Questions tagged [opencv]
OpenCV (Open Source Computer Vision) is a cross-platform library of programming functions for real time computer vision.
472 questions
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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 ...
- 101
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10
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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 ...
- 4,294
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15
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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....
Dragonslayer
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1
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109
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publish and subscribe to numpy.ndarray topic in ROS2
Hello!
My question is quite simple is it possible to create publishers/subscriber of a numpy.ndarray topic and how?
I searched on the internet and I found these two links :
https://answers.ros.org/...
Kreace
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1
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84
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Best OpenCV version for ROS Noetic
I ran this command to find out if my OpenCV version was 4:
kg-config --modversion opencv4
The outcome was:
4.2.0
I also tried ...
ajpaezm
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1
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11
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cv_bridge and OpenCV both define Exception class
I am trying to use cv_bridge in my project on Windows 10 using Visual Studio 2017. When I try to compile my code, I get the following errors:
...
sterlingm
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2
answers
872
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Triangulation: Ceres solver minimizes only the last residual block
I have been attempting to estimate a bunch of 3d coordinates viewed via a multi-view setup with known poses, I have the code running, but the output of ceres seems baffling.
There are 7 image frames/...
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73
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How can I convert the KITTI dataset into a bag file?
Hi, I want to convert the monocular KITTI image dataset and poses into a bag file to test computer vision algorithms. I have done some research, however, I have not found any reliable solution.
...
EDU4RDO-SH
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7
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Problems building melodic compressed_depth_image_transport on 18.04
Following these instructions to do a source build of melodic desktop full (I want to build it with thread sanitizer because of something I'm debugging): http://wiki.ros.org/melodic/Installation/Source
...
tyler-picknik
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2
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303
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OpenCV4.2 and Ubuntu16.04 with python2.7?
Summary:
I'm using new vision of opencv, opencv 4.2 with ubuntu 16.04 and python 2.7
After built cv_bridge, the output is:
...
- 101
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407
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How to find visual odometry by video from cellphone camera mounted on robot?
I am writing codes in python for visual odometry from single camera. I used cell phone camera for testing. I took video of 35 sec with camera moving. I used code below to read first image
...
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23
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How to get OpenCV 4 working with ROS Melodic?
I'm trying to run ROS Melodic with Opencv 4.2.0 on windows
What is wrong with my CMAKELISTS?
I have added opencv to my system path, but Catkin_make always gives this error:
...
wgengland
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1
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28
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0
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1
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52
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catkin_make opencv version conflict
Hello everyone ;
When I write catkin_make it gives such a warning.
...
jahim44229
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1
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71
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rtabmap: g2o, GTSAM
why do I need them?
I have installed rtabmap-ros as ROS package. Have I already running g2o and GTSAM?
Originally posted by june2473 on ROS Answers with karma: 83 on 2020-02-03
Post score: 0
june2473
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15
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Is there a way to publish a video file so it can be displayed with a camera display in RViz? (solved)
I have recorded videos I want to display in RViz with a camera display so that I can overlay them with my other plugins.
Is there a way to do that?
I tried with the video_stream_opencv plugin already ...
Fetzle
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0
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101
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Interpreting results from Camera Calibration?
I used OpenCV's findChessboardCorners on a few checkerboard images (40~) and about 27 seemed to find the corners accurately. How does one proceed from here? Do I calculate the reprojection error over ...
- 161
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105
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Visual-Positioning Method
I'm working on mobile manipulator and trying to do visual-positioning of the end-effector.
My camera will located around 1-2 meters from the robot.
I'm sure i cant use color tracking method because ...
- 649
4
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1
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93
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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 ...
- 41
2
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0
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151
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How do I use the live video stream from my arduino camera (connected by serial), to run with my OpenCV python ball tracking code?
My objective is to have the arduino camera, just to act like a webcam, and have my laptop run a ball tracking script on it. The ball tracking script already works with my laptops camera, and it can ...
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3
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rosrun can't open my video (ROS OpenCV)
Hi guys,
I'm trying to stream some video file (.mp4).
I wrote a node:
...
Jovan
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1
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275
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Path planning or 2D Mapping
i want to collect some ideas about this video. https://www.youtube.com/watch?v=q-ZDB8xqI7M
Is the Left Vacuum cleaner using some 2D Mapping or OpenCV to navigate through the room ?
Or is it just a ...
- 3
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1
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4
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Not able to publish image to std_msg/Image
I am trying to run a publisher code that publishes an Image to a topic. But, whenever I run the code, I get an error. The code I have written is below -
...
TristanNoctis
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1
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14
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I cannot install ROS Kinetic desktop following the tutorial
No way to install ROS Kinetic with OpenCV in RPi4, I followed the official guide, from a fresh install, with swap, with -j1,-j2...
Did somebody get install Kinetic with openCV?
i got install OpenCV 4....
FPSychotic
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1
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3
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Building OpenCV from source for ROS
I'm in need of a newer version or OpenCV than is provided by my Ubuntu repo. Is there a version or fork of OpenCV that contains a package.xml so it can be compiled as part of a ROS workspace? Seems ...
mogumbo
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1
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109
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Display image in RVIZ
Hello
Is there any way to send a captured image to the rviz and display it in a certain position?
similar to a Basic geometric markers for Rviz (visualization_msgs / Marker.msg)...
The idea is to use ...
mateusguilherme
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1
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3
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Combines message for image and information gives "invalid initialization error"
Hello,
I am currently trying to implement a message that includes the images as well as the detected bounding boxes.
The publisher works very well, but the subscriber gives me the following error ...
MarviB16
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1
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57
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display a 16-bit grayscale images from a thermal camera in OpenCV
I would like to display a 16-bit grayscale images from a thermal camera in OpenCV. I tried different images' encoding but what I get is either totally black or totally white picture. my code looks ...
Khalaf90
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1
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107
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How to calculate the distance to object with orbbec astra camera
Hello, I am using orbbec Astra camera in order to get the distance to the already detected object. I have detected the object by using OpenCV and /brg/image_raw topic from Astra camera. Now I want to ...
Yehor
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2
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7
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ROS2 Windows OpenCV self package?
Hi,
I have finished migrating a ROS package to ROS2 and I am currently going to test it on Windows.
I had a question regarding the installation of OpenCV.
Is there a particular reason why OpenCV is ...
Obeseturtle
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3
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506
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Algorithm for centering an object that is changing speed
I'm trying to use a pan / tilt alt-azimuth telescope mount to track an object that is moving in the sky. The problem is that the object is changing speed constantly. I can easily track objects that ...
- 23
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33
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How to use pcl (+ cuda modules) with ROS
Hi,
I want to use pcl and openCV with cuda. I know now that I have to install another version of openCV (since the default version of openCV in ROS kinetic does not include cuda modules) and then call ...
ipgvl
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2
answers
287
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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 ...
veilkrand
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1
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18
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ROS Melodic OpenCV xfeatures2d
On ROS Melodic ros-melodic-opencv3 doesn't exist anymore as e.g. on ROS Kinetic. Instead it is recommended to install libopencv-dev http://wiki.ros.org/melodic/Migration#opencv , however, this package ...
sam_123
1
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1
answer
60
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Image data fusion
I have three cameras separated by some distance, looking at a scene. I have calibrated them using checkerboard and I have their respective intrinsic parameters and their pose and rotation matrix, I am ...
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1
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9
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Image overlay with transparency (sensors_msg/Image) on mapviz
Hi everyone,
I've written a simple node which reads in a png file with transparency and publishes it to a certain topic. The topic is then subscribed by mapviz to display the image as an overlay. ...
rwong
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1
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26
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How to select version OpenCV in ROS?
Hi,
My name is Junifer. I am a student at a university. I am working with ROS and OpenCV. I installed 2 version of OpenCV and Python in my computer.
OpenCV 3.4.3 - Python 3
OpenCV 2.4.8 - Python 2
...
ToanJunifer
3
votes
1
answer
2k
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Trigger two usb cameras at the same time
I'm studyng stereo cameras, and I want to build one. I searched a lot in internet, and the opinions are quite different about this topic.
Basically, my question is:
Can I synchronize two usb ...
0
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1
answer
88
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Fixing robot orientation using AR
I am creating a project where a robot needs to face a control panel and do some specific tasks. Some reference tags will be placed on the panel.
I want to use the tags as AR reference and fix my ...
1
vote
1
answer
88
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How to tringulate many projections of a point to optimal postion?
Suppose we have many images for the same scene (with known poses already,using for ex: a GPS ), and the same feature appear in more than 2 images .
How to use all the available info to compute as ...
- 123
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2
answers
17
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camera_calibration opens gui window but freezes
I'm trying to run the camera_calibration node. I run this command:
...
martinakos
2
votes
1
answer
204
views
Robotic Hand Grasp Planning - How do I find the initial contact point for each finger when grasping an object?
I am trying to design a robotic hand that is able to adaptively grasp unfamiliar objects. I am initially thinking that using OpenCV for pose estimation might make doing so easier.
Assuming that I am ...
0
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1
answer
13
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Using camera calibration results in OpenCV
I've calibrated Kinect intrinsics (both depth and rgb) using camera_calibration module and saved a bunch of rgb images afterwards (calibration file was detected successfully; subscription to kinect1/...
Mikhail K.
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1
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10
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[SOLVED] Cannot use OpenCV trackbar with vision_opencv?
Hi, so I'm making a video publisher that stores frame from webcam as OpenCV image to be HSV-filtered, eroded, and dilated then convert it to a ROS image to be published to a subscriber. The code is ...
adhipatiunus
2
votes
1
answer
689
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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 ...
- 21
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1
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11
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Images from fisheye camera are displayed correctly with BGR8 encoding but not with MONO8
Hi,
I want to output grayscale images from a fisheye camera (FOV < 180 degree). I understand that ROS currently doesn't support fisheye distortion models. However, I see that if I use a BGR8 image ...
tuandl
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votes
2
answers
37
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How to specify my own OpenCV3 for cv_bridge
The ROS1 package cv_bridge can be downloaded here: https://github.com/ros-perception/vision_opencv.git and be found at ...
bear234
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1
answer
11
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undefined reference to `StitchedMap::get_stitch()'
Hi everyone! I am new to ROS.
I am trying to convert the Mapstitch package (https://github.com/tu-darmstadt-ros-pkg/mapstitch) from Rosbuild to Catkin. However, after I created a catkin package and ...
LokJai
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1
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8
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image stream using camera
Hello guys,
My question might seem easy for many since i am still fresh in Ros and Opencv.
I am following the tutorials provided on Ros Website. I am going through the tutorial ''Converting between ...
Firoooo
0
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1
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25
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sensor_msgs - Can't build tutorial project
I am trying to pass images as messages in a simple ROS project. I'm a complete beginner in ROS and robotics. The tutorial I'm trying to follow is here:
http://wiki.ros.org/cv_bridge/Tutorials/...
dharmaforone