vertical band [L, w] and horizontal band [L, h] - L: adjustable bandwidth, which controls the receptive field size of vector elements - much smaller odd number, chosen from 1 to 7 - each band slide on the heatmap and average the values - converting into vector reduce post-processing complexity: O(N^2) -> O(N) - output: [N, C, w/h, 2] - C: number of facial landmark - Aggregated - fusing the vectors generated by different bandwidth - use this method for experiments - bandwidth: 3 and 5