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### Image preprocessing  The only preprocessing step used is convolving the image with a \( (2n+1)\times(2n+1) (2n+1) \times (2n+1)  \) kernel where the center element is \(1/(n+1)\) and the k-th layer surrounding the center is made up of values \(1/(8k\cdot(n+1))\). For example, when n=1 the kernel would be \[  \left(   \begin{array}{ccc}