Exemplo n.º 1
0
        /// <summary>
        /// Deform snake in the given external force field
        ///
        /// [x,y] = snakedeform(x,y,alpha,beta,gamma,kappa,fx,fy,ITER)
        ///
        /// </summary>
        /// <param name="x">轮廓-X</param>
        /// <param name="y">轮廓-Y</param>
        /// <param name="alpha">elasticity parameter</param>
        /// <param name="beta">rigidity parameter</param>
        /// <param name="gamma">viscosity parameter</param>
        /// <param name="kappa">external force weight</param>
        /// <param name="fx">external force field (x)</param>
        /// <param name="fy">external force field (y)</param>
        /// <param name="ITER">iteration</param>
        public void SnakeDeform(ref NcvVector x, ref NcvVector y, double alpha, double beta, double gamma, double kappa, double[] fx, double[] fy, int ITER)
        {
            int       n        = x.n;
            NcvVector vecAlpha = alpha * NcvVector.Ones(n);
            NcvVector vecBeta  = beta * NcvVector.Ones(n);

            // produce the five diagnal vectors
            NcvVector alpham1 = NcvVector.cat(vecAlpha.sub(1, n - 1), vecAlpha.sub(0, 1));
            NcvVector alphap1 = NcvVector.cat(vecAlpha.sub(n - 1, 1), vecAlpha.sub(0, n - 1));
            NcvVector betam1  = NcvVector.cat(vecBeta.sub(1, n - 1), vecBeta.sub(0, 1));
            NcvVector betap1  = NcvVector.cat(vecBeta.sub(n - 1, 1), vecBeta.sub(0, n - 1));

            NcvVector a = betam1;
            NcvVector b = -vecAlpha - 2 * vecBeta - 2 * betam1;
            NcvVector c = vecAlpha + alphap1 + betam1 + 4 * vecBeta + betap1;
            NcvVector d = -alphap1 - 2 * vecBeta - 2 * betap1;
            NcvVector e = betap1;

            // generate the parameters matrix
            NcvMatrix A = NcvMatrix.diag(a.sub(0, n - 2), -2) + NcvMatrix.diag(a.sub(n - 2, 2), n - 2);

            A = A + NcvMatrix.diag(b.sub(0, n - 1), -1) + NcvMatrix.diag(b.sub(n - 1, 1), n - 1);
            A = A + NcvMatrix.diag(c);
            A = A + NcvMatrix.diag(d.sub(0, n - 1), 1) + NcvMatrix.diag(d.sub(n - 1, 1), -(n - 1));
            A = A + NcvMatrix.diag(e.sub(0, n - 2), 2) + NcvMatrix.diag(e.sub(n - 2, 2), -(n - 2));

            //Logger.Info("A=" + A.ToString());

            NcvMatrix invAI = NcvMatrix.inv(A + gamma * NcvMatrix.diag(NcvVector.Ones(n)));

            //Logger.Info("invAI=" + invAI.ToString());

            //Logger.Info("fx=" + new Matrix(fx, m_Cols, m_Rows).ToString());
            //Logger.Info("fy=" + new Matrix(fy, m_Cols, m_Rows).ToString());

            for (int count = 0; count < ITER; count++)
            {
                NcvVector vfx = NcvVector.interp2(fx, m_Cols, m_Rows, x, y, "*linear");
                NcvVector vfy = NcvVector.interp2(fy, m_Cols, m_Rows, x, y, "*linear");

                //Logger.Info("vfx=" + vfx.ToString());
                //Logger.Info("vfy=" + vfy.ToString());

                // deform snake
                x = invAI * (gamma * x + kappa * vfx);
                y = invAI * (gamma * y + kappa * vfy);

                //Logger.Info("x=" + x.ToString());
                //Logger.Info("y=" + y.ToString());
            }
        }
Exemplo n.º 2
0
        /// <summary>
        /// Deform snake in the given external force field with pressure force added
        /// </summary>
        /// <param name="x">轮廓-X</param>
        /// <param name="y">轮廓-Y</param>
        /// <param name="alpha">elasticity parameter</param>
        /// <param name="beta">rigidity parameter</param>
        /// <param name="gamma">viscosity parameter</param>
        /// <param name="kappa">external force weight</param>
        /// <param name="kappap">pressure force weight</param>
        /// <param name="fx">external force field (x)</param>
        /// <param name="fy">external force field (y)</param>
        /// <param name="ITER"></param>
        public void SnakeDeform2(ref NcvVector x, ref NcvVector y, double alpha, double beta, double gamma, double kappa, double kappap, double[] fx, double[] fy, int ITER)
        {
            int n = x.n;

            NcvVector vecAlpha = alpha * NcvVector.Ones(n);
            NcvVector vecBeta  = beta * NcvVector.Ones(n);

            // produce the five diagnal vectors
            NcvVector alpham1 = NcvVector.cat(vecAlpha.sub(1, n - 1), vecAlpha.sub(0, 1));
            NcvVector alphap1 = NcvVector.cat(vecAlpha.sub(n - 1, 1), vecAlpha.sub(0, n - 1));
            NcvVector betam1  = NcvVector.cat(vecBeta.sub(1, n - 1), vecBeta.sub(0, 1));
            NcvVector betap1  = NcvVector.cat(vecBeta.sub(n - 1, 1), vecBeta.sub(0, n - 1));

            NcvVector a = betam1;
            NcvVector b = -vecAlpha - 2 * vecBeta - 2 * betam1;
            NcvVector c = vecAlpha + alphap1 + betam1 + 4 * vecBeta + betap1;
            NcvVector d = -alphap1 - 2 * vecBeta - 2 * betap1;
            NcvVector e = betap1;

            // generate the parameters matrix
            NcvMatrix A = NcvMatrix.diag(a.sub(0, n - 2), -2) + NcvMatrix.diag(a.sub(n - 2, 2), n - 2);

            A = A + NcvMatrix.diag(b.sub(0, n - 1), -1) + NcvMatrix.diag(b.sub(n - 1, 1), n - 1);
            A = A + NcvMatrix.diag(c);
            A = A + NcvMatrix.diag(d.sub(0, n - 1), 1) + NcvMatrix.diag(d.sub(n - 1, 1), -(n - 1));
            A = A + NcvMatrix.diag(e.sub(0, n - 2), 2) + NcvMatrix.diag(e.sub(n - 2, 2), -(n - 2));

            NcvMatrix invAI = NcvMatrix.inv(A + gamma * NcvMatrix.diag(NcvVector.Ones(n)));

            for (int count = 0; count < ITER; count++)
            {
                NcvVector vfx = NcvVector.interp2(fx, m_Cols, m_Rows, x, y, "*linear");
                NcvVector vfy = NcvVector.interp2(fy, m_Cols, m_Rows, x, y, "*linear");

                // adding the pressure force
                NcvVector xp = NcvVector.cat(x.sub(1, n - 1), x.sub(0, 1)); NcvVector yp = NcvVector.cat(y.sub(1, n - 1), y.sub(0, 1));
                NcvVector xm = NcvVector.cat(x.sub(n - 1, 1), x.sub(0, n - 1)); NcvVector ym = NcvVector.cat(y.sub(n - 1, 1), y.sub(0, n - 1));

                NcvVector qx = xp - xm; NcvVector qy = yp - ym;
                NcvVector pmag = NcvVector.Sqrt(NcvVector.DotProduct(qx, qx) + NcvVector.DotProduct(qy, qy));
                NcvVector px = NcvVector.DotDivide(qy, pmag); NcvVector py = NcvVector.DotDivide(-qx, pmag);

                // deform snake
                x = invAI * (gamma * x + kappa * vfx + kappap * px);
                y = invAI * (gamma * y + kappa * vfy + kappap * py);
            }
        }