update LAB5

    return g

def butterworth_filter(b, a, n, sigma):

def butterworth_filter(b, a, cx, cy, n, sigma):

    x, y = np.meshgrid(np.linspace(0, a - 1, a), np.linspace(0, b - 1, b))

    x = x - a / 2

    y = y - b / 2

    x = x - cx

    y = y - cy

    d = np.sqrt(x * x + y * y)

    h = 1/((1+(d/sigma))**(2*n))

    return h

if __name__ == '__main__':

    test_input = np.array([[1, 2, 3, 4], [1, 2, 3, 4], [1, 2, 3, 4], [1, 2, 3, 4]])