Questions tagged [stereo-vision]

Stereo vision, or Stereopsis, is the process in visual perception leading to the perception of depth from the two slightly different projections of an object onto the two eyes. Computer stereo vision mimics this behaviour by having the computer compare multiple images of a scene and determine the differences between identified features.

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44 views

Interpreting the accuracy of solutions to the correspondence problem

I have two pictures of the same object, taken by a car travelling down the road like shown on the right side of the image below. I want to find pixels of the object in each frame that correspond to ...
15 views

Intuition behind cost aggregation functions in stereo correspondence problem?

I don't seem to understand the concept of a cost aggregation function like a Fixed window or an Adaptive window, etc. Why do we need this additional step, and why can't we just calculate the disparity ...
85 views

Why are 8 points needed to compute a fundamental matrix?

Homograpies have 8 degrees of freedom. Fundamental matrices have 7. Essential matrices have 5. To the best I could find, all those matrices are obtained by using the 8 point algorithm. I don't see ...
53 views

Stereo triangulation similar triangle derivation

I understand that the similar triangles are the red and blue triangles. I'm trying to understand where $T + x_r - x_l$ comes from. I understand we are trying to compute the length of the base of the ...
213 views

Is it possible to generate depth map from graycode sequence without using printed calibration patterns?

In a camera-projector system, if only the camera's intrinsics are known, is it possible to generate the depthmap fully automatically through a graycode sequence without any manual calibration process (...
842 views

Resolution and accuracy of a stereo camera

My question is pertaining to how the parameters of a stereo camera system (focal length, base, height, pixel density) affects the accuracy as well as the resolution of depth measurement. I do not ...
1k views

Do we really need two cameras for 3D vision?

I heard that we can see the world 3D or we can detect distance because we have 2 eyes. but I think we can do it with only one eye! (test it!) So why we can do it only with one eye? is it possible to ...
3k views

Why do we need 4 points for homography but 7/8 points for fundamental matrix calculation?

Sorry if this is a trivial question but I could not find a suitable answer elsewhere. I recently learned about homography and fundamental matrices in a CV class. I understand how these matrices are ...
293 views

Why are two cameras mounted in paralle in stereo application?

For stereo cameras on the market, two cameras are always mounted side by side and with a displacement that is perpendicular to the camerasā optical axes. I take this setup for granted. One idea came ...
459 views

Kalman filter for tracking obstacles

I'm developing a Computer Vision project in Matlab as an aid to visually impaired people. The setup would be a stereo pair of cameras which the blind person would carry. Using this stereo information, ...
208 views

Can I use standard computer vision techniques for images taken in the NIR spectral range?

I'm relatively new in Computer Vision and I need some advice with respect to the general possibilities and shortcomings of images taken in the near infrared (NIR) range. I passed a great deal of time ...
3k views

What is the difference between a range image and a depth map?

https://en.wikipedia.org/wiki/Depth_map https://en.wikipedia.org/wiki/Range_imaging To me, it sounds like they are the same thing, except depth map implies only having the z coordinate info. But ...
2k views

Finding Distance between Cameras in Stereo Vision

We know how to create disparity map from stereo vision with OpenCV. My question is How can we find/estimate distance between cameras from two image taken from these cameras in OpenCV?
750 views

Is there a difference between Image Alignment and Stereo Rectification for stereo correspondence or matching?

As far as I know, Image alignment just finds the best fit given two images of the same scene. Whereas Image rectification, with regards to stereo vision, warps the images so that the epipolar lines ...
396 views

What Is the Purpose of Bundle Adjustment?

So, my understanding of stereovision is that you essentially have two cameras. Then, offline, you perform camera calibration with checkerboards to get intrinsic camera properties as well as the ...
3k views

Can disparity range from negative to positive values for parallel cameras?

In my stereo-rectified camera pair (not physical, but two positions of the same camera), when I project some 3D points in both images to find a rough disparity range, I often get a range that goes ...
313 views

How to calculate binocular overlap

I have two cameras of which I know focal length, principal point, rotation and position. The cameras are in an ideal parallel stereo system. I want to know with as few calculations as possible how ...
687 views

Measuring non-planar objects in image

I'm working on a computer vision application (using openCV) and the goal is to measure the width of an object before/after it falls on a container. So after the fall its position will be random, ...
134 views

Image correlation confidence measure

I am trying to calculate the disparity between stereo image pairs. I'm using what appears to be the standard approach of correlating between a window of pixels from one image and a sliding window ...
174 views

Beyond cross-eyed 3D (VR application)

Making static 3D image is very simple - we just take image pair with something like this: then we can see 3D image by putting the left and right eye image side by side and crossing eyes or ...
760 views

Why do object-boundaries look better on a badly rectified image?(openCV stereo correspondence)

I got 2 pictures which is almost parallel, and not positioned very far from each other. I'm using OpenCV to try to create a disparity map (Stereo correspondence). Because I'm trying to use it in a ...
255 views

Incorporating Radial Distortion in Imaging Model

I'm currently developing a multi-view stereo system but I'm confused as to how all the standard equations in Structure from Motion are affected in the presence of radial and decentering distortion. ...
465 views

How do you measure the accuracy of a stereo system?

I have a philosophical question of sorts for users familiar with a multi-view stereo setup. Imagine that I need to measure the dimensions of a large building and I take several photos of the building ...
214 views

Minimization of Essential matrix

A problem in computer vision and 3d reconstruction is getting the camera's intrinsics parameters. A common solution is to use an object in which one knows the measurements of the shape before hand, ...
150 views

In computer stereo vision, what does it mean to “look in”?

In trying to understand this answer to my earlier question, can someone explain why it is important that the cameras are not in the same plane when the focal distance is large compared to the ...