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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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Tracking object in realtime using depth image stream from a RGBD camera

I have an Intel RealSense camera which can stream RGB and depth image. Using those information I want to track an object moving on a table top. More specifically, I want to know position $(x,y)$ and ...
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3answers
61 views

Why do robots need rangefinders while animals don't?

Will vision based system eventually prevail rangefinders based systems given that the most successful autonomous agents in the world like animals use primarily visions to navigate?
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1answer
34 views

Transformation matrix between a 2D and a 3D coordinate system

I have 2 sensors : one has 2D coordinate system and the other has a 3D coordinate system (not same origin). Knowing the positions of some corresponding target points (used as fixed reference) in both ...
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2answers
62 views

Question about Lens distortion

Suppose I have a 240x180 camera with the following distortion co-efficients, $$k_1 = -0.138592767408$$ $$k_2=0.0933736664192$$ $$k_3=0.0$$ $$p_1=k_4=-0.000335586987532$$ $$p_2=k_5=0.000173720158228$$ ...
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1answer
77 views

Fixing the first node in Graph-based SLAM

The first node in the graph SLAM should be fixed. The famous "a tutorial on graph based slam" paper is showing that we can fix a node by adding identity matrix. Why adding identity to the Hessian of ...
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1answer
62 views

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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1answer
54 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 ...
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How to update a new pose in iterative pose optimization problem?

There are multiple ways to update new pose in iterative pose optimization problem. The easiest one we often find in papers in robotics is as SO3 + translation Update on right \begin{equation} \...
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2answers
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Any reference for “3D feature matching + ICP”?

One of the simple tricks in getting high performance for a global 3D point cloud registration is combining "3D feature matching + ICP". For example FPFH matching + RANSAC for initial pose estimation ...
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API/ Library for re-orienting 360 degree camera frame efficiently

I have a camera that produces a 360 degree image output. This camera has an IMU unit integrated with it. I have written a C++ Extended Kalman Filter algorithm to estimate roll, pitch and yaw of the ...
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3answers
119 views

What is the best SE3 library for python?

I am currently googling on this topic but I would like to hear your opinion. What is the best self-contained SE3 library that offers interconversion between quaternion, rotation vector, ...
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How can we perform Image based Visual Servoing when we dont have the depth information

I am trying to perform image based visual servoing for my robot using a monocular camera. The issue is that in order to calculate image jacobian I need depth information Z. Can anyone point me to ...
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114 views

Degrees of Freedom in Affine Transformation and Homogeneous Transformation

I understand that a 2D Affine Transformation has 6 DOF and a 2D Homogeneous Transformation has 8 DOF. However, how can I identify what those independent paramters are? If we consider Euclidean ...
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Algorithm for orientation (pan/tilt) towards a moving point

Main Question: note: The code in this question is pseudo-code, I'm using Python, but my pseudo-code is a mix of Python and C++. I have a camera on the top of my robot's "head" which has pan and tilt ...
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1answer
31 views

Combining multiple constraints in optimization

Let's say we have two equations for a pose $\textbf{R},\textbf{t}$ optimization problem. For ICP constraint $$\textbf{e}{_{I}}=\textbf{n}^\top(\textbf{p}_d-(\textbf{R}\textbf{p}_s+\textbf{t}))$$ For ...
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1answer
103 views

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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How does marginalization of variables effect least squares SLAM energy function?

Consider a simple example of Bundle Adjustment where I have robot and landmark poses $x = \left[ x_p \text{ } x_m\right]^T$ and measurements given by $z$, such that a simple factor graph can be ...
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How can I receive Genicam packets from a device in a docker container?

I installed a command line tool which accepts genicam packets from a device as input into a docker image. If I use the option --network host in the ...
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Designing systems for sharing resources on multiple SOC's

I have some Raspberry Pi's from previous projects/learning and I would like to pool their resources to make a differential drive robot. Two Pi's would have one camera each for a vision system, one ...
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19 views

Map camera image onto sphere

How would I determine what the red point $(\phi', \theta')$ is for a camera oriented at a known $(\phi, \theta)$ is from a given image? The point of this is to determine what $(d\phi, d\theta)$ is so ...
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2answers
215 views

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
37 views

Estimation of Focus of expansion

I am trying to estimate focus of expansion for a moving camera mounted in a mobile robot. I am using the method described in this method page 13-14. My aim is to use it to avoid obstacle using optical ...
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25 views

Turning and crossroad detection

Does anybody know some methods recognizing not only road or lane, but also turnings (e.g branches) and crossroads. Could you suggest some papers reviewing such issues. Thank in advance.
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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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1answer
47 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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48 views

Dataset for monocular visual odometry

I am trying to develop a monocular visual odometry system. Is there any dataset available that includes motion sequences from handheld cameras along with ground truth for the camera pose? I have ...
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0answers
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Can you find object distance using camera pose

I have bounding boxes detected in RGB images, but no information about the camera's intrinsic properties. Using deep learning (preferably) can I find the distance to the object from the camera in real ...
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1answer
147 views

Rotation composition When using Kalman Filter

I am implementing a Kalman Filter for the following situation. I have a camera set in a room that can detect the position and orientation of a marker (ARUCO) in the room. Therefore I have the ...
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0answers
36 views

Separated unscaled translation vector and scale for the ground truth poses of Kitti Odometry datasets

Kitti dataset provides Ground Truth Poses for its odometry datasets.However, can I acquire the unscaled-translation vector of the translation for which I can compute the scale myself? I want to ...
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47 views

Custom camera projection model in Gazebo simulation?

is anybody know if there is any way to simulate vision perception using our own-defined camera projection model in Gazebo instead of using the pinhole or wide-angle type provided by the Gazebo ...
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1answer
50 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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1answer
100 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
70 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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0answers
92 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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2answers
92 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
100 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
81 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
111 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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1answer
51 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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0answers
32 views

How can I make robot follow a particular feature in the image?

I would like to make my robot follow a path that I draw on an image using my mouse. I could use visual servoing to make it follow a particular object or feature? but how can I go about it. My idea is ...
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1answer
205 views

Relative scale in SfM

I'm using monocular visual odometry. As in this case absolute scale can't be recovered, we rather compute relative scale for subsequent transformations as in this tutorial To do this, triple matches ...
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1answer
2k views

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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2answers
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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
100 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
124 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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2answers
365 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
490 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
59 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
200 views

Marginalization in Graph SLAM [duplicate]

I have several questions about the process of marginalization in SLAM algorithms: 0 - What are the mathematic intuition behind marginalization process 1 - I know marginalization of states or points ...
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1answer
233 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 ...