How to initialize CNN Layer with Gammatone Filters (or any filter) for sound regression (Or Classification)?

Question

For my project I need to initialize the CNN 1st Layer kernel with Gammatone filters according to papers ( https://www.mdpi.com/1099-4300/20/12/990/htm ) ,( https://www.groundai.com/project/end-to-end-environmental-sound-classification-using-a-1d-convolutional-neural-network/1 ) and a few others. What does it exactly mean to initialize the cnn kernel with Gammatone filter (Or any filter). How does one implement it? Is it a custom layer? Any tips and guidance would be much appreciated!

for instance

conv_1 = Conv1D(filters = 64, kernel_size = 3, kernel_initializer = *insert Gammatone Filter*, padding = 'same', activation='relu', input_shape = (timesteps, features))(decoder_outputs3)

TIA

Answer 1

You could use TensorFlows constant initializer:

gammatone_filter_kernel = np.array([...])
init_kernel = tf.constant_initializer(gammatone_filter_kernel)
# ...
conv_1 = Conv1D(filters = 64, kernel_size = 3, kernel_initializer = init_kernel, padding = 'same', activation='relu', input_shape = (timesteps, features))(decoder_outputs3)
# ...

If your filter is some kind of preprocessing step to your signal you could set the trainable attribute of the conv laver to False and the weights will be fixed.