Some basic suggestions: All of the blur/ functions could see big improvements with some simple changes: * Use separable kernels whenever possible (this reduce

Some basic suggestions: All of the blur/ functions could see big improvements with some simple changes: * Use separable kernels whenever possible (this reduces a O(K^2) evaluation to 2K evaluations) Some filters (like your box filter) can be done efficiently as a linear combination of IID filters (i.e. implicitly computing a pair of running sums, subtracting one from the other as you go). * The convolve/ package could use some cache blocking, and should definitely have the conditionals on the inner-loop removed. Unfortunately, these changes will likely make your code a bit more difficult to read. This is one of the reasons Halide has become so popular for image-processing (if you're interested in high performance image processing without sacrificing maintainability, Halide is definitely worth looking into!)