17
votes
Why do people use camera instead of laser sensor for robot navigation?
A 3D laser range finder or LIDAR such as the one on the Google Car is far more expensive than a camera. The other reason is that while in case of a LIDAR the distance of every pixel is available, the ...
- 633
11
votes
What is inverse depth (in odometry) and why would I use it?
The inverse depth parameterisation represents a landmark's distance, d, from the camera exactly as it says, as proportional to 1/d within the estimation algorithm. The rational behind the approach is ...
- 111
10
votes
Accepted
AprilTag vs Aruco markers
Aruco (as implemented in OpenCV)
pros
Easy to set up (with readily available aruco marker generator, opencv & ros implementation, etc.)
fewer false detection (with default parameters)
cons
...
- 426
7
votes
What is the best SE3 library for python?
Writing your own package is always the best way to learn. If you want to try something premade here are a few packages to choose from:
Spatial Math Toolbox for Python Python3+numpy+scipy, also ...
- 1,692
7
votes
Accepted
Why do robots need rangefinders while animals don't?
Animals and robots both need to understand something about the 3D structure of the world in order to thrive. Because it's so important, animals have evolved a huge number of strategies to estimate ...
- 1,692
6
votes
How can I improve ZED Camera precision?
I don't know what you mean by "precision" and how do you measure it. The sensing
accuracy will probably go back to the camera calibration precision and the stereo matching algorithm used. If they ...
- 633
6
votes
SLAM: Why use two cameras (stereo) if SLAM can be done using single camera (monocular)?
The most important point is the scale. If you do monocular SLAM, your map will only be accurate up to scale so that you e.g. cannot compute the length of the travelled path in meters. The scale ...
- 1,355
6
votes
Which is the best visual fiducial marker (2D barcode)?
AprilTag is the state-of-the-art solution for pose estimation. The library itself already has pre-built functions to compute the marker position, given its size. The pose is estimated by homography ...
- 161
5
votes
SLAM : Why is marginalization the same as schur's complement?
The following are mostly based on "Factor Graphs for Robot Perception" by Frank Dellaert and Michael Kaess, with additional notes:
As a reminder, marginalization is about having a joint ...
- 51
5
votes
image processing
Ball detection using vision is not extremely difficult, especially if the ball is easy to recognize. There are a lot of tutorials and blogs which give a detailed explanation on how to implement an ...
- 260
5
votes
Accepted
Are there any advantages to using a LIDAR for SLAM vs a standard RGB camera?
My question: are there cases where you'd still need a LIDAR or can
this expensive sensor be replaced with a standard camera? ...
A each one of them has its advantages/disadvantages. Thus in some ...
- 319
5
votes
Why is a computer vision system similar to the human vision
I would argue that the similarities are largely superficial. More "classical" machine vision approaches focused on finding features a human can identify such as lines, texture and blobs of color.
...
- 440
5
votes
Accepted
What is the best SE3 library for python?
ROS's tf.transformations.py has self-contained code for doing these functions and can be used without installing ros. In fact, the python code only depends on numpy!
transformations.py
- 301
4
votes
Accepted
Real-time video processing on video feed from a drone's camera
This AR.Drone provides SDK, therefore, you can access the images on real-time. It is fully compatible with Linux. They have examples also for smartphones. I believe android and iPhone. It has two ...
- 2,453
4
votes
What is inverse depth (in odometry) and why would I use it?
Davison's paper introducing the method is easy enough to understand:
Inverse Depth Parametrization for Monocular SLAM by Javier Civera, Andrew J. Davison, and J. M. Martınez Montiel DOI: 10.1109/TRO....
- 51
4
votes
Accepted
SLAM : Why is marginalization the same as schur's complement?
See the walk-through
The Schur complement helps with the closed form derivation but isn't necessary. It's just a nice convenient property of Gaussians and the covariance matrices.
In these papers,...
- 5,312
4
votes
What the name of this kind of computer vision?
In general, markers used to measure position visually are called fiducial markers.
Some applications have a single type of fiducial (a solid circle or a cross) repeated many times.
Some applications ...
- 4,525
4
votes
Why do people use camera instead of laser sensor for robot navigation?
In addition to those points in Bence's answer, cameras can:
Calculate many complex features that result in very robust matching between frames, and object recognition
High angular resolution (typical ...
- 892
4
votes
Accepted
Smart camera image processing on embedded GPU vs. in the cloud
Performance differences between using an embedded GPU vs. the cloud?
For your context (to my mind, gesture recognition would ideally be realtime), the latency of going over the cloud would push me ...
- 158
4
votes
Accepted
Determine the relative camera pose given two RGB camera frames in openCV-python
If you understand how relative pose estimation works in theory, it should be quite trivial to translate it into OpenCV code. First, you can pick any feature detection/description approach you like (...
- 1,096
4
votes
Accepted
Why do we need a marginalization in Bundle Adjustment?
I am still not entirely sure what you are asking, but I believe this may answer your question. Also note I myself don't fully understand all the details behind the marginalization trick, but I will ...
- 1,831
4
votes
Accepted
Robotic Hand Grasp Planning - How do I find the initial contact point for each finger when grasping an object?
This is an excellent question that is currently being explored directly by field experts. Here are some of the latest publications that consider the problem you are encountering:
Robotic Grasping of ...
- 493
4
votes
Accepted
Visual Odometry terminology: Scale, Relative scale, absolute scale
What does the absolute scale mean? In this context, scale refers to
what property related to an image?
Essentially scale refers to the size of the object/scene that the camera sees.
As a projective ...
- 1,831
3
votes
Accepted
Difference between 3D Camera(using IR projection) and Stereo Camera?
"3D camera" is a generalisation that covers sensors that can observe a point-cloud or depth map of the scene they are observing.
Some 3D cameras use a projector (via various ways) to improve the ...
- 892
3
votes
Is it a bad-design decision to implement high number of moving parts in an automation-robot?
Tough to say without knowing much about the project. More parts = more problems or potential points of failure. A simple design is typically better in that there are less things that can go wrong. If ...
- 157
3
votes
Public dataset for monocular visual odometry
http://vision.in.tum.de/data/datasets/rgbd-dataset
This is a set of recordings for the Kinect and Asus Xtion pro, which are all indoors (in offices and a hangar). It comes with precise ground truth ...
- 176
3
votes
Public dataset for monocular visual odometry
This is another more recent one, based on the paper A Photometrically Calibrated Benchmark For Monocular Visual Odometry by Engel et al:
http://vision.in.tum.de/data/datasets/mono-dataset
This gives ...
3
votes
Accepted
"Ambiguous up to scale" , Explanation required
I don't have access to the quoted reference, but believe the explanation (stated, for simplicity, in terms of a vector rather than a matrix) below will apply.
Consider an $n$-element vector $V$. ...
- 1,991
3
votes
Real-time video processing on video feed from a drone's camera
I bought an AR done 2.0 for my research.
I used Labview to process the realtime video feed from either the bottom camera of the drone or the front camera.
You can read more details on how to setup ...
- 31
3
votes
Why do people use camera instead of laser sensor for robot navigation?
navigation in urban environments
Depending on the laser, there might be legal constraints on where you can use it. Running around town throwing laser rays around might require special permission/...
- 1,425
Only top scored, non community-wiki answers of a minimum length are eligible