基于阈值分类的色调映射方法选择

A tone mapping method based on threshold classification

为了更好发挥全局映射算法和局部映射算法的优点,对20组高动态范围图像(High Dynamic Range Image,HDRI)分别进行全局算法和局部算法映射,由所得结果确定出均值亮度的一个范围,若目标图像的均值亮度落入该范围内,采用局部算法,否则采用全局算法。用4组HDRI进行验证,结果表明,增加均值亮度阈值判决后,可以克服对目标图像盲目使用单一映射方法的缺陷。

In order to make better use of the advantages of both global mapping and local mapping to improve the performance of HDRI （High Dynamic Range Image） mapping, a group of 20 HDRIs with different mean intensities are used with global mapping and local mapping applied respectively. By analyzing the relationship between the HDRI mapping results and the mean intensity values of the HDRIs, a mean-intensity-range for thresholding purpose is determined. If the mean intensity of a HDRI falls into this range, the local mapping algorithm is chose, otherwise global mapping is ap- plied. To verify the performance of the above described process, four groups of HDRI are used for testing. Experimental results show that compared to any other single mapping method, the pro- posed thresholding process can effectively improve the performance of HDRI mapping.