Questions tagged [libopencv]

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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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OpenCV imshow toolbar missing in noetic

I've been using OpenCV with ROS kinetic for years, and have come to rely on the functions toolbar that comes with cv::imshow for debugging. We've successfully transitioned to noetic under Ubuntu 20.04,...
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ROS opencv image publisher

I run a simple program to continuously publish image to ROS server. I cannot get rid of below error, anyone know the solution please help. ...
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[ROS2] Opencv 4 conflicted with cv_bridge causing an error

Hi fellow developers, I am having an issue with ROS2 cv_bridge and opencv 4. The warning below shows that I have a conflict ...
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Jetson Nano comes with OpenCV 4.1.1., do I need to downgrade to 3.2. for melodic?

I just got a Jetson Nano running Ubuntu 18.04 and it comes with OpenCV 4.1.1. pre installed. I've read ROS melodic is meant to work with OpenCV 3.2. and I'm getting some catkin make errors due to ...
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publishing a cv2 image with cv_bridge

I wrote a basic node that reads an image from a local folder and publishes it. However, the topic is empty, i can not display the image when i use the image viewer. The cv2 image is being loaded ...
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Feasibility of using Docker to isolate ROS and other tools in Robotics

I am very new to Docker and I want to use it to isolate ROS (Melodic), OpenCV and Deep Learning libraries. I have Ubuntu 18.04 LTS running with CUDA, Eclipse, cmake and a few other basic tools ...
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converting DisparityImage message to PointCloud2

Hi, I want to convert a DisparityImage message to a PointCloud2 messages such that each pixel disparity value is now a x, y, z ...
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web_video_server installation

I installed web_video_server using the command sudo apt-get install ros-kinetic-web-video-server but trying to run it with ...
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Why do I get inverted colors in my images?

I am fetching images from a camera/webcam and publishing it's images using image_transport. When viewed in RViz the images look correct however when recorded with ...
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Using opencv tracking with ROS kinetic

Hey, i want to use the tracking packageof opencv3 contrib in my ROS package. The tracking packagee seems to be installed correctly, i can find the tracker.cpp in my opencv folder and also use other ...
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Install opencv_contrib Tracking package

Hey there I simply want to use the tracking package of the opencv3 contrib package in my ros kinetic. I figured already out that in particular the tracking package is not contained in one of the ...
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How to get image from custom server using service?

Hello People, I am trying to pass image from server to a client. The code complies when I use cv_bridge::toCvCopy, but it says core dumped when I actually call the image from the server. So I am ...
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Is ROS Kinetic compatible with libopencv-dev-2.4.9?

The REP link suggests to use opencv 3.1.x with ROS Kinetic. However, since the system package libopencv-dev 3.1.x version isn't available in the upstream ubuntu repository yet, I had installed ...
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Crash while launching multiple instances of same nodelet

Hello, I am trying to load a nodelet multiple times. But the node is getting crashed once the second instance of the node let started executing. Below snippet describes the way I am loading the ...
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Having trouble using CUDA enabled OpenCV with kinetic

Hello everyone. I started a new install of ROS Kinetic, and I was hoping to use a few CUDA features from OpenCV. I have successfully compiled and tested CUDA and OpenCV (which is installed in /usr/...
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Best way to render some text on an image?

What is/are the recommended way(s) to render some text onto an image message in ROS Indigo / Ubuntu 14.04? I tried opencv/highgui/addText/fontQt, but that introduces an opencv compile-time dependency ...
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ROS Indigo OpenCV3: undefined reference

Hi! When I try compilling project rpg_monocular_pose_estimator and I get: ...
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opencv3.0 ros indigo

Hi, I want to use opencv 3.0.0 in ros but I have troubles linking my code. When install ros-indigo-desktop-full there are dependencies to opencv2.4 for some pkg like cv_bridge or image_pipeline. When ...
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cv_bridge/OpenCV segmentation fault

Hi, I'm getting a segmentation fault whenever I'm trying to convert an image from subscribed topic to: ...
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How do I use SURF in ROS

Hi there, I was trying to migrate a code that uses SURF from cpp to a kind of ROS cpp. But when i think that the compiler almost done it, it shows me an error after linking the executable. Here is my ...
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Packages for OCR and NLP

Is there any package in ROS hydro for optical character recognition (OCR) and natural language processing (NLP) Originally posted by Kishore Kumar on ROS Answers with karma: 173 on 2015-03-17 Post ...
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Help in making node with OpenCV/cv_bridge and ROS Indigo

Greetings, Running ROS Indigo, Ubuntu 14.04 and catkin_simple. My system has downloaded: <...
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Incorrect cmake opencv lib path leads to failed compilation

I am trying to compile web_video_server on a raspberry pi with all the libopencv-* packages installed. Every time I try to run ...
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1 answer
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capture publish and subscribe image using ROS

Hello Everyone, I am newbie in ROS i have written C code for Capturing images using OpenCV and then using socket communication I am sending that images to remote location. Now I have to create same ...
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Computer vision in ROS

I am new in computer vision but I need to implement a robot with these kind of abilities. It has to identify objects with a particular color and size. For this purpose I have a RGB camera which gives ...
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Depend on OpenCV in Hydro

With this commit in rosdep key that, now from Hydro there are at least 2 ROS ways to depend on OpenCV; via ROS 3rd package "...
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Using rostopic /image_raw for VideoCapture in OpenCV

Hello, All of a sudden, I need to change my approach from calling TheVideoCapturer.open(0); (TheVideoCapturer is of a class VideoCapture) to open my internet camera ...
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Libopencv undefined reference to 'header'

I'm trying to compile ROS on a Raspberry Pi (Raspbian) following these Debian installation instructions and got to the point to compile ROS, which fails at compiling opencv with ...
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2 answers
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OpenCV CMake Error

I have been using OpenCV without issue for months, but today when I catkin_make my workspace I now get the error: -- +++ processing catkin package: 'clam_vision' -- ==> add_subdirectory(...
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Coding using OpenCV2 ROS

#include stdio.h> #include iostream> #include "opencv2/core/core.hpp" #include "opencv2/features2d/features2d.hpp" #include "opencv2/highgui/highgui.hpp" #include &...
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cannot make image_view from source on gumstix Overo

Hi everyone, I am trying to make image_view(fuerte version) from source on gumstix Overo(running Linaro). But I got the following error: ...
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add external opencv libraries to ros package

Hi all i use opencv libraries in ros qt package . i need to use surf feature detector in my work but libraries of this function not exist in ros_opencv . i want to add external opencv libraries to ...
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Corner detection using opencv and ROS

Hi guys, I have implemented an algorithm that uses the opencv2 Harris corner detector. I have a few questions, but first let me explain my system: I have copied the opencv2 Harris corner detector and ...
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Regarding Publishing Kinect Depth Image

Hi All, I have kinect Depth image as mentioned below. I am trying to publish this from my node. I am having problem in converting my image to buffer which is needed to send it as a message. Please ...
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Need Help with Accessing the kinect Depth Image using OpenCV

Hi All, I tried to subscribe to kinect depth and color image topics from openni_launch..(/camera/rgb/image_color and /camera/depth/image ) I converted them to cv::Mat format using below code. cv_rgb = ...
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How to update opencv to latest version?

Hi ! i am new to ros, i installed ros fuerte few days back, the version of opencv installed with ros was 2.4.0, now opencv 2.4.2 has been released, i want to upgrade my current opencv 2.4.0 to opencv ...
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Which topics to use?

Hi all! I am currently deciding which topics from the kinect camera should I use. As I am absolutely new to ROS I thought that maybe someone with more experience could suggest an appropriate way. In ...
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Using FindOpenCV.cmake with libopencv2.3-dev

While installing ros-electric-desktop-full, I ran into a conflict of ros-electric-vision-opencv (through libopencv2.3-dev) with the default OpenCV in Ubuntu 11.10. In order to resolve the conflict, I ...
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ROS OpenCV linker error

I am trying to compile a program I have that uses opencv, and I get the following error: --> Making UTIL -- Linking popup.o to popup (C++) /usr/bin/ld: cannot find -l/usr/lib/libopencv_contrib.so.2....
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libopencv2.3-dev is not updated

The libopencv2.3-dev version is not updated in the ubuntu repository. 2.3.1+svn6514+branch23-1~natty is needed for ros-electric-vision-opencv but 2.3.0+svn5720+trunk-5~natty is in the repository. ...
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