Questions about Omega_train and loss of iou branch

[zhoulukuan]

Hi, i have other two questions and hope to get your help:

1. What's the relationship between Omega_train(0.5) and normalized iou labels range([-1, 1])?
   In another issue What are the target of the IoU-Net branch? #5 , I was told that iou branch labels can be normalized and achieved by 2 * (iou-0.5). I found, after filtering by the threshold of 0.5, the label of the samples is between [0.5,1]. So the normalized target labels is between [0,1]. Is this a intentionally design? If we change the Omega_train, do we need to change the normalized formula?
2. How to compute the loss of iou branch? Dose the output of iou branch need to be activated by sigmoid layer or take an absolute value? What's the weight of the iou branch and original reg/cls branch?