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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44 views

Dual constraint non-linear optimization for SLAM

I am trying to achieve a nonlinear optimization for SLAM on a function that contains two different constraints, like this : $$ T_{opt} = \underset{T}{\arg\min} \sum_i(\left\lVert T.X_i - x_i \right\...
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1answer
39 views

Good Software Projects for Aspiring Engineers [closed]

With the pandemic going on, our school has decided to officially shutdown all sponsored club meetings. Now that we are all digital, our robotics club was looking for projects that students can do at ...
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4answers
9k views

What is inverse depth (in odometry) and why would I use it?

Reading some papers about visual odometry, many use inverse depth. Is it only the mathematical inverse of the depth (meaning 1/d) or does it represent something else. And what are the advantages of ...
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1answer
30 views

Active Light Stereopsis: 1 Camera + Projector Vs. 2 Camera + Projector

What is the difference between using 1 Camera and a Projector and using 2 Cameras and a Projector for creating structure from motion? Is it that if we use only 1 camera and a projector then we will ...
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3answers
2k views

Real-time video processing on video feed from a drone's camera

I am working on a project where I want to run some computer vision algorithms (e.g. face recognition) on the live video stream coming from a flying drone. There are many commercial drones out there ...
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1answer
28 views

Tracking 3D motion using a stereo camera

Assuming you have a fixed stereo camera, looking at a rigid object, what are the techniques used to track the object? My google searches lead me to optical flow and similar algorithms, but I believe ...
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0answers
41 views

Intel Realsense Cameras for Object Avoidance and SLAM to go to destination

My goal is to make a UAV which can search an area while avoiding obstacles. I figured I would navigate using the SLAM and Intel Realsense D435i (a stereoscopic camera with an IMU built in), but all of ...
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0answers
34 views

Intel RealSense Depth Camera D435i Wide Imager questions?

I have just ordered my d435i and while it was not intended to do NDVI I read the data sheet and noticed it had seperate image sensors, it is possible to read the IR image from either left, right or ...
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19 views

Single Camera + Laser Projector Triangulation

I want to combine a laser line projector (projects a laser plane) and a single web camera to determine the X, Y, Z position of the laser point. I am slightly confused as to how to use the fact that we ...
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0answers
45 views

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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1answer
39 views

Camera mounted on robotic arm - XYZ mapping

I have a 5 axis robotic arm that has a depth camera mounted near the toolhead on the left side. I have object detection software running on the camera and can find the XYZ of any object in mm that ...
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0answers
27 views

Disparity error in active light stereo systems?

Based on this relationship, if we have to estimate the 'disparity error' of a stereo system which uses active light on the scene - can we estimate the disparity error to be very small? According to ...
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1answer
231 views

Short range stereo vision

I am designing a stereo vision system for short depth range (15 cm to 35 cm) and I have some problems about baseline, focal length and depth range. My application is to scan an animal tissue (meat, ...
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2answers
484 views

How does structured light improve accuracy in stereo vision?

In my understanding, in order to improve accuracy for the estimation of depth with a stereo vision camera, patterns of light are projected into the scene, because the resulting texture makes it easier ...
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1answer
153 views

Fusing Multiple Lidars Into 1 Point Cloud

I have a car with 8 lidars, each with a field of view of 60 degrees. My car looks like this How can I merge all the lidar readings into 1 point cloud?
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19 views

Detecting pieces of a Version 1 QR code and processing the assembled version

I am building an aerial robot that needs to be able to detect pieces of a QR code (examples below) and combine them to process the information contained in the fully assembled QR code. I don't have ...
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1answer
22 views

Depth images with undetectable outlines

I'm trying to capture depth images with a RGBD camera, but all of the images have undetectable outlines around objects: Is this expected from RGBD cameras or is mine a dud? It's an Astra Pro.
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1answer
159 views

ORB-SLAM pose estimation

I've been reading about ORB-SLAM and ORB-SLAM2, but I can't quite figure out how pose estimation is done. I see that it uses a bag-of-word method for loop detection, but how are current features ...
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0answers
29 views

How to make x variable change each time and read its value from txt file

I am working on my undergraduate project and this is my first time in using use python to control parrot bebop 2 drone and use BCI or BMI technology. I have x variable (int) and I want to read its ...
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4answers
4k views

Computer vision with single camera vs. distance sensors for obstacle detection [closed]

I am going to start a new project consisting in implementing an autonomous driving RC car. The car as it is now, has a camera installed on each side of the car, i.e. 4 cameras in total. They are ...
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1answer
83 views

Efficient sphere surface area search

As shown in the figure, there are objects of arbitrary shapes placed on the surface of the sphere at arbitrary locations. The problem is to search the surface to locate these objects in most efficient ...
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1answer
513 views

What is the relation between FOV, Focal Length and Sensor size in a Pin hole Camera Model?

I aim to recreate the camera parameters of my camera in the Unity rendering system, which has the following variables: 1) I tweaked the focal length and saw that the Field of View is changing (...
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0answers
40 views

Is it possible to calculate a homography matrix for any 2 views?

I've been experimenting with opencv to estimate the homography matrix between 2 images captured with my computer's webcam. I have noticed that when the 2 views are not very far apart (that's when I ...
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0answers
19 views

Undo pitching effect of camera when pose (y-axis) is near 90 degrees?

I am using KITTI odometry dataset whereby the camera's axis is pointing X (east), Y (down) and Z (north). It also contain the frame to frame poses of the camera (first pose is fixed as the map frame). ...
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1answer
130 views

vision guided robotic arm always required 6d pose of object? [closed]

I have an object like attached in image. It is hanging vertical (its position may change but static object) and I want to grasp it using 6DOF Robotic arm. I am Using camera to detect object. I am ...
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1answer
240 views

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
40 views

Obstacle width measurement

On non-lidar equipped rovers, how is the width of an obstacle detected such that it can be avoided? If the ultrasonic sensors are used for obstacle detection, these sensors usually don't give data ...
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0answers
137 views

robot Hand Eye Calibration problem

I am trying to understand the implementations and the relative performance of various classical and new Hand-eye calibration approaches. Note: The following discussion assumes implementations are in ...
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5answers
570 views

Using vision for Monte-Carlo localization

From each step of my vision code I am able to get around 400 coordinates of where the robot thinks the walls are I want to integrate this into Monte-Carlo observation step. I'm storing the map of ...
2
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1answer
47 views

How to perform active search in point feature based monoSLAM?

I am modifying an implementation of SLAM with single camera, MonoSLAM [1]. Instead of image patches, I want to use features points (ORB) to track landmarks. MonoSLAM uses a EKF framework. So for ...
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3answers
185 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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0answers
55 views

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 ...
12
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1answer
409 views

What is the best way to compute the probabilistic belief of a robot equipped with a vision sensor?

I am trying to implement 'belief space' planning for a robot that has a camera as its main sensor. Similar to SLAM, the robot has a map of 3D points, and it localizes by performing 2D-3D matching with ...
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2answers
89 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
67 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
93 views

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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1answer
607 views

Role of Neuromorphic Computing and Quantum Computing in the field of Robotics and AI

I asked a similar kind of question some time ago (Neuromorphic Engineering and Robotics) Since then, many things have come to the point of revelation. A road-map for neuromorphic computing was ...
2
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1answer
112 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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2answers
352 views

Robotic cell simulation software, PLC [closed]

I need to simulate robotic cell where cartesian robot trims a PCB arriving on conveyor, picks it up with vacuum cup and and places in another device. After receiving signal from device the robot would ...
5
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2answers
6k views

How can I improve ZED Camera precision? [closed]

I'm using Stereolabs ZED camera for my computer vision project. I did a small research about several sensors on the market and ultimately we decided to go with the ZED Camera. However I'm finding ...
4
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2answers
5k views

Depth accuracy of the stereo camera

I am doing a project on calibrating stereo ZED camera and finding its accuracy and compare with the Manufacturer's accuracy of 1% at 1m depth accuracy. For this purpose , the formula to calculate the ...
5
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2answers
1k views

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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1answer
81 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 ...
3
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1answer
871 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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0answers
97 views

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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0answers
89 views

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
39 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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0answers
355 views

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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2answers
667 views

Is there a way to combine and sync two 2K cameras @ 90fps with ICs

I am searching for a way to minimize the size of a stereo vision module and cannot find any ICs that will combine and sync two MIPI CSI-2 (4 lane) data streams without an FPGA and too much code. ...
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2answers
197 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 ...