1,134 research outputs found

    Efficient training procedures for multi-spectral demosaicing

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    The simultaneous acquisition of multi-spectral images on a single sensor can be efficiently performed by single shot capture using a mutli-spectral filter array. This paper focused on the demosaicing of color and near-infrared bands and relied on a convolutional neural network (CNN). To train the deep learning model robustly and accurately, it is necessary to provide enough training data, with sufficient variability. We focused on the design of an efficient training procedure by discovering an optimal training dataset. We propose two data selection strategies, motivated by slightly different concepts. The general term that will be used for the proposed models trained using data selection is data selection-based multi-spectral demosaicing (DSMD). The first idea is clustering-based data selection (DSMD-C), with the goal to discover a representative subset with a high variance so as to train a robust model. The second is an adaptive-based data selection (DSMD-A), a self-guided approach that selects new data based on the current model accuracy. We performed a controlled experimental evaluation of the proposed training strategies and the results show that a careful selection of data does benefit the speed and accuracy of training. We are still able to achieve high reconstruction accuracy with a lightweight model

    Machine Learning Approach to Retrieving Physical Variables from Remotely Sensed Data

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    Scientists from all over the world make use of remotely sensed data from hundreds of satellites to better understand the Earth. However, physical measurements from an instrument is sometimes missing either because the instrument hasn\u27t been launched yet or the design of the instrument omitted a particular spectral band. Measurements received from the instrument may also be corrupt due to malfunction in the detectors on the instrument. Fortunately, there are machine learning techniques to estimate the missing or corrupt data. Using these techniques we can make use of the available data to its full potential. We present work on four different problems where the use of machine learning techniques helps to extract more information from available data. We demonstrate how missing or corrupt spectral measurements from a sensor can be accurately interpolated from existing spectral observations. Sometimes this requires data fusion from multiple sensors at different spatial and spectral resolution. The reconstructed measurements can then be used to develop products useful to scientists, such as cloud-top pressure, or produce true color imagery for visualization. Additionally, segmentation and image processing techniques can help solve classification problems important for ocean studies, such as the detection of clear-sky over ocean for a sea surface temperature product. In each case, we provide detailed analysis of the problem and empirical evidence that these problems can be solved effectively using machine learning techniques

    OCM 2021 - Optical Characterization of Materials

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    The state of the art in the optical characterization of materials is advancing rapidly. New insights have been gained into the theoretical foundations of this research and exciting developments have been made in practice, driven by new applications and innovative sensor technologies that are constantly evolving. The great success of past conferences proves the necessity of a platform for presentation, discussion and evaluation of the latest research results in this interdisciplinary field

    OCM 2021 - Optical Characterization of Materials : Conference Proceedings

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    The state of the art in the optical characterization of materials is advancing rapidly. New insights have been gained into the theoretical foundations of this research and exciting developments have been made in practice, driven by new applications and innovative sensor technologies that are constantly evolving. The great success of past conferences proves the necessity of a platform for presentation, discussion and evaluation of the latest research results in this interdisciplinary field

    Bio-Inspired Multi-Spectral and Polarization Imaging Sensors for Image-Guided Surgery

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    Image-guided surgery (IGS) can enhance cancer treatment by decreasing, and ideally eliminating, positive tumor margins and iatrogenic damage to healthy tissue. Current state-of-the-art near-infrared fluorescence imaging systems are bulky, costly, lack sensitivity under surgical illumination, and lack co-registration accuracy between multimodal images. As a result, an overwhelming majority of physicians still rely on their unaided eyes and palpation as the primary sensing modalities to distinguish cancerous from healthy tissue. In my thesis, I have addressed these challenges in IGC by mimicking the visual systems of several animals to construct low power, compact and highly sensitive multi-spectral and color-polarization sensors. I have realized single-chip multi-spectral imagers with 1000-fold higher sensitivity and 7-fold better spatial co-registration accuracy compared to clinical imaging systems in current use by monolithically integrating spectral tapetal and polarization filters with an array of vertically stacked photodetectors. These imaging sensors yield the unique capabilities of imaging simultaneously color, polarization, and multiple fluorophores for near-infrared fluorescence imaging. Preclinical and clinical data demonstrate seamless integration of this technologies in the surgical work flow while providing surgeons with real-time information on the location of cancerous tissue and sentinel lymph nodes, respectively. Due to its low cost, the bio-inspired sensors will provide resource-limited hospitals with much-needed technology to enable more accurate value-based health care

    Spectral Characterization of a Prototype SFA Camera for Joint Visible and NIR Acquisition

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    International audienceMultispectral acquisition improves machine vision since it permits capturing more information on object surface properties than color imaging. The concept of spectral filter arrays has been developed recently and allows multispectral single shot acquisition with a compact camera design. Due to filter manufacturing difficulties, there was, up to recently, no system available for a large span of spectrum, i.e., visible and Near Infra-Red acquisition. This article presents the achievement of a prototype of camera that captures seven visible and one near infra-red bands on the same sensor chip. A calibration is proposed to characterize the sensor, and images are captured. Data are provided as supplementary material for further analysis and simulations. This opens a new range of applications in security, robotics, automotive and medical fields

    Earth observations from DSCOVR EPIC instrument

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    The National Oceanic and Atmospheric Administration (NOAA) Deep Space Climate Observatory (DSCOVR) spacecraft was launched on 11 February 2015 and in June 2015 achieved its orbit at the first Lagrange point (L1), 1.5 million km from Earth toward the sun. There are two National Aeronautics and Space Administration (NASA) Earth-observing instruments on board: the Earth Polychromatic Imaging Camera (EPIC) and the National Institute of Standards and Technology Advanced Radiometer (NISTAR). The purpose of this paper is to describe various capabilities of the DSCOVR EPIC instrument. EPIC views the entire sunlit Earth from sunrise to sunset at the backscattering direction (scattering angles between 168.5ยฐ and 175.5ยฐ) with 10 narrowband filters: 317, 325, 340, 388, 443, 552, 680, 688, 764, and 779 nm. We discuss a number of preprocessing steps necessary for EPIC calibration including the geolocation algorithm and the radiometric calibration for each wavelength channel in terms of EPIC counts per second for conversion to reflectance units. The principal EPIC products are total ozone (O3) amount, scene reflectivity, erythemal irradiance, ultraviolet (UV) aerosol properties, sulfur dioxide (SO2) for volcanic eruptions, surface spectral reflectance, vegetation properties, and cloud products including cloud height. Finally, we describe the observation of horizontally oriented ice crystals in clouds and the unexpected use of the O2 B-band absorption for vegetation properties.The NASA GSFC DSCOVR project is funded by NASA Earth Science Division. We gratefully acknowledge the work by S. Taylor and B. Fisher for help with the SO2 retrievals and Marshall Sutton, Carl Hostetter, and the EPIC NISTAR project for help with EPIC data. We also would like to thank the EPIC Cloud Algorithm team, especially Dr. Gala Wind, for the contribution to the EPIC cloud products. (NASA Earth Science Division)Accepted manuscrip

    Getting simultaneous red and near-infrared band data from a single digital camera for plant monitoring applications: theoretical and practical study

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    Multispectral images, including red and near-infrared bands, have proved efficient for vegetation-soil discrimination and agricultural monitoring in remote-sensing applications. However, they remain little used in ground-based and unmanned aerial vehicle (UAV) imagery, due to a limited availability of adequate 2D imaging devices. A methodology is proposed to obtain simultaneously the near-infrared and red bands from a standard single RGB camera, after having removed the near-infrared blocking filter inside. Its ability to provide satisfactory NDVI (normalised difference vegetation index) computation for vegetation and soil has been assessed through spectral simulations. Application in field conditions with Canon 500 D and Canon 350D cameras has then been considered, taking into account signal-noise and demosaicing concerns. The results obtained have proved the practical usability of this approach, opening new technical possibilities for crop monitoring and agricultural robotics

    ์‹œ๊ณต๊ฐ„ ํ•ด์ƒ๋„ ํ–ฅ์ƒ์„ ํ†ตํ•œ ์‹์ƒ ๋ณ€ํ™” ๋ชจ๋‹ˆํ„ฐ๋ง

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    ํ•™์œ„๋…ผ๋ฌธ(๋ฐ•์‚ฌ) -- ์„œ์šธ๋Œ€ํ•™๊ต๋Œ€ํ•™์› : ํ™˜๊ฒฝ๋Œ€ํ•™์› ํ˜‘๋™๊ณผ์ • ์กฐ๊ฒฝํ•™, 2023. 2. ๋ฅ˜์˜๋ ฌ.์œก์ƒ ์ƒํƒœ๊ณ„์—์„œ ๋Œ€๊ธฐ๊ถŒ๊ณผ ์ƒ๋ฌผ๊ถŒ์˜ ์ƒํ˜ธ ์ž‘์šฉ์„ ์ดํ•ดํ•˜๊ธฐ ์œ„ํ•ด์„œ๋Š” ์‹์ƒ ๋ณ€ํ™”์˜ ๋ชจ๋‹ˆํ„ฐ๋ง์ด ํ•„์š”ํ•˜๋‹ค. ์ด ๋•Œ, ์œ„์„ฑ์˜์ƒ์€ ์ง€ํ‘œ๋ฉด์„ ๊ด€์ธกํ•˜์—ฌ ์‹์ƒ์ง€๋„๋ฅผ ์ œ๊ณตํ•  ์ˆ˜ ์žˆ์ง€๋งŒ, ์ง€ํ‘œ๋ณ€ํ™”์˜ ์ƒ์„ธํ•œ ์ •๋ณด๋Š” ๊ตฌ๋ฆ„์ด๋‚˜ ์œ„์„ฑ ์ด๋ฏธ์ง€์˜ ๊ณต๊ฐ„ ํ•ด์ƒ๋„์— ์˜ํ•ด ์ œํ•œ๋˜์—ˆ๋‹ค. ๋˜ํ•œ ์œ„์„ฑ์˜์ƒ์˜ ์‹œ๊ณต๊ฐ„ ํ•ด์ƒ๋„๊ฐ€ ์‹์ƒ์ง€๋„๋ฅผ ํ†ตํ•œ ๊ด‘ํ•ฉ์„ฑ ๋ชจ๋‹ˆํ„ฐ๋ง์— ๋ฏธ์น˜๋Š” ์˜ํ–ฅ์€ ์™„์ „ํžˆ ๋ฐํ˜€์ง€์ง€ ์•Š์•˜๋‹ค. ๋ณธ ๋…ผ๋ฌธ์—์„œ๋Š” ๊ณ ํ•ด์ƒ๋„ ์‹์ƒ ์ง€๋„๋ฅผ ์ผ๋‹จ์œ„๋กœ ์ƒ์„ฑํ•˜๊ธฐ ์œ„์„ฑ ์˜์ƒ์˜ ์‹œ๊ณต๊ฐ„ ํ•ด์ƒ๋„๋ฅผ ํ–ฅ์ƒ์‹œํ‚ค๋Š” ๊ฒƒ์„ ๋ชฉํ‘œ๋กœ ํ•˜์˜€๋‹ค. ๊ณ ํ•ด์ƒ๋„ ์œ„์„ฑ์˜์ƒ์„ ํ™œ์šฉํ•œ ์‹์ƒ ๋ณ€ํ™” ๋ชจ๋‹ˆํ„ฐ๋ง์„ ์‹œ๊ณต๊ฐ„์ ์œผ๋กœ ํ™•์žฅํ•˜๊ธฐ ์œ„ํ•ด 1) ์ •์ง€๊ถค๋„ ์œ„์„ฑ์„ ํ™œ์šฉํ•œ ์˜์ƒ์œตํ•ฉ์„ ํ†ตํ•ด ์‹œ๊ฐ„ํ•ด์ƒ๋„ ํ–ฅ์ƒ, 2) ์ ๋Œ€์ ์ƒ์„ฑ๋„คํŠธ์›Œํฌ๋ฅผ ํ™œ์šฉํ•œ ๊ณต๊ฐ„ํ•ด์ƒ๋„ ํ–ฅ์ƒ, 3) ์‹œ๊ณต๊ฐ„ํ•ด์ƒ๋„๊ฐ€ ๋†’์€ ์œ„์„ฑ์˜์ƒ์„ ํ† ์ง€ํ”ผ๋ณต์ด ๊ท ์งˆํ•˜์ง€ ์•Š์€ ๊ณต๊ฐ„์—์„œ ์‹๋ฌผ ๊ด‘ํ•ฉ์„ฑ ๋ชจ๋‹ˆํ„ฐ๋ง์„ ์ˆ˜ํ–‰ํ•˜์˜€๋‹ค. ์ด์ฒ˜๋Ÿผ, ์œ„์„ฑ๊ธฐ๋ฐ˜ ์›๊ฒฉํƒ์ง€์—์„œ ์ƒˆ๋กœ์šด ๊ธฐ์ˆ ์ด ๋“ฑ์žฅํ•จ์— ๋”ฐ๋ผ ํ˜„์žฌ ๋ฐ ๊ณผ๊ฑฐ์˜ ์œ„์„ฑ์˜์ƒ์€ ์‹œ๊ณต๊ฐ„ ํ•ด์ƒ๋„ ์ธก๋ฉด์—์„œ ํ–ฅ์ƒ๋˜์–ด ์‹์ƒ ๋ณ€ํ™”์˜ ๋ชจ๋‹ˆํ„ฐ๋ง ํ•  ์ˆ˜ ์žˆ๋‹ค. ์ œ2์žฅ์—์„œ๋Š” ์ •์ง€๊ถค๋„์œ„์„ฑ์˜์ƒ์„ ํ™œ์šฉํ•˜๋Š” ์‹œ๊ณต๊ฐ„ ์˜์ƒ์œตํ•ฉ์œผ๋กœ ์‹๋ฌผ์˜ ๊ด‘ํ•ฉ์„ฑ์„ ๋ชจ๋‹ˆํ„ฐ๋ง ํ–ˆ์„ ๋•Œ, ์‹œ๊ฐ„ํ•ด์ƒ๋„๊ฐ€ ํ–ฅ์ƒ๋จ์„ ๋ณด์˜€๋‹ค. ์‹œ๊ณต๊ฐ„ ์˜์ƒ์œตํ•ฉ ์‹œ, ๊ตฌ๋ฆ„ํƒ์ง€, ์–‘๋ฐฉํ–ฅ ๋ฐ˜์‚ฌ ํ•จ์ˆ˜ ์กฐ์ •, ๊ณต๊ฐ„ ๋“ฑ๋ก, ์‹œ๊ณต๊ฐ„ ์œตํ•ฉ, ์‹œ๊ณต๊ฐ„ ๊ฒฐ์ธก์น˜ ๋ณด์™„ ๋“ฑ์˜ ๊ณผ์ •์„ ๊ฑฐ์นœ๋‹ค. ์ด ์˜์ƒ์œตํ•ฉ ์‚ฐ์ถœ๋ฌผ์€ ๊ฒฝ์ž‘๊ด€๋ฆฌ ๋“ฑ์œผ๋กœ ์‹์ƒ ์ง€์ˆ˜์˜ ์—ฐ๊ฐ„ ๋ณ€๋™์ด ํฐ ๋‘ ์žฅ์†Œ(๋†๊ฒฝ์ง€์™€ ๋‚™์—ฝ์ˆ˜๋ฆผ)์—์„œ ํ‰๊ฐ€ํ•˜์˜€๋‹ค. ๊ทธ ๊ฒฐ๊ณผ, ์‹œ๊ณต๊ฐ„ ์˜์ƒ์œตํ•ฉ ์‚ฐ์ถœ๋ฌผ์€ ๊ฒฐ์ธก์น˜ ์—†์ด ํ˜„์žฅ๊ด€์ธก์„ ์˜ˆ์ธกํ•˜์˜€๋‹ค (R2 = 0.71, ์ƒ๋Œ€ ํŽธํ–ฅ = 5.64% ๋†๊ฒฝ์ง€; R2 = 0.79, ์ƒ๋Œ€ ํŽธํ–ฅ = -13.8%, ํ™œ์—ฝ์ˆ˜๋ฆผ). ์‹œ๊ณต๊ฐ„ ์˜์ƒ์œตํ•ฉ์€ ์‹์ƒ ์ง€๋„์˜ ์‹œ๊ณต๊ฐ„ ํ•ด์ƒ๋„๋ฅผ ์ ์ง„์ ์œผ๋กœ ๊ฐœ์„ ํ•˜์—ฌ, ์‹๋ฌผ ์ƒ์žฅ๊ธฐ๋™์•ˆ ์œ„์„ฑ์˜์ƒ์ด ํ˜„์žฅ ๊ด€์ธก์„ ๊ณผ์†Œ ํ‰๊ฐ€๋ฅผ ์ค„์˜€๋‹ค. ์˜์ƒ์œตํ•ฉ์€ ๋†’์€ ์‹œ๊ณต๊ฐ„ ํ•ด์ƒ๋„๋กœ ๊ด‘ํ•ฉ์„ฑ ์ง€๋„๋ฅผ ์ผ๊ฐ„๊ฒฉ์œผ๋กœ ์ƒ์„ฑํ•˜๊ธฐ์— ์ด๋ฅผ ํ™œ์šฉํ•˜์—ฌ ์œ„์„ฑ ์˜์ƒ์˜ ์ œํ•œ๋œ ์‹œ๊ณต๊ฐ„ ํ•ด์ƒ๋„๋กœ ๋ฐํ˜€์ง€์ง€ ์•Š์€ ์‹๋ฌผ๋ณ€ํ™”์˜ ๊ณผ์ •์„ ๋ฐœ๊ฒฌํ•˜๊ธธ ๊ธฐ๋Œ€ํ•œ๋‹ค. ์‹์ƒ์˜ ๊ณต๊ฐ„๋ถ„ํฌ์€ ์ •๋ฐ€๋†์—…๊ณผ ํ† ์ง€ ํ”ผ๋ณต ๋ณ€ํ™” ๋ชจ๋‹ˆํ„ฐ๋ง์„ ์œ„ํ•ด ํ•„์ˆ˜์ ์ด๋‹ค. ๊ณ ํ•ด์ƒ๋„ ์œ„์„ฑ์˜์ƒ์œผ๋กœ ์ง€๊ตฌ ํ‘œ๋ฉด์„ ๊ด€์ธกํ•˜๋Š” ๊ฒƒ์„ ์šฉ์ดํ•˜๊ฒŒ ํ•ด์กŒ๋‹ค. ํŠนํžˆ Planet Fusion์€ ์ดˆ์†Œํ˜•์œ„์„ฑ๊ตฐ ๋ฐ์ดํ„ฐ๋ฅผ ์ตœ๋Œ€ํ•œ ํ™œ์šฉํ•ด ๋ฐ์ดํ„ฐ ๊ฒฐ์ธก์ด ์—†๋Š” 3m ๊ณต๊ฐ„ ํ•ด์ƒ๋„์˜ ์ง€ํ‘œ ํ‘œ๋ฉด ๋ฐ˜์‚ฌ๋„์ด๋‹ค. ๊ทธ๋Ÿฌ๋‚˜ ๊ณผ๊ฑฐ ์œ„์„ฑ ์„ผ์„œ(Landsat์˜ ๊ฒฝ์šฐ 30~60m)์˜ ๊ณต๊ฐ„ ํ•ด์ƒ๋„๋Š” ์‹์ƒ์˜ ๊ณต๊ฐ„์  ๋ณ€ํ™”๋ฅผ ์ƒ์„ธ ๋ถ„์„ํ•˜๋Š” ๊ฒƒ์„ ์ œํ•œํ–ˆ๋‹ค. ์ œ3์žฅ์—์„œ๋Š” Landsat ๋ฐ์ดํ„ฐ์˜ ๊ณต๊ฐ„ ํ•ด์ƒ๋„๋ฅผ ํ–ฅ์ƒํ•˜๊ธฐ ์œ„ํ•ด Planet Fusion ๋ฐ Landsat 8 ๋ฐ์ดํ„ฐ๋ฅผ ์‚ฌ์šฉํ•˜์—ฌ ์ด์ค‘ ์ ๋Œ€์  ์ƒ์„ฑ ๋„คํŠธ์›Œํฌ(the dual RSS-GAN)๋ฅผ ํ•™์Šต์‹œ์ผœ, ๊ณ ํ•ด์ƒ๋„ ์ •๊ทœํ™” ์‹์ƒ ์ง€์ˆ˜(NDVI)์™€ ์‹๋ฌผ ๊ทผ์ ์™ธ์„  ๋ฐ˜์‚ฌ(NIRv)๋„๋ฅผ ์ƒ์„ฑํ•˜๋Š” ํ•œ๋‹ค. ํƒ€์›Œ๊ธฐ๋ฐ˜ ํ˜„์žฅ ์‹์ƒ์ง€์ˆ˜(์ตœ๋Œ€ 8๋…„)์™€ ๋“œ๋ก ๊ธฐ๋ฐ˜ ์ดˆ๋ถ„๊ด‘์ง€๋„๋กœ the dual RSS-GAN์˜ ์„ฑ๋Šฅ์„ ๋Œ€ํ•œ๋ฏผ๊ตญ ๋‚ด ๋‘ ๋Œ€์ƒ์ง€(๋†๊ฒฝ์ง€์™€ ํ™œ์—ฝ์ˆ˜๋ฆผ)์—์„œ ํ‰๊ฐ€ํ–ˆ๋‹ค. The dual RSS-GAN์€ Landsat 8 ์˜์ƒ์˜ ๊ณต๊ฐ„ํ•ด์ƒ๋„๋ฅผ ํ–ฅ์ƒ์‹œ์ผœ ๊ณต๊ฐ„ ํ‘œํ˜„์„ ๋ณด์™„ํ•˜๊ณ  ์‹์ƒ ์ง€์ˆ˜์˜ ๊ณ„์ ˆ์  ๋ณ€ํ™”๋ฅผ ํฌ์ฐฉํ–ˆ๋‹ค(R2> 0.96). ๊ทธ๋ฆฌ๊ณ  the dual RSS-GAN์€ Landsat 8 ์‹์ƒ ์ง€์ˆ˜๊ฐ€ ํ˜„์žฅ์— ๋น„ํ•ด ๊ณผ์†Œ ํ‰๊ฐ€๋˜๋Š” ๊ฒƒ์„ ์™„ํ™”ํ–ˆ๋‹ค. ํ˜„์žฅ ๊ด€์ธก์— ๋น„ํ•ด ์ด์ค‘ RSS-GAN๊ณผ Landsat 8์˜ ์ƒ๋Œ€ ํŽธํ–ฅ ๊ฐ’ ๊ฐ๊ฐ -0.8% ์—์„œ -1.5%, -10.3% ์—์„œ -4.6% ์˜€๋‹ค. ์ด๋Ÿฌํ•œ ๊ฐœ์„ ์€ Planet Fusion์˜ ๊ณต๊ฐ„์ •๋ณด๋ฅผ ์ด์ค‘ RSS-GAN๋กœ ํ•™์Šตํ•˜์˜€๊ธฐ์— ๊ฐ€๋Šฅํ–ˆ๋‹ค. ํ—ค๋‹น ์—ฐ๊ตฌ ๊ฒฐ๊ณผ๋Š” Landsat ์˜์ƒ์˜ ๊ณต๊ฐ„ ํ•ด์ƒ๋„๋ฅผ ํ–ฅ์ƒ์‹œ์ผœ ์ˆจ๊ฒจ์ง„ ๊ณต๊ฐ„ ์ •๋ณด๋ฅผ ์ œ๊ณตํ•˜๋Š” ์ƒˆ๋กœ์šด ์ ‘๊ทผ ๋ฐฉ์‹์ด๋‹ค. ๊ณ ํ•ด์ƒ๋„์—์„œ ์‹๋ฌผ ๊ด‘ํ•ฉ์„ฑ ์ง€๋„๋Š” ํ† ์ง€ํ”ผ๋ณต์ด ๋ณต์žกํ•œ ๊ณต๊ฐ„์—์„œ ํƒ„์†Œ ์ˆœํ™˜ ๋ชจ๋‹ˆํ„ฐ๋ง์‹œ ํ•„์ˆ˜์ ์ด๋‹ค. ๊ทธ๋Ÿฌ๋‚˜ Sentinel-2, Landsat ๋ฐ MODIS์™€ ๊ฐ™์ด ํƒœ์–‘ ๋™์กฐ ๊ถค๋„์— ์žˆ๋Š” ์œ„์„ฑ์€ ๊ณต๊ฐ„ ํ•ด์ƒ๋„๊ฐ€ ๋†’๊ฑฐ๋‚˜ ์‹œ๊ฐ„ ํ•ด์ƒ๋„ ๋†’์€ ์œ„์„ฑ์˜์ƒ๋งŒ ์ œ๊ณตํ•  ์ˆ˜ ์žˆ๋‹ค. ์ตœ๊ทผ ๋ฐœ์‚ฌ๋œ ์ดˆ์†Œํ˜•์œ„์„ฑ๊ตฐ์€ ์ด๋Ÿฌํ•œ ํ•ด์ƒ๋„ ํ•œ๊ณ„์„ ๊ทน๋ณตํ•  ์ˆ˜ ์žˆ๋‹ค. ํŠนํžˆ Planet Fusion์€ ์ดˆ์†Œํ˜•์œ„์„ฑ ์ž๋ฃŒ์˜ ์‹œ๊ณต๊ฐ„ ํ•ด์ƒ๋„๋กœ ์ง€ํ‘œ๋ฉด์„ ๊ด€์ธกํ•  ์ˆ˜ ์žˆ๋‹ค. 4์žฅ์—์„œ, Planet Fusion ์ง€ํ‘œ๋ฐ˜์‚ฌ๋„๋ฅผ ์ด์šฉํ•˜์—ฌ ์‹์ƒ์—์„œ ๋ฐ˜์‚ฌ๋œ ๊ทผ์ ์™ธ์„  ๋ณต์‚ฌ(NIRvP)๋ฅผ 3m ํ•ด์ƒ๋„ ์ง€๋„๋ฅผ ์ผ๊ฐ„๊ฒฉ์œผ๋กœ ์ƒ์„ฑํ–ˆ๋‹ค. ๊ทธ๋Ÿฐ ๋‹ค์Œ ๋ฏธ๊ตญ ์บ˜๋ฆฌํฌ๋‹ˆ์•„์ฃผ ์ƒˆํฌ๋ผ๋ฉ˜ํ† -์ƒŒ ํ˜ธ์•„ํ‚จ ๋ธํƒ€์˜ ํ”Œ๋Ÿญ์Šค ํƒ€์›Œ ๋„คํŠธ์›Œํฌ ๋ฐ์ดํ„ฐ์™€ ๋น„๊ตํ•˜์—ฌ ์‹๋ฌผ ๊ด‘ํ•ฉ์„ฑ์„ ์ถ”์ •ํ•˜๊ธฐ ์œ„ํ•œ NIRvP ์ง€๋„์˜ ์„ฑ๋Šฅ์„ ํ‰๊ฐ€ํ•˜์˜€๋‹ค. ์ „์ฒด์ ์œผ๋กœ NIRvP ์ง€๋„๋Š” ์Šต์ง€์˜ ์žฆ์€ ์ˆ˜์œ„ ๋ณ€ํ™”์—๋„ ๋ถˆ๊ตฌํ•˜๊ณ  ๊ฐœ๋ณ„ ๋Œ€์ƒ์ง€์˜ ์‹๋ฌผ ๊ด‘ํ•ฉ์„ฑ์˜ ์‹œ๊ฐ„์  ๋ณ€ํ™”๋ฅผ ํฌ์ฐฉํ•˜์˜€๋‹ค. ๊ทธ๋Ÿฌ๋‚˜ ๋Œ€์ƒ์ง€ ์ „์ฒด์— ๋Œ€ํ•œ NIRvP ์ง€๋„์™€ ์‹๋ฌผ ๊ด‘ํ•ฉ์„ฑ ์‚ฌ์ด์˜ ๊ด€๊ณ„๋Š” NIRvP ์ง€๋„๋ฅผ ํ”Œ๋Ÿญ์Šค ํƒ€์›Œ ๊ด€์ธก๋ฒ”์œ„์™€ ์ผ์น˜์‹œํ‚ฌ ๋•Œ๋งŒ ๋†’์€ ์ƒ๊ด€๊ด€๊ณ„๋ฅผ ๋ณด์˜€๋‹ค. ๊ด€์ธก๋ฒ”์œ„๋ฅผ ์ผ์น˜์‹œํ‚ฌ ๊ฒฝ์šฐ, NIRvP ์ง€๋„๋Š” ์‹๋ฌผ ๊ด‘ํ•ฉ์„ฑ์„ ์ถ”์ •ํ•˜๋Š” ๋ฐ ์žˆ์–ด ํ˜„์žฅ NIRvP๋ณด๋‹ค ์šฐ์ˆ˜ํ•œ ์„ฑ๋Šฅ์„ ๋ณด์˜€๋‹ค. ์ด๋Ÿฌํ•œ ์„ฑ๋Šฅ ์ฐจ์ด๋Š” ํ”Œ๋Ÿญ์Šค ํƒ€์›Œ ๊ด€์ธก๋ฒ”์œ„๋ฅผ ์ผ์น˜์‹œํ‚ฌ ๋•Œ, ์—ฐ๊ตฌ ๋Œ€์ƒ์ง€ ๊ฐ„์˜ NIRvP-์‹๋ฌผ ๊ด‘ํ•ฉ์„ฑ ๊ด€๊ณ„์˜ ๊ธฐ์šธ๊ธฐ๊ฐ€ ์ผ๊ด€์„ฑ์„ ๋ณด์˜€๊ธฐ ๋•Œ๋ฌธ์ด๋‹ค. ๋ณธ ์—ฐ๊ตฌ ๊ฒฐ๊ณผ๋Š” ์œ„์„ฑ ๊ด€์ธก์„ ํ”Œ๋Ÿญ์Šค ํƒ€์›Œ ๊ด€์ธก๋ฒ”์œ„์™€ ์ผ์น˜์‹œํ‚ค๋Š” ๊ฒƒ์˜ ์ค‘์š”์„ฑ์„ ๋ณด์—ฌ์ฃผ๊ณ  ๋†’์€ ์‹œ๊ณต๊ฐ„ ํ•ด์ƒ๋„๋กœ ์‹๋ฌผ ๊ด‘ํ•ฉ์„ฑ์„ ์›๊ฒฉ์œผ๋กœ ๋ชจ๋‹ˆํ„ฐ๋งํ•˜๋Š” ์ดˆ์†Œํ˜•์œ„์„ฑ๊ตฐ ์ž๋ฃŒ์˜ ์ž ์žฌ๋ ฅ์„ ๋ณด์—ฌ์ค€๋‹ค.Monitoring changes in terrestrial vegetation is essential to understanding interactions between atmosphere and biosphere, especially terrestrial ecosystem. To this end, satellite remote sensing offer maps for examining land surface in different scales. However, the detailed information was hindered under the clouds or limited by the spatial resolution of satellite imagery. Moreover, the impacts of spatial and temporal resolution in photosynthesis monitoring were not fully revealed. In this dissertation, I aimed to enhance the spatial and temporal resolution of satellite imagery towards daily gap-free vegetation maps with high spatial resolution. In order to expand vegetation change monitoring in time and space using high-resolution satellite images, I 1) improved temporal resolution of satellite dataset through image fusion using geostationary satellites, 2) improved spatial resolution of satellite dataset using generative adversarial networks, and 3) showed the use of high spatiotemporal resolution maps for monitoring plant photosynthesis especially over heterogeneous landscapes. With the advent of new techniques in satellite remote sensing, current and past datasets can be fully utilized for monitoring vegetation changes in the respect of spatial and temporal resolution. In Chapter 2, I developed the integrated system that implemented geostationary satellite products in the spatiotemporal image fusion method for monitoring canopy photosynthesis. The integrated system contains the series of process (i.e., cloud masking, nadir bidirectional reflectance function adjustment, spatial registration, spatiotemporal image fusion, spatial gap-filling, temporal-gap-filling). I conducted the evaluation of the integrated system over heterogeneous rice paddy landscape where the drastic land cover changes were caused by cultivation management and deciduous forest where consecutive changes occurred in time. The results showed that the integrated system well predict in situ measurements without data gaps (R2 = 0.71, relative bias = 5.64% at rice paddy site; R2 = 0.79, relative bias = -13.8% at deciduous forest site). The integrated system gradually improved the spatiotemporal resolution of vegetation maps, reducing the underestimation of in situ measurements, especially during peak growing season. Since the integrated system generates daily canopy photosynthesis maps for monitoring dynamics among regions of interest worldwide with high spatial resolution. I anticipate future efforts to reveal the hindered information by the limited spatial and temporal resolution of satellite imagery. Detailed spatial representations of terrestrial vegetation are essential for precision agricultural applications and the monitoring of land cover changes in heterogeneous landscapes. The advent of satellite-based remote sensing has facilitated daily observations of the Earths surface with high spatial resolution. In particular, a data fusion product such as Planet Fusion has realized the delivery of daily, gap-free surface reflectance data with 3-m pixel resolution through full utilization of relatively recent (i.e., 2018-) CubeSat constellation data. However, the spatial resolution of past satellite sensors (i.e., 30โ€“60 m for Landsat) has restricted the detailed spatial analysis of past changes in vegetation. In Chapter 3, to overcome the spatial resolution constraint of Landsat data for long-term vegetation monitoring, we propose a dual remote-sensing super-resolution generative adversarial network (dual RSS-GAN) combining Planet Fusion and Landsat 8 data to simulate spatially enhanced long-term time-series of the normalized difference vegetation index (NDVI) and near-infrared reflectance from vegetation (NIRv). We evaluated the performance of the dual RSS-GAN against in situ tower-based continuous measurements (up to 8 years) and remotely piloted aerial system-based maps of cropland and deciduous forest in the Republic of Korea. The dual RSS-GAN enhanced spatial representations in Landsat 8 images and captured seasonal variation in vegetation indices (R2 > 0.95, for the dual RSS-GAN maps vs. in situ data from all sites). Overall, the dual RSS-GAN reduced Landsat 8 vegetation index underestimations compared with in situ measurements; relative bias values of NDVI ranged from โˆ’3.2% to 1.2% and โˆ’12.4% to โˆ’3.7% for the dual RSS-GAN and Landsat 8, respectively. This improvement was caused by spatial enhancement through the dual RSS-GAN, which captured fine-scale information from Planet Fusion. This study presents a new approach for the restoration of hidden sub-pixel spatial information in Landsat images. Mapping canopy photosynthesis in both high spatial and temporal resolution is essential for carbon cycle monitoring in heterogeneous areas. However, well established satellites in sun-synchronous orbits such as Sentinel-2, Landsat and MODIS can only provide either high spatial or high temporal resolution but not both. Recently established CubeSat satellite constellations have created an opportunity to overcome this resolution trade-off. In particular, Planet Fusion allows full utilization of the CubeSat data resolution and coverage while maintaining high radiometric quality. In Chapter 4, I used the Planet Fusion surface reflectance product to calculate daily, 3-m resolution, gap-free maps of the near-infrared radiation reflected from vegetation (NIRvP). I then evaluated the performance of these NIRvP maps for estimating canopy photosynthesis by comparing with data from a flux tower network in Sacramento-San Joaquin Delta, California, USA. Overall, NIRvP maps captured temporal variations in canopy photosynthesis of individual sites, despite changes in water extent in the wetlands and frequent mowing in the crop fields. When combining data from all sites, however, I found that robust agreement between NIRvP maps and canopy photosynthesis could only be achieved when matching NIRvP maps to the flux tower footprints. In this case of matched footprints, NIRvP maps showed considerably better performance than in situ NIRvP in estimating canopy photosynthesis both for daily sum and data around the time of satellite overpass (R2 = 0.78 vs. 0.60, for maps vs. in situ for the satellite overpass time case). This difference in performance was mostly due to the higher degree of consistency in slopes of NIRvP-canopy photosynthesis relationships across the study sites for flux tower footprint-matched maps. Our results show the importance of matching satellite observations to the flux tower footprint and demonstrate the potential of CubeSat constellation imagery to monitor canopy photosynthesis remotely at high spatio-temporal resolution.Chapter 1. Introduction 2 1. Background 2 1.1 Daily gap-free surface reflectance using geostationary satellite products 2 1.2 Monitoring past vegetation changes with high-spatial-resolution 3 1.3 High spatiotemporal resolution vegetation photosynthesis maps 4 2. Purpose of Research 4 Chapter 2. Generating daily gap-filled BRDF adjusted surface reflectance product at 10 m resolution using geostationary satellite product for monitoring daily canopy photosynthesis 6 1. Introduction 6 2. Methods 11 2.1 Study sites 11 2.2 In situ measurements 13 2.3 Satellite products 14 2.4 Integrated system 17 2.5 Canopy photosynthesis 21 2.6 Evaluation 23 3. Results and discussion 24 3.1 Comparison of STIF NDVI and NIRv with in situ NDVI and NIRv 24 3.2 Comparison of STIF NIRvP with in situ NIRvP 28 4. Conclusion 31 Chapter 3. Super-resolution of historic Landsat imagery using a dual Generative Adversarial Network (GAN) model with CubeSat constellation imagery for monitoring vegetation changes 32 1. Introduction 32 2. Methods 38 2.1 Real-ESRGAN model 38 2.2 Study sites 40 2.3 In situ measurements 42 2.4 Vegetation index 44 2.5 Satellite data 45 2.6 Planet Fusion 48 2.7 Dual RSS-GAN via fine-tuned Real-ESRGAN 49 2.8 Evaluation 54 3. Results 57 3.1 Comparison of NDVI and NIRv maps from Planet Fusion, Sentinel 2 NBAR, and Landsat 8 NBAR data with in situ NDVI and NIRv 57 3.2 Comparison of dual RSS-SRGAN model results with Landsat 8 NDVI and NIRv 60 3.3 Comparison of dual RSS-GAN model results with respect to in situ time-series NDVI and NIRv 63 3.4 Comparison of the dual RSS-GAN model with NDVI and NIRv maps derived from RPAS 66 4. Discussion 70 4.1 Monitoring changes in terrestrial vegetation using the dual RSS-GAN model 70 4.2 CubeSat data in the dual RSS-GAN model 72 4.3 Perspectives and limitations 73 5. Conclusion 78 Appendices 79 Supplementary material 82 Chapter 4. Matching high resolution satellite data and flux tower footprints improves their agreement in photosynthesis estimates 85 1. Introduction 85 2. Methods 89 2.1 Study sites 89 2.2 In situ measurements 92 2.3 Planet Fusion NIRvP 94 2.4 Flux footprint model 98 2.5 Evaluation 98 3. Results 105 3.1 Comparison of Planet Fusion NIRv and NIRvP with in situ NIRv and NIRvP 105 3.2 Comparison of instantaneous Planet Fusion NIRv and NIRvP with against tower GPP estimates 108 3.3 Daily GPP estimation from Planet Fusion -derived NIRvP 114 4. Discussion 118 4.1 Flux tower footprint matching and effects of spatial and temporal resolution on GPP estimation 118 4.2 Roles of radiation component in GPP mapping 123 4.3 Limitations and perspectives 126 5. Conclusion 133 Appendix 135 Supplementary Materials 144 Chapter 5. Conclusion 153 Bibliography 155 Abstract in Korea 199 Acknowledgements 202๋ฐ•

    Detecting and quantifying a massive invasion of floating aquatic plants in the Rรญo de la Plata turbid waters using high spatial resolution ocean color imagery

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    The massive development of floating plants in floodplain lakes and wetlands in the upper Middle Paranรก river in the La Plata basin is environmentally and socioeconomically important. Every year aquatic plant detachments drift downstream arriving in small amounts to the Rรญo de la Plata, but huge temporary invasions have been observed every 10 or 15 years associated to massive floods. From late December 2015, heavy rains driven by a strong El Niรฑo increased river levels, provoking a large temporary invasion of aquatic plants from January to May 2016. This event caused significant disruption of human activities via clogging of drinking water intakes in the estuary, blocking of ports and marinas and introducing dangerous animals from faraway wetlands into the city. In this study, we developed a scheme to map floating vegetation in turbid waters using high-resolution imagery, like Sentinel-2/SMI (MultiSpectral Imager), Landsat-8/OLI (Operational Land Imager), and Aqua/MODIS (MODerate resolution Imager Spectroradiometer)-250 m. A combination of the Floating Algal Index (that make use of the strong signal in the NIR part of the spectrum), plus conditions set on the RED band (to avoid misclassifying highly turbid waters) and on the CIE La*b* color space coordinates (to confirm the visually "green" pixels as floating vegetation) were used. A time-series of multisensor high resolution imagery was analyzed to study the temporal variability, covered area and distribution of the unusual floating macroalgae invasion that started in January 2016 in the Rรญo de la Plata estuary.Fil: Dogliotti, Ana Inรฉs. Consejo Nacional de Investigaciรณnes Cientรญficas y Tรฉcnicas. Oficina de Coordinaciรณn Administrativa Ciudad Universitaria. Instituto de Astronomรญa y Fรญsica del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomรญa y Fรญsica del Espacio; ArgentinaFil: Gossn, Juan Ignacio. Consejo Nacional de Investigaciรณnes Cientรญficas y Tรฉcnicas. Oficina de Coordinaciรณn Administrativa Ciudad Universitaria. Instituto de Astronomรญa y Fรญsica del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomรญa y Fรญsica del Espacio; ArgentinaFil: Vanhellemont, Quinten. Koninklijk Belgisch Instituut Voor Natuurwetenschappen; BรฉlgicaFil: Ruddick, Kevin G.. Koninklijk Belgisch Instituut Voor Natuurwetenschappen; Bรฉlgic
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