two RealSense connected to a PC - RealSense Viewer - incomplete video frame detected
Hello everyone,
I'm just a beginner in the RealSense world and I'm starting making some experiment with RealSense cameras, RealSense Viewer and Python API.
At the moment my setup consists of two cameras (D455 and D435) connected via USB 3 to a USB-C HUB, which in turn is connected to my Ubuntu 18.04.5 LTS laptop with the RealSense Viewer software version 2.50.0.
My final intention is to be able to use more than two sensors simultaneously connected to the same PC to process the input data.
Already by connecting two, however, I find myself in difficulty. In fact, I notice that on the Realsense Viewer, I get multiple errors relating to 'incomplete frame detected'.
- Is this perhaps an alarm bell that should make me reflect on the infeasibility of what I am proposing?
- Is it perhaps some incorrect setting that I have made?
- Could it instead be the band
Could it be the data band of the USB 3.0 HUB instead?
My questions then are:
- can I use several realsense sensors simultaneously on the same PC?
- If so, what is the recommended connection configuration? Is it possible to use a USB HUB or is it better to use some other type of architecture?
Thank you very much for your support
na
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Hi Nicola Ariutti Welcome to the RealSense community!
Yes, you can use several RealSense cameras on the same computer. If the cameras are all active simultaneously though then the amount of the computer's resources that are consumed increases as more cameras are added. For example, a computer with at least an Intel i7 processor is recommendable for 4 simultaneously active cameras on the same PC. For two cameras you should be able to use a lower hardware specification such as an i3 processor.
I note that the '2.1' beside the camera names in the RealSense Viewer's options side-panel indicates that the two cameras are being detected as being on a USB 2 connection rather than USB 3. Because USB 2 connections are slower than USB 3, the performance of the cameras will be more restricted. Information about this is provided at the link below.
https://www.intelrealsense.com/usb2-support-for-intel-realsense-technology/
Can you confirm that you are using a USB 3 hub and not a USB 2 one, please? Also, are you using the official 1 meter USB cables supplied with the camera, and if you are using your own choice of USB cables then can you confirm that they are USB 3 cables and not USB 2. Either a USB 2 hub or USB 2 cable could cause the cameras to be detected as operating in the slower USB 2 mode instead of being able to take advantage of the full capabilities that the camera has on a USB 3 connection.
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Thank you very much for your exhaustive reply MartyG,
I'm happy to hear that I can use as much as 4 RealSense on a single PC (provided it performs well enough)!
You are right about the USB, I didn't realise there was this indicator in the interface. I am now using a 'real' USB 3.0 HUB and from the interface I see something different and I am no longer experiencing the problems I had before.
I am currently using the two sensors connected to the HUB via the supplied USB cable, but in the past I had done a test with a single sensor and a cable up to 5 metres long, with success.
Do you think it is possible to use even longer connection cables? Maybe up to 15 metres? What could be the difficulties in such a setup? In the past I have had very bad experiences with long cables, extension cables and various ethernet extenders...
But I've found a project inside the official documentation related to the network use of the camera. This would seem to allow me to position the cameras even further away from the host PC.
Do you have experience in using the sensor in this kind of setup?
In your opinion, would this type of setup also allow me to use more sensors than 4?
What could be the cons of this approach?
Thank you so much -
Yes, it is possible to use RealSense cameras with longer cables. The company Newnex supply RealSense-validated premium grade USB-C cables up to 20 m and fiber-optic cabling for using the cameras at 100 meters. The 20 m cables contain active repeater components for boosting the signal over distance.
https://www.newnex.com/realsense-3d-camera-connectivity.php
https://www.youtube.com/watch?v=GLQgR1jT04M
In regard to limitations, it is recommendable to perform firmware driver updates over a short cable instead of a 20 m or longer cable.
The cameras can also be accessed as a 'network camera' over CAT5 ethernet cables at up to 100 m distance using the RealSense networking system in the guide that you linked to. The speed of these cables is faster than USB 2 but slower than USB 3.
Aside from the reduced data transmission speeds over ethernet cable compared to USB 3 cable, the networking system also supports a more limited range of resolution and FPS speed combinations.
Another limitation is that although the networking system can support multiple cameras, each camera should be attached to its own individual computer or computing board instead of all cameras being attached to the same computer. This does not need to be expensive though if Raspberry Pi 4 boards are used as the remote computing board to attach the cameras to.
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Thank you MartyG for the exhaustive answer.
I will take the time to examine everithing.
I will trun back to you if I have further questions
thank you!
bye -
here I am again MartyG with some questions somewhat earlier than expected :P
on the question of using multiple sensors on the same PC, just now, the tests with multiple cams, I did them on an Ubuntu 18.04 Linux PC.
Now instead I am on a Windows 10 Pro PC and, connecting the same USB3.0 HUB (working on linux) to the PC, and both sensors, D435 and D455, opening Realsense Viewer version 2.50.0, I am not able to add one of the two sensors in the interface despite it seems to me that from "Hardware Device Manager" the second sensor is correctly visaulized among the connected devices.
How can I solve this?
What could be additional elements to help you better understand my problem?thank you very much
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The Device Manager does not look correct. Both of the cameras should have their two drivers (Depth and RGB) listed under the Fotocamere category. Your Fotocamere should look like the image below, with 4 RealSense drivers for the 2 cameras.
Please use the instructions in the link below to check that the camera privacy settings have the permission to access the camera hardware and permission for applications to access the camera both set to On.
https://github.com/IntelRealSense/librealsense/issues/3381#issuecomment-503424789
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Thank you MartyG,
I was evnetually able to make all the drivers appear and to use tree cameras at the same time.
bests -
That's great to hear, Nicola Ariutti - thanks very much for the update!
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