4 research outputs found
Automated Cloud Removal on High-Altitude UAV Imagery Through Deep Learning on Synthetic Data
New theories and applications of deep learning have been discovered and implemented within the field of machine learning recently. The high degree of effectiveness of deep learning models span across many domains including image processing and enhancement. Specifically, the automated removal of clouds, smoke, and haze from images has become a prominent and pertinent field of research. In this paper, I propose an analysis and synthetic training data variant for the All-in-One Dehazing Network (AOD-Net) architecture that performs better on removing clouds and haze; most specifically on high altitude unmanned aerial vehicles (UAVs) images
Automated Cloud Removal on High-Altitude UAV Imagery Through Deep Learning on Synthetic Data
New theories and applications of deep learning have been discovered and implemented within the field of machine learning recently. The high degree of effectiveness of deep learning models span across many domains including image processing and enhancement. Specifically, the automated removal of clouds, smoke, and haze from images has become a prominent and pertinent field of research. In this paper, I propose an analysis and synthetic training data variant for the All-in-One Dehazing Network (AOD-Net) architecture that performs better on removing clouds and haze; most specifically on high altitude unmanned aerial vehicles (UAVs) images
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μ£Ό.In this thesis, we discuss regularization methods for denoising images corrupted by Gaussian or Cauchy noise and image dehazing in underwater. In image denoising, we introduce the second-order extension of structure tensor total variation and propose a hybrid method for additive Gaussian noise. Furthermore, we apply the weighted nuclear norm under nonlocal framework to remove additive Cauchy noise in images. We adopt the nonconvex alternating direction method of multiplier to solve the problem iteratively. Subsequently, based on the color ellipsoid prior which is effective for restoring hazy image in the atmosphere, we suggest novel dehazing method adapted for underwater condition. Because attenuation rate of light varies depending on wavelength of light in water, we apply the color ellipsoid prior only for green and blue channels and combine it with intensity map of red channel to refine the obtained depth map further. Numerical experiments show that our proposed methods show superior results compared with other methods both in quantitative and qualitative aspects.λ³Έ λ
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Ήμκ³Ό μ²μ μ±λμ μ μ©νκ³ κ·Έλ‘λΆν° μ»μ κΉμ΄ μ§λλ₯Ό μ μ μ±λμ κ°λ μ§λμ νΌν©νμ¬ κ°μ λ κΉμ΄ μ§λλ₯Ό μ»λλ€. μμΉμ μ€νμ ν΅ν΄μ μ°λ¦¬κ° μ μν λ°©λ²λ€μ λ€λ₯Έ λ°©λ²κ³Ό λΉκ΅νκ³ μ§μ μΈ μΈ‘λ©΄κ³Ό νκ° μ§νμ λ°λ₯Έ μμ μΈ μΈ‘λ©΄ λͺ¨λμμ μ°μν¨μ νμΈνλ€.1 Introduction 1
1.1 Image denoising for Gaussian and Cauchy noise 2
1.2 Underwater image dehazing 5
2 Preliminaries 9
2.1 Variational models for image denoising 9
2.1.1 Data-fidelity 9
2.1.2 Regularization 11
2.1.3 Optimization algorithm 14
2.2 Methods for image dehazing in the air 15
2.2.1 Dark channel prior 16
2.2.2 Color ellipsoid prior 19
3 Image denoising for Gaussian and Cauchy noise 23
3.1 Second-order structure tensor and hybrid STV 23
3.1.1 Structure tensor total variation 24
3.1.2 Proposed model 28
3.1.3 Discretization of the model 31
3.1.4 Numerical algorithm 35
3.1.5 Experimental results 37
3.2 Weighted nuclear norm minimization for Cauchy noise 46
3.2.1 Variational models for Cauchy noise 46
3.2.2 Low rank minimization by weighted nuclear norm 52
3.2.3 Proposed method 55
3.2.4 ADMM algorithm 56
3.2.5 Numerical method and experimental results 58
4 Image restoration in underwater 71
4.1 Scientific background 72
4.2 Proposed method 73
4.2.1 Color ellipsoid prior on underwater 74
4.2.2 Background light estimation 78
4.3 Experimental results 80
5 Conclusion 87
Appendices 89Docto
Computational strategies for understanding underwater optical image datasets
Thesis: Ph. D. in Mechanical and Oceanographic Engineering, Joint Program in Oceanography/Applied Ocean Science and Engineering (Massachusetts Institute of Technology, Department of Mechanical Engineering; and the Woods Hole Oceanographic Institution), 2013.Cataloged from PDF version of thesis.Includes bibliographical references (pages 117-135).A fundamental problem in autonomous underwater robotics is the high latency between the capture of image data and the time at which operators are able to gain a visual understanding of the survey environment. Typical missions can generate imagery at rates hundreds of times greater than highly compressed images can be transmitted acoustically, delaying that understanding until after the vehicle has been recovered and the data analyzed. While automated classification algorithms can lessen the burden on human annotators after a mission, most are too computationally expensive or lack the robustness to run in situ on a vehicle. Fast algorithms designed for mission-time performance could lessen the latency of understanding by producing low-bandwidth semantic maps of the survey area that can then be telemetered back to operators during a mission. This thesis presents a lightweight framework for processing imagery in real time aboard a robotic vehicle. We begin with a review of pre-processing techniques for correcting illumination and attenuation artifacts in underwater images, presenting our own approach based on multi-sensor fusion and a strong physical model. Next, we construct a novel image pyramid structure that can reduce the complexity necessary to compute features across multiple scales by an order of magnitude and recommend features which are fast to compute and invariant to underwater artifacts. Finally, we implement our framework on real underwater datasets and demonstrate how it can be used to select summary images for the purpose of creating low-bandwidth semantic maps capable of being transmitted acoustically.by Jeffrey W. Kaeli.Ph. D. in Mechanical and Oceanographic Engineerin