How can I handle images at headless mode?

Omniverse Isaac Sim
,
1

Hello,

I am trying to handle RGBD images.
Before using images via features, I tried to save images on my disk.

However, I cannot save images in headless mode though I can save images in non-headless mode.

[skrl:INFO] Environment class: omni.isaac.gym.vec_env.vec_env_base.VecEnvBase
[skrl:INFO] Environment wrapper: Omniverse Isaac Gym
Traceback (most recent call last):
  File "/home/bak/.local/share/ov/pkg/isaac_sim-2022.2.1/OmniIsaacGymEnvsAILAB/omniisaacgymenvs/skrl_examples/reaching_ur5e/reaching_ur5e_train.py", line 146, in <module>
    trainer.train()
  File "/home/bak/anaconda3/envs/isaac-sim_22.2.1/lib/python3.7/site-packages/skrl/trainers/torch/sequential.py", line 75, in train
    self.single_agent_train()
  File "/home/bak/anaconda3/envs/isaac-sim_22.2.1/lib/python3.7/site-packages/skrl/trainers/torch/base.py", line 155, in single_agent_train
    states, infos = self.env.reset()
  File "/home/bak/anaconda3/envs/isaac-sim_22.2.1/lib/python3.7/site-packages/skrl/envs/torch/wrappers.py", line 250, in reset
    self._obs_dict = self._env.reset()
  File "/home/bak/anaconda3/envs/isaac-sim_22.2.1/lib/python3.7/site-packages/skrl/utils/omniverse_isaacgym_utils.py", line 226, in reset
    return self.step(actions)[0]
  File "/home/bak/anaconda3/envs/isaac-sim_22.2.1/lib/python3.7/site-packages/skrl/utils/omniverse_isaacgym_utils.py", line 218, in step
    observations, rewards, dones, info = self._task.post_physics_step()
  File "/home/bak/.local/share/ov/pkg/isaac_sim-2022.2.1/OmniIsaacGymEnvsAILAB/omniisaacgymenvs/tasks/base/rl_task.py", line 254, in post_physics_step
    self.get_observations()
  File "/home/bak/.local/share/ov/pkg/isaac_sim-2022.2.1/OmniIsaacGymEnvsAILAB/omniisaacgymenvs/skrl_examples/reaching_ur5e/reaching_ur5e_env.py", line 246, in get_observations
    self.capture_and_save_images()
  File "/home/bak/.local/share/ov/pkg/isaac_sim-2022.2.1/OmniIsaacGymEnvsAILAB/omniisaacgymenvs/skrl_examples/reaching_ur5e/reaching_ur5e_env.py", line 374, in capture_and_save_images
    cam_rgba_img = cv2.cvtColor(cam_rgba, cv2.COLOR_BGRA2RGBA)
cv2.error: OpenCV(4.7.0) /io/opencv/modules/imgproc/src/color.cpp:182: error: (-215:Assertion failed) !_src.empty() in function 'cvtColor'

In my function def capture_and_save_images(self):, there is a creating image function from simulation instance to image that I used by cam_rgba = self._rgb_cameras[idx].rgb_cam.get_rgba().
However cam_rgba is empty.
Is there another way to get images?

Here is my code.
reaching_ur5e.7z (15.7 MB)

Thanks

Actually, I asked before but, there is no more reply. I think the cause of the problem is not come from SKRL so I rewrite the question and change the title.