Rotation angle of scanned document

[gghazaryan]

Hi guys,

Here is the problem:
My document(image) has 4 solid black rectangles with fixed sizes (20 X 20 pixels).
After scanning the document I need to calculate the angle of rotation ? (using these small rectangles at the corners..)

I thing there should be very elegant way in AFORGE.NET.

P.S.
I know about DocumentSkewChecker, but this is not helpful in my case.

[andrew.kirillov]

Hello,

My document(image) has 4 solid black rectangles with fixed sizes (20 X 20 pixels).

Show it then. Descriptions like this tend to be vague.

After scanning the document I need to calculate the angle of rotation ? (using these small rectangles at the corners..)

You may find those rectangles with Blob Counter routine. Then get coordinates of 4 corners using Quadrilateral Finder. When it is done it becomes quite simple geometry to calculate rotation of rectangle when its corners are known.

[gghazaryan]

Thanks Andrew.

[BombosColombos]

I did it like that:

Code: Select all

//Rotating orginal image
            sourceImage = AForge.Imaging.Image.Clone((Bitmap)Orginal, PixelFormat.Format24bppRgb);
            double dx = centers[1].X - centers[0].X;  //centers - a collection of 2 centers of an Image no.0 is the top left center of cube, no.1 is  the top right
            double dy = centers[0].Y - centers[1].Y;   
            double ang = Math.Atan2(dx,dy) * (180 / Math.PI);
            RotateBicubic filter = new RotateBicubic(ang-90, false);
//Apply the filter on your Image


And it worked like a charm...