dicks

        a = np.cos(norm_lines[:,1])
        b = np.sin(norm_lines[:,1])
        x0 = a*norm_lines[:,0]
        y0 = b*norm_lines[:,0]
        norm_line_segs = np.vstack([x0-segment_length*b,
                                    y0+segment_length*a,
                                    x0+segment_length*b,
                                    y0-segment_length*a]).T
        norm_line_segs = np.vectorize(int)(norm_line_segs)