difference between "FPN-Summed" and "Semantic FPN"

[valencebond]

What is the difference between "FPN-Summed" and "Semantic FPN" in table5, described in Section3.3? As far as I know, the high-resolution feature (1/4 scale of the input image) in Semantic FPN is also obtained by upsampling and element-wise summation

[yanwei-li]

Hi, the FPN-Summed represents that we upsample and sum the feature from FPN directly (without convs). And Semantic FPN includes convs in each upsample stage.

[valencebond]

thanks for your response