Fig. 2

Dilated convolution. a Shows a standard 3 × 3 convolution kernel, and b, c show convolution kernels that have been expanded at different rates. b Shows a dilated convolution with an expansion rate of 2 (r = 2), namely r − 1 zeros are added between the elements of a standard 3 × 3 convolution kernel, and its receptive field is equivalent to that of a 7 × 7 convolution kernel. c Shows a dilated convolution with an expansion rate of 5 (r = 5). In this case, four zeros are added between the elements of a standard 3 × 3 convolution kernel, and its receptive field is equivalent to that of an 11 × 11 convolution kernel