Function pdf2

utils/optical_flow_utils.py:184–195

Calculate PDF of the bivariate Gaussian distribution. Args: sigma_matrix (ndarray): with the shape (2, 2) grid (ndarray): generated by :func:`mesh_grid`, with the shape (K, K, 2), K is the kernel size. Returns: kernel (ndarrray): un-normalized kernel.

(sigma_matrix, grid)

def pdf2(sigma_matrix, grid):
    """Calculate PDF of the bivariate Gaussian distribution.
    Args:
        sigma_matrix (ndarray): with the shape (2, 2)
        grid (ndarray): generated by :func:`mesh_grid`,
            with the shape (K, K, 2), K is the kernel size.
    Returns:
        kernel (ndarrray): un-normalized kernel.
    """
    inverse_sigma = np.linalg.inv(sigma_matrix)
    kernel = np.exp(-0.5 * np.sum(np.dot(grid, inverse_sigma) * grid, 2))
    return kernel

def bivariate_Gaussian(kernel_size, sig_x, sig_y, theta, grid=None, isotropic=True):
    """Generate a bivariate isotropic or anisotropic Gaussian kernel.