// Hair component is a particular component not identified by landmarks
// This methods extract hair component starting from the bounding box of face and
// from the bounding box of shape identified by landmarks.
public Image <Gray, byte> GetHairComponent(Image <Gray, byte> image, PointF[] face, PointF[] shape, BoundingBoxParam hairParam)
{
var shapeBox = PointCollection.BoundingRectangle(shape);
var faceBox = Rectangle.Ceiling(new RectangleF(face[0].X, face[0].Y, face[1].X - face[0].X, face[1].Y - face[0].Y));
// calculate height from shape box and top border of image
var height = image.Size.Height - (image.Size.Height - shapeBox.Top);
// calculate the normalized height using the desidered aspect ratio
var normHeight = (int)Math.Floor(faceBox.Width * hairParam.AspectRatio);
// calculate if the normalized height go out of image border
var extra = height - normHeight;
// create the right bounding box, adding on bottom of bounding box the extra height
var hairBox = (extra < 0) ?
new Rectangle(faceBox.X, 0, faceBox.Width, height - extra) :
new Rectangle(faceBox.X, extra, faceBox.Width, normHeight);
var cropHeight = (int)Math.Floor(hairParam.CropWidth * hairParam.AspectRatio);
return(image.GetSubRect(hairBox).Resize(hairParam.CropWidth, cropHeight, Inter.Area));
}
// Extract an sub image using creating a bounding box from the landmarks points.
// Using the BoundingBoxParam, the sub image is resized in order to have same aspect ratio across different subject.
public Image <Gray, byte> CropToBoundingBox(Image <Gray, byte> image, PointF[] componentPoints, BoundingBoxParam param)
{
var bounding = GetBoundingBox(componentPoints, param.AspectRatio, param.Padding);
var cropHeight = (int)Math.Ceiling(param.CropWidth * param.AspectRatio);
return(image.GetSubRect(bounding).Resize(param.CropWidth, cropHeight, Inter.Cubic));
}
/// <summary>
/// Align and extract a component from face.
/// </summary>
/// <param name="image">Image that contains face.</param>
/// <param name="component">Landmark points of component. Ex. Mouth, Eyes, Eyebrows, ...</param>
/// <param name="referenceComponent">Reference landmarks points, which is used for alignement.</param>
/// <param name="param">Paramters for extract the subimage that contains the aligned component.</param>
/// <returns>Aligned component.</returns>
public Image <Gray, byte> AlignComponent(Image <Gray, byte> image, PointF[] component, PointF[] referenceComponent, BoundingBoxParam param)
{
var transformation = Procrustes.OrdinaryAnalysis(component, referenceComponent);
var alignedImage = Warp(image, transformation);
var alignedComponentPoints = CvInvoke.PerspectiveTransform(component, transformation);
var cropped = CropToBoundingBox(alignedImage, alignedComponentPoints, param);
return(cropped);
}
