Abstract In this work, an investigation of the temporal coherence properties of radiation which is emitted by laser modules integrated in headlamps is presented. The motivation for these measurements was difficulties concerning the field of classification for laser products which function as conventional headlamps. Based on an experimental setup including a Michelson interferometer, a goniophotometer and a spectrometer, coherence lengths of 92.5 and 147.0 μm are obtained for two different laser modules. The results show that the temporal coherence of the examined radiation is appreciably higher than the temporal coherence of conventionally produced white light. Therefore, at this point in time, laser modules used in headlamps cannot be considered as customary white light sources.
{"title":"Temporal coherence properties of laser modules used in headlamps determined by a Michelson interferometer","authors":"Valerie Popp, P. Ansorg, B. Fleck, C. Neumann","doi":"10.1515/aot-2020-0039","DOIUrl":"https://doi.org/10.1515/aot-2020-0039","url":null,"abstract":"Abstract In this work, an investigation of the temporal coherence properties of radiation which is emitted by laser modules integrated in headlamps is presented. The motivation for these measurements was difficulties concerning the field of classification for laser products which function as conventional headlamps. Based on an experimental setup including a Michelson interferometer, a goniophotometer and a spectrometer, coherence lengths of 92.5 and 147.0 μm are obtained for two different laser modules. The results show that the temporal coherence of the examined radiation is appreciably higher than the temporal coherence of conventionally produced white light. Therefore, at this point in time, laser modules used in headlamps cannot be considered as customary white light sources.","PeriodicalId":46010,"journal":{"name":"Advanced Optical Technologies","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2020-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1515/aot-2020-0039","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48645343","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}
J. Ziehn, M. Roschani, M. Ruf, D. Bruestle, J. Beyerer, Melanie Helmer
Abstract With advances in automated and connected driving, secure communication is increasingly becoming a safety-critical function. Injection of manipulated radio messages into traffic can cause severe accidents in the foreseeable future, and can currently be achieved without having to manipulate on-board vehicle systems directly, for example by hijacking cellphones instead and using these as senders. Thereby, large-scale attacks on vehicles can be executed remotely, and target relatively vulnerable devices. To mitigate remaining vulnerabilities in current automotive security architectures, this paper proposes a secondary communication channel using vehicle head and taillights. In contrast to existing approaches, this method allows both to achieve a sufficient data rate and to extract the angular position of the sender, by means of an imaging process which only requires close-to-market, cost-efficient technology. Through this, injecting false messages by masquerading as a different sender is considerably more challenging: The receiver can verify a message’s source position with the supposed position of the sender, e.g. by using on-board sensors or communicated information. Thereby, reliably faking both the communicated messages and the position of the sender will require direct manipulation of on-board vehicle systems, raising the security level of the function accordingly, and precluding low-threshold, wide-range attacks.
{"title":"Imaging vehicle-to-vehicle communication using visible light","authors":"J. Ziehn, M. Roschani, M. Ruf, D. Bruestle, J. Beyerer, Melanie Helmer","doi":"10.1515/aot-2020-0038","DOIUrl":"https://doi.org/10.1515/aot-2020-0038","url":null,"abstract":"Abstract With advances in automated and connected driving, secure communication is increasingly becoming a safety-critical function. Injection of manipulated radio messages into traffic can cause severe accidents in the foreseeable future, and can currently be achieved without having to manipulate on-board vehicle systems directly, for example by hijacking cellphones instead and using these as senders. Thereby, large-scale attacks on vehicles can be executed remotely, and target relatively vulnerable devices. To mitigate remaining vulnerabilities in current automotive security architectures, this paper proposes a secondary communication channel using vehicle head and taillights. In contrast to existing approaches, this method allows both to achieve a sufficient data rate and to extract the angular position of the sender, by means of an imaging process which only requires close-to-market, cost-efficient technology. Through this, injecting false messages by masquerading as a different sender is considerably more challenging: The receiver can verify a message’s source position with the supposed position of the sender, e.g. by using on-board sensors or communicated information. Thereby, reliably faking both the communicated messages and the position of the sender will require direct manipulation of on-board vehicle systems, raising the security level of the function accordingly, and precluding low-threshold, wide-range attacks.","PeriodicalId":46010,"journal":{"name":"Advanced Optical Technologies","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2020-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1515/aot-2020-0038","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67328271","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}
Abstract High-resolution headlamp concepts, such as the SSL|HD system from HELLA [1], induce completely new requirements for the evaluation of headlamp light distributions. The subjective perception of image quality is becoming increasingly important compared to the fulfilment of legal lighting values. High-performance projectors allow a good compromise between rapid but theoretical simulations and real but expensive prototypes. These projectors can display different static or dynamic simulations in a realistic way with regard to image quality and light values [2]. This article first introduces the high-performance projectors used for this purpose at HELLA. The projectors can be used to visualize the headlamp light distribution early in the development process, long before prototypes or overall systems are implemented in the vehicle. Following this, two exemplary research questions for static situations are presented, which were answered on the basis of investigations with the high-performance projectors. The requirements for dynamic simulations of real traffic situations, which are described by the interaction of the individual sensors installed in the vehicle (e.g. vehicle dynamics, level sensors, camera), are much more complex. In the paper, a development tool consisting of high-performance projectors and the HELLA simulation software ALiSiA is presented. The aim is a dynamic visualization of the entire system to optimize the development process.
{"title":"Development of HD-headlamps with high-performance projectors","authors":"S. Köhler, Boris Kubitza, A. Thoma","doi":"10.1515/aot-2020-0036","DOIUrl":"https://doi.org/10.1515/aot-2020-0036","url":null,"abstract":"Abstract High-resolution headlamp concepts, such as the SSL|HD system from HELLA [1], induce completely new requirements for the evaluation of headlamp light distributions. The subjective perception of image quality is becoming increasingly important compared to the fulfilment of legal lighting values. High-performance projectors allow a good compromise between rapid but theoretical simulations and real but expensive prototypes. These projectors can display different static or dynamic simulations in a realistic way with regard to image quality and light values [2]. This article first introduces the high-performance projectors used for this purpose at HELLA. The projectors can be used to visualize the headlamp light distribution early in the development process, long before prototypes or overall systems are implemented in the vehicle. Following this, two exemplary research questions for static situations are presented, which were answered on the basis of investigations with the high-performance projectors. The requirements for dynamic simulations of real traffic situations, which are described by the interaction of the individual sensors installed in the vehicle (e.g. vehicle dynamics, level sensors, camera), are much more complex. In the paper, a development tool consisting of high-performance projectors and the HELLA simulation software ALiSiA is presented. The aim is a dynamic visualization of the entire system to optimize the development process.","PeriodicalId":46010,"journal":{"name":"Advanced Optical Technologies","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2020-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1515/aot-2020-0036","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42880587","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}
Abstract Holograms have found their use as optical elements in a variety of applications. Yet using them with incoherent and divergent lightsources like LEDs proves difficult, as their characteristics need to be simulated by lasers during manufacturing to get a correct reconstruction of the desired light distribution. We present a new setup to allow for a high flexibility during the manufacturing process, which is able to produce volume holographic cell arrays (VCAs) that can be illuminated directly with uncollimated LEDs. Results are presented for the case of reflection holograms.
{"title":"Manufacturing of volume holographic cell arrays for usage with uncollimated LEDs in automotive applications","authors":"Markus Giehl, Lukas T. Hiller, C. Neumann","doi":"10.1515/aot-2020-0037","DOIUrl":"https://doi.org/10.1515/aot-2020-0037","url":null,"abstract":"Abstract Holograms have found their use as optical elements in a variety of applications. Yet using them with incoherent and divergent lightsources like LEDs proves difficult, as their characteristics need to be simulated by lasers during manufacturing to get a correct reconstruction of the desired light distribution. We present a new setup to allow for a high flexibility during the manufacturing process, which is able to produce volume holographic cell arrays (VCAs) that can be illuminated directly with uncollimated LEDs. Results are presented for the case of reflection holograms.","PeriodicalId":46010,"journal":{"name":"Advanced Optical Technologies","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2020-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1515/aot-2020-0037","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44035933","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}
Abstract Nanostructured filter arrays on image sensors are promising for miniature spectrometers and spectral imagers. In this work, we report on resonant waveguide gratings fabricated by UV nanoimprint lithography and conformal dielectric-plasmonic coatings. Optical measurements in accordance with numerical simulations report on a resonance bandwidth of 20 nm in transmission in the visible range. The impact of cladding thickness and filter lateral size on the resonance properties is investigated with the help of numerical calculations. Finally, it is shown that the proposed geometry based on conformal coatings has a very efficient blocking rate compared to other nanostructured filter approaches.
{"title":"Narrowband transmission filters based on resonant waveguide gratings and conformal dielectric-plasmonic coatings","authors":"B. Gallinet, Giorgio Quaranta, C. Schneider","doi":"10.1515/aot-2020-0049","DOIUrl":"https://doi.org/10.1515/aot-2020-0049","url":null,"abstract":"Abstract Nanostructured filter arrays on image sensors are promising for miniature spectrometers and spectral imagers. In this work, we report on resonant waveguide gratings fabricated by UV nanoimprint lithography and conformal dielectric-plasmonic coatings. Optical measurements in accordance with numerical simulations report on a resonance bandwidth of 20 nm in transmission in the visible range. The impact of cladding thickness and filter lateral size on the resonance properties is investigated with the help of numerical calculations. Finally, it is shown that the proposed geometry based on conformal coatings has a very efficient blocking rate compared to other nanostructured filter approaches.","PeriodicalId":46010,"journal":{"name":"Advanced Optical Technologies","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2020-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1515/aot-2020-0049","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45476971","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}
Abstract In everyday traffic, pedestrians rely on informal communication with other road users. In case of automated vehicles, this communication can be replaced by light signals, which need to be learned beforehand. Prior to an extensive introduction of automated vehicles, a learning phase for these light signals can be set up in manual driving with help of a driver intention prediction. Therefore, a three-staged algorithm consisting of a neural network, a random forest and a conditional stage, is implemented. Using this algorithm, a true-positive rate (TPR) of 94.0% for a 5.0% false-positive rate (FPR) can be achieved. To improve this process, a personalization procedure is implemented, using driver-specific behaviours, resulting in TPRs ranging from 91.5 to 96.6% for a FPR of 5.0%. Transfer learning of neural networks improves the prediction accuracy of almost all drivers. In order to introduce the implemented algorithm in today’s traffic, especially the FPR has to be improved considerably.
{"title":"Personalised neural networks for a driver intention prediction: communication as enabler for automated driving","authors":"Johannes Reschke, C. Neumann, S. Berlitz","doi":"10.1515/aot-2020-0035","DOIUrl":"https://doi.org/10.1515/aot-2020-0035","url":null,"abstract":"Abstract In everyday traffic, pedestrians rely on informal communication with other road users. In case of automated vehicles, this communication can be replaced by light signals, which need to be learned beforehand. Prior to an extensive introduction of automated vehicles, a learning phase for these light signals can be set up in manual driving with help of a driver intention prediction. Therefore, a three-staged algorithm consisting of a neural network, a random forest and a conditional stage, is implemented. Using this algorithm, a true-positive rate (TPR) of 94.0% for a 5.0% false-positive rate (FPR) can be achieved. To improve this process, a personalization procedure is implemented, using driver-specific behaviours, resulting in TPRs ranging from 91.5 to 96.6% for a FPR of 5.0%. Transfer learning of neural networks improves the prediction accuracy of almost all drivers. In order to introduce the implemented algorithm in today’s traffic, especially the FPR has to be improved considerably.","PeriodicalId":46010,"journal":{"name":"Advanced Optical Technologies","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2020-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1515/aot-2020-0035","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42804070","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}
Abstract Recent rapid progress in automotive lighting technology led to the emergence of headlamps featuring a large variety of light distributions that are highly adapted to provide best possible road illumination in particular traffic situations. Visual assistance systems which highlight relevant objects or project symbols to communicate with other traffic participants, further improve road safety. Implementing all these functions within a single headlamp usually requires the use of several additional modules with high and low resolution. This multitude of modules impacts the installation space, styling and cost of automotive headlamps. This paper presents a high-resolution red-green-blue (RGB) laser headlamp module which provides a good illumination of the road and can also be used for external communication purposes. A specially developed laser scanning unit, based on a bi-axial resonant micro-electro-mechanical systems (MEMS) scanner and a high-power RGB laser, serves as the technical basis. Three module concepts are designed using light simulation, constructed as computer-aided design (CAD) models and integrated into a serial headlamp package. The concepts are based on design, simulation and measurement data of the scanning unit.
{"title":"Development of a high resolution scanning RGB laser headlamp","authors":"Roman Danov, E. Thiessen","doi":"10.1515/aot-2020-0045","DOIUrl":"https://doi.org/10.1515/aot-2020-0045","url":null,"abstract":"Abstract Recent rapid progress in automotive lighting technology led to the emergence of headlamps featuring a large variety of light distributions that are highly adapted to provide best possible road illumination in particular traffic situations. Visual assistance systems which highlight relevant objects or project symbols to communicate with other traffic participants, further improve road safety. Implementing all these functions within a single headlamp usually requires the use of several additional modules with high and low resolution. This multitude of modules impacts the installation space, styling and cost of automotive headlamps. This paper presents a high-resolution red-green-blue (RGB) laser headlamp module which provides a good illumination of the road and can also be used for external communication purposes. A specially developed laser scanning unit, based on a bi-axial resonant micro-electro-mechanical systems (MEMS) scanner and a high-power RGB laser, serves as the technical basis. Three module concepts are designed using light simulation, constructed as computer-aided design (CAD) models and integrated into a serial headlamp package. The concepts are based on design, simulation and measurement data of the scanning unit.","PeriodicalId":46010,"journal":{"name":"Advanced Optical Technologies","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2020-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1515/aot-2020-0045","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44356470","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}
Dong Cheon Kim, A. Hermerschmidt, P. Dyachenko, T. Scharf
Abstract Diffractive optical elements are ultra-thin optical components required for a variety of applications because of their high design flexibility. We introduce a gradient-based optimization method based on a step-transition perturbation approach which is an efficient approximation method using local field perturbations due to sharp surface profile transitions. Step-transition perturbation approach be available to calculate the gradient of figure of merit straightforwardly, we implemented optimization method based on this gradient. This fast and accurate inverse design creates binary (2-level) diffractive elements with small features generating the wide angle beam arrays. The results of the experimental characterization confirm that the optimization based on the perturbation method is valid for 1-to-117 fan-out grating generating beam pattern of linear array.
{"title":"Inverse design of diffractive optical elements using step-transition perturbation approach","authors":"Dong Cheon Kim, A. Hermerschmidt, P. Dyachenko, T. Scharf","doi":"10.1515/aot-2020-0046","DOIUrl":"https://doi.org/10.1515/aot-2020-0046","url":null,"abstract":"Abstract Diffractive optical elements are ultra-thin optical components required for a variety of applications because of their high design flexibility. We introduce a gradient-based optimization method based on a step-transition perturbation approach which is an efficient approximation method using local field perturbations due to sharp surface profile transitions. Step-transition perturbation approach be available to calculate the gradient of figure of merit straightforwardly, we implemented optimization method based on this gradient. This fast and accurate inverse design creates binary (2-level) diffractive elements with small features generating the wide angle beam arrays. The results of the experimental characterization confirm that the optimization based on the perturbation method is valid for 1-to-117 fan-out grating generating beam pattern of linear array.","PeriodicalId":46010,"journal":{"name":"Advanced Optical Technologies","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2020-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1515/aot-2020-0046","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47760028","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}
Arvid Niemeyer, Lucia Rottmair, C. Neumann, C. Möckel
Abstract Light not only enables humans to perceive their surroundings, but also influences their sleep–wake cycle, mood, concentration and performance. Targeted use of these so called nonvisual effects could also have a positive contribution in automobiles by keeping passengers alert, minimizing error rates or bootsting attention in general. Since construction space in vehicle interios is scarce, this study compared the influence of differently-sized light panels and thus solid angles on nonvisual effects. In a counterbalanced order, 32 volunteers were exposed to three lighting conditions in the morning: baseline (12 lx, 2200 K), small (200 lx, 6500 K, 0.05 sr) and large (200 lx, 6500 K, 0.44 sr). During each session of 60 min, alertness, concentration and working memory were assessed before and during light exposure. After data analysis no significant main effects of light, measurement point or interaction between light and measurement point could be seen.
{"title":"Influence of the perceived size of a light source on non-visual effects in humans","authors":"Arvid Niemeyer, Lucia Rottmair, C. Neumann, C. Möckel","doi":"10.1515/aot-2020-0041","DOIUrl":"https://doi.org/10.1515/aot-2020-0041","url":null,"abstract":"Abstract Light not only enables humans to perceive their surroundings, but also influences their sleep–wake cycle, mood, concentration and performance. Targeted use of these so called nonvisual effects could also have a positive contribution in automobiles by keeping passengers alert, minimizing error rates or bootsting attention in general. Since construction space in vehicle interios is scarce, this study compared the influence of differently-sized light panels and thus solid angles on nonvisual effects. In a counterbalanced order, 32 volunteers were exposed to three lighting conditions in the morning: baseline (12 lx, 2200 K), small (200 lx, 6500 K, 0.05 sr) and large (200 lx, 6500 K, 0.44 sr). During each session of 60 min, alertness, concentration and working memory were assessed before and during light exposure. After data analysis no significant main effects of light, measurement point or interaction between light and measurement point could be seen.","PeriodicalId":46010,"journal":{"name":"Advanced Optical Technologies","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2020-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1515/aot-2020-0041","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41711997","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：