I implemented the algorithm for local contrast(fast clahe in fpga ). I need to confirm that it improves the image. I have tried to use different analysis methods, but it seems wrong : take original image and original with noise and after compare them. Also tried to use the method of "reference spectrum", but get incorrect results. Could be we use gradients and detected borders, using the methods of the masks of the Sobel or Roberts or Prewitt or((Histogram of Oriented Gradients, SURF) edge or blobs)? Further the more find edges or blobs the more better improved the image?