Journals >Infrared and Laser Engineering
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2022
Volume: 51 Issue 2
33 Article(s)
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Home-made 6.7 kW narrow linewidth triple-cladding fiber laser
Zhigang Han, Yunhan Zheng, Haoye Wang, Fangxin Li, Jiale Chen, and Rihong Zhu
In order to achieve high-power output of fiber lasers with narrow linewidth, the thermal effect and the four-wave mixing (FWM) effect of the Yb3+ doped large mode area triple-cladding fiber (LMA-YTF) based fiber laser was investigated. Based on the FWM effect model, the influences on the spectral broadening of the largIn order to achieve high-power output of fiber lasers with narrow linewidth, the thermal effect and the four-wave mixing (FWM) effect of the Yb3+ doped large mode area triple-cladding fiber (LMA-YTF) based fiber laser was investigated. Based on the FWM effect model, the influences on the spectral broadening of the large mode area triple-cladding fiber (LMA-TCF) amplifiers were simulated and analyzed. Thermal distribution model of the LMA-YTF was modeled. The effects of the power ratio in the second cladding on the fiber temperature characteristics and the upper limit of the pump power were analyzed. The influence of the thermal conductivity of polymer coatings and external temperature on fiber temperature was discussed. The upper limits of the pump power of different backward combiners were compared experimentally. The experimental results indicate that the (6+1)×1 triple-cladding backward combiner with a lower power ratio in the second cladding has a higher pump power upper limit than the (9+1)×1 combiner, which agree with the simulation results. A triple-cladding fiber laser is constructed with fully home-made devices, achieving an output power of 6.7 kW and a 3 dB linewidth of 0.32 nm..
Infrared and Laser Engineering
- Publication Date: Feb. 25, 2022
- Vol. 51, Issue 2, 20210849 (2022)
Dual-wavelength interferometric diagnosis of double-pulse laser induced aluminium plasma
Chuhui Zhang, Jian Lu, Hongchao Zhang, Lou Gao, and Zhijian Xie
Double-pulse laser-induced plasma has broad application prospects and development space in laser processing, detection of element, material removal and other fields, so it is of great significance to diagnose it. The time evolution law of plasma was obtained by two-wavelength interferometry, to study the effect and mecDouble-pulse laser-induced plasma has broad application prospects and development space in laser processing, detection of element, material removal and other fields, so it is of great significance to diagnose it. The time evolution law of plasma was obtained by two-wavelength interferometry, to study the effect and mechanism of plasma induced by delayed double-pulse laser. A dual-wavelength interference diagnosis system based on the Mach-Zehnder interferometer was established. It had ability to acquire interferogram of the double-pulse laser-induced plasma. By processing and analyzing the interferogram, the evolution law of plasma electron density with the delay time of double-pulse laser was obtained. The result shows that the effect of the second pulse laser on the plasma electron density first enhances and then weakens with the prolongation of the delay time between double-pulse laser. Among them, when the delay time of the double-pulse laser is 10 ns, the enhancement effect on the plasma electron density is the strongest, when 30 ns, the average electron density in the central region can reach 6.49×1019 cm-3, which is 26% higher than that of single-pulse laser-induced plasma with the same energy. Meanwhile, the effect of delay time on the mechanism of secondary pulse laser was studied. The research results provide a reference for the optimization direction of double-pulse laser-induced plasma..
Infrared and Laser Engineering
- Publication Date: Feb. 25, 2022
- Vol. 51, Issue 2, 20210892 (2022)
Discussions on the development of advanced night vision imaging technology
Qian Chen
Night vision imaging technology converts invisible radiation or enhances faint light at night under low illumination conditions to enable human eyes to see covertly at night. It plays an important role in modern military applications such as night detection and targeting, assisited driving, navigation and guidance. In Night vision imaging technology converts invisible radiation or enhances faint light at night under low illumination conditions to enable human eyes to see covertly at night. It plays an important role in modern military applications such as night detection and targeting, assisited driving, navigation and guidance. In order to ensure "one-way transparency" and give full play to the technical advantages of "dominating the night", the world's military powers have invested a lot of human and material resources to carry out research on advanced night vision imaging technology, so that the performance of night vision equipment can be rapidly developed. As the first article of this special issue of "Nanjing University of Science and Technology" for the Journal of Infrared and Laser Engineering, this paper outlines the current progress and challenges of night vision imaging technology, and provides a discussion and outlook of the future development trend of advanced night vision imaging technology——direct imaging based on photoelectric conversion and constructive imaging based on computational imaging, respectively..
Infrared and Laser Engineering
- Publication Date: Feb. 25, 2022
- Vol. 51, Issue 2, 20220128 (2022)
Special Issue-Computational Optical Imaging Technology
Optically realize convolution operation of microlens array
Yuhang Fei, Xiubao Sui, Qingbao Wang, Qian Chen, and Guohua Gu
As a simple linear translation invariant operation, convolution has been widely used in various fields of image processing, and the convolutional neural network derived from it is brilliant in the field of artificial intelligence. In order to deal with the problem of limited computing power of AI reasoning chip in the As a simple linear translation invariant operation, convolution has been widely used in various fields of image processing, and the convolutional neural network derived from it is brilliant in the field of artificial intelligence. In order to deal with the problem of limited computing power of AI reasoning chip in the post-Moore era, optical neural network came into being. As one of the important research hotspots, optical convolutional neural network plays an important role in promoting the development of optical neural network. An optical convolution system was designed, based on the uniform light path formed by micro lens array and lens, the image carried in the light place was convoluted in two-dimensions. The system can complete simple image smoothing and sharpening in the optical path. When the spatial light modulator is used to realize the convolution kernel and input surface, the system can realize three convolution forms of various step sizes, and can also realize multi-channel three-dimensional convolution through multiple projection or flattening, thus laying a foundation for the realization of optical convolution neural network for complex image processing tasks..
Infrared and Laser Engineering
- Publication Date: Feb. 25, 2022
- Vol. 51, Issue 2, 20210887 (2022)
Efficient learning-based phase retrieval method through unknown scattering media
Shuo Zhu, Enlai Guo, Lianfa Bai, and Jing Han
Imaging through scattering media with high fidelity is still one of the main challenges in imaging analysis of deep biological tissues and distant astronomical observations. The computational imaging method based on deep learning has made significant progress in reconstruction quality and other aspects. However, when tImaging through scattering media with high fidelity is still one of the main challenges in imaging analysis of deep biological tissues and distant astronomical observations. The computational imaging method based on deep learning has made significant progress in reconstruction quality and other aspects. However, when the scattering media in the actual system is unstable and the structure of objects is complex, and the obtained scattering dataset for training is limited, the pure data-driven method cannot realize efficient reconstruction. An efficient imaging method was proposed in reconstructing complex objects through unknown thin scattering media with different statistical properties, which was based on the effective combination of the speckle correlation theory and the powerful data mining and mapping capabilities. More information had been unearthed with the redundancy of the speckles and had been fully used with the neural network. This method obtained high-quality recovery of complex objects with complex scattering scenes and the training set is limited. This approach can promote the applications of physics-aware learning in practical scattering scenes..
Infrared and Laser Engineering
- Publication Date: Feb. 25, 2022
- Vol. 51, Issue 2, 20210889 (2022)
Deep learning-based color transfer biomedical imaging technology
Yinxu Bian, Tao Xing, Weijie Deng, Qin Xian, Honglei Qiao, Qian Yu, Jilong Peng, Xiaofei Yang, Yannan Jiang, Jiaxiong Wang, Shenmin Yang, Renbin Shen, Hua Shen, and Cuifang Kuang
In traditional pathology detection, the speed of diagnosis is limited due to the complex staining process and single observation form. The staining process is essentially associating color information with morphological features, and the effect is equivalent to that of biomedical images of modern digital technology. SeIn traditional pathology detection, the speed of diagnosis is limited due to the complex staining process and single observation form. The staining process is essentially associating color information with morphological features, and the effect is equivalent to that of biomedical images of modern digital technology. Sense segmentation, which allows researchers to greatly reduce the steps of biomedical imaging processing samples through computational post-processing, and achieve imaging results consistent with the gold standard of traditional medical staining. In recent years, the development of artificial intelligence deep learning has contributed to the effective combination of computer-aided analysis and clinical medicine, and artificial intelligence color transfer technology has gradually shown high development potential in biomedical imaging analysis. This paper will review the technical principles of deep learning color transfer, enumerate some applications of such technologies in the field of biomedical imaging, and look forward to the research status and possible development trends of artificial intelligence color transfer in the field of biomedical imaging..
Infrared and Laser Engineering
- Publication Date: Feb. 25, 2022
- Vol. 51, Issue 2, 20210891 (2022)
Features of vortex high harmonics generated by the Laguerre-Gaussian beam with nonzero radial node
Beiyu Wang, Jiaxin Han, and Cheng Jin
High harmonic generation (HHG) with orbital angular momentum in the extreme ultraviolet could be produced by the interaction between vortex ultrafast infrared laser pulse and gas medium. In this paper, Laguerre-Gaussian (LG) beam with nonzero radial node was used as the driving laser. And through computing the single-aHigh harmonic generation (HHG) with orbital angular momentum in the extreme ultraviolet could be produced by the interaction between vortex ultrafast infrared laser pulse and gas medium. In this paper, Laguerre-Gaussian (LG) beam with nonzero radial node was used as the driving laser. And through computing the single-atom response with the quantitative rescattering model, distributions of intensity and phase of HHG in the near and far fields were obtained by solving the three-dimensional Maxwell’s equation in the medium and the Huygens’ integral in the paraxial approximation, respectively. With the increase of the radial node in the driving laser, it is indicated that the distribution of HHG intensity shows the multiple-ring structure, the radial-node structure appears in the distribution of HHG phase, and the spatial region of intensity distribution is decreased in the near field, but increased in the far field. The phase-matching analysis showed that maps of spatial coherence length of short- and long-trajectory HHG are very sensitive to the mode of driving laser, qualitatively consistent with the maps of evolution of HHG field inside gas medium, which explained the features of vortex HHG under the LG beam with nonzero radial node..
Infrared and Laser Engineering
- Publication Date: Feb. 25, 2022
- Vol. 51, Issue 2, 20210895 (2022)
A learning based on approach for noise reduction with raster images
Jiaye Wang, Yixuan Li, and Yuzhen Zhang
Three-dimensional (3D) shape measurement based on fringe projection was widely used in industrial manufacturing, quality testing, biomedicine, aerospace and other fields. However, due to the short exposure time of raster images acquisition process, 3D reconstruction results were usually affected by serious image noise Three-dimensional (3D) shape measurement based on fringe projection was widely used in industrial manufacturing, quality testing, biomedicine, aerospace and other fields. However, due to the short exposure time of raster images acquisition process, 3D reconstruction results were usually affected by serious image noise in the scene of high-speed measurement. In recent years, deep learning has been widely used in computer vision and other fields, and has achieved great success. Inspired by this, we proposed a learning based approach for noise reduction with raster images. Firstly, we constructed a convolutional neural network based on U-NET. Secondly, the neural network was constructed to learn the mapping relationship between the noisy fringe images and the corresponding high quality wrapped phase during the training process. With proper training, this network can accurately recovered phase information from noisy fringe images. Aiming at off-line 3D measurement in fast moving scene, experimental results show that the proposed method can recover high-precision phase information by using only one raster image, and the phase accuracy is better than the traditional three-step phase shift method. This method can provide a practical and reliable solution for improving the accuracy of 3D measurement in high-speed scene..
Infrared and Laser Engineering
- Publication Date: Feb. 25, 2022
- Vol. 51, Issue 2, 20220006 (2022)
Simulation of the near-field focusing and the far-field imaging of microspherical lenses: A review
Ran Ye, Chu Xu, Fen Tang, Qingqing Shang, Yao Fan, Jiaji Li, Yonghong Ye, and Chao Zuo
Microsphere-assisted super-resolution microscopy is an emerging technique which can be used to overcome the diffraction limit of conventional optical microscopes and significantly enhance their resolution. This technique is very promising for various applications because of the simplicity of its operation, its label-frMicrosphere-assisted super-resolution microscopy is an emerging technique which can be used to overcome the diffraction limit of conventional optical microscopes and significantly enhance their resolution. This technique is very promising for various applications because of the simplicity of its operation, its label-free and real-time imaging nature and its ability to be performed under white-light illumination with commercially available optical microscopes. Although there are many impressive results coming out along with the development of this technique, most studies are about the imaging properties, imaging quality improvement and manipulation of microspheres. A comprehensive theory on the super-resolution mechanism is still missing. Within this context, the progress of the microsphere’s imaging theory and the numerical methods in simulating the near-field focusing and far-field imaging phenomenon of microspheres was reported in this paper. The challenges and the future of this technique were also discussed..
Infrared and Laser Engineering
- Publication Date: Feb. 25, 2022
- Vol. 51, Issue 2, 20220086 (2022)
Review of computational optical microscopy imaging technology based on smartphone platform
Zeyu Zhang, Yao Fan, Qin Xu, Yuzhou Chen, Jiasong Sun, Qian Chen, and Chao Zuo
Computational optical microscopy imaging technology combines optical encoding and computational decoding to retrieve multi-dimensional information of microscopic objects through optical manipulation and image algorithm reconstruction, providing a powerful boost for microscopy imaging technology to break through traditiComputational optical microscopy imaging technology combines optical encoding and computational decoding to retrieve multi-dimensional information of microscopic objects through optical manipulation and image algorithm reconstruction, providing a powerful boost for microscopy imaging technology to break through traditional imaging capabilities. The development of this technology has benefited from the optimization of modern optical systems, image sensors, and high-performance data processing equipment, and is also enabled by the development of advanced communication technologies and equipment. As a highly integrated electronic device, the smartphone platform has an advanced image sensor and a high-performance processor, which can collect the image of the optical system and run the image processing algorithm, creating a new way for the realization of computational optical microscopy imaging technology. Furthermore, as a mobile communication terminal, the open operating system and various wireless network access methods of the smartphone platform endow the microscope with flexible and intelligent control capabilities and rich display and processing analysis functions, which can be used to realize diversified biological detection applications in various complex environments. In this paper, the computational optical microscopy imaging technology based on the smartphone platform was reviewed from four aspects. First, the design of the new microscopic imaging optical path based on the smartphone platform as an optical imaging device was reviewed. Next, the computational optical high-throughput microscopy imaging technology based on the advanced sensor of the smartphone platform was introduced. Then, the application of the data processing and interconnection capabilities of the smartphone platform in computational microscopy imaging was introduced, and finally some of the existing problems and solutions of this technology were discussed..
Infrared and Laser Engineering
- Publication Date: Feb. 25, 2022
- Vol. 51, Issue 2, 20220095 (2022)
Computational optical imaging: An overview
Chao Zuo, and Qian Chen
Computational optical imaging is an emerging research field to realize specific imaging functions and characteristics by jointly optimizing optical systems and signal processing. It is not a simple supplement to optical imaging and digital image processing, but rather an integrally combination of optical modulation at Computational optical imaging is an emerging research field to realize specific imaging functions and characteristics by jointly optimizing optical systems and signal processing. It is not a simple supplement to optical imaging and digital image processing, but rather an integrally combination of optical modulation at the front end (physical domain) and information processing at the back end (digital domain), where images and information are obtained through optical coding and mathematical modeling of the illumination and imaging system in a computationally reconfigurable manner. This new imaging mechanism is expected to break the limitations of traditional optical imaging technology on the optical system and image detector fabrication, manufacturing, operating conditions, power consumption, and cost, and significantly improve imaging function (phase, spectrum, polarization, light field, coherence, refractive index, 3D morphology, depth of field, blur recovery, digital refocusing, change of view angle), performance (spatial resolution, temporal resolution, spectral resolution, information dimension, sensitivity), reliability, and maintainability. At present, computational optical imaging has been developed into an emerging interdisciplinary research field that integrates geometric optics, information optics, computer vision, digital image processing, modern signal processing, etc., and has become an international research focus and hotspot in the field of optical imaging, representing the future development direction of advanced optical imaging technology. Many universities and research institutes at home and abroad are getting involved, making it a rapidly developing research field where "a hundred flowers bloom and a hundred schools of thought contend". As the first article in the column "Computational optical imaging technology" of the special issue "Nanjing University of Science and Technology" for the Journal Infrared and Laser Engineering, this paper provides a general overview of historical evolution and development status of computational optical imaging, and looks forward to its future development direction and the core enabling technologies on which it relies, to throw bricks and attract jade..
Infrared and Laser Engineering
- Publication Date: Feb. 25, 2022
- Vol. 51, Issue 2, 20220110 (2022)
Special Issue-Infrared Low Light Level Night Vision Technology
Research on infrared/passive millimeter wave compound decoy
Zhongyang Xiong, Chenguang Zhu, Fanshun Duanmu, and Jingwei Li
An infrared/passive millimeter wave compound decoy was prepared. On the basis of MTV pyrotechnic composition, red phosphorus was used to replace part of magnesium powder, short carbon fiber was used as a functional additive, and a thin-film pyrotechnic material was prepared. The infrared radiation and millimeter wave rAn infrared/passive millimeter wave compound decoy was prepared. On the basis of MTV pyrotechnic composition, red phosphorus was used to replace part of magnesium powder, short carbon fiber was used as a functional additive, and a thin-film pyrotechnic material was prepared. The infrared radiation and millimeter wave radiation properties of this material were tested and analyzed. The research results show that the addition of a small amount of red phosphorus was beneficial to increase the radiation area; When the proportion of red phosphorus added is more than 10%, the average flame temperature, infrared radiation intensity and millimeter wave brightness temperature continue to decrease with the increase of red phosphorus content, after adding a suitable amount of carbon fiber, the burning rate, flame temperature and the infrared radiation are both enhanced; The millimeter wave brightness temperature continues to increase with the increase of carbon fiber content, when the amount of red phosphorus added is 10% and the carbon fiber content increases from 0 to 1.75%, the millimeter wave brightness temperature increased from 330 K to 458 K, brightness temperature greater than 400 K, longer duration..
Infrared and Laser Engineering
- Publication Date: Feb. 25, 2022
- Vol. 51, Issue 2, 20210455 (2022)
Ship wake extraction and detection from infrared remote sensing images
Yan Cheng, Xuelian Yu, Weixian Qian, and Ye Qian
In infrared remote sensing images with low or medium spatial resolution, the number of pixels occupied by ships on the sea is very small, and the geometric shape and specific texture structure of the target are difficult to obtain. In order to improve the detection limit signal to clutter ratio, the ship wake feature wIn infrared remote sensing images with low or medium spatial resolution, the number of pixels occupied by ships on the sea is very small, and the geometric shape and specific texture structure of the target are difficult to obtain. In order to improve the detection limit signal to clutter ratio, the ship wake feature with linear feature was taken as the detection element, which was mathematically characterized. The Dot-Curve detection system was established innovatively. Based on the two-dimensional curvature filtering, the ship detection and wake feature extraction were carried out preliminarily. The feature set was established, from which a number of features with large difference from the background interference items, including wake gray variance, positive and negative gray slope on both sides of the wake, wake linearity and the distance from the hull detection results, were selected to identify the detection results of the candidate targets, remove interference items and extract targets. The results show that after target identification, the ship false detection rate in different bands of infrared images is reduced to less than 8.40%, and the detection rate is improved to at least 94.53%. The ship detection algorithm combines the physical and image characteristics of the wake, which is suitable for many scenes and bands. The algorithm is refined and effective, the physical laws are clear, and the samples needed are few..
Infrared and Laser Engineering
- Publication Date: Feb. 25, 2022
- Vol. 51, Issue 2, 20210844 (2022)
Target tracking acceleration scheme adopting adaptive fuzzy optimization
Cong Xu, Daying Sun, Ziqi Cao, Chunqi Li, and Wenhua Gu
As one of the important directions of computer vision, target tracking has a wide range of applications, such as autopilot, UAV tracking, but the target tracking algorithm cannot run effectively on embedded devices. A novel acceleration target tracking scheme based on correlation filtering was proposed to solve the proAs one of the important directions of computer vision, target tracking has a wide range of applications, such as autopilot, UAV tracking, but the target tracking algorithm cannot run effectively on embedded devices. A novel acceleration target tracking scheme based on correlation filtering was proposed to solve the problems of target tracking algorithm, such as high computation and complexity, difficulty application on the resource-constrained embedded devices. Firstly, the adaptive fuzzy algorithm was used to optimize the overall computation of the algorithm, which could decide whether to reduce the image quality based on target size. Secondly, the criterion of Peak-to-Sidelobe Rate and Average Peak-to-Correlation Energy were used to measure the reliability of tracking results, so as to realize adaptive updating of tracking model and re-search of target location. Finally, for the correlation operation and complex matrix multiplication operation in the stage of training tracking detector, which were implemented based on FPGA parallelly to improve the real-time energy efficiency of the algorithm. The proposed acceleration algorithm was deployed on PYNQ-Z2 and verified based on OTB-2015 tracking data set. The tracking accuracy and real-time performance of the algorithm were 65.8% and 17.28 frame/s, respectively, compared with the original algorithm, the tracking accuracy and real-time performance were improved by 9.12% and 703.7%, respectively..
Infrared and Laser Engineering
- Publication Date: Feb. 25, 2022
- Vol. 51, Issue 2, 20210864 (2022)
Single-photon LiDAR imaging method based on sensor fusion network
Xiaoduo Jiang, Xiaochen Zhao, Tianyi Mao, Weiji He, and Qian Chen
LiDAR systems with active illumination obtain depth information of the scene using Single-Photon Avalanche Diode(SPAD) detectors to record the arrival time of reflected photons from the laser pulse. However, there is ambient light that interferes measurements during the detection period. Sensor fusion is one of the effLiDAR systems with active illumination obtain depth information of the scene using Single-Photon Avalanche Diode(SPAD) detectors to record the arrival time of reflected photons from the laser pulse. However, there is ambient light that interferes measurements during the detection period. Sensor fusion is one of the effective methods for single-photon imaging. Recently, many data-driven methods based on intensity-LiDAR fusion have achieved gratifying results, but most of them use the scanning LiDAR which has a slow depth acquisition speed. The advent of the SPAD array can overcome the limitation of frame rates. The SPAD array allows the collection of multiple returned photons at the same time, which accelerates the information collection process. However, the spatial resolution of SPAD array detectors is typically low, and the detection process is also interfered by the ambient light. Therefore, it is necessary to break the inherent limitation of the SPAD array through an algorithm to separate the depth information from the noise. In this paper, for the SPAD array detector with the array size of 32×32 pixel, a convolutional neural network was proposed, which could reconstruct high-resolution clean TCSPC histogram under the guidance of the intensity image. A multi-scale approach was adopted to extract input features, and the fusion of depth data and intensity data was further processed based on the attention mechanism in the network. In addition, a loss function combination suitable for the TCSPC histogram data processing network was designed, where the overall distribution of photons and the ordinal relationship between time bins in the temporal dimension could be simultaneously considered. The method proposed in this paper can successfully increase the depth spatial resolution by 4 times, and the efficacy of proposed method is verified on realistic data, which is superior to state-of-the-art methods qualitatively and quantitatively..
Infrared and Laser Engineering
- Publication Date: Feb. 25, 2022
- Vol. 51, Issue 2, 20210871 (2022)
Time-correlated multi-depth estimation of Single-photon lidar
Miao Wu, Yu Lu, Tianyi Mao, Weiji He, and Qian Chen
Single-photon lidar has been widely used to obtain depth and intensity information of a three-dimensional scene. For multi-surface targets, such as when the laser transmit through a translucent surface, the echo signal detected on one pixel may contain multiple peaks. Traditional methods cannot accurately estimate multSingle-photon lidar has been widely used to obtain depth and intensity information of a three-dimensional scene. For multi-surface targets, such as when the laser transmit through a translucent surface, the echo signal detected on one pixel may contain multiple peaks. Traditional methods cannot accurately estimate multi-depth images under low photon or relatively high background noise levels. Therefore, a time-correlated multi-depth estimation method was introduced. Based on the time correlation of the signal responses, a multi-depth fast denoising method was adopted to point cloud data, and could identify the signal responses of multiple surfaces from background noise on each pixel. Considering the Poisson distribution model of the signal response set, the spatial correlation between pixels was introduced through total variation (TV) regularization to establish a multi-depth estimation cost function. The fast-converging alternating direction method of multipliers (ADMM) was used to estimate the depth image from the cost function. Experimental results on a multi-depth target at a distance of about 1 km show that the root mean square error (RMSE) and signal to reconstruction-error ratio (SRE) of the depth image estimated by the proposed method can be at least 27.05% and 18.39% better than that of other state-of-the-art methods. In addition, the data volume of this method is reduced to 4% of the original. It is proved that this method can effectively improve the multi-depth image estimation of single-photon lidar with smaller memory requirements and computational complexity..
Infrared and Laser Engineering
- Publication Date: Feb. 25, 2022
- Vol. 51, Issue 2, 20210885 (2022)
Infrared remote sensing imaging simulation method for earth’s limb scene
Xueqi Chen, Minjie Wan, Yunkai Xu, Weixian Qian, Qian Chen, and Guohua Gu
Simulation of earth’s limb scene plays a key role in satellite infrared detection field. It is an important basis for long-range detection of high-speed airborne targets. In limb detection, the traditional infrared ocean simulation method based on three-dimensional ocean appearance and the calculation of radiation charSimulation of earth’s limb scene plays a key role in satellite infrared detection field. It is an important basis for long-range detection of high-speed airborne targets. In limb detection, the traditional infrared ocean simulation method based on three-dimensional ocean appearance and the calculation of radiation characteristics is not applicable, because the earth surface approximates a sphere. Also, the thickness and height of clouds have important influence on the calculation of infrared radiative transmission characteristics, where the method of considering the cloud as particle cluster would greatly reduce the speed of simulation. Therefore, the infrared remote sensing imaging simulation method for earth’s limb scene was established by conducting the infrared radiation model of ocean and cloud, the transformation relationship between earth-space coordinate system and infrared camera coordinate system, and the atmospheric transmission model. According to the components of scene, the ocean distribution model and multi-layer clouds distribution model were established respectively, and the infrared radiation model of the earth’s limb scene was established according to the infrared radiation and reflection characteristics of ocean and clouds. The infrared remote sensing simulation images of the earth’s limb scene under various observation angles were calculated by the conversion relationship between earth-space coordinate system and camera coordinate system, the theory of atmospheric transmission and the sensor effect. The simulation results show that the infrared image accord with the infrared radiation characteristics of earth’s limb scene. The average Laplacian sum of simulation images is 0.15, and the grayscale gradient average value of the images is 0.70..
Infrared and Laser Engineering
- Publication Date: Feb. 25, 2022
- Vol. 51, Issue 2, 20210896 (2022)
Dynamic simulation platform of infrared moving target trajectory reconstruction
Chengzhe Yao, Weilan Guo, Qian Chen, Guohua Gu, and Xiubao Sui
A dynamic simulation method for moving target recognition tracking and trajectory reconstruction in infrared thermal imaging video was proposed. Through the generation of virtual infrared images in the simulation environment and the basic model of imaging, a series of preprocessing was performed on the obtained images.A dynamic simulation method for moving target recognition tracking and trajectory reconstruction in infrared thermal imaging video was proposed. Through the generation of virtual infrared images in the simulation environment and the basic model of imaging, a series of preprocessing was performed on the obtained images. A dynamic simulation platform based on Gazebo and OpenCV was built in the air-to-air scene. The smooth constraint algorithm was used to reconstruct the real-time dynamic trajectory of the tracking target. The error analysis model was proposed, and the performance of the trajectory reconstruction algorithm and the effectiveness of the simulation platform were analyzed. The experimental results show that this method has good accuracy and robustness for the trajectory reconstruction of infrared moving target in air-to-air scenario, and basically has no constraint on the motion model of the target. At the same time, the simulation platform has high operation efficiency and real-time performance. The real-time dynamic simulation above 60 fps can be realized by the ordinary household computer, which meets the performance test and training requirements of the trajectory reconstruction algorithm. The core algorithm can also be migrated to the airborne computing platform to realize the real-time trajectory reconstruction in the real scene. The proposed dynamic simulation method of moving target trajectory reconstruction in single-channel thermal imaging video is of great significance to the research of three-dimensional trajectory reconstruction and dynamic ranging and positioning of space targets..
Infrared and Laser Engineering
- Publication Date: Feb. 25, 2022
- Vol. 51, Issue 2, 20210901 (2022)
Special Issue-Laser Technology and Its Application
Design of new-style driving and temperature control circuit for low power diode laser
Tao Yang, Wusen Li, and Wenjian Chen
In order to deal with the influence of the stability of the output optical power of diode laser (LD) on the flatness measurement accuracy of the strip laser flatness measuring instrument, a high stability diode laser constant current driving circuit, temperature control circuit and protective circuit were designed. FPGIn order to deal with the influence of the stability of the output optical power of diode laser (LD) on the flatness measurement accuracy of the strip laser flatness measuring instrument, a high stability diode laser constant current driving circuit, temperature control circuit and protective circuit were designed. FPGA was used as the system control core. Based on the principle of deep negative feedback, the accurate current control was achieved by the constant current driving circuit. The effective control of LD operating temperature was realized by temperature control circuit based on ADN8830. Driving current was slowly and linearly increased to preset value by improved slow-start circuit, and the slow-start time can be controlled precisely. High reliability and high security were realized by current limiting and electrostatic protection circuit. The results show that the driving current can be adjusted continuously from 0 to 75 mA, the adjustment accuracy can reach 0.025 mA, the short-term stability of current can reach 0.014% and the long-term stability can reach 0.016%. When the operating temperature is controlled at 25 ℃, the stability of the output optical power is 0.205%..
Infrared and Laser Engineering
- Publication Date: Feb. 25, 2022
- Vol. 51, Issue 2, 20210764 (2022)
Application of electrostatic jet-print technology in terahertz metasurface devices fabrication
Chunjie Feng, Xiaobo Zhu, Yanghui Wu, Chen Fu, Huiyu Chang, Yutao Yue, and Wenhua Gu
In recent years, terahertz technology has been developed rapidly, and terahertz devices based on metasurfaces have received widespread attention and have been applicated in many areas, including terahertz imaging, spectroscopy, biosensing, and so on. However, the fabrication of the terahertz metasurface devices is compIn recent years, terahertz technology has been developed rapidly, and terahertz devices based on metasurfaces have received widespread attention and have been applicated in many areas, including terahertz imaging, spectroscopy, biosensing, and so on. However, the fabrication of the terahertz metasurface devices is complex and costly, while electrostatic jet-print technology has the advantages of mask-free, low cost, high precision, and special-shaped curved surface conformability. In this work, a terahertz absorber based on the electrostatic jet-print technology was designed and fabricated, and characterized by using a reflective terahertz time-domain spectrometer (THz-TDS). The result shows an absorption rate greater than 90% in the range of 0.098-0.353 THz, which is basically consistent with the simulation result. In addition, a terahertz polarization converter was also designed. The conversion efficiency in the range of 0.167-0.355 THz is greater than 95%, while the relative bandwidth is about 72%. The fabrication process conditions of the designed terahertz polarization converter was then analyzed, and the electrostatic jet-print technology was verified to be a promising fabrication method. The research results show that the electrostatic jet-print technology has broad application prospects in the fabrication of terahertz metasurface devices..
Infrared and Laser Engineering
- Publication Date: Feb. 25, 2022
- Vol. 51, Issue 2, 20210878 (2022)
Perforation effect of CW laser irradiation on aluminum alloy under subsonic flow
Xiaoteng Zhang, Zewen Li, Yiqing Zhou, and Zhonghua Shen
The perforation effect of laser irradiated target is different under different airflow velocity. The perforation effect of 7075 aluminum alloy irradiated by 1070 nm CW laser under subsonic airflow(0-0.7 Ma) was experimentally studied. The temperature history, perforation time, perforation aperture and surface morphologThe perforation effect of laser irradiated target is different under different airflow velocity. The perforation effect of 7075 aluminum alloy irradiated by 1070 nm CW laser under subsonic airflow(0-0.7 Ma) was experimentally studied. The temperature history, perforation time, perforation aperture and surface morphology of the center point of the aluminum alloy were analyzed. The results show that under the same airflow velocity, with the increase of the incident laser power density, the temperature rise rate of the aluminum alloy surface increases and the equilibrium temperature of the final melting layer increases. The perforation time of aluminum alloy decreases exponentially; the increase rate of pore size decreases exponentially. At the same laser power density, with the increase of airflow velocity, the perforation time of aluminum alloy increases first and then decreases to a stable and then increases. Both the removal rate of melt and the cooling effect of airflow lead to the longest perforation time near 0.1Ma and the shortest perforation time near 0.3Ma. The perforation time of 0.6 Ma is roughly equal to that of 0Ma about 5.5 s. With the increase of airflow velocity, the cooling effect increases, and there is no perforation in the aluminum alloy after 0.7Ma. Convection cooling leads to rapid condensation of the melt, and the removed melt concentrates in the downstream area of the airflow..
Infrared and Laser Engineering
- Publication Date: Feb. 25, 2022
- Vol. 51, Issue 2, 20210883 (2022)
Performance test of solar cell under laser energy transmission and signal transmission
Zhiyu Sun, Jian Lu, Hongchao Zhang, Guangji Li, and Zhijian Xie
Laser wireless energy transmission has potential applications prospects in supplying energy for long-distance equipment. And laser wireless communication with energy transmission has important application value. For GaAs solar cell, the laser wireless communication performance of the laser energy transmission system waLaser wireless energy transmission has potential applications prospects in supplying energy for long-distance equipment. And laser wireless communication with energy transmission has important application value. For GaAs solar cell, the laser wireless communication performance of the laser energy transmission system was tested during wireless energy transmission. A wavelength of 808 nm laser to achieve the energy transmission of the GaAs solar cell was used in the experiment, and a wavelength of 650 nm laser was used as the signal transmission. The output characteristics of GaAs solar cell under three conditions of single energy transmission, single signal transmission and energy and signal simultaneous transmission were tested respectively. The results show that when the single energy is transmitted, the performance of the solar cell is closely related to the laser power density. In the range of 54.9-90 mW/cm2 of the laser power density, the maximum energy conversion efficiency is 46.6%; when the single signal is transmitted, by measuring the frequency response of the system, the 3 dB bandwidth of the GaAs solar cell is about 3.7 kHz. And by designing the amplifier circuit, the communication performance of the system is improved and the output waveform is optimized, so that the transmission rate of the system is increased from 10 kbps to 240 kbps, and the output voltage peak-to-peak reaches 7.2 V. Finally, the achievable signal transmission rates under different laser intensities were measured experimentally. When the laser power density is 59.5 mW/cm2, the signal transmission rate of 140 kbps is achieved, so that the laser charging system can perform signal transmission under wireless energy transmission..
Infrared and Laser Engineering
- Publication Date: Feb. 25, 2022
- Vol. 51, Issue 2, 20210888 (2022)
Evolution mechanism of transient optical properties of ultrafast laser-induced monocrystalline silicon
Xiaojie Liao, Suying Lin, and Bing Han
The evolution pattern of the transient optical properties on the surface of monocrystalline silicon materials under the action of lasers with different pulse widths and different energy densities in the sub-picosecond to picosecond range was studied. This research was based on a dual temperature equation, carrier numbeThe evolution pattern of the transient optical properties on the surface of monocrystalline silicon materials under the action of lasers with different pulse widths and different energy densities in the sub-picosecond to picosecond range was studied. This research was based on a dual temperature equation, carrier number density model, that considered the latent heat of phase transition. The carrier temperature, lattice temperature, permittivity, and the number density of excited carriers during laser irradiation were calculated, energy transfers processes from photons to electrons and electrons to phonons was simulated. In the end, the variation results of refractive index and extinction coefficient of the monocrystalline silicon surface were obtained. This result helps to reveal the evolution mechanism of the transient optical properties of monocrystalline silicon materials under the irradiation of ultrashort pulse lasers in the sub-picosecond to picosecond pulse width range. Theoretical calculations show that if a single laser pulse cannot melt monocrystalline silicon, the effects of different laser energy densities and laser pulse widths on the minimum refractive index and extinction coefficient are minimal. In the laser energy density range from 0.3 J/cm2 to 0.4 J/cm2, the minimum refractive index change is less than 0.5% per 0.01 J/cm2 change in energy density. Suppose a single laser pulse can melt monocrystalline silicon. In that case, different laser energy densities and pulse widths have different degrees of influence on the silicon surface's refractive index and extinction coefficient. This research results can provide some theoretical guidance for the processing and surface modification of monocrystalline silicon materials based on ultrashort pulse laser..
Infrared and Laser Engineering
- Publication Date: Feb. 25, 2022
- Vol. 51, Issue 2, 20210907 (2022)
Development and prospect of fiber grating in high-power continuous fiber laser
Hua Shen, Rihong Zhu, and Yinxu Bian
At present, the applications of fiber gratings in high-power fiber lasers mainly include two aspects, be used as cavity mirrors and to suppress nonlinear effects. The development of fiber gratings as cavity mirror was discussed firstly, and then the applications of special structure fiber gratings with nonlinear effectAt present, the applications of fiber gratings in high-power fiber lasers mainly include two aspects, be used as cavity mirrors and to suppress nonlinear effects. The development of fiber gratings as cavity mirror was discussed firstly, and then the applications of special structure fiber gratings with nonlinear effects suppression function was focused on. The stimulated Raman scattering and stimulated Brillouin scattering suppression method were introduced based on tilted fiber Bragg grating in detail. And the feasibility of suppressing stimulated Raman scattering by long-period fiber grating was also discussed. Further, a novel method of suppressing self-phase modulation or four-wave mixing by utilizing phase-shifted long-period fiber grating was presented. Finally, a prospect of the applications of fiber gratings in high-power fiber laser was provided. Higher power durability and longer wavelength were the definite development directions. And also considered that the femtosecond laser lithography technology, cascaded fiber grating that can suppress multiple nonlinear effects, and polarization control technology based on special structure fiber gratings will become a new research hotspot..
Infrared and Laser Engineering
- Publication Date: Feb. 25, 2022
- Vol. 51, Issue 2, 20210908 (2022)
Analysis and treatment of thermal effects in 10 kW-level optic switch
Zhijie Li, Qingqing Kong, Mingdong Zhang, Ziheng Jing, Yinxu Bian, Hua Shen, and Rihong Zhu
The optic switch can output the single laser beam output by the fiber laser through multiple channels to realize the "one device and multiple applications" of the laser. It is the key device of modern laser intelligent manufacturing. As the power of the optic switch is up to 10 kW level, thermal effects happeThe optic switch can output the single laser beam output by the fiber laser through multiple channels to realize the "one device and multiple applications" of the laser. It is the key device of modern laser intelligent manufacturing. As the power of the optic switch is up to 10 kW level, thermal effects happen easily in the coupling system, which affects the performance of the optic switch. In order to solve the problem of effective control of thermal effects, ensure the efficient coupling and high-quality output of the 10 kW-level optic switch, the physical mechanism of thermal effects in the coupling system was studied by finite element analysis. And a novel method based on water circulation and flow around cooling was proposed to control the thermal effects of the system. Through the verification of serial 10 kW-level experiments, it indicated that under the guarantee of the method proposed in this paper, the high-power optic switch was able to carry 10 kW-level power for a long time. The coupling efficiency was maintained above 98%. The thermal aberration of the system was suppressed, and the stability of the beam quality of the laser output by the optic switch can be guaranteed. This study provides an effective means for the analysis and treatment of thermal effects in the high-power laser system..
Infrared and Laser Engineering
- Publication Date: Feb. 25, 2022
- Vol. 51, Issue 2, 20210909 (2022)
Nanosecond laser-induced periodic structures on polyimide film
Suying Lin, Xiaojie Liao, and Bing Han
Laser-induced periodic surface structures (LIPSS) were created by a 355 nm linearly polarized laser with the pulse duration of 7 ns and the pulse repetition rate of 1 Hz on polyimide films. The influences of different laser parameters on the morphology of the formed LIPSS were investigated. It is found that there is a Laser-induced periodic surface structures (LIPSS) were created by a 355 nm linearly polarized laser with the pulse duration of 7 ns and the pulse repetition rate of 1 Hz on polyimide films. The influences of different laser parameters on the morphology of the formed LIPSS were investigated. It is found that there is a certain fluence threshold and pulse number threshold for the generation of periodic structure. When the laser fluence
Infrared and Laser Engineering
- Publication Date: Feb. 25, 2022
- Vol. 51, Issue 2, 20210911 (2022)
Light beam induced current mapping to characterize damage characteristics of silicon solar cell irradiated by continuous-wave laser
Jian Lu, Zhijian Xie, and Hongchao Zhang
Aiming at the damage characteristics of silicon solar cells irradiated by continuous-wave (CW) laser, a light beam induced current (LBIC) mapping system was applied to characterize the damage characteristics of solar cells, and the damage characteristics were analyzed. A 1 070 nm CW laser was used to focus on the surfaAiming at the damage characteristics of silicon solar cells irradiated by continuous-wave (CW) laser, a light beam induced current (LBIC) mapping system was applied to characterize the damage characteristics of solar cells, and the damage characteristics were analyzed. A 1 070 nm CW laser was used to focus on the surface of silicon solar cell to induce damage. A LBIC system was use to obtain the photocurrent spatial distribution of the laser irradiation area of solar cell to analyze the damage. In order to characterize the damage of solar cell at different depths, the LBIC system used 650 nm and 980 nm lasers as probe light sources respectively. The results show that when 1 070 nm CW laser irradiates the non-finger part of a silicon solar cell, the solar cell damage first occurs inside; with the increase of power density, there is an invalid region inside the solar cell before its surface melts. When the laser irradiates fingers, the finger will melting. It will result in a decrease in the photocurrent at the side of the irradiated position which away from the electrode lead. In severe cases, the solar cell will have cracks which perpendicular to fingers, and the cracks will invalidate the cell on the side away from the electrode lead. The results can provide a reference for the research on the damage mechanism of CW laser irradiated solar cells..
Infrared and Laser Engineering
- Publication Date: Feb. 25, 2022
- Vol. 51, Issue 2, 20220022 (2022)
Special Issue-Precision Optical Metrological Testing
Application of binary search and compressive sensing for rapid detection of defects inside laser ultrasound
Qiang Sun, Lunan Dai, Kaining Ying, and Chenyin Ni
Laser ultrasonic inspection technology has a broad application prospect in the field of nondestructive testing due to its non-contact, high sensitivity and high spatial resolution characteristics. However, its practicality is limited by the long scanning time required for large area sweeping at high spatial resolution.Laser ultrasonic inspection technology has a broad application prospect in the field of nondestructive testing due to its non-contact, high sensitivity and high spatial resolution characteristics. However, its practicality is limited by the long scanning time required for large area sweeping at high spatial resolution. To address the above problems, a binary search method was proposed to improve the detection speed, and a compressed sensing algorithm was used to represent the detected laser ultrasound signal as a linear weighted combination of wavelet bases, and finally the entire range to be measured was restored from the less real laser ultrasound signal obtained by binary search. Further, a laser ultrasonic scanning detection device for internal defects was built, the laser excitation of ultrasound was achieved by using a pulsed laser, the non-contact detection of ultrasound was achieved by Doppler vibrometer, and a fast detection of internal defects by laser ultrasound based on binary search and compression perception was achieved by moving the sample at a fixed excitation detection distance. The technique proposed in this paper not only has the characteristics of laser ultrasound such as non-contact, high sensitivity and high spatial resolution, but also can improve the detection efficiency. The experimental results show that it takes 6 min to determine the defect location on a 120 mm×30 mm×8 mm aluminum plate, compared with 14 min for point-by-point sweeping, which shortens the time required for in vivo defect localization.
Infrared and Laser Engineering
- Publication Date: Feb. 25, 2022
- Vol. 51, Issue 2, 20210810 (2022)
Review of design methodology for starting-point of freeform surface imaging optical system
Ningyan Xu, Lu Chen, Jing Huang, Yutong Zou, Qun Yuan, and Zhishan Gao
Freeform surface provides more degrees of freedom for optical system and stronger capability of aberration correction to break the limitation of traditional surface characterization and system structure, which helps engineer to achieve large field of view, large aperture, miniaturization, and lightweight optical systemFreeform surface provides more degrees of freedom for optical system and stronger capability of aberration correction to break the limitation of traditional surface characterization and system structure, which helps engineer to achieve large field of view, large aperture, miniaturization, and lightweight optical system design while improving the imaging quality. A favorable starting-point of freeform surface imaging optical system design can release the potential of freeform surface to correct aberration and improve the efficiency of system design. Comparing to coaxial optical systems, few examples can be referred to for freeform surface imaging optical system and theory for freeform is not perfect yet. Therefore, how to construct and solve a favorable starting-point of freeform surface imaging optical system is one of the frontier issues in the field of optical design. Based on the research experience of author team for many years, this review summarizes the current design methods of freeform surface imaging optical system design, and divides them into disturbing coaxial system method, directly solving method, and expending field or aperture method and stitching and fusion method, according to the construction principle of freeform surface. Finally, the problems to be solved in the design starting-point for freeform surface imaging optical system are analyzed and summarized..
Infrared and Laser Engineering
- Publication Date: Feb. 25, 2022
- Vol. 51, Issue 2, 20210852 (2022)
System error calibration for Φ300 mm vertical Fizeau interferometer based on liquid reference
Zhiyao Ma, Lei Chen, Donghui Zheng, Haiying Ma, Ruokun Li, Chen Huang, and Chenhui Hu
In high-precision interference detection, the calibration of interferometer system errors was important. According to the structural characteristics of the vertical Fizeau interferometer, the liquid reference plane was used as a reference to compensate and calibrate the self-weight deformation and clamping deformation In high-precision interference detection, the calibration of interferometer system errors was important. According to the structural characteristics of the vertical Fizeau interferometer, the liquid reference plane was used as a reference to compensate and calibrate the self-weight deformation and clamping deformation of the reference flat crystal, and calibrate its system error. Theoretically, the curvature of the liquid surface and the radius of the earth were the same, which can be regarded as a plane reference to calibrate the system error of the vertical structure interferometer. For the Φ300 mm vertical Fizeau interferometer, the influence of different liquid viscosity, thickness, interference cavity length and temperature was studied, and a reliable liquid reference plane reference was constructed. Through the liquid reference plane, the interferometer was guided to refer to the installation and calibration of the reference flat crystal, and its system error was compensated. The accuracy of the interferometery reached 0.035λ, which was better than λ/25. In order to further verify the reliability and accuracy of the liquid reference plane, repeatability experiments were carried out, and the liquid reference plane of Φ400 mm and Φ450 mm were used for comparison test. The deviation of the two calibration results was better than λ/100 (6 nm). The reliability and accuracy of the liquid reference plane were verified..
Infrared and Laser Engineering
- Publication Date: Feb. 25, 2022
- Vol. 51, Issue 2, 20210880 (2022)
Measurement of translucent coating thickness based on pulsed thermography
Tao He, Zhonghua Shen, Fei Chen, and Li Chen
To measure the thickness of translucent coating quickly and accurately, the method based on pulse thermography was proposed. A simplified theoretical semi-infinite model of pulsed infrared heating conduction for translucent coating and a two-layer physical model of pulsed infrared heating for translucent coatings were To measure the thickness of translucent coating quickly and accurately, the method based on pulse thermography was proposed. A simplified theoretical semi-infinite model of pulsed infrared heating conduction for translucent coating and a two-layer physical model of pulsed infrared heating for translucent coatings were established. The theoretical analysis and numerical results show that the thickness of the translucent coating is linearly proportional to the peak time of the surface temperature in logarithmic coordinates, through which the thickness of the translucent coating can be derived without spraying black ink on the surface of the sample to avoid the effect of translucency. A translucent coating specimen with continuously varying thickness was fabricated and tested with a flash thermographic system. The result of the measured thicknesses is within 5% of the actual values. It demonstrates that the technique has the potential for fast and non-contact measurement of the thickness for translucent coatings..
Infrared and Laser Engineering
- Publication Date: Feb. 25, 2022
- Vol. 51, Issue 2, 20210890 (2022)
Research on 3-D vision measurement technology based on line structured light rotating scanning and laser stripe repair
Yunjing Ji, Siyue Du, Yang Song, and Zhenhua Li
Non-contact 3-D vision measurement is widely used in industrial manufacturing quality inspection. Aiming at the application scenario of industrial metal parts detection, a 3-D vision measurement scheme based on line structured light rotating scanning and laser stripe repair was proposed. Firstly, through the computer vNon-contact 3-D vision measurement is widely used in industrial manufacturing quality inspection. Aiming at the application scenario of industrial metal parts detection, a 3-D vision measurement scheme based on line structured light rotating scanning and laser stripe repair was proposed. Firstly, through the computer vision technology based on line structured light projection, the line structured light rotating scanning vision subsystem was designed, and the industrial camera, line structured light plane and rotating scanning central axis were calibrated; Then, aiming at the problem of missing data in the low gray area of the collected laser stripe image, a laser stripe center line extraction algorithm based on adaptive gray enhancement of the missing area was proposed, which effectively repaired the line structured light projection stripes of the tested parts; At the same time, using the line structured light 3-D vision measurement scheme proposed in this paper, the accuracy of the measurement system was evaluated by reconstructing the surface point cloud of the standard bat and calculating the diameter and spacing of the two balls. The accuracy of the measurement system was better than 0.06 mm; Finally, the shape of the outer contour of the metal hub was measured, and the maximum radius of the outer contour of the hub was calculated through the repeatability experiment. It is verified that the repeatability error is better than 0.03%. The experimental results show that this method can realize the 3-D measurement of industrial metal parts without damage, high efficiency and high precision, and make up for the defects of the contact 3-D measurement method..
Infrared and Laser Engineering
- Publication Date: Feb. 25, 2022
- Vol. 51, Issue 2, 20210894 (2022)
Design of multi-channel LED constant current driver in radiometric calibration light source
Haixing Li, Xiubao Sui, Zheyi Yao, Qian Chen, and Guohua Gu
In order to deal with the influence of the current stability controllability of LED array in integrating sphere radiometric calibration light source system on the spectrum matching degree at the opening of integrating sphere, a multi-channel, high-precision and high-stability LED current driving circuit was designed. TIn order to deal with the influence of the current stability controllability of LED array in integrating sphere radiometric calibration light source system on the spectrum matching degree at the opening of integrating sphere, a multi-channel, high-precision and high-stability LED current driving circuit was designed. This circuit was a voltage controlled constant current driving circuit, which can realize the linear control of LED array driving current by means of analog dimming. It took FPGA as the control core, read and wrote the AD5371 chip register through SPI interface, and realized high precision control of LED driving current through AD5371 digital-to-analog conversion circuit. The temperature control of LED array was realized based on circulating liquid refrigeration equipment and sink refrigeration base. The experimental results show that the current of LED array can be continuously and linearly adjustable in the range of 0-1 050 mA, and the current adjustment accuracy can reach 0.14% of the range. When the LED lamp holder temperature is controlled at 10 ℃, the LED output light spectral stability is 0.2%..
Infrared and Laser Engineering
- Publication Date: Feb. 25, 2022
- Vol. 51, Issue 2, 20210902 (2022)
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