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Questions tagged [opencv]

OpenCV (Open Source Computer Vision) is a cross-platform library of programming functions for real time computer vision.

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AttributeError when trying to reinsert modified images into ROS2 bag file with Python

I'm currently working with ROS2 and Python to process image data stored in a ROS2 bag file. My task involves extracting images from the bag, performing modifications, and then reinserting them. I am ...
0 votes
1 answer
27 views

Create self-contained standalone ROS1 application for Windows

I created a ROS Noetic package that grabs data from some cameras and performs pose estimation of objects in the field of view (using OpenCV). Simultaneously, IMU data is measured and fused with these ...
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1 answer
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Video from dron camera to RTSP

I am a newcomer to using ROS and am facing the challenge of obtaining a video stream from the camera topic of my robot in Gazebo and transmitting this video via RTSP. I have attempted to use the gi ...
2 votes
1 answer
1k views

Implementing PID on a line following bot using turtlebot

I am using ROS melodic,turtlebot 2 on Ubuntu 18.04. The idea is to create an environment consisting of lines as a path (slightly curved), and to program the turtlebot to follow the lines. Basically, a ...
1 vote
2 answers
181 views

OpenCV camera rvec tvec to ROS world pose

I'm detecting Aruco tags using the OpenCV bridge and I have tvec and rvec returned with the tag pose related to the camera using OpenCV axis notations. I would like convert them to a ROS pose related ...
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2 answers
28 views

Which single board computer should I chose?

Hi ros community I' m working with ros to make a robot which can go itself with image proccessing. I am using lots of hardware in this project and I used pcduino V3 until this time. But I want to ...
1 vote
0 answers
21 views

cv2.stereoRectify works only when the rotation and translation are from camera 2 to camera 1

I am using the euroc-mav dataset to create a disparity map from stereo images: https://projects.asl.ethz.ch/datasets/doku.php?id=kmavvisualinertialdatasets. In this dataset the cameras are already ...
1 vote
2 answers
176 views

Switching between 2 cameras (using opencv)

I have a manipulator in ROS and 2 cameras attached on it. I want to switch the frames of cameras every 5 seconds Both cameras work fine. I do not want to close the window and reopen it (if it is ...
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11 views

Calculate disparity for matching feature points

If I have matched a pair of feature points, could I calculate its disparity by simply subtract the u coordinates(uL - uR)? And could use this disparity to calculate the depth for this 3d point? ...
1 vote
1 answer
351 views

Error when compiling cv_bridge in Raspberry Pi 4B with Raspbian buster and ROS Noetic

Im using Raspberry Pi 4B, with Raspbian Buster and ROS Noetic. When I tried to compile my catkin ws with a cv_bridge package I got the following error: CMake Error at vision_opencv/cv_bridge/...
1 vote
2 answers
918 views

Converting a ros2 bag of color raw images to image files or video

This is using ros2 Humble in Ubuntu 22.04 and native Python 3.10 Eventual goal: capturing depth aligned RGB and Depth streams from Intel RealSense D435 camera and converting them to RGB and Depth ...
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1 answer
127 views

reading depth in mm from ros depth image

I want to read a depth image from ros. I subscribe to the /camera/aligned_depth_to_color/image_raw/compressed topic published by a intel realsense D435i camera. I ...
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1 answer
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Need help in loading occupancy_grid map to OpenCV window

I have generated a map named map_1.pgm using map_server package. I want to display it in an ...
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1 answer
126 views

Calibration of camera using ROS, without camera info

As part of a college project, I need to communicate with a TM5-700 robotic arm developed by Omron, and implement, for now, a pick and place pipeline. For that, I am required to access the camera ...
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i want to run an image publisher in ros2 using opencv but this error apppears i am working with ros2 humble

when i run this qrie@qrie-HP-Laptop-15-rb0xx:~/dev_ws$ ros2 run cv_basics img_publisher i get this error ModuleNotFoundError: No module named 'rclpy._rclpy_pybind11' The C extension '/opt/ros/humble/...
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Error: Could not demultiplex stream video player opencv depth camera

Video player gives "could not demultiplex stream" ...
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0 answers
26 views

opencv StereoSGBM disparity parameters

In my setting I am using a stereo camera which has a baseline of b = 0.092m and a focal lenght in pixels of fx = 256.667. So that when I want to constrain my setup to detect points up to a maximum ...
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13 views

How to transform the detected target pose into the pose in the camera coordinate system in Gazebo

that is my code ...
1 vote
0 answers
51 views

ArUco Markers Distance Estimation Accuracy Difference

The distance estimated (in cm: Because input size of ArUco Markers in cm too) using the code line after importing math module: ...
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0 answers
133 views

ROS2 CV2 imshow and publish in the same loop fails

I attempted to publish and display an image from a video using cv2 and ros2. Although the code compiled successfully, running it consistently resulted in a memory allocation failure. Could someone ...
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1 answer
19 views

ros2- where is the data libopencv-dev

I want to find this github address. (I cant find it,because main opencvs github has opencv/opencv -b 4,3,2,1) Thank you.
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100 views

I am trying to use opencv_cam pkg in ros2 humble with a csi stereo camera imx219-83 in a jetson nano and I get green screen

I am trying to use opencv_cam in ros2 humble for a csi stereo cam in a jetson nano. When I run the node : ros2 run opencv_cam opencv_cam_main ,it publishes the ...
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0 answers
72 views

How do I use a CSI camera with ros?

I am using Jetson Orin Nano connected with raspberry Pi V2.0 Camera. I am using gstreamer pipeline to get the camera feed. It works fine with g++ build and python but as soon as I try to build it with ...
1 vote
2 answers
126 views

colorize area of point cloud on a 2D image

I am projecting a 3D Point Cloud on a 2D image incoming as ROS 2 messages. Now, I want to fill the gaps between pixels from the point cloud, so that I can see an area, instead of single pixels and ...
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80 views

Segmentation fault in cv::findContours call

I am struggling to debug a segmentation fault. Any help is appreciated! The node just crashes whenever I launch it and following is the seg fault I am getting when running through gdb: ...
1 vote
2 answers
23 views

How to use arbitrary version of OpenCV

Hi, i have ROS Kinetic installed and it comes with OpenCV. I also have the latested OpenCV that i downloaded from github and installed in /usr/local. The following code that i wrote will always use ...
0 votes
0 answers
49 views

multiple video streaming

I'm currently experimenting with video stream opencv. But,I think I can only stream one video at a time.Is it possible to stream multiple videos at the same time?If there are other packages that would ...
0 votes
2 answers
100 views

Conversion from 32FC1 to mono8 using cv_bridge

I am trying to use cv_bridge to convert an image from /disp_map/image (32FC1 encoding according to msg->encoding ) to an ...
1 vote
2 answers
118 views

Detecting door blockage using computer vision

I want to detect door blockage on a camera. Basically if the exit door is blocked by an object, it detects it as an anomaly. How can we do it? Is it possible to do it using OpenCV? Remember, it doesn’...
1 vote
2 answers
116 views

Vision programming with OpenCV

I am currently working on a project on NiryoOne which requires facial detection of a person through NiryoOne camera (ELP SONY IMX). The code that I am using works on my laptop running Ubuntu. However, ...
1 vote
1 answer
252 views

Making sense of disparity values after applying `StereoSGBM` from OpenCV

I just started with Kitty Stereo Dataset (2015). The first thing I did was compute the disparity using the stereoSGBM class. And here is the rectified input images ...
0 votes
1 answer
45 views

Trouble aligning/calibrating camera with laser scanner

I have a robot which has 2 multi-spectral cameras and 1 laser scanner attached. In the end I would like to have the images from the cameras aligned with the scanner so that I can have spectral ...
1 vote
0 answers
89 views

WEBOTS - Connect a external Tkinter Script to main controller?

I have a WEBOTS Simulation with an automobile. Now while WEBOTS provides a camera overlay, I want to display the result of image processing along with sensor data in a comprehensive manner. For this I ...
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1 answer
15 views

Convert CameraInfo K & D to OpenCV format convenience functions?

Are there existing functions to convert from camera info arrays of K and D to intrinsic and distortion cv::Mats that can be passed into opencv functions like ...
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1 answer
298 views

Configuring ROS2 for OpenCV and C++

How to properly setup the ROS2 workspace (i.e., cmakelists and package.xml, etc.) for using OpenCV and C++ ? I could not find proper examples for that. Thanks in advance. Originally posted by ...
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1 answer
71 views

How to enable GPU-Features of Rtabmap

OS: Ubuntu 20.04 CUDA 11.6, CuDNN 8.4 (GPU is Nvidia Quadro T 1000) OpenCV 4.5.5 with GPU support also for CUDA and also the opencv_contribs currently using Rtabmap standalone, but I intend to use the ...
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1 answer
43 views

CMake detects intended OpenCV+CUDA, but runtime does not use intended OpenCV version

CMakeLists.txt contains ...
0 votes
1 answer
10 views

Catkin_make failed to build opencv

Hello guys, I want to compile a package (https://github.com/mjshiggins/ros-examples) with the catkin_make command from the catkin_ws folder, but it seems that the OpenCV header file is depreceated or ...
0 votes
2 answers
623 views

OpenCV and ROS2

I've checked all the related questions here and I still wasn't able to get this example to run. I apologize in advance if the solution was right in front of me and if that offended anyone. Problem ...
1 vote
0 answers
197 views

Why would we solve AX=XB instead of just using the Kabsch algorithm?

I have a high precision stereo camera and a robot which are independent units (the camera is not mounted to the robot). I wish to compute a transformation from the camera frame to the robot base frame....
1 vote
1 answer
460 views

ROS2: How to publish cv Mat image?

I'm having trouble understanding how to publish a cv::Mat image in C++, and I can find very little documentation about this. Here's my publish code. I based it on this tutorial: https://docs.ros.org/...
4 votes
1 answer
9k views

Determine the relative camera pose given two RGB camera frames in openCV-python

I would like to determine the relative camera pose given two RGB camera frames. I assume there's overlap in field of view between the two cameras, what I am looking for ultimately is the rotation and ...
0 votes
2 answers
43 views

upgrade opencv version in melodic

Hello, i want to upgrade opencv version to over 3.4 in Melodic. Melodic installs opencv 3.2 originally, so I tried to uninstall opencv 3.2, and re-install opencv 3.4 But some packages which are ...
0 votes
1 answer
61 views

Noetic python raw Image publisher (from video)

Hi everyone, I have spent nearly 2 full days with this problem now and have some extensive research, but just can't figure it out. My apologies for being a burden, I ussually hesitate to waste anyones ...
0 votes
1 answer
32 views

Image Subscriber Lags (despite queue_size=1 and buff_size=2**30)

Hi, I have been working on a Python class that will allow me to spawn an object in gazebo, take an image of the object, and then delete that object, for a given number of objects that I provide. I am ...
0 votes
1 answer
124 views

ModuleNotFoundError: No module named 'cv_bridge' IN windows10 running foxy

I was following this tutorial https://automaticaddison.com/getting-started-with-opencv-in-ros-2-foxy-fitzroy-python/ to implement a simple ros2 image publisher and subscriber. everything was built but ...
4 votes
1 answer
349 views

Does a stable library exist for docking robots using images?

I built a mobile base from scratch, and now I am focused on getting the robot to charge. The robot is using an on-board webcam (and PC) to detect a QR barcode on the charger unit. Using OpenCV I find ...
0 votes
1 answer
32 views

What is the exact format and size of Image() object?

I cannot figure out what is the exact format of the sensor_msg Image() file. When I issue the command: rostopic echo /camera/image_raw I get a massive output ...
4 votes
1 answer
93 views

Make robot drive as far from obstacles as possible

I am trying to make robot drive around the room, avoiding obstacles with pathfinding. The problem is I get few waypoints from pathfinding algorithm for robot to drive to (green dots), but it drive a ...
2 votes
1 answer
676 views

Pictures coordinates to robot coordinates

I have a picture on my C# software and the corresponding object in real world on 2d plane of motorized XY axis table. What I want is when I select a pixel on my picture, the motorized table should be ...

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