  In this paper some of the different techniques used to localize the lips from
the face are discussed and compared along with its processing steps. Lip
localization is the basic step needed to read the lips for extracting visual
information from the video input. The techniques could be applied on asymmetric
lips and also on the mouth with visible teeth, tongue & mouth with moustache.
In the process of Lip reading the following steps are generally used. They are,
initially locating lips in the first frame of the video input, then tracking
the lips in the following frames using the resulting pixel points of initial
step and at last converting the tracked lip model to its corresponding matched
letter to give the visual information. A new proposal is also initiated from
the discussed techniques. The lip reading is useful in Automatic Speech
Recognition when the audio is absent or present low with or without noise in
the communication systems. Human Computer communication also will require
speech recognition.
