What is method for smooth 2d image?

exercise requestes transform in below picture. please help me how to solve it. Thank you.

Would you like to use a neural network for this use case?
What kind of exercise is this? I don’t think someone will (and should) give you a full solution if this is some kind of homework.
Have you tried different methods before? If so, where are you stuck?

this exercise is in wavelet transfom. I try to apply some wavelet filter but it’s not smooth. Thank you @ptrblck relying.