借助opencv库，实现将图片中的阴影去掉，记录下实现代码，如下

+(UIImage*)removeShadow:(UIImage*)processedImage{
    cv::Mat src = [MMOpenCVHelper cvMatFromAdjustedUIImage:processedImage];
    //1.将图像转为灰度图
    cv::Mat gray;
    cv::cvtColor(src, gray, cv::COLOR_BGR2GRAY);
    //定义腐蚀和膨胀的结构化元素和迭代次数
    cv::Mat element = cv::getStructuringElement(cv::MORPH_RECT, cv::Size(3, 3));
    int iteration = 9;
    //2.将灰度图进行膨胀操作
    cv::Mat dilateMat;
    cv::morphologyEx(gray, dilateMat, cv::MORPH_DILATE, element, cv::Point(-1, -1), iteration);
    //3.将膨胀后的图再进行腐蚀
    cv::Mat erodeMat;
    cv::morphologyEx(dilateMat, erodeMat, cv::MORPH_ERODE, element, cv::Point(-1, -1), iteration);
    //4.膨胀再腐蚀后的图减去原灰度图再进行取反操作
    cv::Mat calcMat = ~(erodeMat - gray);
    //5.使用规一化将原来背景白色的改了和原来灰度图差不多的灰色
    cv::Mat removeShadowMat;
    cv::normalize(calcMat, removeShadowMat, 0, 200, cv::NORM_MINMAX);
    //转换成8bit图像显示
    convertScaleAbs(removeShadowMat, removeShadowMat);
    UIImage *resultImage=[MMOpenCVHelper UIImageFromCVMat:removeShadowMat];
    return resultImage;
}