pictures transmission between two pc

[flyover-26]

hi!
I want to use d435i with ros wapper on one pc-1.And use another pc-2 to receive pictures from pc-1 which have a d435i.
However,I found the speed transmission is very slow although I change resolution to 640*360,fps 15.
And in my experienment,I only need color images which is rostopic"/color/image/raw".And I found there are a lot of rostopic which may decrease the speed.
So could you tell me how to shut down these rostopic?or some methods to speed up transmission?
Thank you a lot!

[MartyG-RealSense]

Hi @flyover-26 There is a discussion at IntelRealSense/realsense-ros#1990 about unsubscribing from ROS topics to reduce processing.

If you are using networking, slowdown can sometimes occur, especially if using wireless networking (WLAN / wi-fi), as described in IntelRealSense/realsense-ros#2052 which offers advice on methods to try for improving performance.

[flyover-26]

THANK YOU !
I got another question is that when I test a slam project.I use d435i as an input.
Everything goes well when I use resolution 1280720.However,when I change resolution to 640420 or other,slam will crash with no reason.Could you give me some advice on this?thank you so much.

this is the launch file I use to run d434i.
test.txt

[flyover-26]

1920✖720 is also ok.Which means 1280*720 or above is no problem for the project but below.

[flyover-26]

And I use gdb to find this error.
received signal SIGSEGV, Segmentation fault.

[MartyG-RealSense]

Have you tried 640x480?

Are you using USB 3 or USB 2.1, please? If you are on a USB 2.1 connection instead of USB 3, 848x480 would only be supported up to 10 FPS on D435i for depth resolution and not available for color resolution.

Also, 1280x720 would be limited to 6 FPS when used as depth resolution on USB 2 but be able to be set to up to 15 FPS when used for the RGB resolution.

[flyover-26]

yes.I have tried 640x480.And I got the same error.
I am using USB 3 and librealsense v2.45.0

[MartyG-RealSense]

Looking at the D435i launch file that you kindly provided, I note that you have enable_fisheye set to True. This setting is False by default on the standard wrapper launch files such as rs_camera.launch. The D435i does not have fisheye sensors as they are only on the RealSense T265 Tracking Camera model.

[flyover-26]

thank you so much for your patience!
I change it to false and still get the error.
this is launch file I use now.
launch.txt
and log file.

[MartyG-RealSense]

I see that the log contains a likely requires patch for fourcc code RW16! warning, suggesting that librealsense might be unpatched if you built it from source code.

Let's try using rs_camera.launch with a custom 640x480 color stream configuration to determine whether the problem is in your launch file.

roslaunch realsense2_camera rs_camera.launch color_width:=640 color_height:=480 color_fps:=30

[flyover-26]

YES.I built librealsense from source code.
I run commmand you provided and still get the warning.

[MartyG-RealSense]

When you installed from source code, did you patch the kernel before building librealsense by going to the root directory of librealsense and using the command below (assuming that you are using an LTS kernel such as 5.4):

./scripts/patch-realsense-ubuntu-lts.sh

This is in point 4 of the Prerequisites section of Intel's official documentation for installing librealsense from source code.

https://github.com/IntelRealSense/librealsense/blob/master/doc/installation.md#prerequisites

[flyover-26]

I don't patch my computer before.I read the patch-realsense-ubuntu-lts.sh.
Will this .sh file change my version of kernel?My computer can only be used under LTS kernel 5.4.And I noticed that this .sh file will download linux-headers-4.15.0-161 linux-headers-4.15.0-161-generic.

By the way,I want to use d435i on Xavier NX.Do I need patch its kernel with the same method you provide?Because NX get the same warning.
Thank you!

[MartyG-RealSense]

It would not change the kernel version. If you are concerned about making changes to the kernel then you can avoid doing so by building librealsense from source code with the RSUSB backend method. This method is not dependent on Linux versions or kernel versions and does not require patching. A guide for building on Jetson boards using this method is at #6964 (comment) and these instructions have been successfully tested with Xavier NX.

[flyover-26]

THANK YOU SO MUCH!
When I use RSUSB backend method,I ran the command"cmake ../ -DFORCE_RSUSB_BACKEND=ON -DBUILD_PYTHON_BINDINGS:bool=true -DPYTHON_EXECUTABLE=..." on my pc.

I got an error below.

[MartyG-RealSense]

A Jetson user who experienced this error stated in #6449 (comment) that they could build successfully by leaving out the -DPYTHON_EXECUTABLE command or by using -DPYTHON_EXECUTABLE=/usr/bin/python

If you do not require the RealSense Python compatibility wrapper to be included in your librealsense build then you could also try leaving out the Python commands from the CMake build instruction.

cmake ../ -DFORCE_RSUSB_BACKEND=ON -DCMAKE_BUILD_TYPE=release -DBUILD_EXAMPLES=true -DBUILD_GRAPHICAL_EXAMPLES=true -DBUILD_WITH_CUDA:bool=true

[flyover-26]

hi!
I use -DPYTHON_EXECUTABLE=/usr/bin/python to solve the problem.thank you.
But when I run roslaunch realsense2_camera rs_camera.launch color_width:=640 color_height:=480 color_fps:=30
I got problem like this.

and when I open realsense_viewer,I see some error.

[MartyG-RealSense]

Do the warnings still occur if you add initial_reset:=true to your roslaunch instruction to reset the camera at launch, please?

[flyover-26]

yes.
I still get the warning.
My librealsense is v2.45.

And when I try to run this command " cmake ../ -DFORCE_RSUSB_BACKEND=ON -DCMAKE_BUILD_TYPE=release -DBUILD_EXAMPLES=true -DBUILD_GRAPHICAL_EXAMPLES=true -DBUILD_WITH_CUDA:bool=true"
I got an error like can not find CUDA library.

thank you for your help.

[MartyG-RealSense]

Bearing in mind that you were using 15 FPS at the beginning of this case, how does the ROS launch behave if you set FPS to 15 instead of 30?

roslaunch realsense2_camera rs_camera.launch color_width:=640 color_height:=480 color_fps:=15

If you are using a Jetson Xavier that has CUDA installed then it should be able to make use of CUDA when CUDA support is included in the librealsense SDK, as Jetson boards have the Nvidia graphics GPU that is a requirement of CUDA. The CUDA support would not work on a computer that does not have CUDA and an Nvidia GPU. Can you confirm whether you tested the CMake build instruction on a Jetson board, please?

[flyover-26]

yes.I try roslaunch realsense2_camera rs_camera.launch color_width:=640 color_height:=480 color_fps:=15.
And still got the warning.
I build librealsense on xavier nx.And I use method below.

Download the zip file from https://github.com/IntelRealSense/librealsense/releases/. I am using version 2.38.1

Extract the file, cd into the extracted file .

Create a dir called build and cd into it.

Run the CMake command to test to see if the build will work.
cmake ../ -DFORCE_RSUSB_BACKEND=ON -DBUILD_PYTHON_BINDINGS:bool=true - DPYTHON_EXECUTABLE=/usr/bin/python3.6 -DCMAKE_BUILD_TYPE=release -DPYTHON_EXECUTABLE=/usr/bin/python

If you have issues with the above step, check out this, this and this

Still in the build dir. Run make -j4 and then sudo make install

By the way,after we solve patch for fourcc code RW16.My slam project can run correctly,but it is not stable enough.It will crash sometimes because of unkown problem about realsense i guess.
Thank you for your helping!

[flyover-26]

I use version v2.45

[MartyG-RealSense]

It's excellent to hear that you resolved the 'fourcc code RW16' issue!

Are you using ROS wrapper version 2.3.0 please? This is the correct wrapper version to match with librealsense SDK 2.45.0, as it is important to match a particular wrapper as closely as possible with the librealsense version listed in that wrapper's release notes.

https://github.com/IntelRealSense/realsense-ros/releases/tag/2.3.0

[flyover-26]

yes，it is matched.
And I have no idead how to solve this.
Are there any other reason to lead to this warning?
thank you

[MartyG-RealSense]

How many cameras do you have attached to the same PC? There have been past Jetson cases where if more than one camera is attached then a Failed to set power state error may occur, whereas if only one camera is attached then it works normally.

[MartyG-RealSense]

Hi @flyover-26 Do you require further assistance with this case, please? Thanks!

[MartyG-RealSense]

Case closed due to no further comments received.