An apparatus for an artificial neural network includes a format converter, a sampling unit, and a learning unit. The format converter generates a first format image and a second format image based on an input image. The sampling unit samples the first format image using a first sampling scheme to generate a first feature map, and samples the second format image using a second sampling scheme different from the first sampling scheme to generate a second feature map. The learning unit operates the artificial neural network using the first feature map and the second feature map.