Eliminating blob inside another blob - image-processing

Question

I'm currently working on a program for character recognition using C# and AForge.NET and now I'm struggling with the processing of blobs.
This is how I created the blobs:
BlobCounter bcb = new BlobCounter();
bcb.FilterBlobs = true;
bcb.MinHeight = 30;
bcb.MinWidth = 5;
bcb.ObjectsOrder = ObjectsOrder.XY;
bcb.ProcessImage(image);
I also marked them with rectangles:
Rectangle[] rects;
rects = bcb.GetObjectsRectangles();
Pen pen = new Pen(Color.Red, 1);
Graphics g = Graphics.FromImage(image);
foreach (Rectangle rect in rects)
{
g.DrawRectangle(pen, rect);
}
After execution my reference image looks like this:
BlobImage
As you can see, almost all characters are recognized. Unfortunately, some character include blobs inside a blob, e.g. "g", "o" or "d".
I would like to eliminate the blobs which are inside another blob.
I tried to adjust the drawing of the rectangles to achieve my objective:
foreach (Rectangle rect in rects)
{
for (int i = 0; i < (rects.Length - 1); i++)
{
if (rects[i].Contains(rects[i + 1]))
rects[i] = Rectangle.Union(rects[i], rects[i + 1]);
}
g.DrawRectangle(pen, rect);
}
...but it wasn't successful at all.
Maybe some of you can help me?

Answer 1

you can try to detect rectangles within rectangles by check their corner indices,
I have one MATLAB code for this which i have written for similar kind of problem:
Here is snippet of the code is:
function varargout = isBoxMerg(ReferenceBox,TestBox,isNewBox)
X = ReferenceBox; Y = TestBox;
X1 = X(1);Y1 = X(2);W1 = X(3);H1 = X(4);
X2 = Y(1);Y2 = Y(2);W2 = Y(3);H2 = Y(4);
if ((X1+W1)>=X2 && (Y2+H2)>=Y1 && (Y1+H1)>=Y2 && (X1+W1)>=X2 && (X2+W2)>=X1)
Intersection = true;
else
`Intersection = false;`
end
Where X and Y are upper left corner indices of the bounding rectangle; W and H are width and height respectively.
in above if Intersection variable becomes true that means the boxes having intersection. you can use this code for further customization.
Thank You