message: Fix self converTo.
  We still need images[i] = img because it is used below in buildPyramid.
diff: @@ -176,16 +176,16 @@ public:
  parallel_for_(Range(0, static_cast<int>(images.size())), [&](const Range& range) {
  for(int i = range.start; i < range.end; i++) {
  - Mat& img = images[i];
  - Mat gray, contrast, saturation, wellexp;
  + Mat img, gray, contrast, saturation, wellexp;
  std::vector<Mat> splitted(channels);
  - img.convertTo(img, CV_32F, 1.0f/255.0f);
  + images[i].convertTo(img, CV_32F, 1.0f/255.0f);
  if(channels == 3) {
  cvtColor(img, gray, COLOR_RGB2GRAY);
  } else {
  img.copyTo(gray);
  }
  + images[i] = img;
  split(img, splitted);
  Laplacian(gray, contrast, CV_32F);
  