10 research outputs found
Natural Afforestation on Abandoned Agricultural Lands during Post-Soviet Period: A Comparative Landsat Data Analysis of Bordering Regions in Russia and Belarus
Remote monitoring of natural afforestation processes on abandoned agricultural lands is crucial for assessments and predictions of forest cover dynamics, biodiversity, ecosystem functions and services. In this work, we built on the general approach of combining satellite and field data for forest mapping and developed a simple and robust method for afforestation dynamics assessment. This method is based on Landsat imagery and index-based thresholding and specifically targets suitability for limited field data. We demonstrated method’s details and performance by conducting a case study for two bordering districts of Rudnya (Smolensk region, Russia) and Liozno (Vitebsk region, Belarus). This study area was selected because of the striking differences in the development of the agrarian sectors of these countries during the post-Soviet period (1991-present day). We used Landsat data to generate a consistent time series of five-year cloud-free multispectral composite images for the 1985–2020 period via the Google Earth Engine. Three spectral indices, each specifically designed for either forest, water or bare soil identification, were used for forest cover and arable land mapping. Threshold values for indices classification were both determined and verified based on field data and additional samples obtained by visual interpretation of very high-resolution satellite imagery. The developed approach was applied over the full Landsat time series to quantify 35-year afforestation dynamics over the study area. About 32% of initial arable lands and grasslands in the Russian district were afforested by the end of considered period, while the agricultural lands in Belarus’ district decreased only by around 5%. Obtained results are in the good agreement with the previous studies dedicated to the agricultural lands abandonment in the Eastern Europe region. The proposed method could be further developed into a general universally applicable technique for forest cover mapping in different growing conditions at local and regional spatial levels
Natural Afforestation on Abandoned Agricultural Lands during Post-Soviet Period: A Comparative Landsat Data Analysis of Bordering Regions in Russia and Belarus
Remote monitoring of natural afforestation processes on abandoned agricultural lands is crucial for assessments and predictions of forest cover dynamics, biodiversity, ecosystem functions and services. In this work, we built on the general approach of combining satellite and field data for forest mapping and developed a simple and robust method for afforestation dynamics assessment. This method is based on Landsat imagery and index-based thresholding and specifically targets suitability for limited field data. We demonstrated method’s details and performance by conducting a case study for two bordering districts of Rudnya (Smolensk region, Russia) and Liozno (Vitebsk region, Belarus). This study area was selected because of the striking differences in the development of the agrarian sectors of these countries during the post-Soviet period (1991-present day). We used Landsat data to generate a consistent time series of five-year cloud-free multispectral composite images for the 1985–2020 period via the Google Earth Engine. Three spectral indices, each specifically designed for either forest, water or bare soil identification, were used for forest cover and arable land mapping. Threshold values for indices classification were both determined and verified based on field data and additional samples obtained by visual interpretation of very high-resolution satellite imagery. The developed approach was applied over the full Landsat time series to quantify 35-year afforestation dynamics over the study area. About 32% of initial arable lands and grasslands in the Russian district were afforested by the end of considered period, while the agricultural lands in Belarus’ district decreased only by around 5%. Obtained results are in the good agreement with the previous studies dedicated to the agricultural lands abandonment in the Eastern Europe region. The proposed method could be further developed into a general universally applicable technique for forest cover mapping in different growing conditions at local and regional spatial levels
Learned Smartphone ISP on Mobile GPUs with Deep Learning, Mobile AI & AIM 2022 Challenge: Report
The role of mobile cameras increased dramatically over the past few years,
leading to more and more research in automatic image quality enhancement and
RAW photo processing. In this Mobile AI challenge, the target was to develop an
efficient end-to-end AI-based image signal processing (ISP) pipeline replacing
the standard mobile ISPs that can run on modern smartphone GPUs using
TensorFlow Lite. The participants were provided with a large-scale Fujifilm
UltraISP dataset consisting of thousands of paired photos captured with a
normal mobile camera sensor and a professional 102MP medium-format FujiFilm
GFX100 camera. The runtime of the resulting models was evaluated on the
Snapdragon's 8 Gen 1 GPU that provides excellent acceleration results for the
majority of common deep learning ops. The proposed solutions are compatible
with all recent mobile GPUs, being able to process Full HD photos in less than
20-50 milliseconds while achieving high fidelity results. A detailed
description of all models developed in this challenge is provided in this
paper
Experimental Study of Radial Distortion Compensation for Camera Submerged Underwater Using Open SaltWaterDistortion Data Set
This paper describes a new open data set, consisting of images of a chessboard collected underwater with different refractive indices, which allows for investigation of the quality of different radial distortion correction methods. The refractive index is regulated by the degree of salinity of the water. The collected data set consists of 662 images, and the chessboard cell corners are manually marked for each image (for a total of 35,748 nodes). Two different mobile phone cameras were used for the shooting: telephoto and wide-angle. With the help of the collected data set, the practical applicability of the formula for correction of the radial distortion that occurs when the camera is submerged underwater was investigated. Our experiments show that the radial distortion correction formula makes it possible to correct images with high precision, comparable to the precision of classical calibration algorithms. We also show that this correction method is resistant to small inaccuracies in the indication of the refractive index of water. The data set, as well as the accompanying code, are publicly available
Color Reproduction by Multi-Wavelength Bragg Diffraction of White Light
Accurate color reproduction is highly important in multiple industrial, biomedical and scientific applications. Versatile and tunable light sources with high color-rendering quality are very much in demand. In this study, we demonstrate the feasibility of multi-wavelength Bragg diffraction of light for this task. Tuning the frequencies and amplitudes of bulk acoustic waves in the birefringent crystal demonstrates high precision in setting the number, wavelengths and intensities of the monochromatic components necessary to reproduce a specific color assigned according to its coordinates in the CIE XYZ 1931 space. We assembled a setup based on multi-bandpass acousto-optic (AO) filtration of white light and verified the reproduced color balance in multiple experiments. The proposed approach delivers almost full coverage of the CIE XYZ 1931 space and facilitates building compact color reproduction systems (CRSs) for various purposes
Reliability and Stability of Mean Opinion Score for Image Aesthetic Quality Assessment Obtained through Crowdsourcing
<p>This .zip archieve contains 10 scenes and 5 styles for each scene.</p>
<p>Also there are several folders with experimental data:</p>
<ul>
<li>1-3 indestinguishable runs</li>
<li>run with reduced control</li>
<li>run with specified region</li>
<li>run on weekend</li>
<li>all runs combined in one data</li>
</ul>
<p>Each data contains raw .tsv file with all data extracted from voting procedure. Also there is some procecced data that contains scores of each image, nuber of votes for each image an some extra information. </p>
Transportable double-sided laser heating setup with variable configuration for in-situ synchrotron X-Ray diffraction, X-ray Transmission Microscopy and multimegabar pressure DACs experiments
The diamond anvil cell (DAC) technique combined with laser heating is one of the major methods for studying materials at high pressure and high temperature conditions. In this work, we present a transferable double-sided laser heating setup for DACs with in situ temperature determination. The setup allows precise heating of samples inside a DAC at pressures above 200 GPa and could be combined with synchrotron beamline equipment. It can be applied to X-ray diffraction and X-ray transmission microscopy experiments. In the setup, we use high-magnification and low working distance infinity corrected laser focusing objectives that enable us to decrease the size of the laser beam to less than 5 µm and achieve the maximum optical magnification of 320 times. All optical components of the setup were chosen to minimize chromatic and spatial aberrations for accurate in situ temperature determination by multiwavelength spectroscopy in the 570–830 nm spectral range. Flexible design of our setup allows simple interchange of laser sources and focusing optics for application in different types of studies. The setup was successfully tested in house and at the high-pressure diffraction beamline ID15B at the European Synchrotron Radiation Facility. We demonstrate an example of application of the setup for the high pressure–high temperature powder diffraction study of PdH and X-ray transmission microscopy of platinum at 22(1) GPa as a novel method of melting detection in DACs