SA :)
This is a summary for a paper that proposes an automatic computer-aided diagnosis (CAD) system
for early detection of lung cancer by analyzing chest 3D computed tomography (CT) images. 
This is a very useful paper, it discusses the steps followed by the system and states the algorithms used briefly.


For the summary : Click here
For the original : Go here and then download the full issue, the paper's name is:
"Computer Aided Diagnosis System for Early Detection of Lung Cancer Using Chest Computer Tomography Images" 


It's a good site by the way with many papers available for free :D

السلام عليكم و رحمة الله و بركاته

Before i begin talking about SNAKES, first i have to answer some questions.

What is image segmentation?
- It's subdividing or partitioning an image into it's constituent regions.

Why?
- To extract features of interest in images by looking for mathematical entities which describe the shapes of objects appearing in images.

So, why do we need image segmentation in our project?
- we want to extract the lung area from a CT (Computed Tomography) image which is our interest, for computing and detecting the abnormal shadow areas that are suspicious to be tumors.

What we have to do?
-we have to find a method that looks for any shape in the image that is smooth and forms a closed contour.
-From here we begin our research in "SNAKES".

Introduction:

• The active contour model algorithm, first introduced by Kass et al., deforms a contour to lock onto features of interest within an image.
• Usually the features are lines, edges, and/or object boundaries.
• Kass et al. named their algorithm, “Snakes” because the deformable contours resemble snakes as they move

Framework for Snakes

• The active contour system provides the ability to interactively guide the contour detection by placing initial points
• A higher level process or a user initializes any curve close to the object boundary.
• The snake then starts deforming and moving towards the desired object boundary.
• In the end it completely “shrink-wraps” around the object.