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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How to Reconstruct a Scene with a Single Moving Camera [closed]

What I would like to achieve is this: a single camera feeds a live video stream to the computer the geometry of the scene is determined with some free photogrammetry library the objects are ...
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RealSense Python API: Construct BufData or frame

I need to call rs2_project_color_pixel_to_depth_pixel from Python with synthetic data. The data are generated in Python and do not come directly from the RealSense. ...
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ROS Webcam Stream Really Slow

I am trying to stream the images from my camera to a VM via ROS. Here is my setup: Raspberry Pi 3B+ with Picamera v2. It is running ROS Noetic with cv_camera_node ...
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1answer
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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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Is there any way to know whether the disparity is negative without stereo rectification?

For one stereo camera, stereo calibration is performed to obtain intrinsic and extrinsic parameters during manufacturing. During the process of usage, intrinsic and extrinsic parameters may be changed,...
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1answer
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Trouble aligning/calibrating camera with laser scanner

I have a robot which has 2 multi-spectral cameras and 1 laser scanner attached. In the end I would like to have the images from the cameras aligned with the scanner so that I can have spectral ...
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2answers
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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
31 views

IMU-Camera Senor Fusion

I am working on fusing IMU and Camera Sensor Fusion for the Drone to precisely land on the target location. With the Camera, I am tracking the April Tag which is on the ground. This gives me the x,y,z ...
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What are the parameters that I need to consider when figuring out the horizontal viewing distance of a camera mounted overhead for effective tracking?

I am currently working on developing a hybrid Indoor Positioning system where images from an overhead camera will be used to identify and track people. I am new to the field of visual tracking and a ...
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How to spatially calibrate two FLIR thermal SC8000 cameras?

I have two FLIR SC8000 cameras and I do not know how to spatially calibrate them? I am doing stereo videography of a deformable moving object in a 1mx1m square. I also don't know what angle of these ...
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41 views

3D reconstruction of a moving object from two camera video stream

I have two synchronized video streams of a moving deformable object from two different cameras (same brand/model type) but two different views. How can I do the 3D reconstruction of this moving object?...
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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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How can I calibrate 3 cameras and track the object using only synchronized cameras feeds from all the cameras?

I have camera feed (in the form of RGB images) from 3 cameras with partially overlapping Field-of-view i.e. for the time stamp 0 to 100, I have total 300 frames or say synchronized 100 RGB frames for ...
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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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1answer
100 views

How can I calibrate 3 cameras without knowing global pose of the object & camera locations? How can I find the pose of each camera wrt the first one?

I have camera feed (in the form of RGB images) from 3 cameras with partially overlapping Field-of-view i.e. for the time stamp 0 to 100, I have total 300 frames or say synchronized 100 RGB frames for ...
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What does the normalized image coordinates imply?

In VSLAM or visual odometry, we use a camera matrix P to transform 3D scene points to 2D image points. When using homogeneous representation, we may choose the image coordinates as the normalized ...
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1answer
39 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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How to find visual odometry by video from cellphone camera mounted on robot?

I am writing codes in python for visual odometry from single camera. I used cell phone camera for testing. I took video of 35 sec with camera moving. I used code below to read first image ...
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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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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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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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35 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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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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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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Use Realsense camera to get the camera image

I have to use LIDAR in my project. I was searching for some LIDARs with a camera and came across the Intel RealSense d400 series. I know it has a camera but please suggest a way to use that camera ...
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1answer
58 views

Planar Robot Boundary Detection

I am tasked with building a robot that needs to localise and navigate itself on a rectangular surface (like a large desk). The rectangle's shorter sides will be marked with a red tape (or with two ...
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1answer
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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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Collaboration of mobile robot and survaillance camera - classic localization (still) needed?

Just started with the topic of mobile robotics.. so I'm still into concept making and little programming, but have not setup everything or tested at all. I got a (differential) mobile robot (lego ...
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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
100 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
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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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4answers
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Is there a specific way or module I can use to stream video data from a camera hooked to an Arduino Uno board?

I'm currently thinking about the feasibility of creating a robot which streams live video footage and other data such as temperature, humidity, etc. to a smartphone. Is it possible to do this on an ...
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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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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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1answer
87 views

How to get a wired live feed from camera to phone

I need a clear video live feed from a camera to an android phone. The connection does not have to be wireless because i have to use it without any internet. The camera and phone will be 2 or 3 meters ...
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1answer
344 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
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How do I set all objects in my scene to be aligned with respect to the camera in Unity 3D?

To elaborate further - How do I fix the camera as the origin of the 3D world? The context is I am trying to create some synthetic image data for a robotics project, and I have the coordinates of the ...
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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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1answer
43 views

Questions about customized stereo camera

I am designing my robot and I have quite design issues with the available stereo cameras on a market. For the prototype I am using ZED M but it is too expensive and quite large. The question is, do ...
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1answer
539 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
98 views

RGBD Camera Eye in Hand Calibration

Hello I am new to robotics. So far I have a basic understanding of the camera calibration. One would need rotation and transformation matrices to convert a point from camera coordinate system to robot/...
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1answer
108 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
191 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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1answer
150 views

Extrinsic calibration of a multicamera-rig mounted rigidly on a mobile robot

We have a set of 8 cameras mounted rigidly on a mobile robot. The cameras are forming an arc, which allows a 360º vision. I want the extrinsic parameters of them referred to the robot. Is there any ...
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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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1answer
442 views

How can I preserve a high framerate while using at least 1280x720 resolution on 2 USB cameras on the same computer?

To expand on this, I have a down-facing camera using the whycon ROS node on Ubuntu 16.04 Kinetic on a quad-core computer with 640x480@60fps MJPG video. I'm also using the ...
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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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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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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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1answer
142 views

Setting up a Structured Light Stereo system

I am trying to get started with a stereo experiment and wanted to know the mistakes I might have made during the experiment. The goal is to calculate the depth map of an object using one light ...