CODEWITHSUNDEEP
c#wpfkinectangle
jubueche
jubueche

Reputation: 793

Calculating Angle - Getting same value

in this program I calculate the angle for the right shoulder & right elbow, as well as the angle for the left shoulder & the left elbow. I print these values to the textbox in my WPF application. Now there is a problem: I get around 90° for every angle. I use Kinect for Windows and I am programming in C#. For more information leave a comment and I´ll answer.

    public class Angles
    {
        public double AngleBetweenTwoVectors(Vector3D vectorA, Vector3D vectorB)
        {
            double dotProduct = 0.0;
            dotProduct = Vector3D.DotProduct(vectorA, vectorB);

            return (double)Math.Acos(dotProduct)/Math.PI*180;
        }

        public double[] GetVector(Skeleton skeleton)
        {
            Vector3D ShoulderCenter = new Vector3D(skeleton.Joints[JointType.ShoulderCenter].Position.X, skeleton.Joints[JointType.ShoulderCenter].Position.Y, skeleton.Joints[JointType.ShoulderCenter].Position.Z);
            Vector3D RightShoulder = new Vector3D(skeleton.Joints[JointType.ShoulderRight].Position.X, skeleton.Joints[JointType.ShoulderRight].Position.Y, skeleton.Joints[JointType.ShoulderRight].Position.Z);
            Vector3D LeftShoulder = new Vector3D(skeleton.Joints[JointType.ShoulderLeft].Position.X, skeleton.Joints[JointType.ShoulderLeft].Position.Y, skeleton.Joints[JointType.ShoulderLeft].Position.Z);
            Vector3D RightElbow = new Vector3D(skeleton.Joints[JointType.ElbowRight].Position.X, skeleton.Joints[JointType.ElbowRight].Position.Y, skeleton.Joints[JointType.ElbowRight].Position.Z);
            Vector3D LeftElbow = new Vector3D(skeleton.Joints[JointType.ElbowLeft].Position.X, skeleton.Joints[JointType.ElbowLeft].Position.Y, skeleton.Joints[JointType.ElbowLeft].Position.Z);
            Vector3D RightWrist = new Vector3D(skeleton.Joints[JointType.WristRight].Position.X, skeleton.Joints[JointType.WristRight].Position.Y, skeleton.Joints[JointType.WristRight].Position.Z);
            Vector3D LeftWrist = new Vector3D(skeleton.Joints[JointType.WristLeft].Position.X, skeleton.Joints[JointType.WristLeft].Position.Y, skeleton.Joints[JointType.WristLeft].Position.Z);

           /* ShoulderCenter.Normalize();
            RightShoulder.Normalize();
            LeftShoulder.Normalize();
            RightElbow.Normalize();
            LeftElbow.Normalize();
            RightWrist.Normalize();
            LeftWrist.Normalize();

            if (skeleton.Joints[JointType.ShoulderCenter].TrackingState == JointTrackingState.Tracked) { 

            }
            */

            double AngleRightElbow = AngleBetweenTwoVectors(RightElbow - RightShoulder, RightElbow - RightWrist);
            double AngleRightShoulder = AngleBetweenTwoVectors(RightShoulder - ShoulderCenter, RightShoulder - RightElbow);
            double AngleLeftElbow = AngleBetweenTwoVectors(LeftElbow - LeftShoulder, LeftElbow - LeftWrist);
            double AngleLeftShoulder = AngleBetweenTwoVectors(LeftShoulder - ShoulderCenter, LeftShoulder - LeftElbow);

            double[] Angles = {AngleRightElbow, AngleRightShoulder, AngleLeftElbow, AngleLeftShoulder};
            return Angles;
        }
}

As you can see, I am calculating the angles with the "Dot-Product" and the acos. The (/PI*180)is to turn the number into the angle (0-360). I wonder what is wrong.

Upvotes: 1

Views: 158

Answers (1)

jubueche
jubueche

Reputation: 793

I found the answer: I have to normalize the Vectors in the AngleBetweenTwoVectors method. Then I get the real angle.

Upvotes: 1

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