SimulatedImage.py 文件源码

def generate_img(self, param):
        """
        Generate range compressed image.

        Parameters
        ----------
        param: object (ConfigurationManager instance).
          ConfigurationManager instance to read parameters from file.

        Returns
        -------
        -.
        """

        # Light speed.
        c = 300000000.0

        # Load beamwidth, bandwidth and central frequency to use locally.
        sar_bmw = (param.get_float_parameter("Radar/beamwidth")*np.pi)/180.
        sar_B = param.get_float_parameter("Radar/B")
        sar_f0 = param.get_float_parameter("Radar/f0")

        # Get angles squint and look of view with respect to the antenna coordinate system.
        #self.get_angles_antenna()
        self.local_look, self.local_squint = Utils.get_angles_antenna(self.traj, self.nom_target)

        # Set fast time axis.
        start = 2*(min(self.distances))/c - self.fast_time_pixel_margin_mono*self.radar_dt
        end = 2*(max(self.distances))/c + self.fast_time_pixel_margin_mono*self.radar_dt
        step = self.radar_dt
        self.t_axis_fast_time = np.arange(start, end, step)

        # Number of elements in fast time axis.
        self.Nt = np.size(self.t_axis_fast_time)

        self.freq_axis_fftshift = Utils.freq_axis(self.radar_dt, self.Nt, False, True)

        sar_lambda = c/sar_f0

        # Doppler amplitude (envolvente de la antena).
        doppler_amplitude = (np.sinc( (np.tile(self.local_squint, [self.Nt, 1]))/sar_bmw*(2*0.443) ))**2

        # Range amplitude: range positions in raw data of backscattered signal.
        Nd = np.size(self.distances)
        range_amplitude = np.sinc( sar_B*( (np.tile(self.t_axis_fast_time, [Nd, 1])).transpose() - np.tile(2*self.distances/c, [self.Nt, 1]) ) )

        # Signal phase received: 2*pi*2*r/lambda.
        signal_phase = np.exp(-1j*4*np.pi/sar_lambda*np.tile(self.distances, [self.Nt, 1]))

        # Generate range compressed simulated image.
        self.image = doppler_amplitude*range_amplitude*signal_phase