ZED2i 'grainy' 1080p image

Hardware ZED2
1

We have multiple ZED 2i cameras and have noticed that the 1080p video is very “grainy” for all of them compared to 720p image. We only run one camera at a time.

We’ve tested on both a high-end Linux desktop and Xavier NX Developer Kit with similar results: the 720p video is “clear” and the 1080p adds a lot of grain/noise. We also deploy the ZED 2i onboard an aerial drone and see the grain while on ground and in air.

lsusb -t for USB port on Linux desktop (rear USB 3.0 port):

Bus 10. Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/2p, 10000M
 |__ Port 2: Dev 4, If 0, Class=Video, Driver=uvcvideo, 5000M
 |__ Port 2: Dev 4, If 1, Class=Video, Driver=uvcvideo, 5000M

lsusb -t for Xavier NX (USB 3.1 port):

Bus 02.Port 1: Dev 1, Class=root_hub, Driver=tegra_xusb/4p, 10000M
|__Port 3: Dev 2, If 0, Class=Hub, Driver=hub/4p, 10000M
    |__ port 1: Dev 3, If 0, Class=Video, Driver=uvcvideo, 5000M
    |__ port 1: Dev 3, If 1, Class=Video, Driver=uvcvideo, 5000M

MaxPower for Desktop USB port is 512 mA. MaxPower for Xavier NX USB port is 128 mA (from lsusb -v)

When testing with the Desktop system, we use the USB cables that came with the corresponding ZED camera. The Xavier NX system uses a 3rd party USB cable but has same behavior as ZED USB cables on Desktop system.

In the Google Drive Link are:

  • Diagnostic reports for both systems (different ZED 2i cameras, same behavior)
    – Appears nominal
  • SVOs comparing 720p vs 1080p with same lighting (indoors) and perspective for ZED-M, ZED 2, ZED 2i for the Desktop system
  • SVOs comparing 720p vs 1080p with same lighting (indoors) and perspective for ZED2i on Xavier NX system
  • Example SVO showing 1080p recording while outside on ground and in flight on Xavier NX system
2

Hi @penguin
thank you for reporting this possible problem.
I forwarded all the information to the SDK team.
We’ll verify and try to reproduce the issue to provide an eventual fix to be released in one of the next ZED SDK releases.

Best regards

3

Hi, thank you for the precise report !
I can see what you report in your SVOs, however I cannot on a live camera. Can you tell me a bit more about your streaming program ? Did you set particular streaming parameters (bitrate, codec) ?
Also, I notice you use the 3.8.2 SDK, can you try with 4.0.8 ?

4

The previously posted SVOs were recorded using ZED Explorer with default setting on ZED SDK 3.8.2.

We have recorded 2 more SVOs, this time on a ZED Box running SDK 4.0.8. We used a ZED2i and ZEDX camera with the same environment lighting and all default parameters/settings for ISP. SVOs are recorded using ZED Explorer at 1080@15fps (since ZED2i 1080@30fps on Ubuntu does not work (ZED2i frame drop…)).

Link to SVOs: SVOs

We see considerable less “grain” in the ZEDX than the ZED2i.

5

Sorry about my previous response - I thought you were using the ZED SDK streaming, but you are not.

The ZED2i and ZEDX have different sensors, so different images are expected. About 1080p on ZED2i, this mode add a lot of pixel while reducing the FoV, this is probably why you get more graining than with HD720.

6

Sorry for the last response.

We are targeting upgrading to the ZED-X in the coming months but are unable to at the moment.

We found decreasing the ISP sharpness from default (4) to minimum (0) removed the grain in all environments and still provided a clear image our neural networks can detect our objects of interest in. We have verified on ground and in flight. Thank you!