image.py 文件源码

def build_random_variables(self, **kwargs):
        # All this is done just once per batch (i.e. until `clear_random_variables` is called)
        np.random.seed()
        imshape = kwargs.get('imshape')
        # Build and scale random fields
        random_field_x = np.random.uniform(-1, 1, imshape) * self.alpha
        random_field_y = np.random.uniform(-1, 1, imshape) * self.alpha
        # Smooth random field (this has to be done just once per reset)
        sdx = gaussian_filter(random_field_x, self.sigma, mode='reflect')
        sdy = gaussian_filter(random_field_y, self.sigma, mode='reflect')
        # Make meshgrid
        x, y = np.meshgrid(np.arange(imshape[1]), np.arange(imshape[0]))
        # Make inversion coefficient
        _inverter = 1. if not self.invert else -1.
        # Distort meshgrid indices (invert if required)
        flow_y, flow_x = (y + _inverter * sdy).reshape(-1, 1), (x + _inverter * sdx).reshape(-1, 1)
        # Set random states
        self.set_random_variable('flow_x', flow_x)
        self.set_random_variable('flow_y', flow_y)