Then, a deconvolution layer 1004 expands the image. In this process, the output image from the pooling layer 1003 is partially expanded and then convolution operation is performed across the planes. First, the expansion of the output image data IG3(u, v, p2) from the pooling layer 1003 is performed through the procedure below. IT(2u,2v,p2)=IG3
Then, using the equation below, the deconvolution layer 1004 performs convolution operation with IT obtained by the above expansion process as an input.