In this paper, we investigate the space-alternating generalized expectation-maximization (SAGE) algorithm with virtual carriers (VCs) in orthogonal frequency division multiplexing (OFDM) systems. The channel frequency...
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In this paper, we investigate the space-alternating generalized expectation-maximization (SAGE) algorithm with virtual carriers (VCs) in orthogonal frequency division multiplexing (OFDM) systems. The channel frequency response (CFR) at VCs cannot be estimated accurately due to edge effect after inverse discrete Fourier transform (IDFT). To solve the problem, an improved channel estimation method is introduced to minimize the errors of CFR via iterative technique. Then we apply the SAGE algorithm to estimate the direction of arrival (DOA) and time of arrival (TOA). The SAGE algorithm shows more excellent performance with higher resolution ability than subspace-based algorithms. Based on Monte Carlo trials, we test the performance of the improved method in terms of mean absolute error (MAE) at different signal-to-noise ratios (SNR). Simulation results indicate that the improved method behaves better at any SNR than the conventional DFT-based method.
The aerial image mosaic algorithm needs to ensure the real-time performance of the algorithm and the natural transition of image fusion. In order to improve the matching performance of the algorithm, an improved UAV a...
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ISBN:
(数字)9781728168968
ISBN:
(纸本)9781728168975
The aerial image mosaic algorithm needs to ensure the real-time performance of the algorithm and the natural transition of image fusion. In order to improve the matching performance of the algorithm, an improved UAV aerial image registration algorithm based on GMS-RANSAC is proposed. The improved algorithm introduces the idea of partitioning, divides the image into meshes and then performs feature extraction on each mesh, uses the bidirectional BF algorithm and the GMS algorithm to perform accurate feature value matching, and finally uses the improved RANSAC algorithm for further feature purification to obtain a high-quality correct interior point set. This paper combines the characteristics of GMS algorithm to improve the RANSAC algorithm, reduce the number of iterations of the algorithm, and reduce the time complexity of the algorithm. The improved image registration algorithm has higher accuracy and shorter running time. After the registration is completed, the image is merged to obtain a mosaic image.
During the last two decades, content-based image retrieval (CBIR) has been widely studied. The limitations of low-level feature representation of images have been a thorny issue in image retrieval problems. In this pa...
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In the image stitching technology, traditional feature extraction algorithms have uneven feature points distribution, many redundant features, time-consuming feature points precision matching and low image registratio...
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License plate recognition (LPR) is one of the essential components in intelligent transportation systems. Although the imageprocessingalgorithms for LPR have been extensively studied in the past several years, the r...
ISBN:
(数字)9781509066315
ISBN:
(纸本)9781509066322
License plate recognition (LPR) is one of the essential components in intelligent transportation systems. Although the imageprocessingalgorithms for LPR have been extensively studied in the past several years, the recognition performance is still not satisfactory especially in unconstrained complex scenes. In order to tackle this issue, a novel deep multi-task learning-based method is proposed in this paper by introducing contextual information in multiple license plate frames. Specifically, an end-to-end trainable multi-task architecture, namely IQ-STAN, is developed by joint license plate recognition and image quality scoring. Moreover, we propose an image quality-guided spatio-temporal attention mechanism, which is utilized in the frame-level feature representation during the phase of plate recognition. Extensive experiments are conducted and the competitive results demonstrate the effectiveness of our proposed framework.
Automatic observation has become the development trend of optical observation of space debris, and corresponding automatic target identification without human intervention has become an urgent research topic. This pap...
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Style transfer is an increasingly popular field that can capture the styles of a particular artwork and use them to synthesize a new image with specific content. Previous NST algorithms have the limitation to transfer...
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Background and objective: The X-ray screening is one of the most popular methodologies in detection of respiratory system diseases. Chest organs are screened on the film or digital file which go to the doctor for eval...
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Background and objective: The X-ray screening is one of the most popular methodologies in detection of respiratory system diseases. Chest organs are screened on the film or digital file which go to the doctor for evaluation. However, the analysis of x-ray images requires much experience and time. Clinical decision support is very important for medical examinations. The use of Computational Intelligence can simulate the evaluation and decision processes of a medical expert. We propose a method to provide a decision support for the doctor in order to help to consult each case faster and more precisely. Methods: We use image descriptors based on the spatial distribution of Hue, Saturation and Brightness values in x-ray images, and a neural network co-working with heuristic algorithms (Moth-Flame, Ant Lion) to detect degenerated lung tissues in x-ray image. The neural network evaluates the image and if the possibility of a respiratory disease is detected, the heuristic method identifies the degenerated tissues in the x-ray image in detail based on the use of the proposed fitness function. Results: The average accuracy is 79.06% in pre-detection stage, similarly the sensitivity and the specificity averaged for three pre-classified diseases are 84.22% and 66.7%, respectively. The misclassification errors are 3.23% for false positives and 3.76% for false negatives. Conclusions: The proposed neuro-heuristic approach addresses small changes in the structure of lung tissues, which appear in pneumonia, sarcoidosis or cancer and some consequences that may appear after the treatment. The results show high potential of the newly proposed method. Additionally, the method is flexible and has low computational burden. (C) 2019 Elsevier Ltd. All rights reserved.
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