基于梯度域的保纹理图像阴影去除算法

Texture-preserving shadow removal algorithm based on gradient domain

针对当前自然图像阴影去除算法需要多次人工交互、阴影去除结果纹理信息丢失等问题,提出了基于梯度域的图像保纹理阴影去除算法。该方法只需确定出阴影的大概边界,然后在梯度域中,分别对阴影内部和阴影边界的梯度进行最优化修正,得到无阴影的梯度图像,最后利用泊松方程,恢复出无阴影图像。利用多幅图像的实验结果证明,该算法操作简单,不需要多次人机交互,且阴影区域内纹理细节得到了较好的恢复。

Accurate shadow boundary detecting and texture-preserving are two critical difficulties in shadow removal.To solve these problems,a new shadow removal method based on gradient field was proposed.Firstly,shadow boundary was detected approximately.Then,the gradients in internal shadow region and shadow boundary were modified respectively to obtain the non-shadowed gradient field.Based on the gradient field,the information in shadow regions was recovered with Poisson equation.The experimental results with several images indicate that the method can remove shadow from images easily while preserving the textures in the shadow regions,and it is not sensitive to the accuracy of shadow boundary.