I am doing some researches on lip reading and need to extract the landmarks of the mouth. However, the available tech I know like face++ https://console.faceplusplus.com/documents/5679127 1 can only get the landmark of the complete face or It will complain that cannot detect the human face. My samples look like, which are incomplete human face, only the area of mouth are available.

QQ截图20191002090416.jpg1695×309 39 KB

What can i do to extract the landmarks of the mouth in such a incomplete human face images? Thanks for any advises.