//图像对比度增强 -- 调整过暗或者过亮图像的对比度，使图像更加鲜明。 None
public static void ContrastEnhanceDemo(string pic)
{
client.Timeout = 60000; // 修改超时时间
var image = File.ReadAllBytes(pic);
// 调用图像对比度增强，可能会抛出网络等异常，请使用try/catch捕获
var result = client.ContrastEnhance(image);
FileInfo fileInfo = new FileInfo(pic);
string newfilename = fileInfo.DirectoryName + @"\" + fileInfo.Name.Substring(0, fileInfo.Name.Length - fileInfo.Extension.Length) + "_CEH" + fileInfo.Extension;
SaveBase64Image(result["image"].ToString(), newfilename);
}