Journals > > Topics > Vision, Color, and Visual Optics
Vision, Color, and Visual Optics|49 Article(s)
Detection and Classification of Color Deficiency Using Hue Tests and Anomaloscope
Qiang Gao, Ruiqing Ma, and Yan Qiang
The detection and classification of color deficiency is frequently required in occupational physical examination, computer-aided recognition systems for color deficiency, and basic research on color vision mechanisms. Twenty-two color deficient subjects (eight deuteranopes, two protanopes, six deuteranomalous trichromats, and six protanomalous trichromats) were tested using D-15, FM 100-Hue, and Neitz anomaloscope tests. By comparing the test results of D-15 and FM 100-Hue with those of the anomaloscope, the limitations of hue tests in detecting and classifying color deficiency were revealed. This study provides a reference for detecting and classifying color deficiency in various applications. The detection and classification of color deficiency is frequently required in occupational physical examination, computer-aided recognition systems for color deficiency, and basic research on color vision mechanisms. Twenty-two color deficient subjects (eight deuteranopes, two protanopes, six deuteranomalous trichromats, and six protanomalous trichromats) were tested using D-15, FM 100-Hue, and Neitz anomaloscope tests. By comparing the test results of D-15 and FM 100-Hue with those of the anomaloscope, the limitations of hue tests in detecting and classifying color deficiency were revealed. This study provides a reference for detecting and classifying color deficiency in various applications.
Laser & Optoelectronics Progress
- Publication Date: May. 10, 2023
- Vol. 60, Issue 9, 0933002 (2023)
Influence of Distance Between Remote Phosphor and Chip on Performance of White LEDs
Xue Zheng, Zhimou Xu, Yubo Long, Junping Chen, and Xingao Liu
Phosphor-converted white LEDs have the advantages of high energy efficiency, low cost, and long life. They are widely used in lighting area. Improving the luminous efficiency of phosphor-converted white LEDs has always been a research hotspot. In order to design and optimize the high-performance packaging of white LEDs, combination of simulations and experiments are used to research and analyze LED chip packaging. We use a special bracket and dual-chip package to increase luminous efficiency. On this basis, the phosphor coating process is improved, the phosphor excitation efficiency is improved, and the overall LED luminous efficiency is increased by about 6%. This study also investigates the change in LED luminous efficiency when the distance between the remote phosphor and chip changes. Phosphor-converted white LEDs have the advantages of high energy efficiency, low cost, and long life. They are widely used in lighting area. Improving the luminous efficiency of phosphor-converted white LEDs has always been a research hotspot. In order to design and optimize the high-performance packaging of white LEDs, combination of simulations and experiments are used to research and analyze LED chip packaging. We use a special bracket and dual-chip package to increase luminous efficiency. On this basis, the phosphor coating process is improved, the phosphor excitation efficiency is improved, and the overall LED luminous efficiency is increased by about 6%. This study also investigates the change in LED luminous efficiency when the distance between the remote phosphor and chip changes.
Laser & Optoelectronics Progress
- Publication Date: May. 10, 2023
- Vol. 60, Issue 9, 0933001 (2023)
Simulation and Application of Multi-Channel Light Emitting Diode Spectral Optimization
Jiaqi Ju, Yue Wang, Linyuan Wang, Jukun Liu, and Yan Jin
This paper investigates a spectral optimization simulation method based on multi-channel light-emitting diodes (LEDs). According to the principle of linear superposition of spectra, each color LED spectrum is imported into the program, and the model is programmed to output the best combination of color rendering index, luminous efficacy, and color tolerance under the specified color temperature conditions to guide the dimming and color adjustment applications of multi-channel LED lighting products. The experimental results show that the warm white LEDs mixed with RGB (Red, Green, Blue) light have the best combination of photometric chromaticity parameters in the color temperature range of 3000-5000 K, and the cool white LEDs mixed with RGB light have the best effect in the range of 5000-8000 K. The visual efficacy and non-visual efficacy of each optimal spectral combination solution are discussed, and the optimal solution of the spectrum is experimentally verified. This paper investigates a spectral optimization simulation method based on multi-channel light-emitting diodes (LEDs). According to the principle of linear superposition of spectra, each color LED spectrum is imported into the program, and the model is programmed to output the best combination of color rendering index, luminous efficacy, and color tolerance under the specified color temperature conditions to guide the dimming and color adjustment applications of multi-channel LED lighting products. The experimental results show that the warm white LEDs mixed with RGB (Red, Green, Blue) light have the best combination of photometric chromaticity parameters in the color temperature range of 3000-5000 K, and the cool white LEDs mixed with RGB light have the best effect in the range of 5000-8000 K. The visual efficacy and non-visual efficacy of each optimal spectral combination solution are discussed, and the optimal solution of the spectrum is experimentally verified.
Laser & Optoelectronics Progress
- Publication Date: Mar. 10, 2023
- Vol. 60, Issue 5, 0533001 (2023)
Circular Histogram Breakpoint Selection and Threshold and Color Image Segmentation Method Based on Information Energy
Jipeng Yang, and Jiulun Fan
A new method of color image threshold involves dividing the color image threshold using the H component of the color image hue-saturation-intensity (HSI) model. Considering that the H component is a circular histogram, it is an effective method to break the circular histogram into a linear histogram and subsequently use the linear histogram threshold segmentation method to select the threshold. In information theory, the information energy is the dual of Shannon entropy, and this study first introduces the concept of cumulative distribution information energy of the linear probability distribution, which is used to determine the breakpoint of the circular histogram. Thereafter, it provides the information energy threshold method on the linear histogram, which is used to determine the threshold of the H-component circular histogram. Compared with the Shannon entropy threshold selection criterion based on logarithmic operation, the information energy threshold selection criterion based on square operation has the advantages of simple expression and fast calculation speed. A new method of color image threshold involves dividing the color image threshold using the H component of the color image hue-saturation-intensity (HSI) model. Considering that the H component is a circular histogram, it is an effective method to break the circular histogram into a linear histogram and subsequently use the linear histogram threshold segmentation method to select the threshold. In information theory, the information energy is the dual of Shannon entropy, and this study first introduces the concept of cumulative distribution information energy of the linear probability distribution, which is used to determine the breakpoint of the circular histogram. Thereafter, it provides the information energy threshold method on the linear histogram, which is used to determine the threshold of the H-component circular histogram. Compared with the Shannon entropy threshold selection criterion based on logarithmic operation, the information energy threshold selection criterion based on square operation has the advantages of simple expression and fast calculation speed.
Laser & Optoelectronics Progress
- Publication Date: Jan. 25, 2023
- Vol. 60, Issue 2, 0233002 (2023)
3D Modeling System of Mobile Robot Based on Virtual Reality in Real Environment
Zhongyuan Guo, Feng Xu, Guiyang Wang, Dongying Yu, and Yunxuan Cui
Traditional virtual reality (VR) technology generates indoor three-dimensional (3D) map models using artificial modeling, which has the challenges of slow speed and deviation between the model and real object scale. Therefore, this study proposes a real environment 3D modeling system for mobile robots based on VR. First, the indoor high-precision dense 3D point cloud map can be rapidly obtained by using visual simultaneous localization and mapping (SLAM) technology. Second, the 3D point cloud can be reconstructed into the indoor 3D model through the surface reconstruction algorithm and imported into unity 3D. Next, the indoor 3D model is placed in the 3D virtual environment with the VR equipment's aid. Finally, the relocation of the mobile robot to the indoor environment is achieved by visual SLAM technology, and the pose of the robot in the model is mapped in real time to complete the interaction. Using visual SLAM technology to build the 3D map model is quick, solves the problem of scene scale deviation, and attains the reuse of map. Simultaneously, VR technology also allows operators to obtain a strong sense of immersion to better understand the working environment of the robot. Traditional virtual reality (VR) technology generates indoor three-dimensional (3D) map models using artificial modeling, which has the challenges of slow speed and deviation between the model and real object scale. Therefore, this study proposes a real environment 3D modeling system for mobile robots based on VR. First, the indoor high-precision dense 3D point cloud map can be rapidly obtained by using visual simultaneous localization and mapping (SLAM) technology. Second, the 3D point cloud can be reconstructed into the indoor 3D model through the surface reconstruction algorithm and imported into unity 3D. Next, the indoor 3D model is placed in the 3D virtual environment with the VR equipment's aid. Finally, the relocation of the mobile robot to the indoor environment is achieved by visual SLAM technology, and the pose of the robot in the model is mapped in real time to complete the interaction. Using visual SLAM technology to build the 3D map model is quick, solves the problem of scene scale deviation, and attains the reuse of map. Simultaneously, VR technology also allows operators to obtain a strong sense of immersion to better understand the working environment of the robot.
Laser & Optoelectronics Progress
- Publication Date: Jan. 25, 2023
- Vol. 60, Issue 2, 0233001 (2023)
Mural Style Transfer with Feature Clustering and Deep Residual Shrinkage Network
Meng Wu, Yining Gao, and Jia Wang
Ancient murals are unique surviving copies and unique in artistic style. However, the effect of reconstructing missing information is poor as reference data are scarce. The key to improving the reconstruction process of murals is producing enough reference samples. In this study, an improved style transfer method is proposed to generate high-quality mural images. First, clustering is performed in the low-dimensional space of the input images to maintain their structural integrity. Second, a residual shrinkage module based on the attention mechanism and soft threshold function is introduced to remove redundant information in the images and effectively retain texture details. Finally, the content and matched style clustering sets are converted into real-time features to obtain migration images of any style. The experimental results show that the proposed method can generate natural and clear mural images as well as achieve better results in terms of peak signal-to-noise ratio and structural similarity than other common style transfer methods. Moreover, in an experiment of mural digitization based on a generative adversarial network, the superiority of the proposed method over the conventional augmentation method is verified. Ancient murals are unique surviving copies and unique in artistic style. However, the effect of reconstructing missing information is poor as reference data are scarce. The key to improving the reconstruction process of murals is producing enough reference samples. In this study, an improved style transfer method is proposed to generate high-quality mural images. First, clustering is performed in the low-dimensional space of the input images to maintain their structural integrity. Second, a residual shrinkage module based on the attention mechanism and soft threshold function is introduced to remove redundant information in the images and effectively retain texture details. Finally, the content and matched style clustering sets are converted into real-time features to obtain migration images of any style. The experimental results show that the proposed method can generate natural and clear mural images as well as achieve better results in terms of peak signal-to-noise ratio and structural similarity than other common style transfer methods. Moreover, in an experiment of mural digitization based on a generative adversarial network, the superiority of the proposed method over the conventional augmentation method is verified.
Laser & Optoelectronics Progress
- Publication Date: Aug. 25, 2023
- Vol. 60, Issue 16, 1633001 (2023)
Contribution of Different Lighting Environments to Sound-Light Fusion Effects
Jiaqi Ju, Ke Xu, Yue Wang, Jukun Liu, and Yan Jin
In this paper, the sound-light fusion effect has been studied based on physiological parameters and subjective emotional changes. The influence of western major music, western minor music, 3 kinds of monochromatic lighting (wavelengths of 623, 537, 445 nm) and 2 kinds of white lighting with different color temperatures (color temperature of 3000, 6000 K) on the human body is systematically discussed. The experimental results show that people's physiological response to music is stronger than that of the lighting stimulus. The physiological perception under dual-factor stimulation is stronger than that of single-factor, and sound plays a major role in the sound-light fusion environment. Music and light interact when they stimulate emotions at the same time. The superposition of two positively related emotional environmental factors can strengthen the effect on emotions. It provides theoretical support and opinions for the design of music and light show or immersive interactive lighting. In this paper, the sound-light fusion effect has been studied based on physiological parameters and subjective emotional changes. The influence of western major music, western minor music, 3 kinds of monochromatic lighting (wavelengths of 623, 537, 445 nm) and 2 kinds of white lighting with different color temperatures (color temperature of 3000, 6000 K) on the human body is systematically discussed. The experimental results show that people's physiological response to music is stronger than that of the lighting stimulus. The physiological perception under dual-factor stimulation is stronger than that of single-factor, and sound plays a major role in the sound-light fusion environment. Music and light interact when they stimulate emotions at the same time. The superposition of two positively related emotional environmental factors can strengthen the effect on emotions. It provides theoretical support and opinions for the design of music and light show or immersive interactive lighting.
Laser & Optoelectronics Progress
- Publication Date: Apr. 10, 2022
- Vol. 59, Issue 7, 0733003 (2022)
Research on Prediction of Mixed Spectra of Offset Printing Spot Color Ink
Yiren Liu, Xiaoxia Wan, Jingxiao Mou, and Taichuan Shi
Aiming at the problem that the accuracy of the traditional Kubelka-Munk(K-M) theory spectral prediction model is not ideal when performing offset printing spot color ink spectrum prediction, a color spectrum prediction method for offset printing spot color ink is proposed by constructing a base ink database based on piecewise linear interpolation method, combined with modifying the K-M model with the Stearns-Noechel(S-N) transfer function. The study used 64 spot colors obtained by mixing a certain series of spot color inks of Siegwerk brand as the target color samples for training, carried out two-color, three-color, and four-color mixed spectrum prediction research respectively, and obtained three quantities of primary color inks when mixed . The optimal paper-based weights are -0.5, -0.1, 0.2, respectively. Bringing the best paper-based weight into the prediction model, and using CIE1976 color difference, CIEDE2000 color difference and root mean square error(RMSE) as evaluation indicators, two, three, and four-color spot colors with known formulas were randomly selected for accuracy testing experiments. The experimental results show that compared with the traditional K-M method, the CIE1976 color difference, CIEDE2000 color difference and RMSE of the method proposed in this study are reduced from 5.748, 3.471 and 0.048 to 2.077, 1.441 and 0.011, respectively. Compared with the traditional K-M method, the prediction accuracy of this method is greatly improved, and it can better realize the spectrum prediction of the mixed color of offset printing ink with higher accuracy. Aiming at the problem that the accuracy of the traditional Kubelka-Munk(K-M) theory spectral prediction model is not ideal when performing offset printing spot color ink spectrum prediction, a color spectrum prediction method for offset printing spot color ink is proposed by constructing a base ink database based on piecewise linear interpolation method, combined with modifying the K-M model with the Stearns-Noechel(S-N) transfer function. The study used 64 spot colors obtained by mixing a certain series of spot color inks of Siegwerk brand as the target color samples for training, carried out two-color, three-color, and four-color mixed spectrum prediction research respectively, and obtained three quantities of primary color inks when mixed . The optimal paper-based weights are -0.5, -0.1, 0.2, respectively. Bringing the best paper-based weight into the prediction model, and using CIE1976 color difference, CIEDE2000 color difference and root mean square error(RMSE) as evaluation indicators, two, three, and four-color spot colors with known formulas were randomly selected for accuracy testing experiments. The experimental results show that compared with the traditional K-M method, the CIE1976 color difference, CIEDE2000 color difference and RMSE of the method proposed in this study are reduced from 5.748, 3.471 and 0.048 to 2.077, 1.441 and 0.011, respectively. Compared with the traditional K-M method, the prediction accuracy of this method is greatly improved, and it can better realize the spectrum prediction of the mixed color of offset printing ink with higher accuracy.
Laser & Optoelectronics Progress
- Publication Date: Apr. 10, 2022
- Vol. 59, Issue 7, 0733002 (2022)
Design of Multi-Focal Intraocular Lens Based on Dammann Zone Plate
Junjie Li, Changhe Zhou, Wei Jia, Yuda Chen, Yihan Wang, Weicheng Liu, and Jin Wang
In this paper, a design method of multi-focal intraocular lens is proposed. Dammann zone plate, which consists of a series of concentric rings, is a practical optical element which introduces the phase modulation idea of Dammann grating into the traditional band plate. Through modulating the diffraction order, it can produce a series of axial focal spot distribution in the light field behind the focusing lens. Moreover, by combining the focusing lens with different numerical apertures, the intensity distribution of the focal spot will also change to a certain extent. Through theoretical simulation and experimental verification, it provides an effective design method for fabrication of multi-focus intraocular lens. The multi-focus intraocular lens has five focal points, which can improve cataract patients' vision at different distances simultaneously and provide them with clearer and more detailed images. In this paper, a design method of multi-focal intraocular lens is proposed. Dammann zone plate, which consists of a series of concentric rings, is a practical optical element which introduces the phase modulation idea of Dammann grating into the traditional band plate. Through modulating the diffraction order, it can produce a series of axial focal spot distribution in the light field behind the focusing lens. Moreover, by combining the focusing lens with different numerical apertures, the intensity distribution of the focal spot will also change to a certain extent. Through theoretical simulation and experimental verification, it provides an effective design method for fabrication of multi-focus intraocular lens. The multi-focus intraocular lens has five focal points, which can improve cataract patients' vision at different distances simultaneously and provide them with clearer and more detailed images.
Laser & Optoelectronics Progress
- Publication Date: Apr. 10, 2022
- Vol. 59, Issue 7, 0733001 (2022)
Guiding Method of Linear Pipe Jacking Machine Based on Dual Camera Target
Zhe Huang, Qingde Yan, Zhenyu Shao, Xuye Zhao, and Wenyang Du
Aiming at the problems of slow response speed and high cost faced by linear pipe jacking machine in tunneling guidance, a real-time pose measurement method based on dual camera targets is proposed. The measurement target is composed of two opposite industrial cameras and two photosensitive imaging screens installed in the opposite direction, supplemented by an indicator laser with known spatial orientation information. By using the techniques of spot image analysis and processing, calibration grid retrieval and Euler angle calculation, the proposed method can complete the measurement of horizontal/vertical deviation of machine relative to the planning line in the engineering coordinate system, so as to realize the guidance. The experimental results show that the azimuth repeatability measurement accuracy of the proposed dual camera target is better than 0.03°, the absolute measurement error is less than 0.05° and the horizontal/vertical deviation measurement error is less than 3 mm, which can fully meet the real-time accurate guidance requirements of the linear pipe jacking machine. Aiming at the problems of slow response speed and high cost faced by linear pipe jacking machine in tunneling guidance, a real-time pose measurement method based on dual camera targets is proposed. The measurement target is composed of two opposite industrial cameras and two photosensitive imaging screens installed in the opposite direction, supplemented by an indicator laser with known spatial orientation information. By using the techniques of spot image analysis and processing, calibration grid retrieval and Euler angle calculation, the proposed method can complete the measurement of horizontal/vertical deviation of machine relative to the planning line in the engineering coordinate system, so as to realize the guidance. The experimental results show that the azimuth repeatability measurement accuracy of the proposed dual camera target is better than 0.03°, the absolute measurement error is less than 0.05° and the horizontal/vertical deviation measurement error is less than 3 mm, which can fully meet the real-time accurate guidance requirements of the linear pipe jacking machine.
Laser & Optoelectronics Progress
- Publication Date: Feb. 20, 2022
- Vol. 59, Issue 4, 0433001 (2022)
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