When mapping a biological primary visual cortex to a computational vision system, what does a 'receptive field' define in terms of spatial input?

In a biological primary visual cortex and corresponding computational vision systems, a receptive field defines the specific, localized region of the visual space where a stimulus must be present to trigger a response from a particular neuron. The spatial input is defined by two primary characteristics: position and size. The positional aspect identifies exactly where in the field of vi....