最新刊期
期 9 ， 2023
- 摘要：An important research direction in the field of liquid crystal displays is the improvement of electro-optical properties of liquid crystals. In recent years， liquid crystal-nanoscience has witnessed a paradigm shift in the electro-optical properties of nano-doped enhanced liquid crystals. On the one hand， nanoparticles possess special physicochemical properties that can effectively improve the properties of the dispersed substrates. In addition， the nano-doped liquid crystal composite system occupies an important position in the display field because of its simple preparation process and excellent electro-optical properties. Using the different interactions between liquid crystals and nanoparticles， researchers have designed a series of electro-optical devices with high stability， low cost， tunable and sustainable. However， the doping of nanoparticles has the potential to cause structural defects that are detrimental to the stability of liquid crystals. Therefore， the selection of nanoparticles is crucial to the electro-optical performance of liquid crystals. This paper provides an overview of the electro-optical properties of liquid crystal-nanocomposite systems， focusing on the possible interactions between nanoparticles and liquid crystal molecules. Meanwhile， the current research status of nanoparticle-doped liquid crystals is reviewed， and the effect of nano-doping on the electro-optical properties of liquid crystals is summarized according to the nanoparticle types， and based on this， the future combination of liquid crystal display technology and nanotechnology is prospected.关键词：liquid crystals;nanoparticles;electro-optical performance;interactions
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发布时间：2023-09-27 - 摘要：The nematic liquid crystal is an excellent non-local nonlinear medium for the study of spatial optical solitons. In order to achieve a flexible modulation of the deflection of spatial optical solitons in nematic liquid crystals， the structure of a liquid crystal cell with a comb-shaped electrode structure is designed. Applying an electric field to the liquid crystal cell with customized electrode structure enables modulation of the nematic liquid crystal within the periodic array， thus enabling controlled deflection of the nematicon and nematicon pairs. The incident laser beam can be deflected at different angles in different orientation ranges. When the beam is incident in a liquid crystal cell with a customized electrode width of 910 μm， the deflection of the beam can be adjusted within a range of 60° by changing the incident position. Various combinations of deflections can be formed by two laser beams incident at different positions. By varying the angle of incidence， a non-linear total reflection of the nematicon pairs at the interface can be observed. Furthermore， the width of the customized stripe electrode is changed to 300 μm， the nematicon pairs achieves a switch parallel transmission to mutual convergence and divergence. These methods of modulation nematicons deflection can play an important role in all optical circuit and optical communications.关键词：nematic liquid crystals;Nematicon;Nematicon pairs;Deflection of beams;Liquid crystal arrays
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发布时间：2023-09-27
Material Physics
- 摘要：The phase distribution within the liquid crystal layer of a liquid crystal lens is usually not an ideal parabolic structure， which limits the imaging application of liquid crystal lenses. Using an electrode structure designed based on the linear response region of liquid crystal， a liquid crystal lens is produced. By analyzing the front information of liquid crystal lens waves during operation， the optical power and optical aberration of the liquid crystal lens can be measured. In an imaging system composed of a camera module and a liquid crystal lens that performs a focusing function， quantitative research is conducted on the image formed after passing through the liquid crystal lens. The image of the ISO12233 icon formed by the imaging system is analyzed to obtain the resolution of the imaging system. The results show that the driving of the liquid crystal lens is simple， and the relationship between the optical power and the driving voltage difference is linear， which can be adjusted in the range of -4.9 to+5.2 D， and has a lower than 0.05λ optical aberration. In the application of imaging systems， the liquid crystal lens exhibit excellent focusing performance with little impact on the resolution of the main lens.关键词：liquid crystal device;liquid crystal lenses;lens;modulation transfer function
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发布时间：2023-09-27 - 摘要：In this work， the vertically aligned （VA） liquid crystal devices are prepared on a substrate with serrated ITO electrodes， the laser is coupled into the liquid crystal layer， and the voltage of the ITO electrodes is modulated. The output laser achieves deflection and the deflection angle increases with the increase of voltage until saturation. Under two serrated electrodes with a top angle of 20°， the laser spot deflects by about 4°. At the same time， since the voltage used for driving liquid crystals is an AC signal， by adjusting the minimum driving voltage， which is the bias voltage， the liquid crystal molecules start to rotate from a certain starting angle and are also driven within their fast rotation range， thereby improving the response speed of the liquid crystal molecules.Under the guidance of this strategy， the state and driving speed of liquid crystal molecules are determined by characterizing their polarization state during their rotation. Under the premise of balancing the refractive index and driving speed， the overall response speed of liquid crystal layer molecules under different bias voltages is compared. Under a certain bias voltage， the response time driven by the liquid crystal layer decreases from 55 ms to 2.5 ms， while the relaxation time after power outage decreases from 18 ms to 8.5 ms. This provides a new solution for laser deflection devices using this liquid crystal layer scheme to achieve faster scanning frequency and scanning angle in the future.关键词：Laser deflection;liquid crystal device;Liquid crystal molecular drive
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发布时间：2023-09-27
Device Physics and Device Preparation
- 摘要：With the maturity of stereoscopic display technology， image enhancement methods based on stereoscopic display have become a research hotspot. Human eye gloss perception is a unique visual feature that reflects the physical properties of object surfaces and is crucial to human cognitive activities. The study of binocular glossiness presentation and perception under the stereoscopic display is a powerful extension and supplement to the study of binocular vision， which can provide an application basis for stereoscopic display devices to reproduce a richer image appearance. This paper analyzed the phenomenological， theoretical， and influence cues of binocular gloss， summarized the current status of binocular gloss research under the stereoscopic display， and pointed out the problems of current binocular gloss perception research： the deep neural mechanism of gloss perception for target generation is still unclear； the exploration of cues influencing gloss perception remains on the surface of the phenomenon； the quantitative psychophysical experimental data for glossiness measurement and evaluation are yet to be expanded. In the future， the joint exploration of gloss perception and visual systems based on stereoscopic display technology may become a highly promising research hotspot. Since gloss perception is a psychological quantity and there is specificity in each person’s perception of it， we believe that more experiments on gloss perception need to be carefully designed to investigate the reproduction of gloss properties of target surfaces in stereoscopic displays to expand the underlying representation scenarios under stereoscopic displays.关键词：stereoscopic display;Binocular glossy;Glossy perception cues;Stereoscopic image enhancement;Glossiness evaluation
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发布时间：2023-09-27 - 摘要：To address the issues of low recognition rate， slow recognition speed， and the need for large amounts of data samples in current 3D light field gesture interaction， this paper proposes a method based on a small dataset of hand key points using a multi-layer perceptron（MLP） network to improve the accuracy of 3D light field interaction， with recognition speed reaching the millisecond level. In the process of collecting hand key points， there are significant differences in the three-dimensional data of the same type of hand gesture collected from different locations. In order to eliminate these differences， this paper proposes a method of normalizing the same gesture through pose transformation of the simplified gesture model in the same right-hand Cartesian coordinate system using displacement and Rodrigues rotation formula. An MLP neural network is utilized to extract hand features from the normalized hand key points transition relationships. Experimental results show that the proposed method has a recognition rate of above 95% for simple gestures in 3D light field interaction， and a recognition rate of above 90% for complex gestures. Furthermore， the proposed method demonstrates excellent performance under training with a small dataset， meeting the requirements of both accurate and fast gesture recognition. Finally， this paper presents a successful application of the proposed method to a 3D light field interaction scenario.关键词：interaction;gesture recognition;MLP;small dataset
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发布时间：2023-09-27 - 摘要：The combined measurement methods of subjective questionnaires， ECG signals， eye movement signals and ophthalmological parameters are used to study the effect of different types of display modes on visual fatigue of 2D and 3D TVs. The results show that the relative changes of BCDVA， TBUT， pupil diameter and Shannon entropy after watching 3D mode are significantly greater than those after watching 2D mode. Differences in relative RR interval values and heart rate （HR） induced by viewing 2D and 3D modes gradually increase after 50 min. Different types of display modes have different effects on subjective scoring symptoms， ophthalmological parameters， ECG parameters and eye movement parameters. The visual fatigue caused by watching 3D mode is greater than that caused by watching 2D mode， especially after watching 2D/3D mode 50 min， which has reference value for 3D movie production.关键词：display mode;Heart rate variability;Eye movement;stereo display;visual fatigue
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发布时间：2023-09-27 - 摘要：Visually induced motion sickness （VIMS） is a common symptom in the process of experiencing virtual reality （VR）， which seriously reduces the comfort of users’ VR experience and hinders the promotion and development of VR technology. Virtual space distortion is one of the potential factors affecting the comfort level of the VR experience. Incomplete distortion correction of near-eye display equipment will produce virtual space distortion， which may leads to VIMS. Aiming at the influence degree of virtual space distortion on VIMS， this paper simulated the experience process of VR technology， analyzed the distortion mechanism of near-eye display technology represented by VR technology， designed visual perception experiments of VIMS grade evaluation under three different distortion parameters， and carried out detailed subjective and objective data statistical analysis. The results show that virtual space distortion has a significant impact on VIMS symptoms， the greater the degree of distortion of the stereoscopic images viewed by the subjects， the more obvious the symptoms of VIMS. This study can provide a theoretical basis for improving the comfort level of the VR technology experience.关键词：virtual reality;visual perception;distortion correction;visually induced motion sickness
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发布时间：2023-09-27
Intelligent Displays
- 摘要：Existing super-resolution methods assume a predefined degradation process from high-resolution images to low-resolution images， which is difficult to hold for real-world images with complex degradation types. For this problem， a blind super-resolution model based on degradation-aware is proposed. The model generates low-resolution images with random blur kernels and learns degenerate representations with contrasts. The model generator consists of residual groups containing multiple degradation-aware blocks. Degraded perceptual blocks use degraded representations and image features to do cross-attention to calculate spatial weight maps. In addition， the model collects layer-level features from the output of residual groups and calculates inter-layer attention to reuse layer-level features. This enables the model to pay more attention to high-frequency details， and the model feature extraction capability is further improved. The effectiveness of each module is verified by ablation experiments. On multiple international public test sets， the average PSNR with a magnification of 4 is increased by 1.45 dB， and the SSIM is increased by 0.058. Experimental results show that the model achieves significant performance on blind super-resolution tasks with good visual results.关键词：super resolution;blind super resolution;cross attention;spatial attention;feature reuse
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发布时间：2023-09-27 - 摘要：As the application of image process extends to each emerging field， high-performance salt-and-pepper denoising is still a challenging task. Therefore， a salt-and-pepper denoising method combining training of noise mask and nearest searching mechanism is proposed. Firstly， a lightweight neural network with 9 convolutional layers is constructed to generate a high-quality noise mask. Subsequently， according to the marking result of this mask， the normal pixel is not processed， while gray level of the noise pixel is replaced by that of the nearest normal pixels， which is found by using the nearest searching mechanism. In this paper， a lightweight convolutional neural network for noise labeling is proposed. While reducing the network depth， the conventional convolution for the middle layer is replaced by depth-separable convolution. These two factors reduce computational complexity and parameters number by orders of magnitude. And a denoising method based on the nearest searching mechanism is proposed， which will improve the denoising performance. The pixel units marked as normal points are not processed， and only noise points are processed. Experimental results show that the computational complexity of the proposed network is orders of magnitude lower than that of traditional networks， the misjudging rate for the trained noise mask is 94.79%， 94.79% and 83.65% lower than that of the extreme marking， the extreme image block marking and the average marking， respectively. In addition， PSNR of image processed by the proposed method is 2.53% higher than traditional CNN method， and MSE is 6.76% lower. A lightweight convolutional neural network is applied to salt and pepper denoising for the first time， which reduces network complexity and improves denoising performance.关键词：salt and pepper noise;noise mask;lightweight convolutional neural network;the nearest searching;deep learning
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发布时间：2023-09-27 - 摘要：The existing image conversion algorithms based on generative adversarial network often extract the features of the whole input image indiscriminately in the process of background defocus， which makes it difficult for the network to distinguish the front and back scenes of the image， so it is easy to lead to the phenomenon of image distortion. We propose a background virtualization method of image perception guided CycleGAN network. The image perception information is introduced to improve the performance of the model. The image perception information includes attention information and depth of field information. The former is used to guide the network to pay attention to different foreground and background areas， so as to distinguish the foreground and background. The latter is used to enhance the perception information of foreground targets， achieve effective intelligent focusing， and reduce image distortion， making the background defocus better. The experimental results and data show that the method proposed in this paper can effectively distinguish the foreground and background in the process of background defocus， reduce the phenomenon of image distortion， and make the generated effect more real. In addition， in comparison with the image effect generated by the existing methods， the questionnaire survey is used for evaluation. A background virtualization method for image perception guided CycleGAN network is proposed， comparing with SOTA， the image quality generated is the best， and its model size and image generation rate also have obvious advantages of 56.10 MB and 47 ms， respectively.关键词：background defocus;image perception;CycleGAN Network;intelligent focusing
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发布时间：2023-09-27 - 摘要：In order to realize laboratory fire recognition and solve the problems that the flame is not significant in the image collected by the camera due to the small fire， and the flame with smoke occlusion affects the accuracy of segmentation and recognition， an improved semantic aware real-time thermal infrared and visible image fusion segmentation network is proposed. The thermal radiation information is provided to enhance the spectral information reduced by smoke occlusion in the visible light image， as well as the significance of the flame in the early stage of combustion， and the segmentation of the flame under the laboratory smoke occlusion and the small flame in the early stage of flame combustion is completed. The intermediate feature transfer block （IFTB） is added to the gradient residual dense block （GRDB） in the fusion network， and the weight block is introduced to reduce the information loss of the flame image during fusion， and the visual image structure information is restored with the minimum content loss as the benchmark while enhancing the saliency of the flame image. The edge extraction module based on gradient transformation （EEM） is added to the Deeplabv3+ semantic segmentation network to enhance the edge information of flame and smoke images with significant light and dark transformation in the fusion image， reduce the influence of smoke occlusion on flame segmentation， and improve the accuracy of flame segmentation and recognition. The experimental results show that the accuracy of flame detection segmentation and recognition in the early stage of flame combustion is improved by fusing visible light and thermal infrared images. The average intersection over union ratio of the improved flame segmentation network in the self-collected data set is 91.27%， and the segmentation efficiency is 11.96 FPS. The improved fusion segmentation network significantly improves the effect of laboratory flame and smoke segmentation and recognition， and has practical application value for laboratory flame and smoke detection.关键词：flame smoke detection;image fusion;semantic segmentation;IFTB;edge extraction
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发布时间：2023-09-27 - 摘要：Underwater images often suffer from severe color degradation， haze and local blur， which are attenuated by the scattering of suspended objects in water and the absorption of light by water. Aiming at the problem that the existing underwater image enhancement algorithms based on deep learning use a single convolution， up-sampling and down-sampling mode which leads to insufficient image feature extraction， this paper constructs the down-sampling module， up-sampling module and feature extraction module based on multi-scale feature extraction. On this basis， an underwater image enhancement network framework based on multi-scale feature extraction block cascade （MS-FEBC） is proposed. To further improve the feature extraction capability of the network， the CBAM attention mechanism is added to the high-dimensional feature space of the network. The experimental results demonstrate that compared with the existing algorithms， the algorithm in this paper effectively solves the problem that the underwater images have lower quality such as color-cast， hazing and detail loss. There is a significant improvement in all four objective evaluation indexes. The performance of the image SIFT feature point detection and Canny edge detection vision tasks is significantly improved.关键词：underwater image enhancement;Cascaded network;Multi-scale feature extraction
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发布时间：2023-09-27 - 摘要：Travel has always been a problem for blind people due to their lack of visual perception of the surrounding environment. This paper presents an improved obstacle detection algorithm CE-YOLOX based on YOLOX for guide system. Firstly， in order to reduce semantic information loss caused by feature fusion network when feature channel is reduced， sub-pixel hopping fusion module SSF and sub-pixel context enhancement module SCE are used to make full use of channel information and semantic information of different scales， and channel attention guide module CAG is used to reduce aliasing effect caused by multi-scale feature fusion. Secondly， in order to make the model more focused on effective features， the global attention mechanism GAM is introduced to improve the performance of the model by reducing the information dispersion and amplifying the global interactive representation. Then， the position regression function IOU-LOSS of the original model is replaced by SIOU-LOSS， which speeds up the regression speed and precision of the frame. Finally， the detection platform of the guide system is built and the proposed algorithm is transplanted to the edge computing device NVIDIA Xavier NX. The experimental results show that the obstacle algorithm of the improved guide system has the same mAP on the server and NVIDIA Xavier NX platform， which is improved to 90.53%， 2.45% higher than the original YOLOX model algorithm. The detection speed reaches 75.93 FPS on the server. The model in this paper not only gives consideration to the detection speed but also improves the accuracy， which is significantly better than the comparison algorithm. It meets the requirements of edge computing equipment and has practical application value.关键词：blind system;Obstacle detection;subpixel;CEFPN;GAM;Angle loss;SIOU
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发布时间：2023-09-27 - 摘要：Bone stick is an important cultural relic that records the products handed over by local officials to the central government in the Western Han Dynasty. It is of great significance to accurately detect the written content. In order to solve the problem that bone stick text is difficult to extract under complex texture background and the dense text and adhesion lead to multiple characters in one frame， a bone stick text detection algorithm combining self-attention convolution and improved loss function is proposed. Firstly， a self-attention convolution module is added to the YOLOv5 feature extraction to enhance the network's attention to the features of bone stick， and to make the model capture more global information and suppress the interference of the crack to the feature extraction. In addition， the Focal-EIOU loss function is used to replace the CIOU network for optimization. Focal-EIOU uses the wide-height loss to reduce the wide-height gap between the prediction box and the real box， and eliminates the prediction box larger than the real box， the detection frame redundancy problem caused by text density and adhesion is solved to improve the precision prediction ability of the model. The experimental results show that the average accuracy of the proposed algorithm reaches 93.35%， which is 3.08% higher than that of YOLOv5. It is more suitable for the task of detecting dense adhesive bone stick text in complex texture background.关键词：Text Detection;Bone Stick;attention mechanism;YOLOv5;loss function
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发布时间：2023-09-27
Image Processing
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