+刻画图像内容的颜色特征详解.ppt

颜色相关图定义 Let For p1=(x1,y1) ,p2=(x2,y2), define Denote the set {1,2,…,n} by [n]. 颜色相关图定义 Let a distance d be fixed a priori. Then the color correlogram of I for i,j,k If we only consider the correlogram between the identical colors, we have autocorrelogram, which is defined by 颜色相关图 颜色相关图可以看作是一张用颜色对i, j索引的表，其中i, j的第k个分量表示与颜色为c(i)的像素距离为k的像素集中的颜色为c(j) 的概率 如果考虑到任何颜色之间的相关性，颜色相关图会变得非常复杂和庞大 (空间复杂度为O(m2d))。一种简化的变种是颜色自动相关图（color auto-correlogram）。 实验表明，颜色相关图比颜色直方图和颜色聚合向量具有更高的检索效率，特别是查询空间关系一致的图像。 颜色相关图 Jing Huang, et al, “Image Indexing Using Color Correlograms”, Proceedings of the 1997 Conference on Computer Vision and Pattern Recognition (CVPR 97) 选做作业: 编写一个C++的类用于实现彩色Color correlogram的抽取。 Dark Channel histogram of the intensity of the pixels in all of the 5,000 dark channels (each bin stands for 16 intensity levels). corresponding cumulative distribution. histogram of the average intensity of each dark channel. 旧金山的艺术博物管 加州大学 检索老师 美国邮票、专利和商标 * 。 * *  * * 红色盲；?第一原色盲 * Protanopic 红色盲,怎么样评价图像的Accessibility * It learns a non-linear fitting function by a linear maximum-margin learning machine in a kernel-induced feature space. * * Several typical examples with high, middle and low colorblind accessibilities for protanopic users. We see that the qualities of several images are well preserved while several others significantly degrade due to the loss of color information. Accessibility Assessment Analysis-based Accessibility Assessment 颜色量化 Accessibility Assessment Learning-based Accessibility Assessment 训练数据 用Support Vector Regression (SVR)回归 Accessibility Improvement The re-coloring process is accomplished by two color rotation steps in CIELAB domain. Pearson correlation coefficients between our accessibility measurements and the subjective scores. Pearson相关系数用来衡量两个数据集合是否在一条线上面，它用来衡量定距变量间的线性关系。 思考题　 我们平时怎么描述颜色，喜欢用什么样的颜色空间？ 与前面的颜色空间差别？ 怎么转换到我们喜欢的颜色空间？ 图像的颜色特征 颜色特征对图像本身的尺寸、方向、视角的依赖性较小，从而具有较高的鲁棒性。 需要采用一定的量化方法将颜色特征表达为紧凑的向量形式，从而在向量空间上进行相