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Study on Image Recognition Algorithm for Residual Snow and Ice on Photovoltaic Modules
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作者 Yongcan Zhu JiawenWang +3 位作者 Ye Zhang Long Zhao Botao Jiang Xinbo Huang 《Energy Engineering》 EI 2024年第4期895-911,共17页
The accumulation of snow and ice on PV modules can have a detrimental impact on power generation,leading to reduced efficiency for prolonged periods.Thus,it becomes imperative to develop an intelligent system capable ... The accumulation of snow and ice on PV modules can have a detrimental impact on power generation,leading to reduced efficiency for prolonged periods.Thus,it becomes imperative to develop an intelligent system capable of accurately assessing the extent of snow and ice coverage on PV modules.To address this issue,the article proposes an innovative ice and snow recognition algorithm that effectively segments the ice and snow areas within the collected images.Furthermore,the algorithm incorporates an analysis of the morphological characteristics of ice and snow coverage on PV modules,allowing for the establishment of a residual ice and snow recognition process.This process utilizes both the external ellipse method and the pixel statistical method to refine the identification process.The effectiveness of the proposed algorithm is validated through extensive testing with isolated and continuous snow area pictures.The results demonstrate the algorithm’s accuracy and reliability in identifying and quantifying residual snow and ice on PV modules.In conclusion,this research presents a valuable method for accurately detecting and quantifying snow and ice coverage on PV modules.This breakthrough is of utmost significance for PV power plants,as it enables predictions of power generation efficiency and facilitates efficient PV maintenance during the challenging winter conditions characterized by snow and ice.By proactively managing snow and ice coverage,PV power plants can optimize energy production and minimize downtime,ensuring a sustainable and reliable renewable energy supply. 展开更多
关键词 Photovoltaic(PV)module residual snow and ice snow detection feature extraction image processing
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Unsupervised multi-modal image translation based on the squeeze-and-excitation mechanism and feature attention module
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作者 胡振涛 HU Chonghao +1 位作者 YANG Haoran SHUAI Weiwei 《High Technology Letters》 EI CAS 2024年第1期23-30,共8页
The unsupervised multi-modal image translation is an emerging domain of computer vision whose goal is to transform an image from the source domain into many diverse styles in the target domain.However,the multi-genera... The unsupervised multi-modal image translation is an emerging domain of computer vision whose goal is to transform an image from the source domain into many diverse styles in the target domain.However,the multi-generator mechanism is employed among the advanced approaches available to model different domain mappings,which results in inefficient training of neural networks and pattern collapse,leading to inefficient generation of image diversity.To address this issue,this paper introduces a multi-modal unsupervised image translation framework that uses a generator to perform multi-modal image translation.Specifically,firstly,the domain code is introduced in this paper to explicitly control the different generation tasks.Secondly,this paper brings in the squeeze-and-excitation(SE)mechanism and feature attention(FA)module.Finally,the model integrates multiple optimization objectives to ensure efficient multi-modal translation.This paper performs qualitative and quantitative experiments on multiple non-paired benchmark image translation datasets while demonstrating the benefits of the proposed method over existing technologies.Overall,experimental results have shown that the proposed method is versatile and scalable. 展开更多
关键词 multi-modal image translation generative adversarial network(GAN) squeezeand-excitation(SE)mechanism feature attention(FA)module
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Digital image stabilization system based on inertial measurement module 被引量:1
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作者 金锋 李田 《Journal of Beijing Institute of Technology》 EI CAS 2013年第2期222-227,共6页
In order to stabilize the video module to build digital image stabilization image sequence, a method of using inertial measurement system is proposed. Through applying real-time attitude in- formation of the camera th... In order to stabilize the video module to build digital image stabilization image sequence, a method of using inertial measurement system is proposed. Through applying real-time attitude in- formation of the camera that obtained by high-precision attitude sensor to estimate the image motion vector and then to compensate for image, the purpose of stabilizing the image sequence can be a- chieved. Experiments demonstrate that this method has a high image stabilization precision, and the up to 16 frame/s video output rate completely meets the real-time requirements. 展开更多
关键词 inertial measurement module digital image stabilization system motion vector real- time
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Simplified Inception Module Based Hadamard Attention Mechanism for Medical Image Classification
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作者 Yanlin Jin Zhiming You Ningyin Cai 《Journal of Computer and Communications》 2023年第6期1-18,共18页
Medical image classification has played an important role in the medical field, and the related method based on deep learning has become an important and powerful technique in medical image classification. In this art... Medical image classification has played an important role in the medical field, and the related method based on deep learning has become an important and powerful technique in medical image classification. In this article, we propose a simplified inception module based Hadamard attention (SI + HA) mechanism for medical image classification. Specifically, we propose a new attention mechanism: Hadamard attention mechanism. It improves the accuracy of medical image classification without greatly increasing the complexity of the model. Meanwhile, we adopt a simplified inception module to improve the utilization of parameters. We use two medical image datasets to prove the superiority of our proposed method. In the BreakHis dataset, the AUCs of our method can reach 98.74%, 98.38%, 98.61% and 97.67% under the magnification factors of 40×, 100×, 200× and 400×, respectively. The accuracies can reach 95.67%, 94.17%, 94.53% and 94.12% under the magnification factors of 40×, 100×, 200× and 400×, respectively. In the KIMIA Path 960 dataset, the AUCs and accuracy of our method can reach 99.91% and 99.03%. It is superior to the currently popular methods and can significantly improve the effectiveness of medical image classification. 展开更多
关键词 Deep Learning Medical image Classification Attention Mechanism Inception module
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A Hybrid Cybersecurity Algorithm for Digital Image Transmission over Advanced Communication Channel Models 被引量:1
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作者 Naglaa F.Soliman Fatma E.Fadl-Allah +3 位作者 Walid El-Shafai Mahmoud I.Aly Maali Alabdulhafith Fathi E.Abd El-Samie 《Computers, Materials & Continua》 SCIE EI 2024年第4期201-241,共41页
The efficient transmission of images,which plays a large role inwireless communication systems,poses a significant challenge in the growth of multimedia technology.High-quality images require well-tuned communication ... The efficient transmission of images,which plays a large role inwireless communication systems,poses a significant challenge in the growth of multimedia technology.High-quality images require well-tuned communication standards.The Single Carrier Frequency Division Multiple Access(SC-FDMA)is adopted for broadband wireless communications,because of its low sensitivity to carrier frequency offsets and low Peak-to-Average Power Ratio(PAPR).Data transmission through open-channel networks requires much concentration on security,reliability,and integrity.The data need a space away fromunauthorized access,modification,or deletion.These requirements are to be fulfilled by digital image watermarking and encryption.This paper ismainly concerned with secure image communication over the wireless SC-FDMA systemas an adopted communication standard.It introduces a robust image communication framework over SC-FDMA that comprises digital image watermarking and encryption to improve image security,while maintaining a high-quality reconstruction of images at the receiver side.The proposed framework allows image watermarking based on the Discrete Cosine Transform(DCT)merged with the Singular Value Decomposition(SVD)in the so-called DCT-SVD watermarking.In addition,image encryption is implemented based on chaos and DNA encoding.The encrypted watermarked images are then transmitted through the wireless SC-FDMA system.The linearMinimumMean Square Error(MMSE)equalizer is investigated in this paper to mitigate the effect of channel fading and noise on the transmitted images.Two subcarrier mapping schemes,namely localized and interleaved schemes,are compared in this paper.The study depends on different channelmodels,namely PedestrianAandVehicularA,with a modulation technique namedQuadratureAmplitude Modulation(QAM).Extensive simulation experiments are conducted and introduced in this paper for efficient transmission of encrypted watermarked images.In addition,different variants of SC-FDMA based on the Discrete Wavelet Transform(DWT),Discrete Cosine Transform(DCT),and Fast Fourier Transform(FFT)are considered and compared for the image communication task.The simulation results and comparison demonstrate clearly that DWT-SC-FDMAis better suited to the transmission of the digital images in the case of PedestrianAchannels,while the DCT-SC-FDMA is better suited to the transmission of the digital images in the case of Vehicular A channels. 展开更多
关键词 Cybersecurity applications image transmission channel models modulation techniques watermarking and encryption
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CFM-UNet:A Joint CNN and Transformer Network via Cross Feature Modulation for Remote Sensing Images Segmentation 被引量:4
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作者 Min WANG Peidong WANG 《Journal of Geodesy and Geoinformation Science》 CSCD 2023年第4期40-47,共8页
The semantic segmentation methods based on CNN have made great progress,but there are still some shortcomings in the application of remote sensing images segmentation,such as the small receptive field can not effectiv... The semantic segmentation methods based on CNN have made great progress,but there are still some shortcomings in the application of remote sensing images segmentation,such as the small receptive field can not effectively capture global context.In order to solve this problem,this paper proposes a hybrid model based on ResNet50 and swin transformer to directly capture long-range dependence,which fuses features through Cross Feature Modulation Module(CFMM).Experimental results on two publicly available datasets,Vaihingen and Potsdam,are mIoU of 70.27%and 76.63%,respectively.Thus,CFM-UNet can maintain a high segmentation performance compared with other competitive networks. 展开更多
关键词 remote sensing images semantic segmentation swin transformer feature modulation module
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Computational temporal ghost imaging based on complementary modulation
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作者 Jia-Wei Li Wei Zhang +1 位作者 Xue-Feng Liu Xu-Ri Yao 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第11期278-283,共6页
We report an experimental demonstration of temporal ghost imaging in which a digital micromirror device(DMD)and+1/-1 binary modulation have been combined to give an accurate reconstruction of a nonperiodic time object... We report an experimental demonstration of temporal ghost imaging in which a digital micromirror device(DMD)and+1/-1 binary modulation have been combined to give an accurate reconstruction of a nonperiodic time object.Compared to the 0/1 modulation,the reconstruction signal can be improved greatly by+1/-1 binary modulation even with half of the measurements.Experimental results show that 0/1 binary temporal objects up to 4 kHz and sinusoidal time objects up to 1 kHz can be reconstructed by this method.The influences of modulation speed and array detector gray levels are also discussed. 展开更多
关键词 temporal ghost imaging complementary modulation
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Research on the LA-UMamba Model for Asymmetric Modules with Added Auxiliary Information
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作者 YAN Jing SI Zhan-jun ZHANG Ying-xue 《印刷与数字媒体技术研究》 CAS 北大核心 2024年第4期56-66,共11页
Deep learning techniques are revolutionizing the developmentof medical image segmentation.With the advancement of Transformer models,especially ViT and Swin-Transformer,which enhances the remote-dependent modeling cap... Deep learning techniques are revolutionizing the developmentof medical image segmentation.With the advancement of Transformer models,especially ViT and Swin-Transformer,which enhances the remote-dependent modeling capability of the model through the self-attention mechanism,better segmentation performance can be achieve.Moreover,the high computational cost of Transformer has motivated researchers to explore more efficient models,such as the Mamba model based on state-space modeling(SSM),and for the field of medical segmentation,reducing the number of model parameters is also necessary.In this study,a novel asymmetric model called LA-UMamba was proposed,which integrates visual Mamba module to efficiently capture complex visual features and remote dependencies.The classical design of U-Net was adopted in the upsampling phase to help reduce the number of references and recover more details.To mitigate the information loss problem,an auxiliary U-Net downsampling layer was designed to focus on sizing without extracting features,thus enhancing the protection of input information while maintaining the efficiency of the model.The experiments were conducted on the ACDC MRI cardiac segmentation dataset,and the results showed that the proposed LA-UMamba achieves proved performance compared to the baseline model in several evaluation metrics,such as IoU,Accuracy,Precision,HD and ASD,which improved that the model is successful in optimizing the detail processing and reducing the complexity of the model,providing a new perspective for further optimization of medical image segmentation techniques. 展开更多
关键词 Medical image segmentation U-Net Mamba module Deep Learning
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Irregular and regular LDPC codes with high spectrum efficiency modulation in image transmission over fading channel 被引量:1
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作者 MaPiming YuanDongfeng 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2005年第1期26-30,共5页
If the degree distribution is chosen carefully, the irregular low-density parity-check (LDPC) codes can outperform the regular ones. An image transmission system is proposed by combining regular and irregular LDPC cod... If the degree distribution is chosen carefully, the irregular low-density parity-check (LDPC) codes can outperform the regular ones. An image transmission system is proposed by combining regular and irregular LDPC codes with 16QAM/64QAM modulation to improve both efficiency and reliability. Simulaton results show that LDPC codes are good coding schemes over fading channel in image communication with lower system complexity. More over, irregular codes can obtain a code gain of about 0.7 dB compared with regular ones when BER is 10 -4. So the irregular LDPC codes are more suitable for image transmission than the regular codes. 展开更多
关键词 irregular low-density parity-check (LDPC) codes degree distribution image transmission high spectrum efficiency modulation.
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An Image Steganography Algorithm Based on Quantization Index Modulation Resisting Scaling Attacks and Statistical Detection 被引量:1
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作者 Yue Zhang Dengpan Ye +2 位作者 Junjun Gan Zhenyu Li Qingfeng Cheng 《Computers, Materials & Continua》 SCIE EI 2018年第7期151-167,共17页
In view of the fact that the current adaptive steganography algorithms are difficult to resist scaling attacks and that a method resisting scaling attack is only for the nearest neighbor interpolation method,this pape... In view of the fact that the current adaptive steganography algorithms are difficult to resist scaling attacks and that a method resisting scaling attack is only for the nearest neighbor interpolation method,this paper proposes an image steganography algorithm based on quantization index modulation resisting both scaling attacks and statistical detection.For the spatial image,this paper uses the watermarking algorithm based on quantization index modulation to extract the embedded domain.Then construct the embedding distortion function of the new embedded domain based on S-UNIWARD steganography,and use the minimum distortion coding to realize the embedding of the secret messages.Finally,according to the embedding modification amplitude of secret messages in the new embedded domain,the quantization index modulation algorithm is applied to realize the final embedding of secret messages in the original embedded domain.The experimental results show that the algorithm proposed is robust to the three common interpolation attacks including the nearest neighbor interpolation,the bilinear interpolation and the bicubic interpolation.And the average correct extraction rate of embedded messages increases from 50%to over 93% after 0.5 times-fold scaling attack using the bicubic interpolation method,compared with the classical steganography algorithm S-UNIWARD.Also the algorithm proposed has higher detection resistance than the original watermarking algorithm based on quantization index modulation. 展开更多
关键词 image steganography anti-scaling attack anti-statistical detection quantization index modulation
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Fuzzy image restoration using modulation transfer function
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作者 袁媛 Yi Yaohua Liu Juhua 《High Technology Letters》 EI CAS 2016年第4期461-469,共9页
The key difficulty of restoring a fuzzy image is to estimate its point spread function( PSF). In the paper,PSF is modelled based on modulation transfer function( MTF). The first step is calculating the image MTF. In t... The key difficulty of restoring a fuzzy image is to estimate its point spread function( PSF). In the paper,PSF is modelled based on modulation transfer function( MTF). The first step is calculating the image MTF. In the traditional slanted-edge method,a sub-block is always manually extracted from original image and its MTF will be viewed as the result of the whole image. However,handcraft extraction is inefficient and will lead to inaccurate results. Given this,an automatic MTF computation algorithm is proposed,which extracts and screens out all the effective sub-blocks and calculates their average MTF as the final result. Then,a two-dimensional MTF restoration model is constructed by multiplying the horizontal and vertical MTF,and it is combined with conventional image restoration methods to restore fuzzy image. Experimental results indicate the proposed method implementes a fast and accurate MTF computation and the MTF model improves the performance of conventional restoration methods significantly. 展开更多
关键词 fuzzy image modulation transfer function(MTF) slanted-edge method automatic computation MTF restoration model
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Influence of random phase modulation on the imaging quality of computational ghost imaging 被引量:4
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作者 Chao Gao Xiao-Qian Wang +3 位作者 Hong-Ji Cai Jie Ren Ji-Yuan Liu Zhi-Hai Yao 《Chinese Physics B》 SCIE EI CAS CSCD 2019年第2期77-81,共5页
In this paper, we investigated phase modulation-based computational ghost imaging. According to the results of numerical simulations, we found that the range of the random phase affects the quality of the reconstructe... In this paper, we investigated phase modulation-based computational ghost imaging. According to the results of numerical simulations, we found that the range of the random phase affects the quality of the reconstructed image. Besides,compared with those amplitude modulation-based computational ghost imaging schemes, introducing random phase modulation into the computational ghost imaging scheme could significantly improve the spatial resolution of the reconstructed image, and also extend the field of view. 展开更多
关键词 COMPUTATIONAL GHOST imagING RANDOM PHASE modulATION imagING quality
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Spatially modulated scene illumination for intensity-compensated two-dimensional array photon-counting LiDAR imaging 被引量:1
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作者 Jiaheng Xie Zijing Zhang +3 位作者 Mingwei Huang Jiahuan Li Fan Jia Yuan Zhao 《Chinese Physics B》 SCIE EI CAS CSCD 2022年第9期238-248,共11页
Photon-counting LiDAR using a two-dimensional(2D)array detector has the advantages of high lateral resolution and fast acquisition speed.The non-uniform intensity profile of the illumination beam and non-uniform quant... Photon-counting LiDAR using a two-dimensional(2D)array detector has the advantages of high lateral resolution and fast acquisition speed.The non-uniform intensity profile of the illumination beam and non-uniform quantum efficiency of the detectors in the 2D array deteriorate the imaging quality.Herein,we propose a photon-counting LiDAR system that uses a spatial light modulator to control the spatial intensity to compensate for both the non-uniform intensity profile of the illumination beam,and the variation in the quantum efficiency of the detectors in the 2D array.By using a 635 nm peak wavelength and 4 mW average power semiconductor laser,lab-based experiments at a 4.27 m stand-off distance are performed to verify the effectiveness of the proposed method.Compared with the unmodulated method,the standard deviation of the intensity image of the proposed method is reduced from 0.109 to 0.089 for a whiteboard target,with an average signal photon number of 0.006 per pixel. 展开更多
关键词 avalanche photodiode camera photon counting three-dimensional imaging array modulation
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Single Image Deraining Using Dual Branch Network Based on Attention Mechanism for IoT 被引量:1
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作者 Di Wang Bingcai Wei Liye Zhang 《Computer Modeling in Engineering & Sciences》 SCIE EI 2023年第11期1989-2000,共12页
Extracting useful details from images is essential for the Internet of Things project.However,in real life,various external environments,such as badweather conditions,will cause the occlusion of key target information... Extracting useful details from images is essential for the Internet of Things project.However,in real life,various external environments,such as badweather conditions,will cause the occlusion of key target information and image distortion,resulting in difficulties and obstacles to the extraction of key information,affecting the judgment of the real situation in the process of the Internet of Things,and causing system decision-making errors and accidents.In this paper,we mainly solve the problem of rain on the image occlusion,remove the rain grain in the image,and get a clear image without rain.Therefore,the single image deraining algorithm is studied,and a dual-branch network structure based on the attention module and convolutional neural network(CNN)module is proposed to accomplish the task of rain removal.In order to complete the rain removal of a single image with high quality,we apply the spatial attention module,channel attention module and CNN module to the network structure,and build the network using the coder-decoder structure.In the experiment,with the structural similarity(SSIM)and the peak signal-to-noise ratio(PSNR)as evaluation indexes,the training and testing results on the rain removal dataset show that the proposed structure has a good effect on the single image deraining task. 展开更多
关键词 Internet of Things image deraining dual-branch network structure attention module convolutional neural network
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Characterization of a Multimodal and Multispectral Led Imager: Application to Organic Polymer’s Microspheres with Diameter Φ = 10.2 μm 被引量:2
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作者 Marcel A. Agnero Jérémie T. Zoueu Kouakou Konan 《Optics and Photonics Journal》 2016年第7期171-183,共14页
Multispectral microscopy enables information enhancement in the study of specimens because of the large spectral band used in this technique. A low cost multimode multispectral microscope using a camera and a set of q... Multispectral microscopy enables information enhancement in the study of specimens because of the large spectral band used in this technique. A low cost multimode multispectral microscope using a camera and a set of quasi-monochromatic Light Emitting Diodes (LEDs) ranging from ultraviolet to near-infrared wavelengths as illumination sources was constructed. But the use of a large spectral band provided by non-monochromatic sources induces variation of focal plan of the imager due to chromatic aberration which rises up the diffraction effects and blurs the images causing shadow around them. It results in discrepancies between standard spectra and extracted spectra with microscope. So we need to calibrate that instrument to be a standard one. We proceed with two types of images comparison to choose the reference wavelength for image acquisition where diffraction effect is more reduced. At each wavelength chosen as a reference, one image is well contrasted. First, we compare the thirteen well contrasted images to identify that presenting more reduced shadow. In second time, we determine the mean of the shadow size over the images from each set. The correction of the discrepancies required measurements on filters using a standard spectrometer and the microscope in transmission mode and reflection mode. To evaluate the capacity of our device to transmit information in frequency domain, its modulation transfer function is evaluated. Multivariate analysis is used to test its capacity to recognize properties of well-known sample. The wavelength 700 nm was chosen to be the reference for the image acquisition, because at this wavelength the images are well contrasted. The measurement made on the filters suggested correction coefficients in transmission mode and reflection mode. The experimental instrument recognized the microsphere’s properties and led to the extraction of the standard transmittance and reflectance spectra. Therefore, this microscope is used as a conventional instrument. 展开更多
关键词 Multispectral imaging Reference Wavelength Correction Coefficients modulation Transfer Function
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Phase modulation pseudocolor encoding ghost imaging
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作者 段德洋 张路 +1 位作者 杜少将 夏云杰 《Chinese Physics B》 SCIE EI CAS CSCD 2015年第2期142-145,共4页
We present a ghost imaging scheme that can obtain a good pseudocolor image of black-and-white objects.The essential idea is to use a multi-wavelength thermal light source and the phase modulation pseudocolor encoding ... We present a ghost imaging scheme that can obtain a good pseudocolor image of black-and-white objects.The essential idea is to use a multi-wavelength thermal light source and the phase modulation pseudocolor encoding technique,which overcomes the disadvantages of other methods involved spatial filtering.Therefore,the pseudocolor ghost image achieved by this imaging scheme is better than that obtained by other methods in terms of brightness,color,and signal-tonoise ratio. 展开更多
关键词 ghost imaging pseudocolor phase modulation
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Fractal Image Coding in Lapped Transform Domain
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作者 高西奇 洪波 +1 位作者 张辉 何振亚 《Journal of Southeast University(English Edition)》 EI CAS 1997年第2期24-28,共5页
Lapped transforms are introduced into fractal image coding to remove the block effects which exist in conventional block based fractal image compression both in spatial and frequency domains. The proposed method offe... Lapped transforms are introduced into fractal image coding to remove the block effects which exist in conventional block based fractal image compression both in spatial and frequency domains. The proposed method offers not only an efficient solution to such block effects but also better objective performances. Compared with the fractal image compression methods based on discrete cosine transform, about 1 dB SNR gains can be achieved. 展开更多
关键词 FRACTAL image CODING SUBBAND analysis/synthesis system COSINE modulated filter banks discrete COSINE TRANSFORM
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Calibration and data restoration of light field modulated imaging spectrometer
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作者 Li-Juan Su Qiang-Qiang Yan +2 位作者 Yan Yuan Shi-Feng Wang Yu-Jian Liu 《Chinese Physics B》 SCIE EI CAS CSCD 2018年第8期179-186,共8页
A light field modulated imaging spectrometer (LFMIS) can acquire the spatial-spectral datacube of targets of interest or a scene in a single shot. The spectral information of a point target is imaged on the pixels c... A light field modulated imaging spectrometer (LFMIS) can acquire the spatial-spectral datacube of targets of interest or a scene in a single shot. The spectral information of a point target is imaged on the pixels covered by a microlens. The pixels receive spectral information from different spectral filters to the diffraction and misalignments of the optical components. In this paper, we present a linear spectral multiplexing model of the acquired target spectrum. A calibration method is proposed for calibrating the center wavelengths and bandwidths of channels of an LFMIS system based on the liner-variable filter (LVF) and for determining the spectral multiplexing matrix. In order to improve the accuracy of the restored spectral data, we introduce a reconstruction algorithm based on the total least square (TLS) approach. Simulation and experimental results confirm the performance of the spectrum reconstruction algorithm and validate the feasibility of the proposed calibrating scheme. 展开更多
关键词 light field modulated imaging spectrometer linear-variable filter spectral calibration spectral re-construction
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Image quality evaluation of linear plastic scintillating fiber array detector for X-ray imaging 被引量:1
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作者 Mohammad Mehdi NASSERI 《Nuclear Science and Techniques》 SCIE CAS CSCD 2004年第6期361-364,共4页
It is important to assess image quality, in order to ensure that the imaging system is performing optimally and also identify the weak points in an imaging system. Three parameters mostly leading to image degradation ... It is important to assess image quality, in order to ensure that the imaging system is performing optimally and also identify the weak points in an imaging system. Three parameters mostly leading to image degradation are contrast, spatial resolution and noise. There is always a trade-off between spatial resolution and signal to noise ratio, but in scintillating fiber array detectors spatial resolution is not as important as signal to noise ratio, so we paid more attention to contrast and SNR of the system. By using GEANT4 Monte Carlo detector simulation toolkit, some effec- tive parameters of the linear plastic scintillating fiber (PSF) array as an imaging detector were investigated. Finally we show that it is possible to use this kind of detector to take CT and DR (Digital Radiography) image under certain conditions. 展开更多
关键词 闪烁纤维 X射线 调制变换函数 GEANT4 图象质量
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Usability of Deformable Image Registration for Adaptive Radiotherapy in Head and Neck Cancer and an Automatic Prediction of Replanning
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作者 Masao Tanooka Hiroshi Doi +9 位作者 Toshihisa Ishida Kazuhiro Kitajima Tsukasa Wakayama Toshiyuki Sakai Hiroyuki Inoue Noriko Kotoura Kengo Kosaka Kazuo Tarutani Masayuki Fujiwara Norihiko Kamikonya 《International Journal of Medical Physics, Clinical Engineering and Radiation Oncology》 2017年第1期10-20,共11页
Deformable image registration (DIR) has been an important component in adaptive radiotherapy (ART). Our goal was to examine the accuracy of ART using the dice similarity coefficient (DSC) and to determine the optimal ... Deformable image registration (DIR) has been an important component in adaptive radiotherapy (ART). Our goal was to examine the accuracy of ART using the dice similarity coefficient (DSC) and to determine the optimal timing of replanning. A total of 22 patients who underwent volume modulated arc therapy (VMAT) for head and neck (H&N) cancers were prospectively analyzed. The planning target volume (PTV) was to receive a total of 70 Gy in 33 fractions. A second planning CT scan (rescan) was performed at the 15th fraction. The DSC was calculated for each structure on both CT scans. The continuous variables to predict the need for replanning were assessed. The optimal cut-off value was determined using receiver operating characteristic (ROC) curve analysis. In the correlation between body weight loss and DSC of each structure, weight loss correlated negatively with DSC of the whole face (rs = -0.45) and the face surface (rs = -0.51). Patients who required replanning tended to have experienced rapid weight loss. The threshold DSC was 0.98 and 0.60 in the whole face and the face surface, respectively. Patients who showed low DSC in the whole face and the face surface required replanning at a significantly high rate (P < 0.05 and P < 0.01). Weight loss correlated with DSC in both the whole face and the face surface (P < 0.05 and P < 0.05). The DSC values in the face predicted the need for replanning. In addition, weight loss tended to correlate with DSC. DIR during ART was found to be a useful tool for replanning. 展开更多
关键词 Deformable image Registration Adaptive RADIOTHERAPY Head and NECK Can-cer DICE SIMILARITY Coefficient Volume modulATED Arc Therapy
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