Questions tagged [cameras]

A camera is an optical instrument for recording or capturing images, which may be stored locally, transmitted to another location, or both.

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71 views

How to guide a camera through a circular tube?

Let's say I have a 6-DOF flying camera and I want to make it move through a circular tube autonomously and let's suppose that the camera and the system that makes it fly are considered to be just a ...
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2answers
487 views

Hand eye calibration of robot arm using a 2D camera and marker of known size

If my understanding is correct, one flavor of hand eye calibration requires the following pairs of data for different robot arm positions: The transform from the robot base to the robot hand. The ...
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1answer
1k views

Image coordinate to robot coordinate

I am working with a Nao robot. One if the things I want to do is the following: Take an image of geometrical objects in front of the Nao (done) Extract features from the objects in the image, such as ...
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1answer
61 views

Correct calibration parameters of stereo system due to vibrations

In stereo vision, the camera is calibrated using the popular chessboard before use. During the course of use, the camera maybe be subject to environmental factors such as vibrations.This may cause ...
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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
1k views

Scale problem with monocular visual odometry

Is monocular visual odometry able to estimate relative scale? Say I have a sequence of 10 images that are taken on a single track each 1 m after the previous. Can some mono odometry method distinguish ...
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3answers
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Camera Calibration fails to run on ROS

I am running ROS Indigo on Ubuntu 14.04. I am doing a mono-camera calibration and trying to follow the camera calibration tutorial on the ROS Wiki. I give the following command: rosrun ...
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1answer
1k views

Covariance and optimization

I am trying to build a map containing lamps as landmarks. I drive around with a robot and a monocular camera looking to the ceiling. The first step is detect the edges of each observed rectangular ...
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1answer
368 views

Kalman filter for estimating position with “direction” measurements

I am currently working on a pose estimation problem for which I would like to use filtering. To explain the system briefly, it consists of two cameras and each has its own GPS/IMU module. The main ...
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2answers
329 views

PTAM CameraCalibrator error

I am trying to run the cameracalibrator.launch using PTAM according to this Camera Calibration tutorial. However, when I do so, I get the following error: ...
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1answer
1k views

Do structured light camera sensors work outdoors?

Do structured light camera sensors like the structure.io, Intel RealSense or Microsoft Kinect work outdoors? I read these sensors wont work outdoors because of ambient IR light. Can someone provide ...
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2answers
185 views

Good 3D simulator for outdoor autonomous navigation

What's an appropriate tool for simulating a car driving in a simple closed-loop racetrack? I'm trying to implement the control logic for an autonomous vehicle, and I'd like to be able to first ...
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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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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
70 views

Stereo Rectification when Extrinsics are known

Suppose I have two cameras $C_1$ and $C_2$ arranged in a stereo configuration. Let us assume that the camera is free of distortion with ideal intrinsics and that the camera extrinsics $R$ and $t$ are ...
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0answers
40 views

Accuracy of monocular visual-inertial odometry

I am currently considering to use monocular visual-inertial odometry (VIO) to localize a smartphone relative to a known object. Now, what I would like to understand is, what kind of accuracy I can ...
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0answers
557 views

real-time stereo vision system for long range (up to 100m) depth estimation

I want to implement a FPGA-based real-time stereo vision system for long range (up to 100m) depth estimation. Also, I want to use two ip cameras in the system. I have calculated depth error using the ...
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3answers
593 views

Connect to video stream with Java app instead of console and mplayer [closed]

I'm building a quadcopter using Raspberry Pi. There is the Pi Camera connected to the Raspberry Pi which is streaming the captured video. I can connect to this stream via Wi-Fi on my notebook (Linux) ...
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1answer
55 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 ...
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2answers
45 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 ...
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1answer
36 views

How to derive the camera trajectory from ICP

This may be a very simple question so please bear with me... Suppose I have a stationary object and point clouds, $n$ $(x,y,z)$ points, of that object taken by a moving camera at time steps $t_i$, $...
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1answer
127 views

How to plot the 3D camera trajectory from a VSLAM output

I am totally new to VSLAM algorithms and would want to plot the path followed by the moving camera. I am using the open source implementation of ORB_SLAM2 for a rgb-d camera on benchmark dataset. The ...
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1answer
767 views

Position vs Image based visual servoing?

Can anyone explain Image based visual servoing for robotic arm through example? I can understand Position based based visual servoing like this, .... there is an object and estimating it 6D Pose ...
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1answer
182 views

Analogue video to digital [closed]

I have FPV camera which outputs analog video (RCA, PAL). I want to capture video and do image processing, therefore I need some way to convert the analog video to digital. Can some one recommend me ...
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1answer
1k views

Calculate object distance with camera

Firstly I'm unsure whether this question belongs here or on another SE site (but I'll wing it for now). I've recently been given the job of connecting up a 'smart camera' to a setup where a robotic ...
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1answer
22 views

How to calculate extrinsic calibration of a non-overlapping multicamera rig?

thanks for taking the time to check my question. Firstly, let me describe the current configuration, I am using 4 cameras that produce non-overlapping images and the goal is to calculate their ...
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1answer
47 views

Use 2 Cameras as 1 Stereo Camera

I have one Picamera and one normal USB Webcam and would like to use them together as one stereo camera. Is this even possible as the 2 cameras aren't exactly the same? I would like to use them in ROS ...
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1answer
43 views

Automatic License Plate Recognition System in Highway

We are working on a computer vision project where an automated robotic system will be deployed on a 3-lane highway. We are using a bosch IP camera (I don't remember the model exactly, but it cost ...
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1answer
34 views

Camera Pose Estimation

What is the minimum number of point correspondences required for camera pose estimation given the perspective projections of points with known world coordinates?
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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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1answer
38 views

Determining time difference of image capturing in multi camera setup

it is widely discussed in this forum, how to sync multiple cameras (e.g. best done via hardware trigger). Now I'd like to know how to actually determine the time delay between two image streams and ...
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2answers
357 views

IMU in a gimbal system

I have short question about the alexmos gimbal controller. The Controller receives the gyroscope and accelerometer sensor data from the IMU, that is mounted on the camera. In optimal case, the camera ...
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2answers
452 views

Choose and connect a camera to a robot [closed]

There are tons of cameras in devices around us these days. There are used photo cameras, smartphones, tablets at my home gathering dust. I wonder, what the easiest way could be to get a camera module ...
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2answers
36 views

How well does object detection transfer from simulation to reality? [closed]

I'm looking to learn more about this sim-to-real gap. I'm new to the concept and am trying to understand what to look for. Most notably i'm curious about how well an object detection algorithm trained ...
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0answers
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Size of smallest feature from pixel depth resolution

How do I get the size in mm of the smallest feature a depth camera can detect? Known variables are: distance from the target (for instance 1 meter), depth resolution in pixels (for instance 1280 x 720)...
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0answers
125 views

What is the definition of the phrase “ego robot”?

What does the phrase "ego robot" mean? I see it used in the context of multi robot systems like in the paper Game Theoretic Motion Planning for Multi-robot Racing by Zijian Wang, Riccardo Spica & ...
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0answers
21 views

What type of camera parameters are ideal for image processing on a moving platform?

What type of camera or camera properties should I look for that would be ideal for performing image processing in a moving environment? I'm researching the sensor requirements for processing video in ...
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0answers
36 views

Determining Orientation of a Robot Relative to a Line on Table

I am currently busy with a robot that needs to obtain it's orientation relative to a line seen by a camera. At the moment, I am using Hough lines to obtain a gradient for the line, but the gradient ...
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0answers
23 views

Hint regarding Localization & Map Scaling

I just started with mobile robotics. I'm trying to do a collaborative system between a mobile robot and a ceiling camera (Raspberry). They should do all tasks as a "team". Means Calibration, ...
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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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0answers
163 views

What is the baseline of a RGBD camera?

I'm looking at some ORB SLAM2 settings where there's a parameter for "IR projector baseline times fx". Could someone here explain what exactly is the baseline of an IR projector? Is it the distance ...
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0answers
30 views

Decrease minimum depth of a RGBD camera

I have a Kinect camera which has a minimum depth of 0.5m and I'm trying to find a way to decrease it to around 0.2m for near-depth detection. Does anyone know how this can be done? Can a macro lens be ...
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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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0answers
40 views

Stereo-Calibration with Variable focal cameras

Is it possible to perform stereo-calibration with cameras having variable focus? and if so, how is it done basically?
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0answers
40 views

hand-eye calibration for wheeled mobile robots

I am new to robotics and working with a wheeled mobile robot with one Kinect mounted on top of it currently. The robot knows its position in the environment via some means. I encounter one problem. ...
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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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0answers
200 views

Stereo vision setup to obtain depth map

I am currently working on a project that requires me to obtain depth information and point cloud map of objects in an indoor environment ( roughly twice the size of a normal room). I would like to ...
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0answers
35 views

Are homogeneous coordinates represented by appending image coordinates with a 1 in camera imaging

In camera imaging, there are several terms for point coordinates. World coordinates: [X, Y, Z] in physical unit Image coordinates: [u, v] in pixel. Do these coordinates become homogeneous ...
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0answers
131 views

How does a measurement model for camera based PNP work?

I am trying to write an EKF that can estimate the covariance of a pose estimate, where the estimation is being done by a PNP algorithm and 3D-2D correspondences in images. Although EKF based camera ...
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0answers
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Is the distortion introduced by a lens protector significant in practice?

I have a computer-vision application I made to localize a robot in a room; the software has been in use for a while and is working fine. When I calibrated the camera and got the intrinsics and lens ...