Reconstruct Laplacian Pyramid

reconstruct.jl

# reconstruct an image (approximate, for the time being), from its pyramidal decomposition
function reconstruct(L)
  im = last(L)

  for n = (length(L)-1):-1:1
     # upscale
    im2 = zeros(2*size(im)[1], 2*size(im)[2])
    im2[1:2:end,1:2:end, :] = im

    # gaussian interpolation
    kernel = [1/18, 1/2, 16/18, 1/2, 1/18];
    im2 = imfilter(imfilter(im2, kernel, "reflect"), kernel', "reflect")

    im = im2
    im += L[n]
  end

  return im
end