US Patent 10360470 Implementation of MobileNet in a CNN based digital integrated circuit

Method and systems of replacing operations of depthwise separable filters with first and second replacement convolutional layers are disclosed. Depthwise separable filters contains a combination of a depthwise convolutional layer followed by a pointwise convolutional layer with input of P feature maps and output of Q feature maps. The first replacement convolutional layer contains P×P of 3×3 filter kernels formed by placing each of the P×1 of 3×3 filter kernels of the depthwise convolutional layer on respective P diagonal locations, and zero-value 3×3 filter kernels zero-value 3×3 filter kernels in all off-diagonal locations. The second replacement convolutional layer contains Q×P of 3×3 filter kernels formed by placing Q×P of 1×1 filter coefficients of the pointwise convolutional layer in center position of the respective Q×P of 3×3 filter kernels, and numerical value zero in eight perimeter positions.