How to control viewport draw?

Hi all
I use omni.syntheticdata.sensors get rgb data from viewport, and then save to file.
The problem is render speed, my scene has a moving object, if in low fps, the image saved has a little bit different with high

code snippet as below:

import omni.syntheticdata as syn
vp_iface = omni.kit.viewport.get_viewport_interface()

    async def _wait_for_data(self, vp):
        if vp.is_visible():
            data = np.empty(0)
            start = time()
            while data.size == 0 and time() < start + 200:
                data = syn.sensors.get_rgb(vp)

    async def _write_rgb(self, file):
      vp = vp_iface.get_viewport_window()
      await self._wait_for_data(vp)
      data = syn.sensors.get_rgb(vp)
      cv2.imwrite(file , cv2.cvtColor(data, cv2.COLOR_RGB2BGR))

Thanks in advance

Hello @user76666! I asked the development team for help here. We should hear back from them shortly!