颜色对比度是图像关注区域检测的重要线索,准确地提取反映图像不同颜色特征的区域,非常有助于计算各个区域的对比度.为了得到有效的对比图,首先利用封闭先验通过检测位平面中的连通性来提取具有不同颜色特征的封闭区域.其次,利用背景先验消除与图像边界连通的封闭区域并得到封闭区域掩膜.然后利用对比度先验与封闭先验,提出某区域在各个位平面中表现为封闭的次数越多越有可能是关注区域的假设,并通过封闭区域掩膜的叠加计算各个封闭区域的对比度.同时,结合人眼对小面积的封闭区域与封闭轮廓的感知特性,以及对关注区域视觉资源的分配特性,在获取对比度图的关键环节采取形态学滤波和高斯模糊,最终实现面向凝视点估计的图像显著度检测.与多种经典的检测模型相比,提出的方法取得了较好的性能.

Color contrast is an important cue for image attention region detection. Extracting image regions that contain distinguishing color features is very helpful for computing the contrast of each image region. To obtain an efficient contrast map, the closure prior is firstly exploited to pick up the image regions containing distinguishing color features via connectivity detection in layered bit-planes. Secondly, the background prior is used to remove closed regions that touch image boundaries, and obtain closed region masks, in which the elements of closed regions are labeled with "1". Thirdly, a hypothesis, that a region should have big chance to be an attention region if it appears more times as a closed region in layered bit-planes, is proposed based on the contrast and closure priors. Further, the closed region masks of all bit-planes are accumulated to obtain the contrast of each connected region. Meanwhile, by taking account of the characteristics of human visual system with respect to the perception for small attention region, and visual resource allocation, several morphological filtering technologies are adopted to the key steps of contrast computing. Finally, the saliency map oriented to visual fixation estimation is generated. The experimental results show the presented detection method achieves acceptable performance compared with several state-of-the-art models.

国家自然科学基金(61300140, 61402430)