Receptive Field of a CNN

The receptive field is how many input pixels influence one output unit. For a stack of layers each with kernel $k$ , stride $s$ and dilation $d$ , track the receptive field $r$ and the cumulative stride ("jump") $j$ :

r \leftarrow r + (k_{\text{eff}} - 1)\,j,\qquad j \leftarrow j \cdot s,\qquad k_{\text{eff}} = d(k-1)+1

starting from $r = 1, j = 1$ . Implement receptive_field(layers) where each layer is a dict with kernel, stride (default 1) and dilation (default 1). Return (r, j).