Thank you very much! But I still don’t quite get it. Let me clarify my question a bit.
Suppose I have a data of size (128,28,28), where 128 is batch size, and 28*28 is size of each sample. When applying convolution, I want use different masked convolution filters at different pixel. Namely, at pixel (1,1), maybe I want to mask out all pixels on its right, but at pixel (2,2),  want to mask out all pixels on its left. So do you have any idea here?