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Questions tagged [computer-vision]

The goal of computer vision is an automatic extraction of information out of images. It includes methods for acquiring, processing, analyzing, and understanding images and high-dimensional data from the real world in order to produce numerical or symbolic information, e.g., in the forms of decisions. The image data can take many forms, such as video sequences, views from multiple cameras, or multi-dimensional data from a medical scanner.

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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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What post processing method was used to generate depth image as shown in the given example?

The 32FN method is a fast and effective method to estimate surface normal from a structured depth image. It appears the authors uses a "in-painting" method (please correct me if I am wrong) ...
Azmyin Md. Kamal's user avatar
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Data sent over ROS2 topic is not reliable

Hello everyone of this wonderful forum. I am currently doing my first ROS2 project in which i have send data of aruco id that includes its [id number,x,y,z,orientation] data. I am sending this data ...
joker13's user avatar
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Does ORB-Slam3 perform better than ORB-Slam2?

I was trying to compare ORB-Slam2 performace with ORB-Slam3 performance. Consider following comparison from ORB-Slam3 paper (columns with numbers correspond to different sequences from EuRoC dataset): ...
Mahesha999's user avatar
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How to scale projection matrix?

I was going through the camera calibration lecture by professor Shree Nayar. At 4:49, he is : Scaling the projection matrix implies simultaneously scalign the world and the camera, which does not ...
Mahesha999's user avatar
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Bridging connection between HoloLens2 and a computer running on ROS2 Foxy

I wanted to consider using HoloLens2 for my project using ROS2. But before buying one, I was hoping to ask around if someone already tried using ROS2 FastDDS to make Hololens2 communicate with a ...
Joshua Siy's user avatar
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11 views

Selecting frames from video for surface extraction using feature matching

I have a video of an object sitting on an ArUco board. I am currently using ArUco markers to estimate camera transformation and knowing camera intrinsics assessing F. I use BRISK and FLANN to match ...
Odeaxcsh's user avatar
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1 answer
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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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3 answers
344 views

Installing Ros2 on the Jetson Xavier Nano

My team and I are trying to install Ros2 on the Jetson Xavier Nano so or robot can have computer vision, but the Jetson runs an old version of Ros. How can newer versions of ROS be used on the Jetson ...
Aryan Patel's user avatar
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36 views

Calculate target orientation

I have the following setup: I want to move the "Drill" frame to "Target1" with the opposite Z axis direction. I have calculated translation between "Target1" and "...
Unai Granados Ormaetxea's user avatar
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How to get an axis in camera coordinate system pybullet?

I am using pybullet to render a robot simulation. This robot have 2 joints and hence, 2 corresponding axes of rotation. I know that when I use getJointInfo on this ...
Anmol Gupta's user avatar
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Gazebo Garden : Green line in camera image with OGRE 1 render engine but not with OGRE 2

While loading the same map in gazebo garden with ogre 1 or ogre 2, the map looks the same in the GUI, but a green line appears in the camera image when using ogre1 (no distortion or noise applied, ...
Jacques's user avatar
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World to pixel transformation in Pyrender

I'm trying to transform a point in a 3D world rendered with pyrender to pixel coordinates. The world to camera frame transformation seems to work, however the camera to pixel frame transformation is ...
nona's user avatar
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1 vote
2 answers
101 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 answer
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Move gantry system to detected position in image plane

I have the following simplified gantry system (cartesian robot) that can move in the x axis direction: My goal is to position the red pointer on top of the target (i.e., I want the real world x-...
Optical_flow_lover's user avatar
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Python How to fuse road segmentation data from an image to AOA data(distance, angle)

I have road segmentation data which is highlighted by the semi-transparent blue color. It is an Numpy matrix with 0 means not road, 1 represents road. I also have AOA data which tells the distance and ...
Franva's user avatar
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Making an automated chessboard

I want to create an automated chessboard. At the moment, I'm making the project and deciding what technology to use to detect which piece is at what position and how to move them. I'm not so skilled ...
Mukund's user avatar
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3 votes
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How is the Homography formula derived?

In the Wikipedia article about Homography, the projective transformation between picture A to picture B is defined as: $H_{ab} = R - \frac{t n^T}{d}$ However, the formula lacks the derivation. How is ...
Tommaso Bendinelli's user avatar
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67 views

Stereo Bundle Adjustment

When doing stereo based visual odometry and bundle adjustment how does the stereo constraint get factored into the photometric error? Do you use the fact the second cameras location is known wrt the ...
FourierFlux's user avatar
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1 answer
75 views

Question about bundle adjustment

When doing bundle adjustment do landmarks gets optimized as stand alone variables or are they viewed as a function of the robots first position when they are detected?
FourierFlux's user avatar
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1 answer
203 views

Why would you use direct SLAM over feature-based?

I am curious, why would you ever choose direct slam(photometric consistency, etc) over feature based slam? Particularly for dynamic scenes? It seems you're always better off aligning fewer points ...
FourierFlux's user avatar
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Stabilising 3d cameras for mapping outdoors - mechanical or programmatic

I am preparing to mount Intel Realsense and Zed and Oak-d cameras onto a 4 wheel mobility scooter to do mapping of my local area. I'm not looking for recommendations but rather an understanding of ...
brianlmerritt's user avatar
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277 views

IMU to Camera transformation

Suppose you are implementing SLAM or VIO system, you have your camera C and IMU and a coordinate transformation between them (R, T). How do convert IMU measurements to camera accelerations and ...
FourierFlux's user avatar
1 vote
1 answer
163 views

Calculating the depth in a general stereo vision system

When calculating the depth of a pixel using two cameras, most of the literature I have read describes stereo vision with the cameras having parallel optical axis as shown in the picture below. Because ...
NMO's user avatar
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2 votes
1 answer
274 views

Pipeline for dense reconstruction using pose estimation from orb-slam and stereo camera

I am trying to perform dense reconstruction using a sequence of images from a calibrated stereo camera. I have been using orb-slam3 to give me the camera's pose estimation. I am also generating the ...
JBurn93's user avatar
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1 answer
262 views

How to perform time-offset calibration use GTSAM in Camera-IMU system?

Assume we have camera poses data and IMU data(which include gyr and acc data) with different timestamps, now I want to estimate this value, I known that this can be done in many ways(EKF,MSCKF), but I ...
milin's user avatar
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0 votes
1 answer
83 views

Camera Calibration Matrix accuracy

When we do camera calibration, we have to find calibration matrix $M$, which is found by first finding extrinsic matrix and then intrinsic matrix. To validate the accuracy of calibration matrix, we ...
Avv's user avatar
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1 answer
98 views

6D pose estimation of a known 3D CAD object [closed]

I'm looking for a codebase for 6DOF pose estimation of a known 3D CAD object with RGB or RGBD. It must be: -Usable commercially (licensed under BSD, MIT, BOOST, etc.), not GPL. -Easy to setup and use (...
Rexcirus's user avatar
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1 answer
96 views

How to find the camera matrix and distortion matrix from the given data

...
Amit's user avatar
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2 votes
0 answers
67 views

Monocular SLAM position estimation

I have been reading about mono SLAM and I have a couple questions which are not so clear: When doing pose estimation, I have seen people both reference homography transformation and also reference 5\...
FourierFlux's user avatar
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0 answers
43 views

How to find fundamental matrix based on other fundamental matrix and camera movement?

I am trying to speed up some multi-camera system that relies on calculation of fundamental matrices between each camera pair. Please notice the following is pseudocode. ...
Gulzar's user avatar
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1 answer
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Center line steering with differential drive

I’ve got 2 motors that drives my unit and I can easily steer it manually by simply adding more speed to one wheel vs the other. Now I’m automating the rover using image processing to follow a driveway....
DaveInPA's user avatar
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1 answer
73 views

How does baseline work with forward motion in Monocular Visual Odometry

In my computer vision class we are studying visual odometry. In this we calculate the Fundamental matrix using 2 frames from forward motion using the concept of stereo-vision. But in stereo vision the ...
sdhar's user avatar
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1 vote
2 answers
711 views

roslaunch exit code 2 error

I am implementing a simple roslaunch file but I am getting an exit code 2 status I have pasted the exact log below any idea what would cause this and how I can rectify it. ...
NOVA1323's user avatar
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1 answer
187 views

Mobile robotic arm camera position

I'm working on my graduation project which is a mobile robotic arm that performs pick and place tasks. I wanted to know the possible ways to mount the camera where i can reach the desired destination ...
Samba's user avatar
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0 votes
1 answer
28 views

Explanation of the epipolar constraint in stereo imaging

I am watching this video, in which the epipolar constraint is defined as $x_l \cdot (x_l \times t)=0$ It means that the vector $x_l$ that passes through the observed point and the left camera origin ...
noam steiner's user avatar
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1 answer
23 views

What are the usual results for pedestrian posture detection?

When talking about lane detection in a road, usually robotic computer vision system give lines in an image. For detecting obstacles, those system give Bounding Boxes. My question is, for pedestrian (...
KansaiRobot's user avatar
3 votes
1 answer
292 views

Unstable principal point estimation in zoom camera calibration

I have a camera with a 1/2.9" image sensor from FLIR and a 12-50mm motorized zoom lens from Theia. Because the lens is a motorized zoom lens, I tried to calibrate the camera for different zoom ...
sixer's user avatar
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0 votes
2 answers
989 views

Number of pixels required to identify something

When using an RGB camera, what is the minimum number of pixels of an object that you need to identify something (theoretical or rule of thumb)? The image would be taken out in the wild with a complex ...
qwertyuiop's user avatar
1 vote
1 answer
44 views

Can you plug a CMOS camera (like the iPhone 8 back camera) into an mPCIe in a laptop?

I read that 12 megapixel iPhone cameras don’t record video in 12 megapixels because the processors are not able to keep up. It seems though, that if I could plug the CMOS sensor to the CPU of a laptop,...
user11937382's user avatar
1 vote
0 answers
161 views

Cheap global shutter cameras with external synchronization

Please recommend cameras for multi-camera setup satisfying the following conditions: Relatively cheap (up to 100$ per camera). Global shutter. No filters on lenses or pixels. Resolution of 1 MP or ...
user3234005's user avatar
1 vote
1 answer
48 views

Autonomous harvesting robots. What are model possible components and interactions for the entire system? [closed]

I found a video which talk about best autonomous robots that use IA technology to harvest crops. The video is very interesting because, the “ecosystem” of each robot varies a lot from company to ...
Hokage's user avatar
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2 votes
1 answer
210 views

Depth camera pixel values to 3D coordinates

I have a robotic arm 6-DOF and an Intel RealSense depth camera. I want to go from pixel values to 3D world coordinates, is it possible with eye-in-hand calibration? If yes can you guide me on how to ...
Jasmeet Singh's user avatar
0 votes
3 answers
1k views

ROS Webcam Stream Really Slow

I am trying to stream the images from my camera to a VM via ROS. Here is my setup: Raspberry Pi 3B+ with Picamera v2. It is running ROS Noetic with cv_camera_node ...
DragonflyRobotics's user avatar
2 votes
1 answer
692 views

Visual Odometry terminology: Scale, Relative scale, absolute scale

I'm watching a MOOC about Machine Vision for Robotics, but I really do not know the meaning of some vocabulary of this domain. For example, What does the professor mean when he says this: However, we ...
sci9's user avatar
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1 vote
2 answers
529 views

Is two cameras equivalent to Stereo camera setup?

I have two webcams, which are mounted close together. I plan to use them to find out the true depth of certain pixels of images. Suppose I use a standard multi camera calibration setup and find out ...
OlorinIstari's user avatar
1 vote
0 answers
78 views

Is there any RAPID instruction to save image as variable in YuMi integrated vision without using RobotStudio?

I want to perceive the images from the cameras embedded in YuMi IRB 14000 arms and store them as videos, in Ubuntu without using ABB RobotStudio. is there any way to do that? if yes how can I do that ...
Bilal's user avatar
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1 vote
2 answers
4k views

What are the purpose of pre-trained weights for YOLO object detector?

Dear Research Community, I am new to object detection research and currently working on a project which will detect people using YOLO from a top-down camera image. While looking through tutorials for ...
Azmyin Md. Kamal's user avatar
1 vote
1 answer
1k views

Is easier to detect a large or a small marker? (Aruco / Apriltags)

I need to detect Aruco/Apriltags markers and perform pose estimation, but I've no particular constraint on their physical size. I'm not talking about the number of square (e.g. 4x4, 6x6, etc.), but of ...
Rexcirus's user avatar
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2 votes
0 answers
52 views

Choosing cameras for stereo vision system?

I'm in the process of building a stereo vision system with YOLO detection. The system have to detect airplanes in far distance and also measure the depth from the airplane to the camera. I think ...
Joaquin Gonzalez's user avatar

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