Predict alpha result

[Jason-xin]

After trained, I got alpha results like this:

Then, Is this correct alpha result? And, how can I get the final result like this:

[xiankgx]

Alpha result should be in the range of 0 to 1, or 0 to 255. You seemed to have trained the model to convert from color to grayscale. Note that grayscale is not alpha.