How to get 106 landmarks?

[Tallisgo]

hi, I have some questions about generate the coordinates of keypoints. Why Face_Alignment_prob need to plus1 and then divide 2? What is the meaning of Face_Alignment_prob

alignmentface.landmarks[start]=int((Face_Alignment_prob[start]+1)*img.cols / 2); alignmentface.landmarks[start+1]=int((Face_Alignment_prob[start+1]+1)*img.cols / 2);

Thanks for your help.