landmark losss problem
yutaka329 opened this issue · comments
nice work, I dont comprehend heatmap offset format. such as x_offset= 223 * log(p/(1-p)) / 16.
can you provide some explanation? thank you.
Hi!
Offset values are in the range [0, 1), normalized with respect to the full resolution of the image. However, during training, the model was not able to learn offsets very well, because the differences from pixel to pixel were very slight. To make the differences stronger and offsets easier to learn, when creating the offset maps for training, I multiply offsets by 16 and take the sigmoid to bring them back into the range of [0, 1). log(p/(1-p)) / 16 is the inverse of multiplying by 16 and taking the sigmoid.
I hope that helps a bit. If you have any further questions, please let me know.
got it , thank you a lot for your reply