This paper introduces a novel approach for post-processing of depth map which enhances the depth map resolution in order to achieve visually pleasing 3D models from a new monocular 2D/3D imaging system consists of a Photonic mixer device (PMD) range camera and a standard color camera. The proposed method adopts the revolutionary inversion theory framework called Compressive Sensing (CS). The depth map of low resolution is considered as the result of applying blurring and down-sampling techniques to that of high-resolution. Based on the underlying assumption that the high-resolution depth map is compressible in frequency domain and recent theoretical work on CS, the high-resolution version can be estimated and furthermore reconstructed via solving non-linear optimization problem. And therefore the improved depth map reconstruction provides a useful help to build an improved 3D model of a scene. The experimental results on the real data are presented. In the meanwhile the proposed scheme opens new possibilities to apply CS to a multitude of potential applications on various multimodal data analysis and processing.
{"title":"Depth map resolution enhancement for 2D/3D imaging system via compressive sensing","authors":"J. Han, O. Loffeld, K. Hartmann","doi":"10.1117/12.901006","DOIUrl":"https://doi.org/10.1117/12.901006","url":null,"abstract":"This paper introduces a novel approach for post-processing of depth map which enhances the depth map resolution in order to achieve visually pleasing 3D models from a new monocular 2D/3D imaging system consists of a Photonic mixer device (PMD) range camera and a standard color camera. The proposed method adopts the revolutionary inversion theory framework called Compressive Sensing (CS). The depth map of low resolution is considered as the result of applying blurring and down-sampling techniques to that of high-resolution. Based on the underlying assumption that the high-resolution depth map is compressible in frequency domain and recent theoretical work on CS, the high-resolution version can be estimated and furthermore reconstructed via solving non-linear optimization problem. And therefore the improved depth map reconstruction provides a useful help to build an improved 3D model of a scene. The experimental results on the real data are presented. In the meanwhile the proposed scheme opens new possibilities to apply CS to a multitude of potential applications on various multimodal data analysis and processing.","PeriodicalId":355017,"journal":{"name":"Photoelectronic Detection and Imaging","volume":"73 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115396472","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}
Fu Li, P. Ruan, Ting Li, Gang-zhou Xu, Di Lu, Haichao Pan
The carbon-carbon composite (CCC) was applied in order to design and fabricate much more predominant lunar optical telescope (LOT). The fabricating technics of CCC and machining technics of load-carrying cylinder assembly are introduced. The density of CCC is 1.73g/cm3, and the coefficient of thermal expansion is 0.5×10-6/°C. The thermal adaptability of LOT was analyzed, the operating temperature of LOT will be improved to -20°C~+40°C that the carbon-carbon cylinder is used. Finite element analysis of LOT with CCC cylinder was performed, and the results show that the first frequency of LOT is 185Hz. The machining and assembling of LOT have been performed. The vibration testing has been accomplished and the testing results are consistent with finite element analysis. The testing results show that load-carrying cylinder of CCC can stand the mechanical proof. All analysis and testing indicate that CCC can be competent for LOT.
{"title":"Application of carbon-carbon composite for load-carrying cylinder in lunar optical telescope","authors":"Fu Li, P. Ruan, Ting Li, Gang-zhou Xu, Di Lu, Haichao Pan","doi":"10.1117/12.900738","DOIUrl":"https://doi.org/10.1117/12.900738","url":null,"abstract":"The carbon-carbon composite (CCC) was applied in order to design and fabricate much more predominant lunar optical telescope (LOT). The fabricating technics of CCC and machining technics of load-carrying cylinder assembly are introduced. The density of CCC is 1.73g/cm3, and the coefficient of thermal expansion is 0.5×10-6/°C. The thermal adaptability of LOT was analyzed, the operating temperature of LOT will be improved to -20°C~+40°C that the carbon-carbon cylinder is used. Finite element analysis of LOT with CCC cylinder was performed, and the results show that the first frequency of LOT is 185Hz. The machining and assembling of LOT have been performed. The vibration testing has been accomplished and the testing results are consistent with finite element analysis. The testing results show that load-carrying cylinder of CCC can stand the mechanical proof. All analysis and testing indicate that CCC can be competent for LOT.","PeriodicalId":355017,"journal":{"name":"Photoelectronic Detection and Imaging","volume":"81 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122499895","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}
Rima Bao, Lu Tian, K. Zhao, Shouming Zhu, Li-ming Liu, Guozong Zhao
In this paper, the optical characteristics of crude oil samples from selected territories in Tuha oil field have been investigated with THz-TDS at room temperature in nitrogen environment. The absorption coefficient and refraction index of crude oil are calculated in the frequency range of 0.20~2.5 THz. No distinct absorption peak has been found in the spectra, which may result from the complexity of the constitution of the samples and the water content. The absorption coefficients increase with the content of wax in the samples with different slopes, which means the intensity of absorption in THz wave band increases with enhanced density of the sample and unaltered thickness. The average refractive indices were 0.62070, 0.59767 and 0.59290 corresponding to TuLuFan, ShanShan and WenMi territories, respectively. The refractive values show the phenomenon of abnormal dispersion, which meant the samples had the characters of strong selective absorption in this wave band. In contrast, we have also utilized Fourier transform infrared spectroscopy (FTIR) in the 400-4000cm-1 to measure the mid-IR absorption spectra, and the results revealed that the crude oil is more active in the range of Terahertz than in the mid-IR band. The experiments demonstrated that THz-TDS is a powerful tool to complement the conventional analytical approaches and can be applied to detect and analyze the features of the constituent in crude oil.
{"title":"Spectroscopy studies on the Tuha crude oil in the terahertz range","authors":"Rima Bao, Lu Tian, K. Zhao, Shouming Zhu, Li-ming Liu, Guozong Zhao","doi":"10.1117/12.900988","DOIUrl":"https://doi.org/10.1117/12.900988","url":null,"abstract":"In this paper, the optical characteristics of crude oil samples from selected territories in Tuha oil field have been investigated with THz-TDS at room temperature in nitrogen environment. The absorption coefficient and refraction index of crude oil are calculated in the frequency range of 0.20~2.5 THz. No distinct absorption peak has been found in the spectra, which may result from the complexity of the constitution of the samples and the water content. The absorption coefficients increase with the content of wax in the samples with different slopes, which means the intensity of absorption in THz wave band increases with enhanced density of the sample and unaltered thickness. The average refractive indices were 0.62070, 0.59767 and 0.59290 corresponding to TuLuFan, ShanShan and WenMi territories, respectively. The refractive values show the phenomenon of abnormal dispersion, which meant the samples had the characters of strong selective absorption in this wave band. In contrast, we have also utilized Fourier transform infrared spectroscopy (FTIR) in the 400-4000cm-1 to measure the mid-IR absorption spectra, and the results revealed that the crude oil is more active in the range of Terahertz than in the mid-IR band. The experiments demonstrated that THz-TDS is a powerful tool to complement the conventional analytical approaches and can be applied to detect and analyze the features of the constituent in crude oil.","PeriodicalId":355017,"journal":{"name":"Photoelectronic Detection and Imaging","volume":"91 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122598774","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}
Dongjun Yang, W. Fang, Xin Ye, Yu-peng Wang, Chenghu Gong, Guang-wei Zhang
The solar irradiance monitor (SIM), with the design accuracy of 5%, used to monitor the secular changes of the total solar irradiance on FY-3 satellite, takes the sun-scanning measurement method on-orbit. Compared to the sun-tracking measurement method, this method simplifies the structure and cuts the cost, but the measuring accuracy is affected by the sun-synchronous orbit, sunlight incidence angle and the installing angle of the SIM in the satellite. Through the ground calibration experiment, studies on the affection of different sunlight incidence angles to the measurement accuracy. First, by the satellite tool kit (STK) simulation software, simulates the orbital parameters of the sun-synchronous satellite, and calculates the Sun ascension and declination at any time. By the orbit coordinate transformation matrix gets the components of the Sun vectors to the axes of the satellite, and base on the components designs the field of view and the installing angles of the SIM. Then, designs and completes the calibration experiment to calibrate the affection of the incidence angles. Selecting 11 different angles between the sunlight and the satellite X-axis, measures the total solar irradiance by the SIM at each angle, and compares to the irradiances of the SIAR reference radiometers, and gets the coefficient curves of the three channels of the SIM. Finally, by the quadratic fitting, gets the correction equations on the incidence angles: 5 2 3 R1 5.71x10-5α2 - 2.453 10-5 α2 1.0302, R2 = 2.84×10-5α2-1.965x10-3α+1.0314 and R3 =1.72x10-5α2-4.184x10-4α+0.9946. The equations will improve the on-orbit measurement accuracy of the solar irradiance, and are very important to the on-orbit data processing after the satellite launched.
{"title":"Design and calibration of the solar irradiance monitor","authors":"Dongjun Yang, W. Fang, Xin Ye, Yu-peng Wang, Chenghu Gong, Guang-wei Zhang","doi":"10.1117/12.900121","DOIUrl":"https://doi.org/10.1117/12.900121","url":null,"abstract":"The solar irradiance monitor (SIM), with the design accuracy of 5%, used to monitor the secular changes of the total solar irradiance on FY-3 satellite, takes the sun-scanning measurement method on-orbit. Compared to the sun-tracking measurement method, this method simplifies the structure and cuts the cost, but the measuring accuracy is affected by the sun-synchronous orbit, sunlight incidence angle and the installing angle of the SIM in the satellite. Through the ground calibration experiment, studies on the affection of different sunlight incidence angles to the measurement accuracy. First, by the satellite tool kit (STK) simulation software, simulates the orbital parameters of the sun-synchronous satellite, and calculates the Sun ascension and declination at any time. By the orbit coordinate transformation matrix gets the components of the Sun vectors to the axes of the satellite, and base on the components designs the field of view and the installing angles of the SIM. Then, designs and completes the calibration experiment to calibrate the affection of the incidence angles. Selecting 11 different angles between the sunlight and the satellite X-axis, measures the total solar irradiance by the SIM at each angle, and compares to the irradiances of the SIAR reference radiometers, and gets the coefficient curves of the three channels of the SIM. Finally, by the quadratic fitting, gets the correction equations on the incidence angles: 5 2 3 R1 5.71x10-5α2 - 2.453 10-5 α2 1.0302, R2 = 2.84×10-5α2-1.965x10-3α+1.0314 and R3 =1.72x10-5α2-4.184x10-4α+0.9946. The equations will improve the on-orbit measurement accuracy of the solar irradiance, and are very important to the on-orbit data processing after the satellite launched.","PeriodicalId":355017,"journal":{"name":"Photoelectronic Detection and Imaging","volume":"69 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127264608","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}
Insulating oil is widely used in transformer and other large high-voltage electrical equipment.Its main functions are insulation, cooling and arc extinction. When the transformer runs, it may emit heat or discharge, which generate gas, micro water and trace metals in transformer oil. This will not only reduce the insulation capacity of insulating oil,and will greatly reduce the ability of its extinction, causing the transformers or other oil-filled electrical equipment appearing Internal latent malfunction, which would affect the operation of equipment. In this Paper, we simulate the transformer discharge effect to discharge in transformer oil. Then we use spectral theory and photo-spectroscopy technology to measure and analyse the oil sample, combining with IR absorption peaks of main fault characteristic gases, and qualitatively analyse CO, CO2, CH4, C2H6, C2H4, C2H2, H2 in gas mixture. The results show that the Fourier transform infrared spectroscopy can be very effective for analysing gases in transformer oil, which can quickly detect possible problems in the equipment.
{"title":"Research on gas within transformer oil based on photo-spectroscopy technology","authors":"Guicai Song, Y. Na, Q. Zhang, Wen-zong Shi","doi":"10.1117/12.900474","DOIUrl":"https://doi.org/10.1117/12.900474","url":null,"abstract":"Insulating oil is widely used in transformer and other large high-voltage electrical equipment.Its main functions are insulation, cooling and arc extinction. When the transformer runs, it may emit heat or discharge, which generate gas, micro water and trace metals in transformer oil. This will not only reduce the insulation capacity of insulating oil,and will greatly reduce the ability of its extinction, causing the transformers or other oil-filled electrical equipment appearing Internal latent malfunction, which would affect the operation of equipment. In this Paper, we simulate the transformer discharge effect to discharge in transformer oil. Then we use spectral theory and photo-spectroscopy technology to measure and analyse the oil sample, combining with IR absorption peaks of main fault characteristic gases, and qualitatively analyse CO, CO2, CH4, C2H6, C2H4, C2H2, H2 in gas mixture. The results show that the Fourier transform infrared spectroscopy can be very effective for analysing gases in transformer oil, which can quickly detect possible problems in the equipment.","PeriodicalId":355017,"journal":{"name":"Photoelectronic Detection and Imaging","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122384325","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}
Yan Tian, Jianzhong Cao, Da-wei Yao, Zhaohui Xu, Jingqiu Huang
This paper researches the digital high definition imaging technology and successfully designs a digital high definition camera system .The system takes large array CCD(KAI-2093CM) which conforms to SMEPT 274M standard as photoelectric transfer device, FPGA+AFE as framework, HD-SDI as transforming interface, and combines with the current advanced digital high definition video standard. The result of imaging shows that the high definition camera can realize high definition shooting. The pictures are clear and can be displayed with no stagnation in real time. Moreover, the small camera with high resolution can be applied for high definition shooting in aerospace and other fields.
{"title":"Technology research of high-definition CCD camera Based on FPGA","authors":"Yan Tian, Jianzhong Cao, Da-wei Yao, Zhaohui Xu, Jingqiu Huang","doi":"10.1117/12.900523","DOIUrl":"https://doi.org/10.1117/12.900523","url":null,"abstract":"This paper researches the digital high definition imaging technology and successfully designs a digital high definition camera system .The system takes large array CCD(KAI-2093CM) which conforms to SMEPT 274M standard as photoelectric transfer device, FPGA+AFE as framework, HD-SDI as transforming interface, and combines with the current advanced digital high definition video standard. The result of imaging shows that the high definition camera can realize high definition shooting. The pictures are clear and can be displayed with no stagnation in real time. Moreover, the small camera with high resolution can be applied for high definition shooting in aerospace and other fields.","PeriodicalId":355017,"journal":{"name":"Photoelectronic Detection and Imaging","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122579000","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}
Based on Talbot effect and Moiré fringes of Ronchi gratings which is defined as Moiré Deflection Technology (MDT), lenses' power is calculated. Moiré Deflection Technology can be used for non-contact measurement of phase objects and surfaces and MDT is more widely used in the lenses' power measurement. The power of measured lenses can be figured out accurately according to the relationship between moiré fringes tilting angle and the tested lens's power. Area array CCD recorded moiré fringe image generated by two gratings mechanical interference to measure lenses' power. After appropriate digital image processing such as gray scale equality, image enhancement, image thinning etc, the moiré fringes image is processed by thinning to single pixel width. The pixels of the moiré fringes are labeled to fitting lines to calculate the slope coefficients. However, the moiré fringe image appears to have an unequal light distribution. Based on this phenomenon, a binary processing method, which is based on background gray-scale extension, was proposed. At first, a statistical method is used to calculate gray values from a sampling image with block-based processing. Then the linear interpolation is employed to generate new gray values instead of image pixels to obtain a background image and the moiré fringe image should be corrected by the obtained background image. At last, binarized the image by 2D OTSU threshold algorithm. The experimental results show that the method is simple and effective to segment the moiré pattern from the original moiré fringe image. This method can be used to improve precision of lenses measurement.
{"title":"The research on the moire fringe image preprocessing","authors":"Xiaoxia Xiao, M. Ao, Chunping Yang, Ruofu Yang","doi":"10.1117/12.900127","DOIUrl":"https://doi.org/10.1117/12.900127","url":null,"abstract":"Based on Talbot effect and Moiré fringes of Ronchi gratings which is defined as Moiré Deflection Technology (MDT), lenses' power is calculated. Moiré Deflection Technology can be used for non-contact measurement of phase objects and surfaces and MDT is more widely used in the lenses' power measurement. The power of measured lenses can be figured out accurately according to the relationship between moiré fringes tilting angle and the tested lens's power. Area array CCD recorded moiré fringe image generated by two gratings mechanical interference to measure lenses' power. After appropriate digital image processing such as gray scale equality, image enhancement, image thinning etc, the moiré fringes image is processed by thinning to single pixel width. The pixels of the moiré fringes are labeled to fitting lines to calculate the slope coefficients. However, the moiré fringe image appears to have an unequal light distribution. Based on this phenomenon, a binary processing method, which is based on background gray-scale extension, was proposed. At first, a statistical method is used to calculate gray values from a sampling image with block-based processing. Then the linear interpolation is employed to generate new gray values instead of image pixels to obtain a background image and the moiré fringe image should be corrected by the obtained background image. At last, binarized the image by 2D OTSU threshold algorithm. The experimental results show that the method is simple and effective to segment the moiré pattern from the original moiré fringe image. This method can be used to improve precision of lenses measurement.","PeriodicalId":355017,"journal":{"name":"Photoelectronic Detection and Imaging","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120977936","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}
Precise ground target localization is an interesting problem and relevant not only for military but also for civilian applications, and this is expected to be an emerging field with many potential applications. Ground Target Location Using Loitering Munitions (LM) requires estimation of aircraft position and attitude to a high degree of accuracy, and data derived by processing sensor images might be useful for supplementing other navigation sensor information and increasing the reliability and accuracy of navigation estimates during this flight phase. This paper presents a method for high accuracy ground target localization using Loitering Munitions (LM) equipped with a video camera sensor. The proposed method is based on a satellite or aerial image matching technique. In order to acquire the target position of ground intelligently and rapidly and to improve the localization accuracy estimating the target position jointly with the systematic LM and camera attitude measurement errors, several techniques have been proposed. Firstly, ground target geo-location based on tray tracing was used for comparison against our approach. By proposed methods the calculation from pixel to world coordinates can be done. Then Hough transform was used to image alignment and a median filter was applied for removing small details which are visible from the sensed image but not visible from the reference image. Finally, A novel edge detection method and an image matching algorithm based on bifurcation extraction were proposed. This method did not require accurate knowledge of the aircraft position and attitude and high performance sensors, therefore it is especially suitable for LM which did not have capability to carry accurate sensors due to their limited play weight and power resources. The results of simulation experiments and theory analyzing demonstrate that high accuracy ground target localization is reached with low performance sensors, and achieve timely. The method is used in reconnaissance and surveillance missions, or applicable in any other environment with a relevantly structured clutter.
{"title":"High accuracy ground target location using loitering munitions platforms","authors":"Zhifei Wang, Hua Wang, Jing Han","doi":"10.1117/12.900519","DOIUrl":"https://doi.org/10.1117/12.900519","url":null,"abstract":"Precise ground target localization is an interesting problem and relevant not only for military but also for civilian applications, and this is expected to be an emerging field with many potential applications. Ground Target Location Using Loitering Munitions (LM) requires estimation of aircraft position and attitude to a high degree of accuracy, and data derived by processing sensor images might be useful for supplementing other navigation sensor information and increasing the reliability and accuracy of navigation estimates during this flight phase. This paper presents a method for high accuracy ground target localization using Loitering Munitions (LM) equipped with a video camera sensor. The proposed method is based on a satellite or aerial image matching technique. In order to acquire the target position of ground intelligently and rapidly and to improve the localization accuracy estimating the target position jointly with the systematic LM and camera attitude measurement errors, several techniques have been proposed. Firstly, ground target geo-location based on tray tracing was used for comparison against our approach. By proposed methods the calculation from pixel to world coordinates can be done. Then Hough transform was used to image alignment and a median filter was applied for removing small details which are visible from the sensed image but not visible from the reference image. Finally, A novel edge detection method and an image matching algorithm based on bifurcation extraction were proposed. This method did not require accurate knowledge of the aircraft position and attitude and high performance sensors, therefore it is especially suitable for LM which did not have capability to carry accurate sensors due to their limited play weight and power resources. The results of simulation experiments and theory analyzing demonstrate that high accuracy ground target localization is reached with low performance sensors, and achieve timely. The method is used in reconnaissance and surveillance missions, or applicable in any other environment with a relevantly structured clutter.","PeriodicalId":355017,"journal":{"name":"Photoelectronic Detection and Imaging","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116413905","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}
B. Duan, D. Hei, G. Song, Jiming Ma, Zhan-hong Zhang, Changcai Han, Yan Song, Ming Zhou, Lan Lei
In this paper, based on the mechanism of CCD camera, an event-based simulation method of γ-ray-induced transient noise was developed, which applying MCNP5 Code based on Monte Carlo methods. On the mono-energy γ-ray sources, the transient noises of two different CCD cameras have been measured at different doses (from 0.001mR to 1mR) and different incidence angles. The 60Co and 137Cs were used as the mono-energy γ-ray sources, and the Compton Scattering technique were adopted to get lower energy γ-ray sources. In order to get the pure transient noise induced by γ-ray, a method was advanced for extracting the transient noise from the image mixed the background noise. And the transient noise was characterized, including the number of noise clusters, the noise intensity spectrum and the size spectrum of noise clusters. The variation characteristics of noise have been draw from the simulation and experiment, which induced by γ-rays of different dose, or different energy or different incidence angle.
{"title":"Study on transient noise of CCD camera induced by γ-ray","authors":"B. Duan, D. Hei, G. Song, Jiming Ma, Zhan-hong Zhang, Changcai Han, Yan Song, Ming Zhou, Lan Lei","doi":"10.1117/12.901769","DOIUrl":"https://doi.org/10.1117/12.901769","url":null,"abstract":"In this paper, based on the mechanism of CCD camera, an event-based simulation method of γ-ray-induced transient noise was developed, which applying MCNP5 Code based on Monte Carlo methods. On the mono-energy γ-ray sources, the transient noises of two different CCD cameras have been measured at different doses (from 0.001mR to 1mR) and different incidence angles. The 60Co and 137Cs were used as the mono-energy γ-ray sources, and the Compton Scattering technique were adopted to get lower energy γ-ray sources. In order to get the pure transient noise induced by γ-ray, a method was advanced for extracting the transient noise from the image mixed the background noise. And the transient noise was characterized, including the number of noise clusters, the noise intensity spectrum and the size spectrum of noise clusters. The variation characteristics of noise have been draw from the simulation and experiment, which induced by γ-rays of different dose, or different energy or different incidence angle.","PeriodicalId":355017,"journal":{"name":"Photoelectronic Detection and Imaging","volume":"61 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121511447","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 spatiotemporal and spectral characteristics of ultrawide-band terahertz pulses after passing through a Fresnel lens are studied by using scalar diffraction theory. The simulation shows that the transmitted terahertz waveforms compress with increasing propagation distance, and the multi-frequency focusing phenomenon at different focal points is observed. Additionally, the distribution of terahertz fields in planes perpendicular to the axis is also discussed, and it is found that the diffraction not only induces focusing on axis but also inhibit focusing at off-axis positions. Therefore, the Fresnel lens may be a useful alternative approach to be a terahertz filter. Moreover, the terahertz pulses travelling as basic mode of Gaussian beam is discussed in detail.
{"title":"Focalizing of terahertz waves with a Fresnel lens","authors":"Yu-lei Shi, Wei Liu, Qing-li Zhou, Cunlin Zhang","doi":"10.1117/12.899428","DOIUrl":"https://doi.org/10.1117/12.899428","url":null,"abstract":"The spatiotemporal and spectral characteristics of ultrawide-band terahertz pulses after passing through a Fresnel lens are studied by using scalar diffraction theory. The simulation shows that the transmitted terahertz waveforms compress with increasing propagation distance, and the multi-frequency focusing phenomenon at different focal points is observed. Additionally, the distribution of terahertz fields in planes perpendicular to the axis is also discussed, and it is found that the diffraction not only induces focusing on axis but also inhibit focusing at off-axis positions. Therefore, the Fresnel lens may be a useful alternative approach to be a terahertz filter. Moreover, the terahertz pulses travelling as basic mode of Gaussian beam is discussed in detail.","PeriodicalId":355017,"journal":{"name":"Photoelectronic Detection and Imaging","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127833248","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}
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