亮度分区自适应对数色调映射算法*

色调映射可将高动态范围图像显示在低动态范围显示器上。常用的对数全局色调映射算法由于压缩范围有限容易引起细节丢失,为此本文给出一种基于亮度分区的自适应对数色调映射算法。首先将高动态范围图像由RGB颜色空间转换为XYZ颜色空间以提取图像亮度信息,然后将亮度图分为高、中、低三个照度区域。根据区域亮度属性实施对数色调映射实现动态范围局部压缩,并进行融合处理以消除区域交界处的显示效果。同时采用双边滤波技术进行细节补偿。实验结果表明,此算法能有效压缩动态范围并再现真实场景信息,同时可以保留丰富的细节。

An adaptive logarithmic tone mapping arithmetic with luminance regionalization

High dynamic range image can be displayed in the traditional low dynamic device with tone mapping technology. logarithmic tone mapping is widely used but it suffers from the limited range compression ability and the lost of details. An adaptive logarithmic tone mapping arithmetic is proposed in this paper. The input high dynamic range image is transformed to XYZ color space and obtain brightness information, then it is devided into three regions: the bright region, the middle region and the dark region. Then the algorithm is applied to each region according its luminance features. A fusion arithmetic is used for region merge near edges to improve visual effect. The bilateral filter is used to detail compensation. Experimental results show that this algorithm can reproduce the real information, and details are well preserved.