Nuscenes——环视相机数据准备：当前帧与前一帧所有数据的获取及操作细节

获取sample

self.samples = [samp for samp in self.nusc.sample if self.nusc.get('scene', samp['scene_token'])['name'] in scenes]

rec = self.samples[idx]

1. 获取当前帧数据

• 获取当前帧环视图像：

self.cam_keys = ['CAM_FRONT_LEFT', 'CAM_FRONT', 'CAM_FRONT_RIGHT', 'CAM_BACK_RIGHT', 'CAM_BACK', 'CAM_BACK_LEFT']

sample_path = []
for cam_key in self.cam_keys:
    samp = self.nusc.get('sample_data', rec['data'][cam_key])
    cam_path = samp['filename']            
    sample_path.append(cam_path)

• 获取当前帧ego pose：

ego_pose = self.nusc.get('ego_pose', self.nusc.get('sample_data', rec['data']['CAM_FRONT'])['ego_pose_token'])

2. 获取前一帧或后一帧帧数据

关键字：前一帧为'prev'，后一帧为'next'。

• 获取前一帧环视图像：

self.cam_keys = ['CAM_FRONT_LEFT', 'CAM_FRONT', 'CAM_FRONT_RIGHT', 'CAM_BACK_RIGHT', 'CAM_BACK', 'CAM_BACK_LEFT']

sample_path = []
for cam_key in self.cam_keys:
    last_samp = self.nusc.get('sample_data',samp['prev']) # 获取前一帧的sample
    lst_cam_path = last_samp['filename']
    lst_sample_path.append(lst_cam_path)

• 获取前一帧ego pose：

if samp['prev'] == '':
    last_ego_pose = ego_pose # 如果没有前一帧，则保持不变
else:
    last_ego_pose = self.nusc.get('ego_pose', self.nusc.get('sample_data', rec['data']['CAM_FRONT'])['prev'])

前一帧和后一帧的ego_pose