最新刊期
- 摘要：Morphological parameters such as the diameter and bifurcation of retinal blood vessels serve as important references for clinical diagnosis， and accurate segmentation of microvessels is essential for the early diagnosis of related diseases. Existing segmentation methods often suffer from blurred edges， fractured topological structures， and inadequate fusion of thick and thin vessel features in microvessel detection.To address these issues， this paper proposes a dual-branch segmentation network. We adopt IterMiUnet as the coarse segmentation branch to extract global vascular features， and introduce Haar wavelet prior to enhance the frequency-domain representation and edge details of microvessels. Since coarse segmentation struggles to identify weak boundaries and fractured vessels accurately， we take uncertain pixels from coarse segmentation probability as prior guidance， enabling the fine segmentation model to focus on these challenging regions and boost segmentation precision.A dual-scale probability encoding fusion mechanism combined with temperature scaling and background suppression is also constructed. The outputs of coarse segmentation are optimized using fine segmentation results to realize adaptive fusion and reduce background interference. Experiments on DRIVE， CHASE_DB1 and STARE datasets demonstrate that the proposed algorithm outperforms mainstream methods， with F1 scores of 0.825 7， 0.836 0 and 0.835 7 respectively. It achieves stable and reliable performance， and can effectively capture microvascular details while maintaining the topological integrity of blood vessels.关键词：computer vision;deep learning;image segmentation;retinal blood vessels0|0|0更新时间：2026-07-30
- 摘要：Owing to their unique physical properties， liquid crystals have evolved into an important category of optical modulation devices， and Dye-Doped Liquid Crystal （DDLC） serves as one critical technical route to achieve electrically tunable light intensity modulation. To tackle the lack of quantitative theoretical correlation between optical rotation and the coupling effect of dye anisotropic absorption in Twisted Nematic （TN） DDLC devices， this work established a complex Jones matrix theoretical model for TN liquid crystals incorporating absorption losses， derived an analytical formula of dark-state transmittance for the light-modulating structure including single-layer TN cells integrated with a polarizer （TN+P）， and systematically investigated how twist angles， liquid crystal cell gaps， dye absorption coefficients and birefringence regulate devices’ optical performance； closed-loop verification integrating theoretical calculation， Techwiz LCD 1D optical simulation and sample fabrication was carried out using commercial positive DDLC mixtures as the core functional material， and theoretical calculations revealed that twisted liquid crystal structures alter polarization evolution along the optical path， break the matching conditions for efficient dye absorption and thus induce dark-state light leakage， while high-birefringence materials enhance optical rotation and boost light absorption efficiency， with software simulations and contrast ratio viewing angle distributions further confirming that twist angles increase dark-state transmittance and degrade device performance. Samples with cell gaps of 5， 8 and 10 μm and twist angles ranging from 180° to 360° were experimentally fabricated， and measured results demonstrated that the TN+P device with a 10 μm cell gap and a 0° twist angle achieves optimal light-shielding performance with a dark-state transmittance as low as 1.03%， all 8 μm devices exhibit millisecond-scale fall times， and the 90° twisted structure exhibited the slowest fall time governed by the twist elastic torque. This study refines the quantitative optical analysis system for twisted DDLC， providing a complete theoretical basis and experimental support for the structural design of DDLC-based smart windows and optical shutters with excellent light-shielding performance and continuous electrical tunability.关键词：dye-doped liquid crystal;twisted nematic;complex Jones matrix;transmittance modulation;optical simulation0|0|0更新时间：2026-07-30
- 摘要：Overdriving technology （OD） accelerates the response of liquid crystal （LC） devices but frequently induces significant optical bounce （OB）. Based on the Ericksen-Leslie continuum theory， this paper establishes a finite-difference model and reveals that the physical origin of OB lies in the asynchronous relaxation of LC directors within the confined space. By simulating the spatial distributions of director tilt angle and angular velocity， it is found that the interlayer angular velocity difference induced by overdrive is the microscopic source triggering OB. Focusing on the cell gap （5~15 µm） as a key geometric parameter， this paper reveals the evolutionary laws of asynchronous relaxation constrained by cell gap and its regulatory mechanism on the asymmetric OB characteristics under overdrive modes. The simulated and experimental results exhibit consistent trends. The results demonstrate that， under a constant overdrive voltage difference， overshoot and undershoot driving exhibit opposite relaxation trends： during undershoot driving， the elastic restoring force decays quadratically with cell gap， making it difficult for thicker cells to suppress interlayer asynchronous relaxation； the bounce depth ratio （BDR） increases from approximately 2% at 5 µm to over 20% at 15 µm. During overshoot driving， the internal electric field attenuates linearly with cell gap， weakening the interlayer angular velocity difference at its source； the BDR decreases from 15.7% to below 4%. After eliminating the interference of driving field attenuation through constant electric field control experiments and constant average tilt-angle simulations， the BDR for both modes increases monotonically with cell gap. From the perspective of asynchronous relaxation， this study clarifies the dominant role of cell gap in governing asymmetric OB， providing a theoretical basis for the dimensional optimization of high-speed LC devices.关键词：overdrive technology;optical bounce;angular velocity difference;asynchronous relaxation0|0|0更新时间：2026-07-30
- 摘要：Residual stress in optical glass induces stress-induced birefringence， resulting in phase retardation of polarized light. The phase retardation is an important parameter for quantitative residual stress characterization. To address the instability of phase determination in conventional polarization phase retrieval methods over a large phase retardation range， a polarization imaging measurement method for optical glass residual stress based on liquid crystal device phase compensation is proposed. A liquid crystal device is introduced into the polarization optical path， and the compensation phase is continuously adjusted by the driving voltage to achieve phase matching between the liquid crystal compensation and the phase retardation of the tested optical glass. The difference between the image grayscale and the background grayscale is used as the evaluation metric， and the optimal compensation state is determined by minimizing the grayscale difference， thereby obtaining the phase retardation of the optical glass. The residual stress is then determined based on the stress-optic law. Experimental results show that the optimal compensation state is achieved at a driving voltage of 3.8 V， corresponding to a residual stress of 36.235 nm/cm. Compared with the result obtained using the standard polarization phase retrieval method （34.128 nm/cm）， the proposed method exhibits a relative deviation of 6.17%， indicating good consistency between the two results and validating the effectiveness of the proposed method.关键词：optical glass;residual stress;phase retardation;liquid crystal device;phase compensation;polarization imaging1|0|0更新时间：2026-07-30
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Zwitterionic lyotropic liquid-crystalline ion conductors featuring ordered hydrophilic channels AI导读
摘要：In this study， ion conductors were constructed through lyotropic liquid-crystal self-assembly using a polymerizable zwitterionic amphiphile， SB11-1MA， and aqueous LiCl solutions as the model system. By varying the SB11-1MA content and the concentration of the LiCl aqueous solution， the room-temperature phase behavior and ion-transport properties of the liquid-crystalline system were systematically investigated. Polarized optical microscopy （POM） and small-angle X-ray scattering （SAXS） results show that this system forms a normal hexagonal phase （H₁）. The introduction of LiCl shifts the H₁ phase region toward lower SB11-1MA contents and broadens the phase window. Electrochemical impedance spectroscopy （EIS） measurements reveal that the liquid-crystalline material exhibits a maximum room-temperature ionic conductivity of 1.1 × 10-3 S cm-1， and that its ion-transport behavior is jointly governed by ion concentration and the structure of the hydrophilic channels.关键词：Lyotropic liquid crystal;zwitterionic amphiphile;ion transport;normal hexagonal phase13|5|0更新时间：2026-07-16 -
Distortion-Free 3D rendering and display method using perspective transformation for curved screens AI导读
摘要：To eliminate geometric distortion on self-luminous curved screens caused by physical curvature， enabling viewers to see the rendered scene as equivalent to directly viewing the 3D scene without the screen.The curved screen is approximated as multiple planar segments. Using perspective transformation and the known viewpoint， the object-image relationship is reversed， and the perspective matrix computes images on each segment. Adaptive partitioning minimizes the 2D mean square error （Loss） between the curve and fitted polyline via the Adam algorithm. Stitching boundaries are smoothed with overlapping regions Δw and linear interpolation.Blender 4.0 simulations show the proposed method achieves a PSNR of 13.23 dB， which is 5.58 dB higher than direct rendering （7.65 dB）， exceeding the 12 dB distortion threshold. Using m=30 planar segments balances high PSNR and computational cost.This method significantly reduces distortion on curved screens and applies to large outdoor curved LEDs and flexible consumer electronics， offering a feasible path for glasses-free 3D on curved displays.关键词：3D rendering;curved screen;distortion-free display;perspective transformation;region partition19|3|0更新时间：2026-07-16 - 摘要：The efficient silica coating of quantum dots （QDs） has long been hindered by the fluorescence quenching problem caused by traditional surfactants. The fundamental reason lies in the competitive adsorption of the hydrophobic chains of surfactants and the surface ligands of QDs， resulting in ligand detachment and the formation of surface defect states.This paper proposes a "soap-free" reverse microemulsion method （Surfactant-Free Reverse Microemulsion， SFRM）， completely eliminating traditional amphiphilic surfactants and using isopropanol/ethylene glycol as dual cosolvents to form a stable interface film at the oil-water interface. A nano-reactor without traditional amphiphilic surfactants is constructed， successfully achieving efficient silica coating of CdSe/ZnS quantum dots.Systematic studies show that the photoluminescence quantum yield （PLQY） of QD@SiO2 after coating remains at 78.7%~80.6% （average 79.6 ± 0.78%）， which is much higher than 26% of the traditional Triton X-100 method. Transmission electron microscopy （TEM） shows that the thickness of the SiO2 shell layer is uniform （14.7 nm） and the particle dispersion is excellent. Based on the initial power （1.0 mW at t=0）， the green light power retention rate after 250 hour anti-blue light aging test is 93%， significantly better than 55% of the traditional method.This study clarifies the formation mechanism of the nano-reactor without traditional amphiphilic surfactants from the perspective of interface thermodynamics and kinetics， and the protection mechanism of the optical properties of quantum dots. It provides a new path for the controllable synthesis of high-brightness and long-life quantum dot composite materials.关键词：quantum dots;silica coating;surfactant;reverse microemulsion method;fluorescence stability14|3|0更新时间：2026-07-16
- 摘要：According to the characteristics of infrared dim small target image， such as low signal strength， small size， susceptible to noise interference and complex background clutter， this paper proposes a new infrared dim and small target detection method based on the combination of a new morphological Top-hat operator and wavelet transform. Firstly， the improved morphological filtering was used to suppress the background of the infrared image， so as to reduce the interference of clouds， ground cover fluctuation and local strong clutter on target detection. Secondly， the preprocessed image was decomposed by wavelet， and the low frequency component was used for background suppression and target enhancement by using the Local Gradient and Local Intensity algorithm. At the same time， the three high frequency components were accumulated to further enhance the feature information of the target point. Finally， the infrared dim and small target was extracted by adaptive threshold segmentation method. The experimental results show that the proposed method achieves the optimal Signal-to-Clutter Ratio Gain （SCRG）， second only to the PTCTV algorithm in the Background Suppression Factor （BSF）， and the overall performance is better than other comparison methods. Among them， SCRG and BSF on Seq6 are 14.16 and 82.49， respectively. In the ROC curve， the detection rate of the proposed method in Seq3， Seq5 and Seq6 is more than 95%， which fully verifies that the algorithm can effectively suppress background and noise in complex scenes， and has strong stability and robustness.关键词：infrared small target detection;background suppression;wavelet transform;local intensity and gradient;adaptive threshold segmentation16|2|0更新时间：2026-07-16
- 摘要：Four major limitations exist when the conventional Hungarian algorithm is applied to space target detection in star images， including the lack of motion prediction， redundant global searching， single matching feature， and poor adaptability of fixed weights. In complex scenarios with coexisting high-speed and low-speed targets， densely distributed and closely approaching targets， dynamically varying target sizes， and low signal-to-noise ratios， the above drawbacks significantly degrade tracking accuracy and identity consistency. An improved Hungarian matching algorithm based on progressive multi-feature optimization is proposed. Firstly， a Kalman filter is introduced to predict the position and velocity of space targets， and predicted coordinates are adopted to construct matching costs instead of static observations. Secondly， a Mahalanobis distance gating mechanism is established using the covariance matrix derived from Kalman prediction， which constrains the matching search range from the global image to the local region within the predicted ellipsoid and reduces computational redundancy. Thirdly， a dynamic multi-feature weighting strategy is designed to adaptively adjust the cost contribution of position， area and aspect ratio according to their real-time reliability. Furthermore， an anomaly penalty term is added to impose extra costs on matching pairs with abrupt changes in area or aspect ratio to suppress false associations. Comparative experiments are carried out on five types of simulated star image scenes. The experimental results show that the average MOTA of the proposed algorithm reaches 88.3%， which is 5.9 percentage points higher than the conventional Hungarian algorithm， and 23.7 and 6.0 percentage points higher than PPMHT and the nearest neighbor method， respectively. Its average IDF1 is 65.8%， 9.5 percentage points higher than that of the conventional Hungarian algorithm. The average IDS is only 1.6， 2.3 and 3.6 lower than the conventional Hungarian algorithm and the nearest neighbor method， respectively. The average processing time per frame is 41.2 ms， which meets real-time operation requirements. Ablation experiments verify that the Kalman prediction module， Mahalanobis distance gating， dynamic weighting and anomaly penalty bring MOTA gains of 8.8， 6.5， 3.2 and 1.2 percentage points， respectively. The proposed four-module progressive optimization framework achieves an effective balance among tracking accuracy， identity consistency and computational efficiency， and provides a reliable solution for inter-frame association of space targets in star images..关键词：star image space target detection;hungarian algorithm;multi-feature optimization;Kalman filter;mahalanobis distance gating;dynamic weight13|4|0更新时间：2026-07-16
- 摘要：Aiming to address the challenges of missed detections and false positives in UAV aerial imagery caused by densely distributed small objects， small sizes， and complex backgrounds， this paper proposes an improved MCF-YOLO object detection algorithm based on YOLOv11n. First， a Multi-scale Feature Enhancement （MSFE） module is designed to enhance feature representation of small targets through high-resolution preservation， convolutional layer deepening， and residual connections. Second， a Contextual Anchor Attention （CAA） mechanism is integrated into the C3k2 module， leveraging horizontal and vertical separable convolutions to capture long-range spatial dependencies， thereby improving global contextual awareness and mitigating background interference and occlusion issues. Furthermore， the Focaler-DIoU loss function is employed to optimize the bounding box regression process through a dynamic sample weight adjustment mechanism， enhancing localization accuracy for small objects while reducing false positives and missed detections. Tests conducted on the VisDrone2019 dataset show that our method brings substantial performance enhancements relative to YOLOv11n， with increases of 6.8% in precision， 3.2% in recall， 6.6% in mAP@0.5， and 3.9% in mAP@0.5：0.95， outperforming other mainstream approaches. Additional cross-dataset validation on VEDAI and DOTA datasets shows mAP@0.5 improvements of 1.2% and 2.2% respectively， confirming the method's effectiveness and strong adaptability across various scenarios.关键词：deep learning;unmanned aerial vehicle （UAV）;small object detection;YOLOv11n;feature enhancement56|24|0更新时间：2026-06-25
- 摘要：The electroacoustic effect allows electrical control of acoustic waves through the converse piezoelectric effect， which is intrinsic to non‑centrosymmetric materials. Ferroelectric nematic liquid crystals （NF‑LCs） combine fluidity with spontaneous polarization， competing with traditional solid ferroelectrics. Here， we show that a confined ferroelectric nematic liquid crystal exhibits a pronounced electroacoustic response under an alternating electric field. The material emits audible sound only upon entering the ferroelectric nematic phase， with a sharp increase in recorded acoustic amplitude. Fourier analysis reveals the distinct underlying electromechanical coupling： the nonpolar nematic phase produces mainly even harmonics under weak electrostriction effect， whereas the polar NF phase manifests dominant odd harmonics with a low onset voltage （~2 V）， owing to a converse piezoelectric effect. The fundamental harmonic strongly dominates over the second harmonic， indicating a pronounced converse-piezoelectric contribution. The acoustic signal amplitude increases monotonically with cell thickness at a constant electric field， consistent with the piezoelectric displacement relation. The programmable operation is demonstrated by reproducing a melody by modulating the driving frequency over time while maintaining a constant voltage. This study presents fluid ferroelectric nematics as a platform for soft， reconfigurable acoustic transducers and sensors with low driving voltages and high piezoelectric responses.关键词：Ferroelectric nematic liquid crystal;electro-acoustic effect;harmonics;piezoelectricity;electrostriction28|19|0更新时间：2026-06-25
- 摘要：To address the issues of insufficient frequency information utilization and the limited capability to represent high-frequency details in complex distortion scenarios for no-reference image quality assessment （NR-IQA）， a frequency-aware quality assessment method guided by human visual system （HVS） characteristics is proposed. First， a lightweight hierarchical Vision Transformer network is employed as the backbone for multi-scale feature extraction， enabling information modeling from local textures to global semantics. Second， a frequency-aware gating module inspired by the contrast sensitivity function （CSF） is introduced. This module adaptively modulates distortion features across channel， frequency， and spatial dimensions to enhance the model’s perceptual sensitivity to sensitive frequency information. Subsequently， a high-frequency enhancement module based on the Discrete Cosine Transform （DCT） is designed， which strengthens the model's response to local high-frequency degradation through spatial and channel interactions in the frequency domain. Finally， multi-level features are aggregated to improve the collaborative representation capability among features. Experimental results demonstrate that the proposed method achieves a Pearson Linear Correlation Coefficient （PLCC） of 0.981 and a Spearman Rank-order Correlation Coefficient （SRCC） of 0.980 on the LIVE dataset. On the authentic distortion dataset LIVEC， the PLCC and SRCC reach 0.911 and 0.888， respectively， while the SRCC in the cross-dataset evaluation reaches 0.907. The proposed method effectively improves quality prediction accuracy in complex distortion scenarios， exhibits strong generalization and robustness， and can provide reliable support for perceptual quality optimization in intelligent visual systems.关键词：No-reference image quality assessment;contrast sensitivity function;frequency perception;discrete cosine transform;feature fusion31|23|0更新时间：2026-06-25
- 摘要：In space early warning and space target surveillance systems， aiming to effectively detect various space debris and other small-size， weak-signal celestial targets， it is necessary to address the challenges in deep space environments such as noise interference， faint target features and discontinuous trajectories. Therefore， a target detection and tracking algorithm based on improved YOLO26 is proposed. Firstly， an image sub-region self-perception enhancement module is deployed to enhance the visual clarity of dim and dark targets via local contrast optimization and edge preservation mechanism. Secondly， the YOLO26 detection network is lightweighted， and an improved multi-scale attention module GCEMA is introduced to strengthen the detection capability for dim and small targets. Finally， combined with the OCSort tracking algorithm and the appearance re-identification model CosmicReID， multi-target cataloging and stable tracking are realized. Experimental results show that compared with the original YOLO26 network and OCSort algorithm， the improved network has fewer parameters and faster inference speed， with the detection speed increased by 11.9%； the tracking accuracy of the integrated system is improved by 6.2%， and the frequency of target identity switching is reduced by 48.5%. The proposed method meets the requirements on detection accuracy and tracking accuracy of automatic tracking and measurement systems.关键词：multi-target tracking;image processing;object detection;data association41|36|0更新时间：2026-06-25
- 摘要：To address the problems of local texture and edge-detail loss， limited receptive fields in the convolution branch， and insufficient use of cross-layer structural information in the graph branch for hyperspectral image classification， this paper proposes a CNN-GCN joint classification model with high-low frequency enhancement and cross-layer graph convolution aggregation. The model improves input representation through high-low frequency residual enhancement， extracts multi-scale spectral-spatial features using a multi-stage dynamic convolution encoder， enhances regional structural modeling by cross-layer weighted aggregation in the graph branch， and performs collaborative modeling through cross-branch attention fusion. Experiments on three public datasets， Indian Pines， Pavia University， and Salinas， achieve overall accuracies of 92.94%， 95.11%， and 97.50%， with corresponding Kappa coefficients of 91.94%， 93.50%， and 97.22%， respectively. The results show that the proposed method can effectively integrate local details， spatial context， and regional topological structure information， achieving competitive classification performance across different types of hyperspectral classification scenes.关键词：Hyperspectral image classification;spectral-spatial joint features;graph convolution network;attention fusion199|254|0更新时间：2026-04-15
- 摘要：Infrared and visible image fusion aims to retain the complementary features of different modalities to achieve robust perception of complex scenes， and it plays a crucial role in numerous fields such as security monitoring， military reconnaissance， and autonomous driving. However， existing image fusion algorithms focus on enhancing the visual effects of images， leading to the ineffective preservation of key semantic information during the fusion process， which in turn affects the application performance of fused images in high-level visual tasks. Although existing methods attempt to cascade the fusion task with high-level visual tasks （segmentation， detection， etc.）， this sequential connection has limited enhancement on semantic information. To balance visual effects and downstream tasks， this paper proposes a semantic-driven infrared and visible image fusion network， SDFusion. First， a shared feature encoder is adopted to perform multi-level cross-modal feature extraction for infrared and visible images， fully mining the useful information in both modal images. Then， through the parallel collaborative optimization of the image fusion decoder and the semantic segmentation decoder， while hierarchically injecting encoded features into decoded features to enhance feature representation， the joint modeling of fusion features and semantic features is achieved. Experimental results on public datasets show that compared with traditional methods， this method significantly improves seven objective evaluation indicators. Specifically， EN is improved by 3.7%， SD by 7.3%， MI by 45.3%， VIFF by 18.5%， and
- 摘要：Aiming at the problem that the stitching of borehole wall images in geological exploration is easily affected by multiple factors such as imaging illumination conditions， probe disturbance， and information missing of depth or azimuth， a robust stitching method for borehole wall images under multi-interference imaging conditions is proposed. Firstly， an image mapping method with conditional constraints is adopted to expand a specific sampling region of the borehole wall image into a narrowband image that can be effectively used for stitching under the interference of the imaging light source. Then， the intrinsic characteristics of the images in borehole video are utilized， and an ROI-based registration strategy is adopted to realize the accurate registration of the unfolded narrowband borehole images under the conditions of probe disturbance and information missing of depth and azimuth， and then a precise registration of the unfolded narrowband image of the borehole under the conditions of probe disturbance， missing depth or azimuthal angle. At the same time， a grid-based matching strategy is applied to improve the registration speed. Finally， a row-by-row dynamically weighted image fusion method is adopted to eliminate the stitching traces according to the registration results， which further optimizes the quality of the stitched images. Through the experiments on the simulated images under different geological conditions， the performance indexes of the proposed method with average value of SSIM of 71.39%， average value of PSNR of 26.74， and average value of registration accuracy of 92.38% are better than those of the comparison method. and through the experimental results on the real images of different borehole videos， the objective evaluation indexes of the stitching results obtained by the proposed method， such as EN， SF， AG， MI， and Q_MI， etc.， are all improved.关键词：image stitching;image registration;image fusion;borehole wall image219|406|0更新时间：2025-02-25
- 摘要：Manganese （Mn2+） ion-doped all-inorganicCsPbCl3 perovskite quantum dots have shown great potential for application in Mini/Micro-LED display devices due to their unique photoluminescence properties and nano-scale particle size. However， the current photoluminescence quantum yields of CsPbCl3：Mn2+ perovskite quantum dots is low and cannot meet the needs of practical applications. Herein， the potassium （K+） and Mn2+ ions co-doped CsPbCl3 perovskite quantum dots are synthesized via the hot injection method. The prepared CsPbCl3：（K+， Mn2+） perovskite quantum dots present a dual-color emission， which can be assigned to the perovskite excitons emission and Mn2+ ions emission. The photoluminescence quantum yield of CsPbCl3：（K+， Mn2+） perovskite quantum dots is improved from 16.5% of original to 66.2% through the optimization of K+ ions doping concentration. Meanwhile， the regulation mechanism of K+ ions doping on the photoluminescence properties of CsPbCl3：Mn2+ perovskite quantum dots are investigated. It is shown that the incorporation of K+ ions can effectively inhibit the formation of intrinsic defect states and Mn-Mn dimers or Mn-related defects in CsPbCl3：（K+， Mn2+） perovskite quantum dots， thus enhancing the radiative recombination luminescence of carriers in perovskite quantum dots. Benefiting from the strategy of hetero-ions doping， these doped perovskite quantum dots are expected to be applied in Mini/Micro-LED display fields.关键词：CsPbCl3： Mn2+ perovskite quantum dots;K+ ions doping;dual-color emission;photoluminescence quantum yields249|364|0更新时间：2024-09-04
- 摘要：Polymer dispersed liquid crystal （PDLC） is a thin film formed by liquid crystal （LC） droplets embedded in a continuous polymer matrix in the form of micron-sized droplets. The use of click chemistry method to prepare PDLC can avoid the problems of dye decomposition caused by traditional photopolymerization-induced phase separation. In this study， four polyethylene glycol diacrylates （PEGDA） of different alkyl chain lengths were used as raw materials to synthesize PDLC films through thiol-ene click reaction and thiol-isocyanate coupling reaction， to study the effects of different alkyl chain length olefin monomers on the electro-optical properties of PDLC films. The results showed that as the chain length of olefin alkyl chain in the system increased， the threshold voltage （Vth） ， saturation voltage （Vsat） and contrast ratio （CR） decreased， while off-state transmittance （Toff） and on-state transmittance （Ton） increased. By selecting olefin with appropriate alkyl chain length， PDLC films with good electro-optical properties can be prepared.关键词：polymer dispersed liquid crystal;click reaction;monomer alkyl chain length;electro-optical property379|382|3更新时间：2024-09-04
- 摘要：Virtual reality technology has huge application potential in many fields， and panoramic cameras are one of the important tools to realize virtual reality.Aiming at the problem that occlusions such as brackets occlude the bottom image of a 720° panoramic camera， this paper proposes a method for eliminating the occlusion of the bottom bracket based on step-by-step shooting. Eliminate bottom occlusion by shooting the side and top once and shooting twice on the bottom.On this basis， optimized for the inconsistency of image brightness on the side， top， and bottom.The global uniformity algorithm will cause images in different regions to influence each other， causing deviations in the uniformity results.Therefore， this paper proposes a Wallis uniform color algorithm based on region growing method image segmentation.The experimental results show that the method in this paper can eliminate the bottom image occlusion； using the algorithm in this paper to even color， the image color difference is reduced by 59.3% compared with the global algorithm.关键词：panoramic camera;panoramic image stitching;dodging algorithm176|378|0更新时间：2024-09-04
- 摘要：Aiming at the problem of large scene， large field of view image applications and the slow speed of traditional image stitching algorithms， a fast image stitching algorithm based on offline calibration is adopted. In practical applications， the positions of multiple cameras are fixed， and offline calibration is used to calculate the homography matrix of image--stitching， which saves a lot of feature extraction and registration time. On the basis of fast image alignment， this paper proposes a fast image fusion algorithm based on the Laplacian pyramid of YUV color space， and it has better fusion effect and faster speed than the traditional Laplacian pyramid fusion algorithm. Experimental results show that The image fusion speed of the article algorithm is three times that of traditional Laplacian image fusion. Meet the real-time image stitching speed requirements in application scenarios， with good image stitching effects.关键词：image stitching;Laplacian pyramid;feature extraction;fast fusion343|629|5更新时间：2022-11-07
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