针对高动态范围图像在亮度压缩过程中损坏色度信息,导致映射后图像明暗不同区域色偏严重的问题,提出一种基于颜色校正模型的梯度域自适应色调映射改进算法。通过建立图像亮度空间高斯金字塔并结合泊松方程恢复图像亮度;再引入色度空间颜色校正算法,在图像色差和消色差颜色之间进行线性插值,并通过计算处理前后的亮度比值调节颜色校正因子用来增强图像饱和度;最终实现自适应校正图像色度信息的功能。与Larson、Drago、Reinhard和梯度域色调映射的局部色调映射算法作对比,结果表明经改进算法处理后的图像在信息熵、对比度和平均梯度方面均有良好的优化效果,有效减少了亮度压缩引起的色偏问题,增强了图像整体色彩感观度。

In this study, we propose an improved gradient domain adaptive tone mapping algorithm based on the color correction model to solve the damage of chromaticity information with respect to the process of image brightness compression in a high dynamic range, resulting in severe color gradation in regions having different image brightness and shade after tone mapping. The image brightness can be restored by combining the Gaussian pyramid of the image luminance space and Poisson equation. Subsequently, we introduce the chromaticity space color correction algorithm and apply linear interpolation between the chromatic aberration of the image and the achromatic color. Further, we adjust the color correction factor by calculating the brightness ratio before and after processing to enhance image saturation. Finally, we realize adaptive correction of the image chromaticity information. We also perform a comparison with the typical Larson, Drago, Reinhard, and gradient domain local tone mapping algorithms. The results prove that the image processed using the improved algorithm exhibits good optimization with respect to the information entropy, contrast, and average gradient. The proposed method effectively reduces the color shift because of brightness compression and enhances the overall color perception of the image.