sensing (RS) are used to solve tasks related to the identification of the type of agricultural crops; additionally, modern technologies using AI methods are desired in the postprocessing stage. In this paper, we develop a methodology for the supervised classification of time series of Sentinel-2 and Sentinel-1 data, compare the accuracies based on different input datasets and find how the accuracy of classification develops during the season. In the EU, a unified Land Parcel Identification System (LPIS) is available to provide essential field borders. To increase usability, we also provide a classification of the entire field. This field classification also improves overall accuracy. [ABSTRACT FROM AUTHOR]

Crop type classification with satellite imageries is widely applied in support of crop production management and food security strategy. The abundant supply of these satellite data is accelerating and blooming the application of crop classification as satellite data at 10 m to 30 m spatial resolution have been made accessible easily, widely and free of charge, including optical sensors, the wide field of viewer (WFV) onboard the GaoFen (GF, high resolution in English) series from China, the MultiSpectral Instrument (MSI) onboard Sentinel 2 (S2) from Europe and the Operational Land Imager (OLI) onboard Landsat 8 (L8) from USA, thanks to the implementation of the open data policy. There are more options in using the satellite data as these three data sources are available. This paper explored the different capability of these three data sources for the crop type mapping in the same area and within the same growing season. The study was executed in a flat and irrigated area in Northwest China. Nine types of crop were classified using these three kinds of time series of data sources in 2017 and 2018, respectively. The same suites of the training samples and validation samples were applied for each of the data sources. Random Forest (RF) was used as the classifier for the crop type classification. The confusion error matrix with the OA, Kappa and F1-score was used to evaluate the accuracy of the classifications. The result shows that GF-1 relatively has the lowest accuracy as a consequence of the limited spectral bands, but the accuracy is at 93–94%, which is still excellent and acceptable for crop type classification. S2 achieved the highest accuracy of 96–98%, with 10 available bands for the crop type classification at either 10 m or 20 m. The accuracy of 97–98% for L8 is in the middle but the difference is small in comparison with S2. Any of these satellite data may be used for the crop type classification within the growing season, with a very good accuracy if the training datasets were well tuned. [ABSTRACT FROM AUTHOR]

Selective laser melting (SLM) as an additive manufacturing technology enables the quick production of complex shaped three-dimensional (3D) specimens directly from a metal powder. Various metal powders, including different steels, are used in this technology. The influence of the SLM process on the phase composition of the final 3D specimen has been examined by Mössbauer spectroscopy (MS) The surface quality has been examined by scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). The maraging steel 1.2709 (CL50WS), an iron-nickel steel alloy, which is often used in applications where high fracture toughness and strength are required has been investigated. The difference between the phase composition of the initial CL50WS powder and the final specimen identified via MS demonstrated transformation of a martensitic phase into an austenitic one. This transformation proceeds during the whole SLM process. SEM presented imperfections of the surface of the final specimen. The spherical and irregular pores were observed as well as the particles of initial powder bonded to face. Inhomogeneity of elements on the face has been observed by EDS. [ABSTRACT FROM AUTHOR]