我需要在C++中实现调整图像级别的算法，该算法类似于Photoshop或GIMP中的级别功能。即，输入为：色彩RGB图像要调整，调整边点、黑点、中间调点、输出自/到值。但我还没有找到任何关于如何执行此调整的信息。可能有人推荐我学习算法描述或资料。
到目前为止，我自己想出了以下代码，但它没有给予预期的结果，类似于我所看到的，例如在GIMP中，图像变得太亮。下面是我当前的代码片段：

const int normalBlackPoint = 0;
const int normalMidtonePoint = 127;
const int normalWhitePoint = 255;
const double normalLowRange = normalMidtonePoint - normalBlackPoint + 1;
const double normalHighRange = normalWhitePoint - normalMidtonePoint;

int blackPoint = 53;
int midtonePoint = 110;
int whitePoint = 168;
int outputFrom = 0;
int outputTo = 255;

double outputRange = outputTo - outputFrom + 1;
double lowRange = midtonePoint - blackPoint + 1;
double highRange = whitePoint - midtonePoint;
double fullRange = whitePoint - blackPoint + 1;
double lowPart = lowRange / fullRange; 
double highPart = highRange / fullRange; 

int dim(256);
cv::Mat lut(1, &dim, CV_8U);
for(int i = 0; i < 256; ++i)
{
    double p = i > normalMidtonePoint
        ? (static_cast<double>(i - normalMidtonePoint) / normalHighRange) * highRange * highPart + lowPart
        : (static_cast<double>(i + 1) / normalLowRange) * lowRange * lowPart;
    int v = static_cast<int>(outputRange * p ) + outputFrom - 1;
    if(v < 0) v = 0;
    else if(v > 255) v = 255;
    lut.at<uchar>(i) = v;
}

....

    cv::Mat sourceImage = cv::imread(inputFileName, CV_LOAD_IMAGE_COLOR);
    if(!sourceImage.data)
    {
        std::cerr << "Error: couldn't load image " << inputFileName << "." << std::endl;
        continue;
    }

#if 0       
    const int forwardConversion = CV_BGR2YUV;
    const int reverseConversion = CV_YUV2BGR;
#else
    const int forwardConversion = CV_BGR2Lab;
    const int reverseConversion = CV_Lab2BGR;
#endif

    cv::Mat convertedImage;
    cv::cvtColor(sourceImage, convertedImage, forwardConversion);

    // Extract the L channel
    std::vector<cv::Mat> convertedPlanes(3);
    cv::split(convertedImage, convertedPlanes);

    cv::LUT(convertedPlanes[0], lut, convertedPlanes[0]);

    //dst.copyTo(convertedPlanes[0]);
    cv::merge(convertedPlanes, convertedImage);

    cv::Mat resImage;
    cv::cvtColor(convertedImage, resImage, reverseConversion);
    cv::imwrite(outputFileName, resImage);