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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 ...
franzele's user avatar
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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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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 ...
Idan Aviv's user avatar
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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? ...
Ben's user avatar
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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/...
Meriem Ghrissi's user avatar
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1 answer
73 views

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 ...
Jazx Jazx's user avatar
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93 views

Error: Could not demultiplex stream video player opencv depth camera

Video player gives "could not demultiplex stream" ...
Vrushab Jain's user avatar
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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 ...
kilianf's user avatar
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How to transform the detected target pose into the pose in the camera coordinate system in Gazebo

that is my code ...
chan mlen's user avatar
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: ...
Mhd Afz's user avatar
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1 answer
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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.
ertretff's user avatar
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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 ...
Onee's user avatar
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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 ...
Thiago Blanco's user avatar
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 ...
user37201's user avatar
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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 ...
lonewolf's user avatar
1 vote
2 answers
928 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 ...
Mona Jalal's user avatar
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1 answer
129 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 ...
Franci's user avatar
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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 ...
renan's user avatar
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1 answer
127 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 ...
noobcoder's user avatar
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81 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: ...
nebula's user avatar
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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 ...
whvauwgruivariuvba's user avatar
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’...
Tina J's user avatar
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1 vote
1 answer
254 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 ...
vyi's user avatar
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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 ...
senSMEM8's user avatar
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1 answer
16 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 ...
Lucas Walter's user avatar
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1 answer
299 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 ...
user avatar
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, ...
astabc44's user avatar
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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 ...
user avatar
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1 answer
44 views

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

CMakeLists.txt contains ...
user avatar
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 ...
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1 vote
0 answers
200 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....
Alexander Soare's user avatar
1 vote
1 answer
461 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/...
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2 answers
44 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 ...
user avatar
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/...
bob's user avatar
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1 answer
62 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 ...
user avatar
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 ...
user avatar
0 votes
1 answer
125 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 ...
user avatar
4 votes
1 answer
350 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 ...
Mike's user avatar
  • 361
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 ...
satan 29's user avatar
  • 131
0 votes
1 answer
33 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 ...
user avatar
1 vote
2 answers
116 views

Reflective surface

Have you encountered the problem of reflective surfaces for realsense camera (d435 or t265) and lidar (A1 or A2). I would like to know what are the ways to solve problems with reflective surfaces for ...
Splinter1984's user avatar
0 votes
2 answers
633 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 ...
user avatar
0 votes
1 answer
57 views

Compress Image topic with h264 streaming for low bandwidth connection?

Hello, I faced the problem that sending the video with big resolution (1920x1080) is very difficult even with image transport. The raw or compressed images are too bit for sending over the network (...
user avatar
0 votes
1 answer
63 views

Find intrisic camera matrix from gazebo model

Hello, I made a my camera model in gazebo and I want to extract the intrinsic matrix to use Opencv matrix. Here is my model: ...
user avatar
1 vote
1 answer
371 views

Path planning for robot car on grid

I am currently doing a project as my hobby. I am trying to simulate a robot car in a grid arena. Below is the image of the arena: The start point of the car is the bottom-right corner(dark green ...
UJM's user avatar
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1 answer
194 views

Eliminate grey space around the saved map

I have mapped my Gazebo environment using the slam_gmapping node. On running ...
skpro19's user avatar
  • 314
0 votes
1 answer
472 views

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 ...
skpro19's user avatar
  • 314
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 ...
Steve Ahlswede's user avatar
0 votes
1 answer
7 views

Finding OpenCV Paths in ROS Builds

Short version: How do I find the path to haarcascade_frontalface_alt.xml provided by opencv? Long version: I'm working on getting the ...
DLu's user avatar
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0 votes
1 answer
11 views

openCV transform datatypes to ROS msg tf/goal

Hi, Iam looking for the best practice to make a openCV transform (getAffineTransform() ) into a pathplanner goal message (angle, translation). I dont really understand all the different datatypes used....
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