  Recently, methods based on Convolutional Neural Networks (CNN) achieved
impressive success in semantic segmentation tasks. However, challenges such as
the class imbalance and the uncertainty in the pixel-labeling process are not
completely addressed. As such, we present a new approach that calculates a
weight for each pixel considering its class and uncertainty during the labeling
process. The pixel-wise weights are used during training to increase or
decrease the importance of the pixels. Experimental results show that the
proposed approach leads to significant improvements in three challenging
segmentation tasks in comparison to baseline methods. It was also proved to be
more invariant to noise. The approach presented here may be used within a wide
range of semantic segmentation methods to improve their robustness.
