基于笔画的图像色调调整.pdf

A Dissertation Submitted to Shanghai Jiao Tong University forthe Degree puter ScienceMaster STROKE-BASED IMAGE TONAL ADJUSTMENT Author:Huang Shanshan Specialty: Computer Applied Technology Advisor:Prof. MaLizhuang School of Electronic,Information andElectricalEngineering Shanghai Jiao Tong University Shanghai, December 1, 2010 上海交通大学工学硕士学位论文摘要第 I 页基于笔画的图像色调调整摘要随着当今时代数码相机的平民化,对数码相片的后期编辑与处理的需求日益提高,而色调调整是其重要一方面。传统的局部色调调整工具如Photoshop面临一个较大的缺陷:人们在选择物体或区域时,往往需要经过细致的抠取过程,而这将耗费大量时间与精力。本文提出了一种基于笔画的图像局部色调调整方法。该方法的核心是基于笔画的编辑传播,即用户仅需要在感兴趣区域内的任意位置画上几笔,并指定需要调整的参数(如亮度、对比度、饱和度等)及大小, 该方法不需要繁杂的边界标定过程,即可将用户笔画约束传播到相应图像区域,达到局部色调调整的目的。本文首先为用户笔画统一定义了编辑量与编辑图的概念,本着“相似区域应获得相似编辑”的原则,选取一种可以较好地保持模糊物体边缘的相似度计算,建立编辑传播能量公式系统,并用能量最小化方程求解这个系统。之后,以编辑图为指导, 将编辑量映射到不同色彩空间上调整色调参数。本文的创新是,通过比较基于邻域的matting相似度及传统使用的全局相似度,改进了编辑传播能量公式系统,并将其应用于包含复杂物体上海交通大学工学硕士学位论文摘要第 II 页的自然图像中。与此同时,本文实现了一个局部色调调整工具,在两种设备无关的色彩空间(Lab及HSI空间)中对图像进行了颜色、亮度、饱和度等色调参数的调整实验,并与传统方法进行了比较。实验结果表明,本文的方法对自然图像的局部色调调整更行之有效。关键词:图像编辑,基于笔画,编辑传播,相似度上海交通大学工学硕士学位论文 ABSTRACT 第 III 页 STROKE-BASED IMAGE TONALADJUSTMENT ABSTRACT paniedwith the population of digital camera, the desire for tonal adjustment hasbeen increasingsignificantly. However, existinglocal tonal adjustment tools such as Photoshop often suffer from the fact that the fine selection process of an object or a region is time-consumingand labor- intensive. This thesisproposesa stroke-based local tonal adjustmentapproach, the kernelof whichis stroke-based edit propagation. Itallows users to roughly paint on regionsof interest and specify the editparameter(such as color, brightness, saturation, etc.)as well as edit value on each region, and propagatesthese user constraintsto the rest of the imagewithout segmentation. Firstly, edit-value and edits-map aredefined to generally support different image appearance edits. Then, an edge-preservingaffinity for natural image with fuzzy object is presented to measure the similarit