Asia-Pacific Remote Sensing最新文献

{"title":"Comparing U-Net convolutional network with mask R-CNN in the performances of pomegranate tree canopy segmentation","authors":"Tiebiao Zhao, Yonghuan Yang, Haoyu Niu, Dong Wang, Y. Chen","doi":"10.1117/12.2325570","DOIUrl":"https://doi.org/10.1117/12.2325570","url":null,"abstract":"In the last decade, technologies of unmanned aerial vehicles (UAVs) and small imaging sensors have achieved a significant improvement in terms of equipment cost, operation cost and image quality. These low-cost platforms provide flexible access to high resolution visible and multispectral images. As a result, many studies have been conducted regarding the applications in precision agriculture, such as water stress detection, nutrient status detection, yield prediction, etc. Different from traditional satellite low-resolution images, high-resolution UAVbased images allow much more freedom in image post-processing. For example, the very first procedure in post-processing is pixel classification, or image segmentation for extracting region of interest(ROI). With the very high resolution, it becomes possible to classify pixels from a UAV-based image, yet it is still a challenge to conduct pixel classification using traditional remote sensing features such as vegetation indices (VIs), especially considering various changes during the growing season such as light intensity, crop size, crop color etc. Thanks to the development of deep learning technologies, it provides a general framework to solve this problem. In this study, we proposed to use deep learning methods to conduct image segmentation. We created our data set of pomegranate trees by flying an off-shelf commercial camera at 30 meters above the ground around noon, during the whole growing season from the beginning of April to the middle of October 2017. We then trained and tested two convolutional network based methods U-Net and Mask R-CNN using this data set. Finally, we compared their performances with our dataset aerial images of pomegranate trees. [Tiebiao- add a sentence to summarize the findings and their implications to precision agriculture]","PeriodicalId":370971,"journal":{"name":"Asia-Pacific Remote Sensing","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127041966","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Advances in utilizing deep convective cloud targets to inter-calibrate geostationary reflective solar band imagers with well calibrated imagers","authors":"C. Haney, D. Doelling, R. Bhatt, B. Scarino, A. Gopalan","doi":"10.1117/12.2324786","DOIUrl":"https://doi.org/10.1117/12.2324786","url":null,"abstract":"The CERES project utilizes geostationary-derived broadband measurements to infer the regional diurnal flux in between CERES instantaneous measurements to estimate the daily-averaged flux. The geostationary (GEO) imager radiances must be calibrated to the same reference to ensure spatial and temporal consistency of cloud properties and fluxes across the contiguous GEO domains. In order to place all of the GEO visible imagers on the same radiometric scale, the CERES project inter-calibrates the GEO imagers with Aqua-MODIS using multiple independent approaches. The primary inter-calibration approach relies on coincident, ray-matched GEO and MODIS radiance pairs over all-sky tropical ocean scenes (ATO). Another ray-matching approach was recently developed to take advantage of the visible spectral uniformity and near-Lambertian reflectance of deep convective clouds (DCC). The success of the DCC raymatching (DCC-RM) approach has been demonstrated by comparing the calibration with the ATO ray-matching (ATORM) approach for the 0.65-μm GEO and MODIS bands. Now that many of the recently launched GEO imagers have multiple reflective solar band channels, the DCCRM algorithm is being modified to inter-calibrate those channels as well, especially for the SWIR bands. The spectral uniformity of the DCC over the SWIR bands is not uniform, given that the ice particle absorption is a function of wavelength. New Spectral Band Adjustment Factor (SBAF) strategies will need to be developed. DCC-RM is also wellsuited to inter-calibrate historical near-broadband visible GEO imagers. DCC are spectrally flat across the visible spectrum, which reduces the SBAF uncertainty between two ray-matched sensors. Applying the DCC-RM technique on historical GEO imagers is challenging due to the coarser pixel and temporal resolution of the ISCCP B1U formatted dataset. The ATO-RM and DCC-RM calibration methods were applied to multiple visible bands on Himawari-8 using MODIS as the calibration reference. The Aqua-MODIS and Himawari-8 calibration difference was less than 0.4% for wavelengths less than 1 µm and for the Terra-MODIS 0.65-μm channel. Other channel combinations would need further examination to obtain consistent ATO and DCC gain results. The ATO-RM and DCC-RM calibration methods were also applied to GOES-8 in the ISCCP B1U format with NOAA-14 AVHRR as the calibration reference. The GOES-8 ATO and DCC calibration gain difference was within 0.15%. The agreement between ATO and DCC gains provides confidence in both methods.","PeriodicalId":370971,"journal":{"name":"Asia-Pacific Remote Sensing","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130274525","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Classification of Chinese cabbage and radish based on the reflectance of hyperspectral imagery","authors":"Ye-Seong Kang, C. Ryu, S. Jun, Si-Hyeong Jang, J. W. Park, Hye-young Song, T. Sarkar","doi":"10.1117/12.2325020","DOIUrl":"https://doi.org/10.1117/12.2325020","url":null,"abstract":"In this research, the ground based hyperspectral reflectance of Chinese cabbage and radish depending on the vegetation growth stages was compared to each other. The classifiers namely decision tree, random forest and support vector machine were tested to check the feasibility of classification depending on the difference in hyperspectral reflectance. The ability of classifier was compared with the overall accuracy and kappa coefficient depending on the vegetation growth stages. The spectral merging was applied to find out the optimal spectral bands to make new multispectral sensor based on the commercial band pass filter with full width at half maximum (FWHM) such as 10nm, 25nm, 40nm, 50nm and 80nm. It was ascertained that the pattern of hyperspectral reflectance varied in Chinese cabbage and radish and also found a certain disparity of pattern in different vegetation growing stage. Although the classifying ability of support vector machine with linear method was higher than the other six methods, it was not suitable for new multispectral sensor. Hence, the decision tree with Rpart method is advantageous as a best classifier to make new multispectral sensor in order to separate the hyperspectral reflectance of Chinese cabbage and radish depending on the vegetation growth stages. The substantiates two alternative aggregate of bands 410nm, 430nm, 700nm and 720nm with 10nm of FWHM or 410nm, 440nm, 690nm and 720nm with 25nm of FWHM were suggested to be the best combinations to make new multispectral sensor without the overlap of FWHM.","PeriodicalId":370971,"journal":{"name":"Asia-Pacific Remote Sensing","volume":"124 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123250810","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"On-orbit calibration analysis of FY-4A AGRI solar bands","authors":"Ling Sun, Boyang Chen, Yan Zhang, Ling Gao, Min Min, Q. Guo, Zhiqing Zhang","doi":"10.1117/12.2324288","DOIUrl":"https://doi.org/10.1117/12.2324288","url":null,"abstract":"FengYun-4A (FY-4A) is the first three-axis stabilized geostationary meteorological satellite in China, which was launched in the early morning of 11 Dec., 2016. Advanced Geosynchronous Radiation Imager (AGRI) is one of the four payloads onboard FY-4A, and acquired the first image on 20 Feb., 2017. FY-4A AGRI contains 14 spectral bands, in which 6 bands are in reflective solar region, with the nominal wavelengths at 0.47, 0.65, 0.825, 1.375, 1.61 and 2.25μm. The spatial resolution is 0.5 km for 0.65 μm band, 2 km for the shortwave infrared bands and 1 km for others. AGRI is designed with a solar diffuser, however it revealed the insufficient capacity for in-flight calibration mainly due to the partial aperture effect. The first vicarious calibration field campaign was conducted at the Dunhuang site of China Radiometric Calibration Site (CRCS) in Apr. 2017. It revealed the large bias of the AGRI data calibrated using the prelaunch calibration parameters, mostly underestimated. Using multiple land sites in Asia and Oceania, the calibration correction factors were derived combined with the CRCS data. The sensor's on-orbit radiometric response variation and observation bias against the simulated radiation were also monitored. It revealed that the bands at 0.65 μm was most stable, while 0.47 μm band showed the large degradation with an annual rate nearly 17%. In this paper, the calibration status of the FY-4A AGRI solar bands was presented.","PeriodicalId":370971,"journal":{"name":"Asia-Pacific Remote Sensing","volume":"79 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127718435","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Prelaunch and on-orbit electronic calibration for Earth-observing instruments","authors":"A. Angal, X. Xiong, J. Mcintire, N. Chen, H. Oudrari","doi":"10.1117/12.2500057","DOIUrl":"https://doi.org/10.1117/12.2500057","url":null,"abstract":"The Electronic Calibration (Ecal) tests are performed during various stages of instrument development to examine the linearity of the instrument electronics. During this process, charges with stepwise increments are injected in the analog electronics circuitry to generate a ramp signal that can be used to characterize any nonlinearities in the electronics. The prelaunch characterization of MODIS (on the Terra and Aqua platforms) and VIIRS (on SNPP, JPSS-1 and JPSS-2) involved a regular evaluation of the electronics linearity using the Ecal tests. On orbit, the Ecal tests have been regularly performed over the mission for both the MODIS instruments to derive the electronics gain and linearity. Unlike MODIS, the Ecal tests on the VIIRS instruments are performed on an as-needed basis. To date, no Ecal tests were performed for S-NPP VIIRS on orbit. The VIIRS instrument on JPSS-1 (now NOAA 20) was launched on November 18, 2017. An Ecal test was performed to support the instruments initial post-launch performance assessment. Shortly after the","PeriodicalId":370971,"journal":{"name":"Asia-Pacific Remote Sensing","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132738363","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Volcanic gas measurements using a compact mid-wave infrared hyperspectral imager","authors":"C. Honniball, R. Wright, P. Lucey, A. Gabrieli, A. Khayat","doi":"10.1117/12.2324627","DOIUrl":"https://doi.org/10.1117/12.2324627","url":null,"abstract":"Gases released from a volcano, such as sulfur dioxide (SO2) and carbon dioxide (CO2), present hazards to the environment and local populations as well as providing a means to monitor volcanic activity and study pre-eruptive signatures. In the Mid-Wave InfraRed (MWIR) from 3 to 5 microns both the aforementioned volcanic gases exhibit characteristic absorptions. Remote sensing in the MWIR, however, is challenging due to the limited amount of signal available to measure. This presents technical challenges on achieving high signal-to-noise ratios; therefore, acquiring adequate data in the MWIR has been difficult without cryogenically cooling the instrument. However, ecent improvements to microbolometer technology and emerging interferometric techniques have allowed us to acquire good thermal infrared data without the need for cooling. By utilizing the advantages of an imaging interferometer paired with an uncooled microbolometer, we demonstrate the use of a MWIR compact, hyperspectral imager for volcanic gas detection. The instrument, the Miniaturized Infrared Detector of Atmospheric Species (MIDAS), is representative of an instrument that could feasibly be flown on a small satellite in low earth orbit for the detection and monitoring of volcanic gases. Recently MIDAS was deployed to Kilauea’s Halema’uma’u pit crater which during the deployment had an active lava lake that was continuously releasing volcanic gases. Sources like the Kilauea lava lake provide high background temperatures that aid MWIR measurements of volcanic gases. We present hyperspectral analysis of volcanic gases from the Kilauea lava lake using data from the MIDAS instrument and line by line radiative transfer analysis. Brightness temperature maps of the lake surface show values consistent with direct thermocouple measurements and point radiometer measurements. Here we present resolved images of spectral radiance, brightness temperature, and CO2 concentrations. The map of CO2 is relatively uniform, but show subtle variation at the 2553 - 3313+/- 167 ppm level.","PeriodicalId":370971,"journal":{"name":"Asia-Pacific Remote Sensing","volume":"129 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134228998","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Multi-factor analysis on polarized spectral reflectance of bare soil surface with different particle size","authors":"Yang Han, Ziping Liu, Y. Zhang, Yunsheng Zhao, Ping Wang","doi":"10.1117/12.2323958","DOIUrl":"https://doi.org/10.1117/12.2323958","url":null,"abstract":"The linear polarization of light reflected from soil surfaces was measured by an instrument composed of a semi-automatic goniometer and an ASD spectroradiometer under a direct lamp to determine its potential to detect differences in different particle size. In this paper we tested and analyzed the polarization spectra of soils to determine the spectral response and changes in soil particle size, and to establish models of the relationship between spectral data and soil particle size. An orthogonal test was also designed for the various factors that affect soil spectral polarization characteristics and their interactions. All above measurements were carried out in the laboratory where the atmospheric contribution was ignored. The results show that particle size is one of the most important parameter affecting soil spectra, and is critical to soil remote sensing band selection and image interpretation. It also provides information required for soil investigation and analysis of physical and chemical properties.","PeriodicalId":370971,"journal":{"name":"Asia-Pacific Remote Sensing","volume":"116 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133477361","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Interpreting millimeter-wave radiances over convective clouds","authors":"Z. Haddad, Raul Moreno Galdon, R. Sawaya, F. Tapiador","doi":"10.1117/12.2500284","DOIUrl":"https://doi.org/10.1117/12.2500284","url":null,"abstract":"Attempts to interpret the measurements of millimeter-wave radiometers over tropical storms must overcome the difficulty of modeling the scattering signatures of hydrometeors at these frequencies. Approaches to date try to retrieve surface precipitation, to which the observations are not directly sensitive. Millimeter wavelengths are most sensitive to the scattering from hydrometeors in the cloud upper levels. Millimeter-wavelength radiometers have a definite advantage over the lower frequency radiometers in that they have finer spatial resolution to resolve deep convection. Preliminary analyses indicate that the measurements are indeed sensitive to the depth and intensity of convection. The challenge is to derive a robust approach to estimate the characteristics of the convection directly from the observations, and conversely to derive a robust forward representation of the dependence of the radiances on the underlying moisture fields. This is done in a two-step semi-empirical approach.","PeriodicalId":370971,"journal":{"name":"Asia-Pacific Remote Sensing","volume":"64 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115331651","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A novel imaging spectrometer form for the solar reflective spectral range for size, weight, and power limited applications","authors":"M. Chrisp, R. Lockwood, Melissa A. Smith, Christopher Holtsberg, G. Balonek, K. Thome, S. Babu, P. Ghuman","doi":"10.1117/12.2324453","DOIUrl":"https://doi.org/10.1117/12.2324453","url":null,"abstract":"The intense development in imaging spectrometers and related technology has yielded systems that are highly performing. Current grating-based designs utilize focal plane arrays with aberrations controlled to a fraction of a detector element and low F-numbers for high étendue to maximize the signal to noise performance. Tailored grating facets using two or more blaze angles optimize the optical efficiency across the full 400-2500 nm solar reflective spectral range. Two commonly used forms, the Offner-Chrisp and Dyson designs, are adaptations of microlithographic projectors with a concave or convex mirror replaced by a shaped grating; maintain a high degree of spatial-spectral uniformity. These gratings are relatively difficult to manufacture using either e-beam lithography or diamond machining. The challenge for optical designers is to create optical forms with reduced size, weight, and power (SWaP) requirements while maintaining high performance. We have focused our work in this area and are developing a breadboard prototype imaging spectrometer that covers the full VNIR/SWIR spectral range at 10 nm spectral sampling, has a large swath of 1500 spatial samples, and is compact. The current prototype is for an F/3.3 system that is 7 cm long with an 8 cm diameter with aberration control better than 0.1 pixel assuming an 18 μm pixel pitch. The form utilizes a catadioptric lens and a flat dual-blaze immersion grating. The flat grating simplifies manufacturing and we are currently exploring the manufacture of the grating through grayscale optical lithography where the entire pattern can be exposed at once without stitching errors.","PeriodicalId":370971,"journal":{"name":"Asia-Pacific Remote Sensing","volume":"101 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114426957","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evaluating radiometric calibration of ASTER VNIR band with Terra MODIS, Landsat 7 ETM+, and Landsat 8 OLI","authors":"K. Obata, S. Tsuchida, H. Yoshioka","doi":"10.1117/12.2324419","DOIUrl":"https://doi.org/10.1117/12.2324419","url":null,"abstract":"On-orbit radiometric calibration of Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) visible and near-infrared (VNIR) band involves vicarious calibration using reflectance-based method, onboard lamp calibration, and cross-calibration with Moderate Resolution Imaging Spectroradiometer (MODIS) onboard Terra. The ASTER calibration was evaluated with reference to MODIS using an improved cross-calibration algorithm in the previous study (Obata et al., Sensors, 2017). In the present study, the evaluation is expanded by using other sensors that are highly calibrated, including the Landsat 7 Enhanced Thematic Mapper Plus (ETM+) and Landsat 8 Operational Land Imager (OLI). The objective of the present study is to evaluate radiometric calibration of ASTER VNIR band using MODIS, ETM+, and OLI counterparts over Railroad Valley Playa for the period from 2000 to 2018. Results indicate that ASTER bands 1 and 2 are in average 4.2-4.5% and 1.8-3.3% greater than MODIS/ETM+ and that ASTER band 3N agrees well with MODIS/ETM+. The behavior of ASTER surface reflectances along time shows similar trend to that of OLI. The number of sample data for ASTER and OLI comparison should be, however, increased for accurate analysis of statistics. Nevertheless, insights obtained by cross-comparisons provide beneficial information for evaluating ASTER radiometric calibration. The consistency among radiometric calibrations of multiple sensors is of significance importance in the context of data continuity and sensor fusion studies.","PeriodicalId":370971,"journal":{"name":"Asia-Pacific Remote Sensing","volume":"47 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115485690","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}