Find max and min of convolution without doing convolution
You simply cannot skip doing the convolution altogether. There's no way to just bypass it. This scenario would be similar to trying to find the height of the Eiffel Tower without out already knowing it, looking it up, or measuring it somehow. Although convolutions can be slow on many machines, you will unfortunately need to perform the operation to get the minimum and maximum values.
Is it possible to find the max and min of both the horizontal and vertical convolution axis without going through and performing the actual convolution?