Shuli Dong, Q. He, Tianqing Zhang, Yang Li, Li Yuan, R. Zhang, Wenbo Wu
In the infrared detection of small targets, the blind pixels greatly interfere with the detection accuracy of the target. Therefore, the way how to correctly detect and eliminate blind pixels is of great importance. In this paper, an in-orbit real-time blind pixel detection method that combines the time-domain noise of imaging sensor and the characteristics of non-uniform correction coefficients is proposed. Firstly, according to the in-orbit working condition of the remote sensing camera, the imaging data of the reference source that under high and low temperature circumstances is acquired, and the pixels of which the noise exceeds the threshold are marked out through the real-time analysis of time-domain noise of the imaging data. Secondly, a time domain filter is applied to the imaging data of both high temperature reference source and low temperature reference source to reduce noise interference. The two-point correction is then implemented on the filtered imaging data to obtain the gain correction coefficient and the offset correction coefficient of each pixel, and a limitation process is given on the pixel coefficients which are beyond range of bit width or cannot be corrected by hardware. After that the statistical distribution chart of coefficients is acquired through the statistical analysis of the gain coefficient and offset coefficient of all pixels, and according to the statistical characteristic value “μ” and “σ”, the pixels of which the distribution of its coefficients exceeds “±3σ” boundary are marked out. Finally, seeking the union of the two marking position sets, and the marking position of the “union” indicates the coordinate position of the blind pixel detected in real time in orbit. The method proposed in this paper takes the use of the in-orbit calibration mode of the remote sensing camera to realize the in-orbit real-time detection of blind pixels, which made a superiority of this method in identification accuracy comparing to the laboratory reference-source based blind pixel detection method, as the imaging mode and the environmental circumstance of the camera are based on actual working condition. Moreover, comparing to the scene-based detection methods, this method proposed proceeds before ground imaging, which means it does not lead to the misjudgment of infrared small targets to blind pixels. According to the experiment data comparison, the method proposed in this paper provides a matching rate of blind pixel identification of above 90% to the result obtained through the way of the Military Standard of China under the same condition, which demonstrates it has the capability to be widely applied to the infrared remote sensing cameras that have reference-source attached.
{"title":"An in-orbit real-time blind pixel detection method capable for infrared small target detection","authors":"Shuli Dong, Q. He, Tianqing Zhang, Yang Li, Li Yuan, R. Zhang, Wenbo Wu","doi":"10.1117/12.2665995","DOIUrl":"https://doi.org/10.1117/12.2665995","url":null,"abstract":"In the infrared detection of small targets, the blind pixels greatly interfere with the detection accuracy of the target. Therefore, the way how to correctly detect and eliminate blind pixels is of great importance. In this paper, an in-orbit real-time blind pixel detection method that combines the time-domain noise of imaging sensor and the characteristics of non-uniform correction coefficients is proposed. Firstly, according to the in-orbit working condition of the remote sensing camera, the imaging data of the reference source that under high and low temperature circumstances is acquired, and the pixels of which the noise exceeds the threshold are marked out through the real-time analysis of time-domain noise of the imaging data. Secondly, a time domain filter is applied to the imaging data of both high temperature reference source and low temperature reference source to reduce noise interference. The two-point correction is then implemented on the filtered imaging data to obtain the gain correction coefficient and the offset correction coefficient of each pixel, and a limitation process is given on the pixel coefficients which are beyond range of bit width or cannot be corrected by hardware. After that the statistical distribution chart of coefficients is acquired through the statistical analysis of the gain coefficient and offset coefficient of all pixels, and according to the statistical characteristic value “μ” and “σ”, the pixels of which the distribution of its coefficients exceeds “±3σ” boundary are marked out. Finally, seeking the union of the two marking position sets, and the marking position of the “union” indicates the coordinate position of the blind pixel detected in real time in orbit. The method proposed in this paper takes the use of the in-orbit calibration mode of the remote sensing camera to realize the in-orbit real-time detection of blind pixels, which made a superiority of this method in identification accuracy comparing to the laboratory reference-source based blind pixel detection method, as the imaging mode and the environmental circumstance of the camera are based on actual working condition. Moreover, comparing to the scene-based detection methods, this method proposed proceeds before ground imaging, which means it does not lead to the misjudgment of infrared small targets to blind pixels. According to the experiment data comparison, the method proposed in this paper provides a matching rate of blind pixel identification of above 90% to the result obtained through the way of the Military Standard of China under the same condition, which demonstrates it has the capability to be widely applied to the infrared remote sensing cameras that have reference-source attached.","PeriodicalId":258680,"journal":{"name":"Earth and Space From Infrared to Terahertz (ESIT 2022)","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131729649","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}
X. Yu, Yizhen Yu, X. Shao, Yu Tian, Chunlei Yu, H. Gong
InGaAs/InP Focal Plane Array (FPA) photodetector, which responses from 400nm-1700nm, is widely used in many applications, while its quantum efficiency in visible spectrum is commonly lower than Shortwave Infrared (SWIR) spectrum. In order to improve the quantum efficiency in visible spectrum, new methods need to be applied. Based on Mie scattering, sub-wavelength nanostructure arrays have been demonstrated that can be used as anti-reflecting mechanism in visible spectrum. Here we present the design and simulation of the parameters of nanostructure arrays, which aims at suppressing the reflection in visible spectrum, thus the transmittance of visible light from the back-illuminated side gets improved. Simulation results prove that designed nanostructure arrays can decrease the reflectance in visible spectrum, and integrating designed nanostructure arrays on ultra-thin back-illuminated layer can improve the transmittance, which improves the quantum efficiency of photodetector.
{"title":"Design and simulation of anti-reflecting nanostructure for visible shortwave infrared focal plane array detectors","authors":"X. Yu, Yizhen Yu, X. Shao, Yu Tian, Chunlei Yu, H. Gong","doi":"10.1117/12.2666003","DOIUrl":"https://doi.org/10.1117/12.2666003","url":null,"abstract":"InGaAs/InP Focal Plane Array (FPA) photodetector, which responses from 400nm-1700nm, is widely used in many applications, while its quantum efficiency in visible spectrum is commonly lower than Shortwave Infrared (SWIR) spectrum. In order to improve the quantum efficiency in visible spectrum, new methods need to be applied. Based on Mie scattering, sub-wavelength nanostructure arrays have been demonstrated that can be used as anti-reflecting mechanism in visible spectrum. Here we present the design and simulation of the parameters of nanostructure arrays, which aims at suppressing the reflection in visible spectrum, thus the transmittance of visible light from the back-illuminated side gets improved. Simulation results prove that designed nanostructure arrays can decrease the reflectance in visible spectrum, and integrating designed nanostructure arrays on ultra-thin back-illuminated layer can improve the transmittance, which improves the quantum efficiency of photodetector.","PeriodicalId":258680,"journal":{"name":"Earth and Space From Infrared to Terahertz (ESIT 2022)","volume":"106 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131527360","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}
Infrared imaging technology has an increasingly wide range of needs in application scenarios such as tracking and detection of high-speed targets and readout of region of interest, and system applications often have requirements for small size and low power consumption. In order to increase the frame rate of the IR detector and solve the difficulty of high power consumption faced at high speed readout, this paper proposes a programmable arbitrary windowing IP module based on a standard digital IC design and achieves ultra-low power optimization of the column-level module of the readout circuit through time-sharing multiplexing techniques. The overall design is a mixture of analogue and digital circuits, with compromises to optimize the area, noise and gain of the circuit, resulting in the integration of analogue and digital circuit layouts. In this paper, a low noise, high speed programmable arbitrary windowing ROIC has been fabricated in the 0.18μm CMOS process, the pixel array is 640×512 and the pixel pitch is 15μm. It is coupled with a short-wave infrared InGaAs detector chip to form a FPA assembly and tested. The results show that the readout rate is greater than 15MHz, the column-level power consumption is only 15mW, the total power consumption is less than 100mW, and the windowing function can be specified in any area with a minimum windowing size of 8×8.
{"title":"A low-power, high-speed, programmable arbitrary windowing infrared focal plane readout circuit","authors":"Hongyi Wang, Yifan Lu, Wengang Tao, Yonggang Zhang, Songlei Huang, Jiaxiong Fang","doi":"10.1117/12.2664767","DOIUrl":"https://doi.org/10.1117/12.2664767","url":null,"abstract":"Infrared imaging technology has an increasingly wide range of needs in application scenarios such as tracking and detection of high-speed targets and readout of region of interest, and system applications often have requirements for small size and low power consumption. In order to increase the frame rate of the IR detector and solve the difficulty of high power consumption faced at high speed readout, this paper proposes a programmable arbitrary windowing IP module based on a standard digital IC design and achieves ultra-low power optimization of the column-level module of the readout circuit through time-sharing multiplexing techniques. The overall design is a mixture of analogue and digital circuits, with compromises to optimize the area, noise and gain of the circuit, resulting in the integration of analogue and digital circuit layouts. In this paper, a low noise, high speed programmable arbitrary windowing ROIC has been fabricated in the 0.18μm CMOS process, the pixel array is 640×512 and the pixel pitch is 15μm. It is coupled with a short-wave infrared InGaAs detector chip to form a FPA assembly and tested. The results show that the readout rate is greater than 15MHz, the column-level power consumption is only 15mW, the total power consumption is less than 100mW, and the windowing function can be specified in any area with a minimum windowing size of 8×8.","PeriodicalId":258680,"journal":{"name":"Earth and Space From Infrared to Terahertz (ESIT 2022)","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132606772","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}
Recently, many state-of-the-art methods have been proposed for infrared (IR) dim and small target detection, but the performance of IR small target detection still faces with challenges in complicated environments. In this paper, we propose a novel IR small target detection method named local entropy characterization prior with multi-mode weighted tensor nuclear norm (LEC-MTNN) that combines local entropy characterization prior (LEC) and multi-mode weighted tensor nuclear norm (MTNN). First, we transform the original infrared image sequence into a nonoverlapping spatial-temporal patch-tensor to fully utilize the spatial and temporal information in image sequences. Second, a nonconvex surrogate of tensor rank called MTNN is proposed to approximate background tensor rank, which organically combines the sum of the Laplace function of all the singular values and multi-mode tensor extension of the construct tensor without destroying the inherent structural information in the spatial-temporal tensor. Third, we introduce a new sparse prior map named LEC via an image entropy characterization operator and structure tensor theory, and more effective target prior can be extracted. As a sparse weight, it is beneficial to further preserve the targets and suppress the background components simultaneously. To solve the proposed model, an efficient optimization scheme utilizing the alternating direction multiplier method (ADMM) is designed to retrieve the small targets from IR sequence. Comprehensive experiments on four IR sequences of complex scenes demonstrate that LEC-MTNN has the superior target detectability (TD) and background suppressibility (BS) performance compared with other five state-of-the-art detection methods.
{"title":"LEC-MTNN: a novel multi-frame infrared small target detection method based on spatial-temporal patch-tensor","authors":"Yuan Luo, Xiaorun Li, Shuhan Chen, C. Xia","doi":"10.1117/12.2664542","DOIUrl":"https://doi.org/10.1117/12.2664542","url":null,"abstract":"Recently, many state-of-the-art methods have been proposed for infrared (IR) dim and small target detection, but the performance of IR small target detection still faces with challenges in complicated environments. In this paper, we propose a novel IR small target detection method named local entropy characterization prior with multi-mode weighted tensor nuclear norm (LEC-MTNN) that combines local entropy characterization prior (LEC) and multi-mode weighted tensor nuclear norm (MTNN). First, we transform the original infrared image sequence into a nonoverlapping spatial-temporal patch-tensor to fully utilize the spatial and temporal information in image sequences. Second, a nonconvex surrogate of tensor rank called MTNN is proposed to approximate background tensor rank, which organically combines the sum of the Laplace function of all the singular values and multi-mode tensor extension of the construct tensor without destroying the inherent structural information in the spatial-temporal tensor. Third, we introduce a new sparse prior map named LEC via an image entropy characterization operator and structure tensor theory, and more effective target prior can be extracted. As a sparse weight, it is beneficial to further preserve the targets and suppress the background components simultaneously. To solve the proposed model, an efficient optimization scheme utilizing the alternating direction multiplier method (ADMM) is designed to retrieve the small targets from IR sequence. Comprehensive experiments on four IR sequences of complex scenes demonstrate that LEC-MTNN has the superior target detectability (TD) and background suppressibility (BS) performance compared with other five state-of-the-art detection methods.","PeriodicalId":258680,"journal":{"name":"Earth and Space From Infrared to Terahertz (ESIT 2022)","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123408650","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}
In Fourier Transform Infrared spectroscopy (FTIR), the original interferometric image needs to be pre-processed by apodization, trend term removal and phase correction before the gas irradiance signal can be obtained by Fourier transform, of which trend term removal is the most important. The common method is least squares (LS), which requires high initial values and is susceptible to noise interference. In this paper, M-estimated sample consistency (MSAC) and Genetic Algorithm (GA) are used to remove the trend term from methane FTIR simulated interference data and compare them with the least squares method. The results show that: compared with the least squares method, the MSAC algorithm can improve the trend term fit by about 20%, but the trend term pattern needs to be known in advance; compared with the MSAC algorithm, the GA algorithm has a slightly lower fit effect of about 5%, but requires lower initial values, is more robust and is suitable for situations where the trend term pattern is unknown; combining the two, the GA-MSAC algorithm proposed in this paper, which both reduces the initial value requirement and greatly improves the accuracy of the trend term removal, is of great importance to Fourier transform infrared spectroscopy.
{"title":"FTIR trend term removal method based on GA and MSAC algorithms","authors":"Bo Yan, Jun-yong Fang, Hao Chen, Shuaihui Li","doi":"10.1117/12.2664634","DOIUrl":"https://doi.org/10.1117/12.2664634","url":null,"abstract":"In Fourier Transform Infrared spectroscopy (FTIR), the original interferometric image needs to be pre-processed by apodization, trend term removal and phase correction before the gas irradiance signal can be obtained by Fourier transform, of which trend term removal is the most important. The common method is least squares (LS), which requires high initial values and is susceptible to noise interference. In this paper, M-estimated sample consistency (MSAC) and Genetic Algorithm (GA) are used to remove the trend term from methane FTIR simulated interference data and compare them with the least squares method. The results show that: compared with the least squares method, the MSAC algorithm can improve the trend term fit by about 20%, but the trend term pattern needs to be known in advance; compared with the MSAC algorithm, the GA algorithm has a slightly lower fit effect of about 5%, but requires lower initial values, is more robust and is suitable for situations where the trend term pattern is unknown; combining the two, the GA-MSAC algorithm proposed in this paper, which both reduces the initial value requirement and greatly improves the accuracy of the trend term removal, is of great importance to Fourier transform infrared spectroscopy.","PeriodicalId":258680,"journal":{"name":"Earth and Space From Infrared to Terahertz (ESIT 2022)","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122496772","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}
Ji Feng, Rong Huang, Huan Xie, Yaqiong Wang, Xiangsui Zeng, Jie Chen, Yifan Wang, Hongji Ni
The OSIRIS-Rex Laser Altimeter (OLA) is the first scanning lidar instrument to fly a planetary mission. The OLA scans Bennu for about a month during the Orbit B mission phase and obtains 911 frames of point clouds. Due to the uncertainty of spacecraft position and pointing, there will be offsets between overlapping point clouds. In our method, the point cloud is first projected onto a plane, and then the keypoints are extracted using the SIFT algorithm. Finally, we perform coarse and global adjustments based on keypoints. However, low accuracy of the corresponding keypoints will lead to bad registration. In order to improve the accuracy of keypoints matching and point cloud registration, we use the tuple test and RANSAC algorithm to eliminate mismatched points. For the overlapping point clouds of two frames, the RMSE between keypoints is about 0.04m after registration. The results show that this method can improve the accuracy of point cloud registration to a certain extent and meet the application requirements.
{"title":"OSIRIS-REx OLA point cloud registration based on keypoints matching","authors":"Ji Feng, Rong Huang, Huan Xie, Yaqiong Wang, Xiangsui Zeng, Jie Chen, Yifan Wang, Hongji Ni","doi":"10.1117/12.2665810","DOIUrl":"https://doi.org/10.1117/12.2665810","url":null,"abstract":"The OSIRIS-Rex Laser Altimeter (OLA) is the first scanning lidar instrument to fly a planetary mission. The OLA scans Bennu for about a month during the Orbit B mission phase and obtains 911 frames of point clouds. Due to the uncertainty of spacecraft position and pointing, there will be offsets between overlapping point clouds. In our method, the point cloud is first projected onto a plane, and then the keypoints are extracted using the SIFT algorithm. Finally, we perform coarse and global adjustments based on keypoints. However, low accuracy of the corresponding keypoints will lead to bad registration. In order to improve the accuracy of keypoints matching and point cloud registration, we use the tuple test and RANSAC algorithm to eliminate mismatched points. For the overlapping point clouds of two frames, the RMSE between keypoints is about 0.04m after registration. The results show that this method can improve the accuracy of point cloud registration to a certain extent and meet the application requirements.","PeriodicalId":258680,"journal":{"name":"Earth and Space From Infrared to Terahertz (ESIT 2022)","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128699567","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}
The targets of landing missions on small celestial bodies usually have high scientific value but complex terrain. Therefore, there are high demands for the landing trajectory planning method with regard to the safety and precise landing. The artificial potential function method is one of the commonly used methods in trajectory planning for small celestial body landing. It is performed by applying attractive force form the target and repulsive force from the obstacles to the moving spacecraft. The attractive and repulsive forces are generated by the corresponding potential functions, which involves several parameters needed to be determined. Improper parameters may lead to low efficiency of trajectory calculation, collision with obstacles or failure of reaching the target. However, the parameters in the artificial potential functions are usually set as empirical values without consideration of different application scenarios. In this paper, the setting methods of the weight matrices 𝑃𝑟 and 𝑃𝑉 in the attractive potential function, the parameter matrix 𝛭 in the Lyapunov function and the parameters 𝑘1 and 𝑘2 in the Gaussian-type repulsive potential function are studied, and several simulation experiments are conducted to verify the parameter values. And suggestions are given on the setting of these parameters. Keywords: artificial potential function, parameter setting, landing trajectory planning.
{"title":"Parameter setting and analysis for the artificial potential functions in the application of small celestial bodies landing trajectory planning","authors":"Lizhou Sun, Yanmin Jin, X. Tong","doi":"10.1117/12.2665825","DOIUrl":"https://doi.org/10.1117/12.2665825","url":null,"abstract":"The targets of landing missions on small celestial bodies usually have high scientific value but complex terrain. Therefore, there are high demands for the landing trajectory planning method with regard to the safety and precise landing. The artificial potential function method is one of the commonly used methods in trajectory planning for small celestial body landing. It is performed by applying attractive force form the target and repulsive force from the obstacles to the moving spacecraft. The attractive and repulsive forces are generated by the corresponding potential functions, which involves several parameters needed to be determined. Improper parameters may lead to low efficiency of trajectory calculation, collision with obstacles or failure of reaching the target. However, the parameters in the artificial potential functions are usually set as empirical values without consideration of different application scenarios. In this paper, the setting methods of the weight matrices 𝑃𝑟 and 𝑃𝑉 in the attractive potential function, the parameter matrix 𝛭 in the Lyapunov function and the parameters 𝑘1 and 𝑘2 in the Gaussian-type repulsive potential function are studied, and several simulation experiments are conducted to verify the parameter values. And suggestions are given on the setting of these parameters. Keywords: artificial potential function, parameter setting, landing trajectory planning.","PeriodicalId":258680,"journal":{"name":"Earth and Space From Infrared to Terahertz (ESIT 2022)","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125399449","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}
Water, especially liquid water, strongly absorbs terahertz (THz) waves. Generating or detecting THz waves with liquid water has long been thought impossible. Some recent literatures have reported the successful radiation of THz waves from liquid water, which brings new opportunities for the development of THz-related devices based on liquid media. However, the radiation mechanism has not been well elucidated, and the generation efficiency needs to be further improved. We experimentally show that the application of liquid water lines instead of liquid films as THz radiation sources can effectively enhance THz signals. Generally, the generation and detection of THz waves are considered to be "reversible" physical processes. In view of this, we realized the coherent detection of THz waves for the first time based on plasma in liquid water, filling the gap in the field of coherent detection of THz waves in liquid media. Meanwhile, the THz Kerr effect technique for THz-driven liquid water, as a novel tool, is expected to help explore the low-frequency molecular dynamics associated with hydrogen bonding in liquid water.
{"title":"Terahertz wave generation and detection using liquid water","authors":"Minghao Zhang, Wen Xiao, Cunlin Zhang, Liangliang Zhang","doi":"10.1117/12.2664559","DOIUrl":"https://doi.org/10.1117/12.2664559","url":null,"abstract":"Water, especially liquid water, strongly absorbs terahertz (THz) waves. Generating or detecting THz waves with liquid water has long been thought impossible. Some recent literatures have reported the successful radiation of THz waves from liquid water, which brings new opportunities for the development of THz-related devices based on liquid media. However, the radiation mechanism has not been well elucidated, and the generation efficiency needs to be further improved. We experimentally show that the application of liquid water lines instead of liquid films as THz radiation sources can effectively enhance THz signals. Generally, the generation and detection of THz waves are considered to be \"reversible\" physical processes. In view of this, we realized the coherent detection of THz waves for the first time based on plasma in liquid water, filling the gap in the field of coherent detection of THz waves in liquid media. Meanwhile, the THz Kerr effect technique for THz-driven liquid water, as a novel tool, is expected to help explore the low-frequency molecular dynamics associated with hydrogen bonding in liquid water.","PeriodicalId":258680,"journal":{"name":"Earth and Space From Infrared to Terahertz (ESIT 2022)","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129157308","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}
H. Han, Xiao Xu, P. Zhang, Yun Xiao, Yuan-Yuan Jia
Deep space exploration is an important way for mankind to innovate space science and technology, and to promote the development and utilization of space resources. Remote sensing technology plays an extremely important role in these exploration missions. Visible and near infrared reflectance spectra are the effective means to study the composition of celestial objects. The Chang’E-5 (CE-5) lunar exploration mission has achieved China’s first sample return from the moon, helping scientific research on the origin and evolution of the moon. The landing areas of CE-5 and Apollo 12 were located in the north and south of the Oceanus Procellarum, respectively. In this paper, the spectral data of the craters near the CE- 5 landing site and the similar Apollo 12 lunar rock (12063) spectrum with its mineral composition are compared and analyzed. The band area ratio method and the modified Gaussian model method were applied to study the spectral characteristics and mineral composition of these craters and rocks. The chemical compositions and evolutionary trends of major constituent minerals are consistent with the basalts returned by the Apollo missions. The spectral deconvolution results indicate that the mafic minerals in the crater rocks near the CE-5 landing site are dominated by clinopyroxene, followed by orthopyroxene and olivine, which is significantly lower than the orthopyroxene mineral abundance in the Apollo 12063 lunar rock. It may indicate that the young basalts of CE-5 landing area originate from the lunar mantle source region, which is rich in clinopyroxene and contains a small amount of olivine material. Remote sensing and space exploration help us solve many meaningful scientific problems. In general, remote sensing is an important and useful, even the only, means for us to understand the solar system and extrasolar celestial bodies.
{"title":"Near-infrared spectral characteristics and composition analysis of impact craters near the Chang’E-5 landing site","authors":"H. Han, Xiao Xu, P. Zhang, Yun Xiao, Yuan-Yuan Jia","doi":"10.1117/12.2664621","DOIUrl":"https://doi.org/10.1117/12.2664621","url":null,"abstract":"Deep space exploration is an important way for mankind to innovate space science and technology, and to promote the development and utilization of space resources. Remote sensing technology plays an extremely important role in these exploration missions. Visible and near infrared reflectance spectra are the effective means to study the composition of celestial objects. The Chang’E-5 (CE-5) lunar exploration mission has achieved China’s first sample return from the moon, helping scientific research on the origin and evolution of the moon. The landing areas of CE-5 and Apollo 12 were located in the north and south of the Oceanus Procellarum, respectively. In this paper, the spectral data of the craters near the CE- 5 landing site and the similar Apollo 12 lunar rock (12063) spectrum with its mineral composition are compared and analyzed. The band area ratio method and the modified Gaussian model method were applied to study the spectral characteristics and mineral composition of these craters and rocks. The chemical compositions and evolutionary trends of major constituent minerals are consistent with the basalts returned by the Apollo missions. The spectral deconvolution results indicate that the mafic minerals in the crater rocks near the CE-5 landing site are dominated by clinopyroxene, followed by orthopyroxene and olivine, which is significantly lower than the orthopyroxene mineral abundance in the Apollo 12063 lunar rock. It may indicate that the young basalts of CE-5 landing area originate from the lunar mantle source region, which is rich in clinopyroxene and contains a small amount of olivine material. Remote sensing and space exploration help us solve many meaningful scientific problems. In general, remote sensing is an important and useful, even the only, means for us to understand the solar system and extrasolar celestial bodies.","PeriodicalId":258680,"journal":{"name":"Earth and Space From Infrared to Terahertz (ESIT 2022)","volume":"121 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125469056","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}
This paper describes the significance of infrared astronomy and the development of infrared detectors for astronomical telescope applications. First, the requirements of astronomical observations on infrared focal plane detector indicators such as dark current, readout noise, and image element size are analyzed, and the infrared detector performance parameters of major domestic and foreign astronomical telescopes in recent decades are summarized. Compared with foreign countries, the performance of domestic infrared astronomical telescopes, especially dedicated astronomical infrared detectors, is still very backward. For example, the readout noise is two orders of magnitude higher than the Webb telescope's 5.9e-, and the dark current is four orders of magnitude higher than the Webb telescope's 0.001e− / pixel∙s. Based on the NIR spectroscopic observation requirements of the 1-meter infrared solar telescope at Yunnan Observatory, we developed a low dark current and low noise 640×512 InGaAs NIR focal plane detector module and a dedicated imaging circuit for sunspot imaging and spectroscopic testing. Measurements using the photon curve transfer method showed that the dark current of the InGaAs NIR focal plane camera was as low as 64e−/ pixel∙s, and the average readout noise of the image elements was 25.4e−.Finally, the research direction of special infrared detectors for astronomical observation is discussed, and this paper has implications for the research of next-generation astronomical infrared telescopes in China.
{"title":"Performance of infrared detectors applied in astronomical telescopes","authors":"Yongsheng Xiang, Guo Jie, Fangyu Xu, Baicheng Sun, Xiaoxia Gong, Mingguo Fan, Yong-Fang Luo","doi":"10.1117/12.2664991","DOIUrl":"https://doi.org/10.1117/12.2664991","url":null,"abstract":"This paper describes the significance of infrared astronomy and the development of infrared detectors for astronomical telescope applications. First, the requirements of astronomical observations on infrared focal plane detector indicators such as dark current, readout noise, and image element size are analyzed, and the infrared detector performance parameters of major domestic and foreign astronomical telescopes in recent decades are summarized. Compared with foreign countries, the performance of domestic infrared astronomical telescopes, especially dedicated astronomical infrared detectors, is still very backward. For example, the readout noise is two orders of magnitude higher than the Webb telescope's 5.9e-, and the dark current is four orders of magnitude higher than the Webb telescope's 0.001e− / pixel∙s. Based on the NIR spectroscopic observation requirements of the 1-meter infrared solar telescope at Yunnan Observatory, we developed a low dark current and low noise 640×512 InGaAs NIR focal plane detector module and a dedicated imaging circuit for sunspot imaging and spectroscopic testing. Measurements using the photon curve transfer method showed that the dark current of the InGaAs NIR focal plane camera was as low as 64e−/ pixel∙s, and the average readout noise of the image elements was 25.4e−.Finally, the research direction of special infrared detectors for astronomical observation is discussed, and this paper has implications for the research of next-generation astronomical infrared telescopes in China.","PeriodicalId":258680,"journal":{"name":"Earth and Space From Infrared to Terahertz (ESIT 2022)","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123513691","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：