Examples with SteerableKernel boofcv.alg.filter.kernel.SteerableKernel used on opensource projects

Example 1 with SteerableKernel

use of boofcv.alg.filter.kernel.SteerableKernel in project BoofCV by lessthanoptimal.

the class FactorySteerable method gaussian.

/**
 * Steerable filter for 2D Gaussian derivatives.  The basis is composed of a set of rotated kernels.
 *
 * @param kernelType Specifies which type of 2D kernel should be generated.
 * @param orderX Order of the derivative in the x-axis.
 * @param orderY Order of the derivative in the y-axis.
 *
 * @param sigma
 *@param radius Radius of the kernel.  @return Steerable kernel generator for the specified gaussian derivative.
 */
public static <K extends Kernel2D> SteerableKernel<K> gaussian(Class<K> kernelType, int orderX, int orderY, double sigma, int radius) {
    if (orderX < 0 || orderX > 4)
        throw new IllegalArgumentException("derivX must be from 0 to 4 inclusive.");
    if (orderY < 0 || orderY > 4)
        throw new IllegalArgumentException("derivT must be from 0 to 4 inclusive.");
    int order = orderX + orderY;
    if (order > 4) {
        throw new IllegalArgumentException("The total order of x and y can't be greater than 4");
    }
    int maxOrder = Math.max(orderX, orderY);
    if (sigma <= 0)
        sigma = (float) FactoryKernelGaussian.sigmaForRadius(radius, maxOrder);
    else if (radius <= 0)
        radius = FactoryKernelGaussian.radiusForSigma(sigma, maxOrder);
    Class kernel1DType = FactoryKernel.get1DType(kernelType);
    Kernel1D kerX = FactoryKernelGaussian.derivativeK(kernel1DType, orderX, sigma, radius);
    Kernel1D kerY = FactoryKernelGaussian.derivativeK(kernel1DType, orderY, sigma, radius);
    Kernel2D kernel = GKernelMath.convolve(kerY, kerX);
    Kernel2D[] basis = new Kernel2D[order + 1];
    // convert it into an image which can be rotated
    ImageGray image = GKernelMath.convertToImage(kernel);
    ImageGray imageRotated = (ImageGray) image.createNew(image.width, image.height);
    basis[0] = kernel;
    // form the basis by created rotated versions of the kernel
    double angleStep = Math.PI / basis.length;
    for (int index = 1; index <= order; index++) {
        float angle = (float) (angleStep * index);
        GImageMiscOps.fill(imageRotated, 0);
        new FDistort(image, imageRotated).rotate(angle).apply();
        basis[index] = GKernelMath.convertToKernel(imageRotated);
    }
    SteerableKernel<K> ret;
    if (kernelType == Kernel2D_F32.class)
        ret = (SteerableKernel<K>) new SteerableKernel_F32();
    else
        ret = (SteerableKernel<K>) new SteerableKernel_I32();
    ret.setBasis(FactorySteerCoefficients.polynomial(order), basis);
    return ret;
}