Multichannel synthetic aperture radar (MC-SAR) allows for high-resolution imaging of a wide swath (HRWS), at the cost of acquiring and downlinking a significantly larger amount of data, compared with conventional SAR systems. In this letter, we discuss the potential of efficient data volume reduction (DVR) for MC-SAR. Specifically, we focus on methods based on transform coding (TC) and linear predictive coding (LPC), which exploit the redundancy introduced in the raw data by the finer azimuth sampling peculiar to the MC system. The proposed approaches, in combination with a variable-bit quantization, allow for the optimization of the resulting performance and data rate. We consider three exemplary yet realistic MC-SAR systems, and we conduct simulations and analyses on synthetic SAR data considering different radar backscatter distributions, which demonstrate the effectiveness of the proposed methods.
{"title":"Coding-Based Data Compression for Multichannel SAR","authors":"Michele Martone;Nicola Gollin;Gerhard Krieger;Ernesto Imbembo;Paola Rizzoli","doi":"10.1109/LGRS.2024.3510433","DOIUrl":"https://doi.org/10.1109/LGRS.2024.3510433","url":null,"abstract":"Multichannel synthetic aperture radar (MC-SAR) allows for high-resolution imaging of a wide swath (HRWS), at the cost of acquiring and downlinking a significantly larger amount of data, compared with conventional SAR systems. In this letter, we discuss the potential of efficient data volume reduction (DVR) for MC-SAR. Specifically, we focus on methods based on transform coding (TC) and linear predictive coding (LPC), which exploit the redundancy introduced in the raw data by the finer azimuth sampling peculiar to the MC system. The proposed approaches, in combination with a variable-bit quantization, allow for the optimization of the resulting performance and data rate. We consider three exemplary yet realistic MC-SAR systems, and we conduct simulations and analyses on synthetic SAR data considering different radar backscatter distributions, which demonstrate the effectiveness of the proposed methods.","PeriodicalId":91017,"journal":{"name":"IEEE geoscience and remote sensing letters : a publication of the IEEE Geoscience and Remote Sensing Society","volume":"22 ","pages":"1-5"},"PeriodicalIF":0.0,"publicationDate":"2024-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10772623","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142821182","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The first experiment was conducted to monitor vertical distributions of carbon dioxide (CO2) and aerosols in the low troposphere (below 1 km) using a self-developed mobile, integrated, and 3-D scannable ground-based Mie-Raman lidar in Nanyang, Henan Province, China. The mean volume ratio of CO2 at low altitude (below 200 m) ranged from 418 to 419 ppm, with an average fluctuation of 7–9 ppm, and the mean volume ratio of CO2 was primarily distributed between 406 and 420 ppm during experimental periods. The vertical distribution of CO2 volume ratios exhibited a gradually decrease trends with increasing altitude integrally indicating that observation site belonged to carbon source regions. The quality of the CO2 echo signal was improved with decreasing daylight intensity. Specifically, the stratification of CO2 with time is gradually evident in the observations. The high aerosol extinction coefficients in Nanyang were mainly concentrated below an altitude of approximately 300 m, indicating that pollution near the ground was heavy. The vertical distribution of aerosol extinction coefficients was characterized by the phenomenon that altitudes of high value declined at night due to atmospheric dry deposition. This study demonstrated that our Mie-Raman scattering lidar can successfully obtain the vertical distribution of CO2 volume ratio and aerosol extinction coefficient, which can provide new datasets and technological support for local environmental department and “carbon neutrality” scientific research.
{"title":"Vertical Distributions of CO2 Volume Ratio and Aerosol Extinction Coefficients in Low-Altitude Utilizing Mie–Raman Lidar at Nanyang City, China","authors":"Miao Zhang;Yanli Yang;Jiawen Wu;Renjie Lan;Jun Zhang;Xiaoge Chang","doi":"10.1109/LGRS.2024.3509974","DOIUrl":"https://doi.org/10.1109/LGRS.2024.3509974","url":null,"abstract":"The first experiment was conducted to monitor vertical distributions of carbon dioxide (CO2) and aerosols in the low troposphere (below 1 km) using a self-developed mobile, integrated, and 3-D scannable ground-based Mie-Raman lidar in Nanyang, Henan Province, China. The mean volume ratio of CO2 at low altitude (below 200 m) ranged from 418 to 419 ppm, with an average fluctuation of 7–9 ppm, and the mean volume ratio of CO2 was primarily distributed between 406 and 420 ppm during experimental periods. The vertical distribution of CO2 volume ratios exhibited a gradually decrease trends with increasing altitude integrally indicating that observation site belonged to carbon source regions. The quality of the CO2 echo signal was improved with decreasing daylight intensity. Specifically, the stratification of CO2 with time is gradually evident in the observations. The high aerosol extinction coefficients in Nanyang were mainly concentrated below an altitude of approximately 300 m, indicating that pollution near the ground was heavy. The vertical distribution of aerosol extinction coefficients was characterized by the phenomenon that altitudes of high value declined at night due to atmospheric dry deposition. This study demonstrated that our Mie-Raman scattering lidar can successfully obtain the vertical distribution of CO2 volume ratio and aerosol extinction coefficient, which can provide new datasets and technological support for local environmental department and “carbon neutrality” scientific research.","PeriodicalId":91017,"journal":{"name":"IEEE geoscience and remote sensing letters : a publication of the IEEE Geoscience and Remote Sensing Society","volume":"22 ","pages":"1-4"},"PeriodicalIF":0.0,"publicationDate":"2024-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142821191","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}
Pub Date : 2024-11-29DOI: 10.1109/LGRS.2024.3509393
Yingjie Kong;Xuquan Wang;Kai Zhang;Hong Li;Wenbo Wan;Jiande Sun
In this letter, we proposed a multiscale integration network with quaternion convolution (MQ-Net) for the fusion of low spatial resolution multispectral (LRMS) and panchromatic (PAN) images. In this network, LRMS and PAN images are resampled at different scales and fed into feature fusion modules (FFMs) to merge the spatial and spectral information among them. Then, multiscale feature enhancement modules (MFEMs) are designed to sufficiently learn the spatial and spectral information at different scales. Meanwhile, we employ a quaternion convolution module (QCM) to better capture the dependencies within spectral bands of LRMS images. Then, the quaternion features are introduced into MFEMs for efficient feature enhancement. Finally, all information from different scales is integrated for the reconstruction of high LRMS images. Reduced- and full-resolution experiments are performed on GeoEye-1 and WorldView-2 satellite datasets. Compared to some state-of-the-art pansharpening methods, the proposed MQ-Net obtains better results in terms of qualitative and quantitative evaluations. The code is available at https://github.com/RSMagneto/MQ-Net