The error message says it was expecting a 3-D array and it only received a 2-D array. You can use numpy.reshape to reshape your 2-D array to 3-D. Without knowing more about your data structure, I may just share with you this article that talks about the 3-D array for CNN: https://towardsdatascience.com/convolutional-autoencoders-for-image-noise-reduction-32fce9fc1763. Let me know how it goes.