NuScenes关于Radar的配置信息

Nuscenes关于雷达处理的部分：

• 以上包含传感器性能信息：
  radar检测距离：≤250m
  77GHz电磁波频率
  速度精度±0.1km/h
  13Hz的工作频率

雷达点云多视角可视化

Nuscenes毫米波雷达多视角可视化

格式定义

1. 包含nuscenes内部数据中radar的数据格式、数据单位
2. 内部定义了雷达预先滤波和非滤波模式
3. 关于内部格式：

        FIELDS x y z dyn_prop id rcs vx vy vx_comp vy_comp is_quality_valid ambig_state x_rms y_rms invalid_state pdh0 vx_rms vy_rms
        SIZE 4 4 4 1 2 4 4 4 4 4 1 1 1 1 1 1 1 1
        TYPE F F F I I F F F F F I I I I I I I I

源码部分：/nuscenes/utils/data_classes.py

class RadarPointCloud(PointCloud):

    # Class-level settings for radar pointclouds, see from_file().
    invalid_states = [0]  # type: List[int]
    dynprop_states = range(7)  # type: List[int] # Use [0, 2, 6] for moving objects only.
    ambig_states = [3]  # type: List[int]

    @classmethod
    def disable_filters(cls) -> None:
        """ Disable all radar filter settings. Use this method to plot all radar returns. Note that this method affects the global settings. """
        cls.invalid_states = list(range(18))
        cls.dynprop_states = list(range(8))
        cls.ambig_states = list(range(5))

    @classmethod
    def default_filters(cls) -> None:
        """ Set the defaults for all radar filter settings. Note that this method affects the global settings. """
        cls.invalid_states = [0]
        cls.dynprop_states = range(7)
        cls.ambig_states = [3]

    @staticmethod
    def nbr_dims() -> int:
        """ Returns the number of dimensions. :return: Number of dimensions. """
        return 18

    @classmethod
    def from_file(cls,
                  file_name: str,
                  invalid_states: List[int] = None,
                  dynprop_states: List[int] = None,
                  ambig_states: List[int] = None) -> 'RadarPointCloud':
        """ Loads RADAR data from a Point Cloud Data file. See details below. :param file_name: The path of the pointcloud file. :param invalid_states: Radar states to be kept. See details below. :param dynprop_states: Radar states to be kept. Use [0, 2, 6] for moving objects only. See details below. :param ambig_states: Radar states to be kept. See details below. To keep all radar returns, set each state filter to range(18). :return: <np.float: d, n>. Point cloud matrix with d dimensions and n points. Example of the header fields: # .PCD v0.7 - Point Cloud Data file format VERSION 0.7 FIELDS x y z dyn_prop id rcs vx vy vx_comp vy_comp is_quality_valid ambig_state x_rms y_rms invalid_state pdh0 vx_rms vy_rms SIZE 4 4 4 1 2 4 4 4 4 4 1 1 1 1 1 1 1 1 TYPE F F F I I F F F F F I I I I I I I I COUNT 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 WIDTH 125 HEIGHT 1 VIEWPOINT 0 0 0 1 0 0 0 POINTS 125 DATA binary Below some of the fields are explained in more detail: x is front, y is left vx, vy are the velocities in m/s. vx_comp, vy_comp are the velocities in m/s compensated by the ego motion. We recommend using the compensated velocities. invalid_state: state of Cluster validity state. (Invalid states) 0x01 invalid due to low RCS 0x02 invalid due to near-field artefact 0x03 invalid far range cluster because not confirmed in near range 0x05 reserved 0x06 invalid cluster due to high mirror probability 0x07 Invalid cluster because outside sensor field of view 0x0d reserved 0x0e invalid cluster because it is a harmonics (Valid states) 0x00 valid 0x04 valid cluster with low RCS 0x08 valid cluster with azimuth correction due to elevation 0x09 valid cluster with high child probability 0x0a valid cluster with high probability of being a 50 deg artefact 0x0b valid cluster but no local maximum 0x0c valid cluster with high artefact probability 0x0f valid cluster with above 95m in near range 0x10 valid cluster with high multi-target probability 0x11 valid cluster with suspicious angle dynProp: Dynamic property of cluster to indicate if is moving or not. 0: moving 1: stationary 2: oncoming 3: stationary candidate 4: unknown 5: crossing stationary 6: crossing moving 7: stopped ambig_state: State of Doppler (radial velocity) ambiguity solution. 0: invalid 1: ambiguous 2: staggered ramp 3: unambiguous 4: stationary candidates pdh0: False alarm probability of cluster (i.e. probability of being an artefact caused by multipath or similar). 0: invalid 1: <25% 2: 50% 3: 75% 4: 90% 5: 99% 6: 99.9% 7: <=100% """

        assert file_name.endswith('.pcd'), 'Unsupported filetype {}'.format(file_name)

        meta = []
        with open(file_name, 'rb') as f:
            for line in f:
                line = line.strip().decode('utf-8')
                meta.append(line)
                if line.startswith('DATA'):
                    break

            data_binary = f.read()

        # Get the header rows and check if they appear as expected.
        assert meta[0].startswith('#'), 'First line must be comment'
        assert meta[1].startswith('VERSION'), 'Second line must be VERSION'
        sizes = meta[3].split(' ')[1:]
        types = meta[4].split(' ')[1:]
        counts = meta[5].split(' ')[1:]
        width = int(meta[6].split(' ')[1])
        height = int(meta[7].split(' ')[1])
        data = meta[10].split(' ')[1]
        feature_count = len(types)
        assert width > 0
        assert len([c for c in counts if c != c]) == 0, 'Error: COUNT not supported!'
        assert height == 1, 'Error: height != 0 not supported!'
        assert data == 'binary'

        # Lookup table for how to decode the binaries.
        unpacking_lut = {
    'F': {
    2: 'e', 4: 'f', 8: 'd'},
                         'I': {
    1: 'b', 2: 'h', 4: 'i', 8: 'q'},
                         'U': {
    1: 'B', 2: 'H', 4: 'I', 8: 'Q'}}
        types_str = ''.join([unpacking_lut[t][int(s)] for t, s in zip(types, sizes)])

        # Decode each point.
        offset = 0
        point_count = width
        points = []
        for i in range(point_count):
            point = []
            for p in range(feature_count):
                start_p = offset
                end_p = start_p + int(sizes[p])
                assert end_p < len(data_binary)
                point_p = struct.unpack(types_str[p], data_binary[start_p:end_p])[0]
                point.append(point_p)
                offset = end_p
            points.append(point)

        # A NaN in the first point indicates an empty pointcloud.
        point = np.array(points[0])
        if np.any(np.isnan(point)):
            return cls(np.zeros((feature_count, 0)))

        # Convert to numpy matrix.
        points = np.array(points).transpose()

        # If no parameters are provided, use default settings.
        invalid_states = cls.invalid_states if invalid_states is None else invalid_states
        dynprop_states = cls.dynprop_states if dynprop_states is None else dynprop_states
        ambig_states = cls.ambig_states if ambig_states is None else ambig_states

        # Filter points with an invalid state.
        valid = [p in invalid_states for p in points[-4, :]]
        points = points[:, valid]

        # Filter by dynProp.
        valid = [p in dynprop_states for p in points[3, :]]
        points = points[:, valid]

        # Filter by ambig_state.
        valid = [p in ambig_states for p in points[11, :]]
        points = points[:, valid]

        return cls(points)