Correlators at fixed redshifts z_i = z_j = 0,1,5,10,30 from top to bottom (from red to yellow) for high-density regions. Note that in this figure we define the high-density regions as the ones where the pixel values on the largest smoothed wavelet field reach the top 10% of all the values. Using these pixels, we define the mask, which is used for correlating only the highest density pixels with the corresponding values smoothed on a smaller scale.