please explain FACIAL ALIGNMENT and ACTIVE APPERANCE MODELSo

please explain FACIAL ALIGNMENT and ACTIVE APPERANCE MODEL

Solution

In face recognition application, accurate face alignment has determinative effect. Active Appearance Model (AAM) is one of the most studied methods for accurate locating objects. Active Appearance Models is a model-based algorithm that can automatically localize the object\'s features if there is a proper initialization. The idea of AAM is to combine the shape and texture information to form an appearance data, and an iterative algorithm is used to search facial features with minimum squared error. The AAM can be seen as an extension of Active Shape Model (ASM) which is also an extraction approach using only shape information directly.When applying Active Appearance Model, firstly we collect enough face images with various shapes as training set. Then we use a set of points to annotate face shape, so face shape can be represented by the coordinates of these landmarks.

After a series of transformation such as Principal Component Analysis, the mean shape of all the faces can be obtained to construct shape model for face alignment.
Given a new face image, we estimate the model’s initial position, compute the suggested movements, then we can get a good face alignment result.