<p>SDM is a method to align shapes in images. It uses feature extractors (SIFT and HoG) in the process, but is not a feature extractor.
Similar methods are ASM, AAM or CLM, but SDM has better performance and accuracy. </p>

<p>In the case of SDM, in the training process, the system learns some descent vectors from a initial shape configuration (different from the shapes in the database) to the database sets. Those vectors have the hability of fitting a new initial configuration with the face shape in the image you want to fit in.</p>

<p>This link can help you to learn more about it: <a href="http://arxiv.org/pdf/1405.0601v1.pdf" rel="nofollow">http://arxiv.org/pdf/1405.0601v1.pdf</a></p>

<p>About the code, there is some demo samples in the main page of <a href="http://www.humansensing.cs.cmu.edu/intraface/" rel="nofollow">IntraFace</a> but if you are looking for the code, I don´t think you can find it.</p>
Supervised Descent Method (SDM)
<p>Can someone explain briefly how SDM (Supervised Descent Method) for Feature Extraction works?
I searched a lot on the Internet but couldn't found what I was looking for.</p>

<p>Is it only for feature extraction in videos, or can it be used in both videos and images?</p>

<p>If someone can explain, it would be of great help.</p>