From what I understand, in all of the R-CNN family of models (R-CNN, Fast R-CNN, and Faster R-CNN) there is a regression head that specifies how the bounding box should be modified from the proposed region. But the regression head is not given the information of the entire image, it's only given the part of the feature map that corresponds to the proposed section. If this proposed section isn't large enough to contain all of the object, how is the regression head supposed to know how much bigger the bounding box needs to be?