Doubts about the alpha_loss

[huochaitiantang]

Doubts about the alpha_loss

[babyformula]

After another review, I started to understand the trimap code part. But there still some code maybe typos or something:

1. the alpha prediction loss function: alpha_loss = torch.sqrt((pred_alpha - alpha)**2 + 1e-12), as alpha = alpha/255, but pred_alpha did not divided by 255.
2. (alpha_loss * t_wi).sum() / (unknown_region_size + 1.), was it meant to be (unknown_region_size + epsilon)?

Thanks

[huochaitiantang]

1, the pred_alpha is the output of network and whose value is 0~1.
2, +1. can avoid dividing by 0.