In this paper, we construct a laser 3D imaging simulation model based on the 3D imaging principle of electro-optical crystal modulation. Unlike the traditional 3D imaging simulation method, this paper focuses on the laser scattering characteristics of the target scene. To accurately analyze and simulate the scattering characteristic model of the target under laser irradiation, we propose a BRDF (Bidirectional Reflectance Distribution Function) model fitting algorithm based on the hybrid BBO-Firefly model, which can accurately simulate the laser scattering distribution of the target at different angles.
View Article and Find Full Text PDFThe design of intelligent expressway transportation system based on the Internet of Things is studied to improve the safety, travel experience, and operation management of expressway. The characteristics of the Internet of Things and cloud computing technology and its application on the expressway are analyzed, and the system design requirements of expressway intelligent transportation are understood. Besides, the overall architecture of the system is studied and designed.
View Article and Find Full Text PDFA method for enhancing the resolution of 3D imaging reconstruction by employing the polarization modulation of electro-optical crystals is proposed. This technique utilizes two polarizers oriented perpendicular to each other along with an electro-optical modulation crystal to achieve high repetition frequency and narrow pulse width gating. By varying the modulation time series of the electro-optical crystal, three-dimensional gray images of the laser at different distances are acquired, and the three-dimensional information of the target is reconstructed using the range energy recovery algorithm.
View Article and Find Full Text PDFLiDAR offers a wide range of uses in autonomous driving, remote sensing, urban planning, and other areas. The laser 3D point cloud acquired by LiDAR typically encounters issues during registration, including laser speckle noise, Gaussian noise, data loss, and data disorder. This work suggests a novel Student's t-distribution point cloud registration algorithm based on the local features of point clouds to address these issues.
View Article and Find Full Text PDFPerovskite nanocrystals are advantageous for interfacial passivation of perovskite solar cells (PSCs), but the insulating long alkyl chain surface ligands impede the charge transfer, while the conventional ligand exchange would possibly introduce surface defects to the nanocrystals. In this work, we reported novel in situ modification of CsPbBr nanocrystals using a short chain conjugated molecule 2-methoxyphenylethylammonium iodide (2-MeO-PEAI) for interfacial passivation of PSCs. Transmission electron microscopy studies with atomic resolution unveil the transformation from cubic CsPbBr to Ruddlesden-Popper phase (RPP) nanocrystals due to halogen exchange.
View Article and Find Full Text PDFThe range-gated laser imaging instrument can capture face images in a dark environment, which provides a new idea for long-distance face recognition at night. However, the laser image has low contrast, low SNR and no color information, which affects observation and recognition. Therefore, it becomes important to convert laser images into visible images and then identify them.
View Article and Find Full Text PDFNovel methylthiophene/benzo[]thiophene perylene bisimide thiol-precursors that would generate thiols via a green-light-induced (λ = 530 nm, φ = 0.33) photorearrangement are presented herein. The "no-wash", photoreleased thiols thus enabled a subsequent thiol-ene click ligation with electron-deficient substrates.
View Article and Find Full Text PDFIn order to achieve wide field-of-view, high-resolution LIDAR, a gating imaging structure combining an electro-optic crystal and an electron multiplication CCD is constructed. According to the index ellipsoid theory, a 3D ray tracing model is established to explore the principle of electro-optic modulation. The field-of-view and interference intensity distribution of the LiNbO3(LN) crystal electro-optic modulation are studied by using the proposed model.
View Article and Find Full Text PDFSensors (Basel)
September 2022
This paper proposes a photoelectric target detection algorithm for NVIDIA Jeston Nano embedded devices, exploiting the characteristics of active and passive differential images of lasers after denoising. An adaptive threshold segmentation method was developed based on the statistical characteristics of photoelectric target echo light intensity, which effectively improves detection of the target area. The proposed method's effectiveness is compared and analyzed against a typical lightweight network that was knowledge-distilled by ResNet18 on target region detection tasks.
View Article and Find Full Text PDFCycleGAN is widely used in various image translations, such as thermal-infrared-visible-image translation, near-infrared-visible-image translation, and shortwave-infrared-visible-image translation. However, most image translations are used for infrared-to-visible translation, and the wide application of laser imaging has an increasingly strong demand for laser-visible image translation. In addition, the current image translation is mainly aimed at frontal face images, which cannot be effectively utilized to translate faces at a certain angle.
View Article and Find Full Text PDFAiming at the application of laser active imaging detection technology, this paper studied the beam homogenization system of a semiconductor laser based on a homogenizing pipe. Firstly, the principle of the homogenizing pipe was introduced. Secondly, the homogenization effect, which was influenced by several geometric parameters (aperture size, length, and taper) of the homogenizing pipe using the optical design software, was simulated for the fiber-coupled semiconductor laser.
View Article and Find Full Text PDFThe widely used carbamazepine (CBZ) is one of the most persistent pharmaceuticals and suffers insufficient removal efficiency by conventional wastewater treatment. A synthesized Co-based perovskite (LaCoO) was used to activate peroxymonosulfate (PMS) in order to degrade CBZ. Results showed that LaCoO exhibited an excellent performance in PMS activation and CBZ degradation at neutral pH, with low cobalt leaching.
View Article and Find Full Text PDFGlobal registration is an important step in the three-dimensional reconstruction of multi-view laser point clouds for moving objects, but the severe noise, density variation, and overlap ratio between multi-view laser point clouds present significant challenges to global registration. In this paper, a multi-view laser point cloud global registration method based on low-rank sparse decomposition is proposed. Firstly, the spatial distribution features of point clouds were extracted by spatial rasterization to realize loop-closure detection, and the corresponding weight matrix was established according to the similarities of spatial distribution features.
View Article and Find Full Text PDFThis paper utilizes the optical cross section (OCS) to characterize the optical scattering characteristics of a space target under the conditions of Sun lighting. We derive the mathematical expression of OCS according to the radiometric theory, and put forward a fast visualization calculation method of complex space targets' OCS based on an OpenGL and 3D model. Through the OCS simulation of Lambert bodies (cylinder and sphere), the computational accuracy and speed of the algorithm were verified.
View Article and Find Full Text PDFGuang Pu Xue Yu Guang Pu Fen Xi
September 2011
A novel kind of carbon nanotubes/titanium dioxide (CNTs/TiO2) composite photocatalyst was prepared by a modified sol-gel method in which the nanoscaled TiO2 particles were uniformly deposited on the CNTs modified with poly(vinyl pyrrolidone) (PVP). The composites were characterized by a range of analytical techniques including high resolution transmission electron microscopy (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The results show the successful covering of the CNTs with PVP, forming core-shell structure.
View Article and Find Full Text PDFGuang Pu Xue Yu Guang Pu Fen Xi
August 2011
Hydrous oxides of cerium, aluminum, nickel and copper were prepared by alkaline precipitation method. Langmuir adsorption isotherm was studied and specific surface area was measured by BET method through N2 adsorption-desorption process. IR characterization of hydrous metal oxides before and after fluoride adsorption was also studied.
View Article and Find Full Text PDFGuang Pu Xue Yu Guang Pu Fen Xi
January 2011
Ferrocene was used as a catalyst, and xylene as carbon source. Chemical vapor deposition method was used to synthesize carbon nanotubes (CNTs). The CNTs were treated by oxidation method with concentrated nitric acid.
View Article and Find Full Text PDF