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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Which is the best visual fiducial marker (2D barcode)?
Which is the best visual fiducial marker (2D barcode) for detection and robust and accurate pose estimation?
Im not looking for a fiducial marker which can store lot of information. The main goal is ...
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How to check lane departure in OpenCV?
I'm using OpenCV 3 in Python 2.7 on a Raspberry Pi 3. My project's aim is to build an autonomous lane departing robot that can detect the two lanes on its sides and continuously correct itself to ...
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Tracking objects from camera; PID controlling; Parrot AR Drone 2
I am working on a project where I should perform object tracking using the camera of Parrot AR Drone 2.0. So the main idea is, a drone should be able to identify a specified colour and then follow it ...
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Transforming Point Cloud to get Top Down Image [closed]
My task:
I have a task where I am asked to track parcels(carton boxes) of different dimensions moving on a conveyor. I am using Asus Xtion pro camera mounted on top of a conveyor in any inclined ...
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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 ...
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4
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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 ...
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2
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Stereo Camera calibration with different camera types
I'm trying to perform stereo camera calibration, rectification and disparity map generation. It's working fine with normal sample data. However, I'm trying to use the dual cameras on an iPhone 7+, ...
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4
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1
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Image registration with ground plane for surround view
I am currently working on a project which which involves surround view.
I have 4 fish eye cameras and are fixed at 4 sides of a car.The fish eye cameras are corrected for radial distortion.
After ...
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4
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1
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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 ...
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4
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1
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Scale problem with monocular visual odometry
Is monocular visual odometry able to estimate relative scale? Say I have a sequence of 10 images that are taken on a single track each 1 m after the previous. Can some mono odometry method distinguish ...
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3
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2
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Real-time object classification for an indoor autonomous quad-rotor
I am designing an indoor autonomous drone. I am currently writing an object classification program in OpenCV for this purpose. My objects of interests for classification are: ceiling fans; AC units; ...
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3
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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 ...
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1
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OpenCV get topdown view of planar pattern by using intrinsic and extrinsic from cameraCalibrate
Originally I have a image with a perfect circle grid, denoted as A
I add some lens distortion and perspective transformation to it, and it becomes B
In camera calibration, A would be my destination ...
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3
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1
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Converting Image Coordinates to (x, y) Position for Robotic Arm
I have a Robotic Arm with a camera mounted above it looking down at a slight angle.
Assuming I know the height of the camera, the angle of tilt and the small distance from the center of the robot ...
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3
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0
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Obstacle avoiding by Pi camera [closed]
I designed a mobile robot with my colleagues for our graduation project, the purpose of it is to detect mines (metals) in a specific area
We are programming the robot using Python on Raspberry Pi 3
...
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3
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2
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Suggestions on object types (features) to track from ARDrone 2 camera
UPDATE
I have aded 50 bounty for this question on the StackOverflow
I am trying to implement object tracking from the camera(just one camera, no Z info). Camera has 720*1280 resolution, but I ...
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2
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1
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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 ...
2
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1
answer
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Stereo Vision Using Compute Module: Pi camera synchronization
Good day,
I am currently working on an obstacle avoiding UAV using stereo vision to obtain depth maps. I noticed that the quadcopter would sometimes not steer to the correct direction.
I am using ...
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2
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1
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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 ...
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2
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1
answer
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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 ...
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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 ...
2
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1
answer
643
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Mobile robot pose estimation
I want to plot the path of a vehicle via the estimation of egomotion based on essential matrix.
Everything was fine with openCV and the following function.
...
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0
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333
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Maintaining scale factor for essential matrix
I want to recover the trajectory of a vehicle using a monocular camera via the computation of the essential matrix between t-1 and ...
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2
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130
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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’...
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1
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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 ...
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2
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130
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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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2
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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 ...
sep_vanmarcke
1
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1
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309
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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 ...
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1
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2
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118
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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 ...
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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 ...
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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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1
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2
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122
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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, ...
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1
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1
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374
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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 ...
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1
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2
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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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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 ...
1
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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 ...
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2
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Scan an Auditorium, Count People, and Display Open Seats [closed]
I'm looking for any recommended approaches to be able to digitally process a room full people, like an auditorium or a movie theater and output the following information:
How many people are in the ...
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1
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1
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Difficulties transforming binary mask from camera frame to world frame
I have 2 RGB cameras in Gazebo11 looking at the same scene from different locations. I threshold the floor space and create a binary mask with white being the ground (free space) and black being ...
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0
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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 ...
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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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2
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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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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/...
zjeffer
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2
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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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0
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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 ...
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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....
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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/...
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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 ...
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0
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711
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How to make a line following algortihm for an A.R Drone 2.0? [closed]
I am trying to develop a line following algorithm where a drone will detect a bounding box and follow what is inside the bounding box.
I am filtering all the colors to only see the color white. Once ...
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111
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Drone Feedback: Object Detection / Color Detection [closed]
I have been working on a code where an A.R Drone 2.0 will detect color and put a red dot in the middle of the image. I am using streaming for the drone. The goal is for the drone to detect a white ...
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Are homogeneous coordinates represented by appending image coordinates with a 1 in camera imaging
In camera imaging, there are several terms for point coordinates.
World coordinates: [X, Y, Z] in physical unit
Image coordinates: [u, v] in pixel.
Do these coordinates become homogeneous ...
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