What if the training pairs are without bbox?

            area[i, 0] = obj['bbox'][2]*obj['bbox'][3]

This method requires bbox during training. What if the training pairs are without bbox?

How can we calculate the area and loss of offset?

[Gengzigang]

The normalization tool should be designed for your project. You can use any length that reflects the size of the person, or you can directly regress the offsets without this normalization.

OK. I am trying the BBox generation based on the projection. But the BB is for the head rather than the whole body.

Thank you very much!

For your case, I think the heatmap is more suitable because you just need to detect the head keypoints and the heatmap can detect all the same kind of the keypoints precisely and efficiently.

[Gengzigang]

Hi, we use the area of one person’s bounding box to normalize this person’s offset during calculating the loss of the offset map. Alternatively, you can use the maximum and minimum coordinates of the key points to estimate the size of the people. The selection of this normalization tool doesn’t influence the performance.

By the way, we use the average of all keypoints belong to the same person as the center of this person. In the code, we can choose the center of the person’s bounding box as the center of this person, which may cause confusion. The APs of the two choices are the same.