Pyramid pooling module used in PSPNet and UPPNet networks. The PPM pools input feature maps at different scales, processes them using residual stages, linearly upsamples features to input resolution, and finally concatenates them with input features. In this work, the PPM pools the input features to all resolutions that strictly divide the input resolution, e.g. for feature resolutions equal to 32, it pools at scales of 2, 4, 8, and 16. The number of residual blocks in each RS and the number of features in each residual block were the same for all PPMs used in exploratory tests and were equal to 4 and 8, respectively.