I'm working with a Convolutional Neural Network in Matlab, and I'm struggling to understand the output dimensionality of a convolutional layer.
The input is an image:
227 x 227 x 3 (last dimension is rgb). Filter size is
11 x 11, and there are
96 filters. Vertical and horizontal stride is 4. There is no padding.
I tried calculating the output dimensionality as follows:
output_width = (Width - FilterWidth + 2*Padding)/StrideHorizontal = (227 - 11 + 0)/4 = 55.
Now, I expected an output of
55 x 55 x 3 x 96, as there are
96 filters, but I get
55 x 55 x 96. What I don't understand is, what happened to the color dimension?