Apply Bezier Curve on Lip
In the lip box, there is lip and may be some part of nose. So, around the box there is skin color or the skin. So, we convert the skin pixel to white pixel and other pixel as black. We also find those pixels which are similar to skin pixels and convert them to white pixel. Here, if two pixels RGB values difference is less than or equal 10, then we called them similar pixel. Here, we use histogram for finding the distance between the lower average RGB value and higher average RGB value. If the distance is less than 70, then we use 7 for finding similar pixel and if the distance is getter than or equal 70 then we use 10 for finding similar pixel. So, the value for finding similar pixel depends on the quality of the image. If the image quality is high, we use 7 for finding similar pixel and if the image quality is low, we use 10.
So, in the binary image, there are black regions on lip, nose and may some other little part which have a little different than skin color. Then we apply big connected region for finding the black region which contain lip in binary image. And we are sure that the big connected region is the lip because in the lip box, lip is the largest thing which is different than skin.
Then we have to apply Bezier curve on the binary lip. For apply Bezier curve, we find the starting and ending pixel of the lip in horizontal. Then we draw two tangents on upper lip from the starting and ending pixel and also find two points on the tangent which is not the part of the lip. For the lower lip, we find two point similar process of the upper lip. We use Cubic Bezier curves for draw the Bezier curve of the lip. We draw two Bezier curve for the lip, one for upper lip and one for lower lip.
Apply Bezier Curve on Eye
For apply Bezier curve on eyes, first we have to remove eyebrow from eye. For remove eyebrow, we search 1stcontinuous black pixel then continuous white pixel and then continuous black pixel from the binary image of the eye box. Then we remove the 1st continuous black pixel from the box and then we get the box which only contains the eye.
Now, the eye box which contains only eye, has some skin or skin color around the box. So, we apply similar skin color like the lip for finding the region of eye. Then we apply big connect for finding the highest connected region and this is the eye because in the eye box, eye is the biggest thing which is not similar to the skin color.
Then we apply the Bezier curve on the eye box, similar to the lip. Then we get the shape of the eye.