CLAHE in opencv for 16 bit image enhancement display

cv::Mat src(HEIGHT,WIDTH,CV_16UC1);
//... load image data to .src
cv::Mat tmp;
cv::Ptr<cv::CLAHE> clahe = createCLAHE(20.0,cv::Size(8,8));
clahe->apply(src,tmp);
double minVal,maxVal;
minMaxIdx(tmp,&minVal,&maxVal);
double scaleVal = (maxVal - minVal) > 1.0 ? (maxVal - minVal) : 1.0; // Avoid exemption 0
tmp -= minVal; // Normalize to [0-255]
tmp.convertTo(dst,CV_8UC1,255.0/scaleVal,0.0);// Normalize to [0-255]