Don't assume that the dst is all black
Small changes
1) The laplacian pyramid should contain the lowest level of the associated gaussian
2) We should use I1-I2, not |I1-I2| : we want to be able to fully recover the picture using the pyramid, we can't loose sign information
Added function to rebuild image from it's laplacian pyramid
Again, small changes
Fix Laplacian merging, integrated it into the enhancement process