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Alternative TitleResearch and application of Lambert’s Reflectance Model using spherical harmonic frames
Thesis Advisor彭思龙
Degree Grantor中国科学院大学
Place of Conferral中国科学院自动化研究所
Degree Discipline模式识别与智能系统
Keyword球面调和基 球面调和框架 Lambert 光照模型 图像篡改检测 Spherical Harmonics Spherical Harmonic Frame Lambert Lighting Model Image Forensics
Abstract建立自然复杂环境光照模型是处理和模拟现实世界光照环境的有效方法, 具有十分重要的理论研究价值和实际应用价值。首先,它涉及数学、计算机科 学、信息科学、生物认知等多个领域,是当前前沿性的交叉科学研究。其次, 全局复杂环境光照模型促进了多个领域的技术发展。最后,复杂环境光照模型 在图形渲染、模式识别、三维重建及数字篡改鉴别等应用领域都有极高的研究 价值。尽管基于球面调和基函数的光照模型在理论分析和实际处理自然复杂光 照环境问题上取得了成功,但在实际应用中仍面临很多挑战性的问题。我们针 对实际情况中遇到的关键性问题进行了深入的研究,取得了一系列成果: 1、针对抑制退化效应和光照区分的问题,我们提出了一种基于球面调和 框架的光照模型。为了获得自然环境光场下Lambert物体的鲁棒性光照估计和 提升不同环境光场的光照区分能力,基于框架表示的光照模型利用多方向投影 的冗余度,一方面抑制了数据缺失和噪声干扰等退化效应在光照估计时的影 响,另一方面提升了区分漫反射物体的反射光照的能力。 2、针对自然环境光信号统计特性的问题,我们提出了一种基于加权球面 调和框架的光照模型。根据自然环境光场的信号统计特性,同时考虑到确保光 照估计时的鲁棒性和区分不同环境光场的需求,基于加权球面调和框架的光照 模型不仅拥有基于球面调和框架的鲁棒特性,而且本身具有的随光照信号调制 的特性保证了光照区分的优势。 3、针对图像篡改检测应用的问题,我们利用图像目标的二维轮廓线信息 结合基于(加权)球面调和框架的光照模型,提出了一种鲁棒的图像篡改检测方 法。该方法在不同环境下漫反射物体的光照一致性度量和区分上具有更好的性 能,同时也为图像篡改认证技术提供了一种有效方法。
Other AbstractPresenting a lighting model of a complex natural environment is an effective method to deal with and simulate the real world lighting environment, and deserve deep research in both theory and application. First, the lighting model of natural com plex lighting environments is interdisciplinary and frontier fields of mathematics, com puter science, information science and cognitive science. Second, the lighting model has advanced the development of several techniques. Finally, the lighting model of complex lighting environments has the important research value in pattern recogni tion, digital forensics, 3D reconstruction and so on. Although the lighting model in terms of spherical harmonics has achieved great success in both theory and application, there are still many unaddressed issues. In this thesis, we focus on several key prob lems which have happened in the real situation, and make a series of achievements, as introduced in the following: 1、For the resistance to the degradation and the lighting discriminability prob lem, we propose to utilize spherical harmonic frame to represent the lighting model. To obtain the robustness of lighting estimation of Lambert objects in natural light ing fields and improve the discriminability of the complex lighting environments, the lighting model in terms of spherical harmonic frame which possesses the redundancy of multi-direction projections, not only has the resistance to the data completion and noise contamination which may occur in the lighting estimation, but also provide a better discriminability of the complex lighting environments. 2、For the statistical property of natural lighting environments, we present a lighting model in terms of weighted spherical harmonic frame. Considering the sta tistical property of natural lighting environments, the lighting model using weighted spherical harmonic frame not only has the robustness similar to spherical harmonic frame, but also has the advantage of discriminating different lighting environments which results from the modulation property of weighted lighting model. 3、For the application of image forensics, we describe a robust technique for exposing digital forgeries that we utilize the information along a 2D occluding contour and estimate the lighting feature using (weighted) spherical harmonic frame. The technique has advantage in measuring the lighting consistency and discriminating dif fuse objects in different lighting environments. Moreover, it is then u...
Other Identifier200718014628080
Document Type学位论文
Recommended Citation
GB/T 7714
赵文勇. 基于球面调和框架的凸Lambert物体光照模型的研究及应用[D]. 中国科学院自动化研究所. 中国科学院大学,2012.
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