This paper investigates by simulation some of the capabilities of near-field and three-dimensional imaging which are made possible by accessing phase and amplitude of electric fields from radiometric emission using aperture synthesis systems. The aperture synthesis technique is the main stay of high resolution radio astronomy and is investigated here for the near-field application of personnel security screening in the millimetre wave band. The limitations of the standard radio astronomy visibility-function technique and a matrix method for image generation are investigated for this purpose. It is concluded that several hundred receivers are required for high pixel count (> few thousand) and good quality images and that a new and more efficient algorithms is required to process such numbers of channels from non-planar imaging arrays in the near-field. Investigating the resolution limits of three-dimensional imaging in the near-field region with this technique indicates sub-wavelength resolution may be possible
{"title":"Near-field and three-dimensional aperture synthesis imaging","authors":"N. Salmon, N. Bowring","doi":"10.1117/12.2030797","DOIUrl":"https://doi.org/10.1117/12.2030797","url":null,"abstract":"This paper investigates by simulation some of the capabilities of near-field and three-dimensional imaging which are made possible by accessing phase and amplitude of electric fields from radiometric emission using aperture synthesis systems. The aperture synthesis technique is the main stay of high resolution radio astronomy and is investigated here for the near-field application of personnel security screening in the millimetre wave band. The limitations of the standard radio astronomy visibility-function technique and a matrix method for image generation are investigated for this purpose. It is concluded that several hundred receivers are required for high pixel count (> few thousand) and good quality images and that a new and more efficient algorithms is required to process such numbers of channels from non-planar imaging arrays in the near-field. Investigating the resolution limits of three-dimensional imaging in the near-field region with this technique indicates sub-wavelength resolution may be possible","PeriodicalId":344928,"journal":{"name":"Optics/Photonics in Security and Defence","volume":"138 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133672599","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}
Armed forces nowadays have to cope with a wide variety of mission scenarios in military or peace keeping operations. In urban environments, for example, convoy commanders are confronted with a very complex threat situation, due to so called IEDs (Improvised explosive devices) or landmines. The detection of threats due to advanced reconnaissance sensors will provide an important advantage. The aim of the SUM project (Surveillance in an urban environment using mobile sensors) was to develop a cost-effective multi-sensor vehicle based surveillance system in order to enhance the knowledge of the actual threat situation on and nearby the road ahead of the convoy. The SUMIRAD (SUM imaging radiometer) system, developed by DLR, is a fast radiometric imager and part of the SUM sensor suite. This paper will describe the challenges for the design of the SUMIRAD system and the image processing features in order to provide high-quality images of sufficient resolution for a large field of view at a moderate frame rate. Imaging results of several measurement campaigns will be presented.
{"title":"A fast imaging MMW radiometer system for security and safety applications","authors":"S. Dill, M. Peichl","doi":"10.1117/12.2028646","DOIUrl":"https://doi.org/10.1117/12.2028646","url":null,"abstract":"Armed forces nowadays have to cope with a wide variety of mission scenarios in military or peace keeping operations. In urban environments, for example, convoy commanders are confronted with a very complex threat situation, due to so called IEDs (Improvised explosive devices) or landmines. The detection of threats due to advanced reconnaissance sensors will provide an important advantage. The aim of the SUM project (Surveillance in an urban environment using mobile sensors) was to develop a cost-effective multi-sensor vehicle based surveillance system in order to enhance the knowledge of the actual threat situation on and nearby the road ahead of the convoy. The SUMIRAD (SUM imaging radiometer) system, developed by DLR, is a fast radiometric imager and part of the SUM sensor suite. This paper will describe the challenges for the design of the SUMIRAD system and the image processing features in order to provide high-quality images of sufficient resolution for a large field of view at a moderate frame rate. Imaging results of several measurement campaigns will be presented.","PeriodicalId":344928,"journal":{"name":"Optics/Photonics in Security and Defence","volume":"46 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121094214","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 the paper a frequency modulated THz system is presented. The system is constructed with a solid state THz source and is modulated approx. ±10% of central frequency of 0.3THz. The detector is room temperature sensor array with a square low characteristic allowing a mixer operation between a portion of transmitted signal from the beam splitter and the received signal. Due to this heterodyne approach a very good signal to noise ratio has been achieved, allowing accurate and repeatable signal analysis. The phase of the received signal is very stable and can be used for fine position measurements with the resolution well below 1μm. In this paper the focus is on measurements of thin foil thickness. Various experiments set-ups and measured results are presented.
{"title":"THz remote sensing with μm resolution","authors":"J. Trontelj, A. Sešek, A. Svigelj","doi":"10.1117/12.2028857","DOIUrl":"https://doi.org/10.1117/12.2028857","url":null,"abstract":"In the paper a frequency modulated THz system is presented. The system is constructed with a solid state THz source and is modulated approx. ±10% of central frequency of 0.3THz. The detector is room temperature sensor array with a square low characteristic allowing a mixer operation between a portion of transmitted signal from the beam splitter and the received signal. Due to this heterodyne approach a very good signal to noise ratio has been achieved, allowing accurate and repeatable signal analysis. The phase of the received signal is very stable and can be used for fine position measurements with the resolution well below 1μm. In this paper the focus is on measurements of thin foil thickness. Various experiments set-ups and measured results are presented.","PeriodicalId":344928,"journal":{"name":"Optics/Photonics in Security and Defence","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124676340","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}
Target decomposition is of interest to the security and defence community as it enables data sets to be reduced to their principal identifying components as a pre-processor to running pattern recognition algorithms. An investigation into the application of target decomposition theory for concealed threat detection is presented. A validation study has been conducted in which the scattering of an EM wave by a number of primitive radar calibration targets has been simulated using an EM FEA solver. A knife has then been illuminated with quad polar radar again in a simulation conducted using an EM FEA solver. The validation of the target decomposition algorithm is achieved by analysing the calibration targets with well-known scattering mechanisms. The decomposition of more complex targets such as those encountered in Concealed Threat Detection (CTD) scenarios are then analysed. The decomposition is performed as prescribed by Cloude et al and the scattering of the illuminating wave due to the target is mapped onto a 3D space detailing polarimetric entropy (H), anisotropy (A) and alpha-angle (α). The decomposition of these complex scattering mechanisms is then used to classify the data. Both theoretical and simulated data sets are used to validate this technique.
{"title":"Target decomposition and polarimetric radar applied to concealed threat detection","authors":"Dean O'Reilly, N. Bowring, N. Rezgui, D. Andrews","doi":"10.1117/12.2034125","DOIUrl":"https://doi.org/10.1117/12.2034125","url":null,"abstract":"Target decomposition is of interest to the security and defence community as it enables data sets to be reduced to their principal identifying components as a pre-processor to running pattern recognition algorithms. An investigation into the application of target decomposition theory for concealed threat detection is presented. A validation study has been conducted in which the scattering of an EM wave by a number of primitive radar calibration targets has been simulated using an EM FEA solver. A knife has then been illuminated with quad polar radar again in a simulation conducted using an EM FEA solver. The validation of the target decomposition algorithm is achieved by analysing the calibration targets with well-known scattering mechanisms. The decomposition of more complex targets such as those encountered in Concealed Threat Detection (CTD) scenarios are then analysed. The decomposition is performed as prescribed by Cloude et al and the scattering of the illuminating wave due to the target is mapped onto a 3D space detailing polarimetric entropy (H), anisotropy (A) and alpha-angle (α). The decomposition of these complex scattering mechanisms is then used to classify the data. Both theoretical and simulated data sets are used to validate this technique.","PeriodicalId":344928,"journal":{"name":"Optics/Photonics in Security and Defence","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131719076","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}
N. Rezgui, N. Bowring, D. Andrews, S. Harmer, M. Southgate, Dean O'Reilly
At airports, security screening can cause long delays. In order to speed up screening a solution to avoid passengers removing their shoes to have them X-ray scanned is required. To detect threats or contraband items hidden within the shoe, a method of screening using frequency swept signals between 15 to 40 GHz has been developed, where the scan is carried out whilst the shoes are being worn. Most footwear is transparent to microwaves to some extent in this band. The scans, data processing and interpretation of the 2D image of the cross section of the shoe are completed in a few seconds. Using safe low power UWB radar, scattered signals from the shoe can be observed which are caused by changes in material properties such as cavities, dielectric or metal objects concealed within the shoe. By moving the transmission horn along the length of the shoe a 2D image corresponding to a cross section through the footwear is built up, which can be interpreted by the user, or automatically, to reveal the presence of concealed threat within the shoe. A prototype system with a resolution of 6 mm or less has been developed and results obtained for a wide range of commonly worn footwear, some modified by the inclusion of concealed material. Clear differences between the measured images of modified and unmodified shoes are seen. Procedures for enhancing the image through electronic image synthesis techniques and image processing methods are discussed and preliminary performance data presented.
{"title":"Development of an ultra wide band microwave radar based footwear scanning system","authors":"N. Rezgui, N. Bowring, D. Andrews, S. Harmer, M. Southgate, Dean O'Reilly","doi":"10.1117/12.2030836","DOIUrl":"https://doi.org/10.1117/12.2030836","url":null,"abstract":"At airports, security screening can cause long delays. In order to speed up screening a solution to avoid passengers removing their shoes to have them X-ray scanned is required. To detect threats or contraband items hidden within the shoe, a method of screening using frequency swept signals between 15 to 40 GHz has been developed, where the scan is carried out whilst the shoes are being worn. Most footwear is transparent to microwaves to some extent in this band. The scans, data processing and interpretation of the 2D image of the cross section of the shoe are completed in a few seconds. Using safe low power UWB radar, scattered signals from the shoe can be observed which are caused by changes in material properties such as cavities, dielectric or metal objects concealed within the shoe. By moving the transmission horn along the length of the shoe a 2D image corresponding to a cross section through the footwear is built up, which can be interpreted by the user, or automatically, to reveal the presence of concealed threat within the shoe. A prototype system with a resolution of 6 mm or less has been developed and results obtained for a wide range of commonly worn footwear, some modified by the inclusion of concealed material. Clear differences between the measured images of modified and unmodified shoes are seen. Procedures for enhancing the image through electronic image synthesis techniques and image processing methods are discussed and preliminary performance data presented.","PeriodicalId":344928,"journal":{"name":"Optics/Photonics in Security and Defence","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132423687","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}
N. Salmon, N. Bowring, S. Hutchinson, M. Southgate, Dean O'Reilly
The unique selling proposition of millimetre wave technology for security screening is that it provides a stand-off or portal scenario sensing capability for non-metallic threats. The capabilities to detect some non-metallic threats are investigated in this paper, whilst recommissioning the AVSEC portal screening system at the Manchester Metropolitan University. The AVSEC system is a large aperture (1.6 m) portal screening imager which uses spatially incoherent illumination at 28-33 GHz from mode scrambling cavities to illuminate the subject. The imaging capability is critically analysed in terms of this illumination. A novel technique for the measurement of reflectance, refractive index and extinction coefficient is investigated and this then use to characterise the signatures of nitromethane, hexane, methanol, bees wax and baking flour. Millimetre wave images are shown how these liquids in polycarbonate bottles and the other materials appear against the human body.
{"title":"An aviation security (AVSEC) screening demonstrator for the detection of non-metallic threats at 28-33 GHz","authors":"N. Salmon, N. Bowring, S. Hutchinson, M. Southgate, Dean O'Reilly","doi":"10.1117/12.2030795","DOIUrl":"https://doi.org/10.1117/12.2030795","url":null,"abstract":"The unique selling proposition of millimetre wave technology for security screening is that it provides a stand-off or portal scenario sensing capability for non-metallic threats. The capabilities to detect some non-metallic threats are investigated in this paper, whilst recommissioning the AVSEC portal screening system at the Manchester Metropolitan University. The AVSEC system is a large aperture (1.6 m) portal screening imager which uses spatially incoherent illumination at 28-33 GHz from mode scrambling cavities to illuminate the subject. The imaging capability is critically analysed in terms of this illumination. A novel technique for the measurement of reflectance, refractive index and extinction coefficient is investigated and this then use to characterise the signatures of nitromethane, hexane, methanol, bees wax and baking flour. Millimetre wave images are shown how these liquids in polycarbonate bottles and the other materials appear against the human body.","PeriodicalId":344928,"journal":{"name":"Optics/Photonics in Security and Defence","volume":"83 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114178853","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}
S. Preu, S. Regensburger, S. Kim, M. Mittendorff, S. Winnerl, S. Malzer, H. Lu, P. Burke, A. Gossard, H. Weber, M. Sherwin
We report on Terahertz (THz) detectors based on III-V high-electron-mobility field-effect transistors (FET). The detection results from a rectification process that is still highly efficient far above frequencies where the transistor provides gain. Several detector layouts have been optimized for specific applications at room temperature: we show a broadband detector layout, where the rectifying FET is coupled to a broadband logarithmic-periodic antenna. Another layout is optimized for mixing of two orthogonal THz beams at 370 GHz or, alternatively, 570 GHz. A third version uses a large array of FETs with very low access resistance allowing for detection of very short high-power THz pulses. We reached a time resolution of 20 ps.
{"title":"Broadband THz detection and homodyne mixing using GaAs high-electron-mobility transistor rectifiers","authors":"S. Preu, S. Regensburger, S. Kim, M. Mittendorff, S. Winnerl, S. Malzer, H. Lu, P. Burke, A. Gossard, H. Weber, M. Sherwin","doi":"10.1117/12.2029478","DOIUrl":"https://doi.org/10.1117/12.2029478","url":null,"abstract":"We report on Terahertz (THz) detectors based on III-V high-electron-mobility field-effect transistors (FET). The detection results from a rectification process that is still highly efficient far above frequencies where the transistor provides gain. Several detector layouts have been optimized for specific applications at room temperature: we show a broadband detector layout, where the rectifying FET is coupled to a broadband logarithmic-periodic antenna. Another layout is optimized for mixing of two orthogonal THz beams at 370 GHz or, alternatively, 570 GHz. A third version uses a large array of FETs with very low access resistance allowing for detection of very short high-power THz pulses. We reached a time resolution of 20 ps.","PeriodicalId":344928,"journal":{"name":"Optics/Photonics in Security and Defence","volume":"91 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116623855","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}
M. Szustakowski, M. Życzkowski, M. Karol, M. Kastek, R. Dulski, J. Barela, P. Markowski, M. Kowalski
Visible, LLTV and anti-fog cameras have different abilities to capture external information, and combining these abilities of the three cameras can greatly improve the environment perception ability of intruders or emergency situations. Designed specifically for professional surveillance use, multi active pixel sensor camera of this type allows targets to be monitored at long distance and tracked using the proportional pan, tilt and zoom system. In the article the research results of the camera to determine realistic and standardized parameters, e.g. range of detection, recognition and identification of humans are described. The paper presents measuring equipment, procedures and results.
{"title":"Ultra long range surveillance camera for critical infrastructure protection research range","authors":"M. Szustakowski, M. Życzkowski, M. Karol, M. Kastek, R. Dulski, J. Barela, P. Markowski, M. Kowalski","doi":"10.1117/12.2028722","DOIUrl":"https://doi.org/10.1117/12.2028722","url":null,"abstract":"Visible, LLTV and anti-fog cameras have different abilities to capture external information, and combining these abilities of the three cameras can greatly improve the environment perception ability of intruders or emergency situations. Designed specifically for professional surveillance use, multi active pixel sensor camera of this type allows targets to be monitored at long distance and tracked using the proportional pan, tilt and zoom system. In the article the research results of the camera to determine realistic and standardized parameters, e.g. range of detection, recognition and identification of humans are described. The paper presents measuring equipment, procedures and results.","PeriodicalId":344928,"journal":{"name":"Optics/Photonics in Security and Defence","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122037500","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}
We present the theoretical and computer simulation studies of photo-mechanics in glassy azo-oligomers. Angular distributions of chromophores in respect to the backbones obtained at different temperatures served as input into a theoretical expression for the striction stress, which was found to be positive for the structure under investigation. The light-induced reorientation of typical propeller-like structures is shown to be a microscopic reason of the sample elongation. The azo-propellers work as nanoscopic actuators which convert the light energy into material deformation. This finding opens a way for prediction of photomechanical properties of glassy azo-compounds directly from their chemical structure.
{"title":"Nanoscopic actuators in light-induced deformation of glassy azo-polymers","authors":"M. Saphiannikova, V. Toshchevikov, J. Ilnytskyi","doi":"10.1117/12.2031775","DOIUrl":"https://doi.org/10.1117/12.2031775","url":null,"abstract":"We present the theoretical and computer simulation studies of photo-mechanics in glassy azo-oligomers. Angular distributions of chromophores in respect to the backbones obtained at different temperatures served as input into a theoretical expression for the striction stress, which was found to be positive for the structure under investigation. The light-induced reorientation of typical propeller-like structures is shown to be a microscopic reason of the sample elongation. The azo-propellers work as nanoscopic actuators which convert the light energy into material deformation. This finding opens a way for prediction of photomechanical properties of glassy azo-compounds directly from their chemical structure.","PeriodicalId":344928,"journal":{"name":"Optics/Photonics in Security and Defence","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126440996","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}
L. Sznitko, K. Cyprych, A. Szukalski, A. Miniewicz, I. Rău, F. Kajzar, J. Myśliwiec
In this article we present the results of studies carried out on the selected polymeric systems doped with luminescent dyes. Our studies focused on polymers like DNA-CTMA and PVK which were doped with common laser dyes Rh6G and DCM. We show that simple incorporation of highly luminescent dye into polymeric matrix can form ;efficient solid laser materials. Moreover, naturally occurring inhomogeneities of polymeric layers prepared by a drop casting process can scatter out pumping light in such a way that a feedback is introduced to the system and coherent and incoherent random lasing can be observed.
{"title":"Lasing and random lasing based on organic molecules","authors":"L. Sznitko, K. Cyprych, A. Szukalski, A. Miniewicz, I. Rău, F. Kajzar, J. Myśliwiec","doi":"10.1117/12.2029793","DOIUrl":"https://doi.org/10.1117/12.2029793","url":null,"abstract":"In this article we present the results of studies carried out on the selected polymeric systems doped with luminescent dyes. Our studies focused on polymers like DNA-CTMA and PVK which were doped with common laser dyes Rh6G and DCM. We show that simple incorporation of highly luminescent dye into polymeric matrix can form ;efficient solid laser materials. Moreover, naturally occurring inhomogeneities of polymeric layers prepared by a drop casting process can scatter out pumping light in such a way that a feedback is introduced to the system and coherent and incoherent random lasing can be observed.","PeriodicalId":344928,"journal":{"name":"Optics/Photonics in Security and Defence","volume":"8901 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130255491","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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