Examples with Complex imagingbook.lib.math.Complex used on opensource projects

Example 11 with Complex

use of imagingbook.lib.math.Complex in project imagingbook-common by imagingbook.

the class FourierDescriptor method makeComplex.

// ----------------------------------------------------------------
protected static Complex[] makeComplex(Point2D[] points) {
    int N = points.length;
    Complex[] samples = new Complex[N];
    for (int i = 0; i < N; i++) {
        samples[i] = new Complex(points[i].getX(), points[i].getY());
    }
    return samples;
}

Example 12 with Complex

use of imagingbook.lib.math.Complex in project imagingbook-common by imagingbook.

the class FourierDescriptor method getEllipsePoint.

/**
 * Get the reconstructed point for two DFT coefficients G1, G2 at a given
 * position t.
 * @param G1 first coefficient
 * @param G2 second coefficient
 * @param m frequency number
 * @param t contour position
 * @return reconstructed point
 */
public Complex getEllipsePoint(Complex G1, Complex G2, int m, double t) {
    Complex p1 = getReconstructionPoint(G1, -m, t);
    Complex p2 = getReconstructionPoint(G2, m, t);
    return p1.add(p2);
}

Example 13 with Complex

use of imagingbook.lib.math.Complex in project imagingbook-common by imagingbook.

the class FourierDescriptorUniform method DFT.

/**
 * As above, but the length P of the resulting spectrum (signal, if inverse)
 * is explicitly specified.
 * @param g signal vector
 * @param P length of the resulting  DFT spectrum
 * @return DFT spectrum
 */
private Complex[] DFT(Complex[] g, int P) {
    int M = g.length;
    // double[] cosTable = makeCosTable(M);	// cosTable[m] == cos(2*pi*m/M)
    // double[] sinTable = makeSinTable(M);
    Complex[] G = new Complex[P];
    // common scale factor (fwd/inverse differ!)
    double s = 1.0 / M;
    for (int m = P / 2 - P + 1; m <= P / 2; m++) {
        double Am = 0;
        double Bm = 0;
        for (int k = 0; k < M; k++) {
            double x = g[k].re;
            double y = g[k].im;
            // int mk = (m * k) % M; double phi = 2 * Math.PI * mk / M;
            double phi = 2 * Math.PI * m * k / M;
            double cosPhi = Math.cos(phi);
            double sinPhi = Math.sin(phi);
            Am = Am + x * cosPhi + y * sinPhi;
            Bm = Bm - x * sinPhi + y * cosPhi;
        }
        G[Arithmetic.mod(m, P)] = new Complex(s * Am, s * Bm);
    }
    return G;
}

Example 14 with Complex

use of imagingbook.lib.math.Complex in project imagingbook-common by imagingbook.

the class Dft1d method DFT.

public Complex[] DFT(Complex[] g, boolean forward) {
    int M = g.length;
    // common scale factor
    double s = 1 / Math.sqrt(M);
    for (int u = 0; u < M; u++) {
        double sumRe = 0;
        double sumIm = 0;
        for (int m = 0; m < M; m++) {
            double gRe = g[m].re;
            double gIm = g[m].im;
            int k = (u * m) % M;
            double cosPhi = cosTable[k];
            double sinPhi = sinTable[k];
            if (forward)
                sinPhi = -sinPhi;
            // complex multiplication: (gRe + i gIm) * (cosPhi + i sinPhi)
            sumRe += gRe * cosPhi - gIm * sinPhi;
            sumIm += gRe * sinPhi + gIm * cosPhi;
        }
        // G[u].re = s * sumRe;
        // G[u].im = s * sumIm;
        G[u] = new Complex(s * sumRe, s * sumIm);
    }
    return G;
}