FMix Low-Frequency Mask

Problem

Build a deterministic low-frequency mask for FMix-style augmentation.

At pixel (i, j) compute v = 0.5 * (cos(2*pi*i/h) + cos(2*pi*j/w)); the mask value is 1 when v > threshold, otherwise 0. Return the H x W mask.

case 1

in: [4,4,0]

expected: [[1,1,0,1],[1,1,0,0],[0,0,0,0],[1,0,0,0]]

case 2

in: [4,4,0.5]

expected: [[1,0,0,0],[0,0,0,0],[0,0,0,0],[0,0,0,0]]

case 3

in: [2,2,-0.5]

expected: [[1,1],[1,0]]

Starter codePython

def fmix_mask(h, w, threshold):
    # Your code here
    pass

3 test cases · run your code against them in the editor