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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Why do we need a marginalization in Bundle Adjustment?

A common practice in Bundle Adjustment is to reduce the state dimension by marginalizing structure or pose states to improve the optimization speed. In case 3d points(structure) $\textbf{p}_i$ are ...
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2answers
829 views

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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1answer
175 views

Object Detection and Pose Estimaion

I am working on a robotics project for fun and can't really wrap my head around a solution to my perception problem. Setup: My robot will have a stereo vision setup and will have to detect certain ...
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1answer
71 views

Calculating covariance of parameter estimation from Hessian

I need a covariance of parameter estimation for reliability estimation. According to the this post, I know the approximation of the Hessian can be calculated as $$ \sigma^2 H^{-1} = C $$ where H is ...
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0answers
171 views

Which Kinect to use for robotic arm pick and place application with object detection?

I am building a robotic arm for pick and place application. The robot is going to recognize several objects using the RGB feed from Kinect (will use a model such as YOLOv2 for object detection, ...
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2answers
150 views

Smart camera image processing on embedded GPU vs. in the cloud

I'm working on a smart camera that does key point prediction (predicting locations of wrists, elbow, shoulder, ears, eyes, nose, etc.) for gesture recognition. Right now, the neural net is running on ...
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1answer
889 views

Correct Fish eye camera radial distortion and blurry stretch at the image edges

There are a lot of questions regarding this topic, but I am trying to get a more clear picture from these questions. I am trying to calibrate a fish eye camera and I am using OpenCV ...
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1answer
152 views

Perspective N point solution: Position drifting linearly with rotation angles?

I am using a PNP algorithm to compute the rotation and translation of a camera given pre-mapped 3D points, and their corresponding projections on the 2D plane. The algorithm I am using is the one ...
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2answers
173 views

TU Munich Monocular Visual Odometry Dataset has NaN values in the ground truth data.

I am trying to use the motion sequences in the dataset to create trajectories for VR systems. A major portion of the ground truth data in almost all sequences has NaN values. Is there any other source ...
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1answer
227 views

How can I compute the covariance of a camera-based relative pose measurement?

I am trying to compute the relative pose between two cameras using their captured images through the usual way of feature correspondences. I use these feature matches to compute the essential matrix, ...
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4answers
5k views

How to obtain dense point clouds from stereo cameras?

I am trying to use a stereo camera for scene reconstruction, but I can usually only obtain sparse point clouds (i.e. over half the image does not have any proper depth information). I realize that ...
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1answer
131 views

Once matching features are computed between a stereo pair, how can they be tracked?

I am currently working on a SLAM-like application using a variable baseline stereo rig. Assuming I'm trying to perform visual SLAM using a stereo camera, my initialization routine would involve ...
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1answer
247 views

Methods for odometry/IMU/Gyro free lidar pointcloud registration for pose estimation

I am currently trying to register a pointcloud in time to find my change in position and heading at each timestep (High speed application). So this is essentially an implementation of SLAM. I am ...
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1answer
215 views

How to build a robotics ontology?

According to some papers about robotics soccer Ontology Driven Development of Domain-Specific Languages, 2000 and Domain knowledge for surveillance applications, 2007, i need an ontology for ...
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0answers
103 views

Monocular SLAM depth reconstruction

I am trying to derive the inverse depth equation used in monocular SLAM algorithms. Specifically the equation 8 of the ORB SLAM paper I am very close, except I do not understand where the (u_j-c) ...
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1answer
194 views

How can I estimate depth of a feature point / object using single camera?

I am trying to estimate depth of a feature point that i find in my image. I read this paper that estimates the depth using a motionless camera and an object of known height to calculate horizon line. ...
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2answers
177 views

Depth sensing for a pick-and-place robot

I am supposed to design a pick-and-place robot. I have a prismatic joint to go down to a particular depth to pick an object which is located in 2D using computer vision. What is the recommended way to ...
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1answer
54 views

Pointing at a moving object

I'm a complete novice when it comes to robotics and/or computer vision, so I'm looking for a place to start - simply googling has not located what I want. I want to build a device that continuously ...
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1answer
853 views

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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1answer
256 views

Kalman filter for vision based pose estimation: 'good' measurements not improving system covariance

I am starting off with a very simple Kalman filter for vision based pose estimation (PnP algorithm). The filter is inspired by the constant velocity model in this OpenCV tutorial, but I am ignoring ...
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1answer
1k views

How many AR markers should I use to get the object pose?

I'd like to get the object pose based on the attached AR marker to the object. I believe I only need one tag to get the 6D pose. However, I sometimes see more than one AR markers are used in the ...
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1answer
61 views

Why is a computer vision system similar to the human vision

Does computer vision intentionally mimic the vision of a human or is it just coincidental that a good computer vision system (with convolutional neural networks for example) reassembles some ...
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1answer
100 views

Best way to detect a range of key points in the image of a given cloth article

I am designing a robot which irons and folds clothes autonomously. For this purpose, I need the robot to detect a certain number of key points in a given cloth in order to execute a certain folding or ...
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1answer
2k views

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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1answer
4k views

normalized point coordinates in undistortPoints function

In undistortPoints function from OpenCV, the documentations says that http://docs.opencv.org/2.4/modules/imgproc/doc/geometric_transformations.html#undistortpoints where undistort() is an ...
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1answer
526 views

How to eliminate motion blur with realtime performance

I have a robotic system to develop, in first phase of the project I need to track an object. So I placed a geometrical marker on the object to estimate it's pose (rotation, translation). It all works ...
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1answer
2k views

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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3answers
39 views

Sensing an actuator using vision [closed]

I am looking forward for a method to sense in real time, using computer vision for a control application. For this I am unsure of which is the right platform . I am well versed with MATLAB, but I am ...
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1answer
507 views

Tracking a ball returning its x,y,z coordinates [closed]

I'm a Mechatronics Student Engineer, and still new with the computer vision field and am now working on a project that needs to Tracks a small ball and need to determine it's (x,y,z). 1st) Kinect was ...
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1answer
556 views

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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4answers
11k views

Using C++ to control a drone

I am relatively new to using drones and was wondering if someone more experienced in the topic could lend a hand. I am familiar with C++ and OpenCV, a facial recognition software that has libraries in ...
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0answers
288 views

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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1answer
55 views

Calculate Transformation between two point sets - but with constrained Degrees of Freedom

How can I calculate the rigid-body transformation [R|t] between two 3d triangles, but restricted to a given N degrees of freedom (for N = 1..6) ? I know for N=6 I can get a least-squares solution via ...
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0answers
86 views

Consitent Scale in Monocular pose estimation

I just wanted to know if scale is conserved across multiple images, when doing a process such as monocular odometry. I know in reality the scale tends to drift over time due to accumulation of small ...
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3answers
243 views

What the name of this kind of computer vision?

Whats the name of the technique used to read symbols with computer vision? Like the one used for this wood cutter: I want to use something like this to measure distance from the camera to a piece of ...
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1answer
857 views

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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1answer
341 views

setup requirement of stereo camera

In the stereo camera system, two cameras are needed and should be mounted side by side. I see someone just glues two cameras to a wooden board. However one mobile phone manufacture claimed that the ...
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2answers
397 views

Using Standard Digital camera for Computer Vision

For a University project I have to use computer vision to detect small drones within 40 feet. I know there exists a pixycam for this purpose, but I was not happy with it, when I used it for CV. I ...
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1answer
53 views

Is there a better way to deal with untextured regions in stereo matching

Texture is very helpful for stereo matching. However in real environment, untextured areas always exit. Consistent semi-global matching is proposed to deal with untextured regions. I start to read the ...
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1answer
183 views

Google's 'Tango' - How it works and what's special about the hardware?

I'm looking for a good breakdown and explanation of Google's 'Tango' AR platform. Specifically how the hardware works together to generate depth maps and the SDK's use of it. I know the hardware ...
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2answers
91 views

Detect road surface in a traffic scene point cloud

I want to analyze a traffic scene. My source data is a point cloud like this one (see images at the bottom of that post). I want to be able to detect objects that are on the road (cars, cyclists etc.)....
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1answer
639 views

Stereo camera vs. one camera for player detection & ball tracking in basketball scenes?

There are a number of similar questions such as Monocular vs. stereo computer vision robustness for object detection, but none that address my question specifically. My weekend project is to build a ...
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6answers
3k views

Low power computer for stereo vision

I would like to build a motorized robot with stereo vision that sends visual input to a PC over wifi for processing. A Raspberry Pi would have been perfect for the task if it would be possible to ...
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1answer
444 views

detect post-it from an image of a visual management Board [closed]

'm trying to detect all the post-it in an image and get them into an arrayList. I tried many alternatives (removing backgroud -> detecting contours, haar Cascade classifier, detecting rectangular ...
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1answer
2k views

SLAM: Why use two cameras (stereo) if SLAM can be done using single camera (monocular)?

I am aware that algorithm for monocular SLAM is complex compared to stereo SLAM. But my question is if by any means it is possible to do SLAM using one camera why one should use two cameras to do the ...
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0answers
77 views

Cloth (non-rigid body) manipulation with computer vision? [closed]

I am currently working on a prototype device to automate cloth ironing task. So basically the mechanical design involves 4 manipulators and a separate manipulator arm with a hot pad (iron) to ...
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1answer
104 views

Road Detection When the Robot is Off-Road

I'm trying to make a lightweight method of outdoor road following for a small ground robot. In nearly all road detection work that I've seen, they all assume that the robot is already on the road, ...
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4answers
2k views

Public dataset for monocular visual odometry

I am planning to develop a monocular visual odometry system. Is there any indoor dataset available to the public, along with the ground truth, on which I can test my approach? Note: I am already ...
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1answer
151 views

Can I use a FTC regulation phone to use the camera on multiple tasks?

PREFACE: THIS QUESTION REGARDS FTC ROBOTICS I am aware that a question similar to this exists on SE and I have looked at it, but the solutions provided did not solve my problem, and the nature of my ...
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2answers
153 views

On-site waste-sorting robot feasibility and availability [closed]

I am thinking about a project at my university for doing on-site waste sorting. The problem with having one waste bin for recyclables, compost and landfill and doing the sorting at a facility, is that ...