Stack Overflow
Stack Overflow

Questions tagged [projective-geometry]

Projective geometry is an incidence geometry of colinearity preserving transformations. Its use is widespread in computer graphics, computer vision, image registration, photography, among others. Homogeneous coordinates are commonly used to represent objects (point, lines, planes etc.) in real projective geometry. These are well-known to represent translation, rotation and perspective transformation simply as matrix-vector multiplication.

100 questions
5
votes
4 answers

How is the reprojection error calculated in Matlab's triangulate function? Sadly, the documentation gives no mathematical formula

How is the reprojection error calculated in Matlab's triangulate function? Sadly, the documentation gives no mathematical formula. It only says: The vector contains the average reprojection error for each M world point. What is the procedure/Matlab…
jhegedus
  • 20,244
  • 16
  • 99
  • 167
5
votes
1 answer

Multiple-View Geometry

I've two images captured from two cameras of same make placed some distance apart, capturing the same scene. I want to calculate the real world rotation and translation among the two cameras. In order to achieve this, I first extracted the SIFT…
Aarambh
  • 133
  • 1
  • 6
5
votes
2 answers

Different fundamental matrix from the same projection matrices

I use two projection matrices P1 and P2 (for example I'm using dinosaur dataset) and I need to compute the fundamental matrix F. So I use two Matlab functions: Peter Kovesi's function:…
Roberto Iacono
  • 51
  • 4
4
votes
1 answer

Mapping between different camera views

I have a calibrated (virtual) camera in Blender that views a roughly planar object. I make an image from a first camera pose P0 and move the camera to a new pose P1. So I have the 4x4 camera matrix for both views from which I can calculate the…
chronosynclastic
  • 1,585
  • 3
  • 19
  • 40
4
votes
0 answers

Normals from projective depth

I want to compute a normal map N(i,j) from a depth map D(i,j), where (i,j) describes 2D pixel location. A basic case of this problem is discussed here: Calculate surface normals from depth image using neighboring pixels cross product In my case,…
ASML
  • 199
  • 12
4
votes
1 answer

Rectify perspective image of planar structure given the normal vector of the plane and viewing direction of the camera

I have taken images of the facade of a building under multiple view points. Then I use bundler to reconstruct the 3D point cloud of the building. Then I use a RANSAC method to find the plane of the facade in the point cloud. This gives me the…
user473453
  • 894
  • 2
  • 11
  • 23
4
votes
0 answers

Calculate square bounds on Earth with given radius for center point

I'm trying to calculate bounds for square with particular radius and when center of square is known(longitude, latitude). But I'm getting into troubles with it. I've tried to use haversine formula from here : But I'm getting into troubles when…
hades
  • 1,077
  • 3
  • 11
  • 19
3
votes
1 answer

Need some help to understanding the formula

This is pinhole camera model: (I don't get, is there [R t], or (R, t)) This formula is translating the 3d coordinates of the point, to the 2d coordinates of a picture, which is obtained by pinhole camera. Projection drawing: Tilde over vector,…
Userr
  • 43
  • 4
3
votes
2 answers

Finding Projection and z distance

I have an image that represents a projection. I am going to explain the problem with an example: In the screen, there is a line from one point E(100,200) to another point H (150,100). A represent one point that in the real world is at 200 cm…
manuz
  • 31
  • 2
3
votes
1 answer

How to get rotation angles of Image Plane relative to the World Plane?

So we have such situation: In this illustration, the first quadrilateral is shown on the Image Plane and the second quadrilateral is shown on the World Plane. [1] In my particular case the Image Plane has 3 quadrilaterals - projections of real…
Rella
  • 65,003
  • 109
  • 363
  • 636
3
votes
1 answer

3D reconstruction using the projection matrices from the trifocal tensor

I have computed the trifocal tensor and corresponding projection matrices P_0, P_1 and P_2 from line correspondences over 3 views, according to 'Multiple View Geometry by Hartley & Zisserman, 2nd edition', Chapter 16. The computed matrices are: P_0…
takahashi
  • 2,081
  • 3
  • 14
  • 24
3
votes
0 answers

Projection matrix + world plane ~> Homography from image plane to world plane

I think I have my wires crossed on this, it should be quite easy. I have a projection matrix from world coordinates to image coordinates (4D homogeneous to 3D homgeneous), and therefore I also have the inverse projection matrix from image…
B3ret
  • 31
  • 2
3
votes
1 answer

Uncalibrated multi-view reconstruction depth estimation

I'm trying to make a 3D reconstruction from a set of uncalibrated photographs in MATLAB. I use SIFT to detect feature points and matches between images. I want to make a projective reconstruction first and then update this to a metric one using…
Hera
  • 48
  • 4
2
votes
1 answer

Compute Homography Matrix based on intrinsic and extrinsic camera parameters

I am willing to perform a 360° Panorama stitching for 6 fish-eye cameras. In order to find the relation among cameras I need to compute the Homography Matrix. The latter is usually computed by finding features in the images and matching…
makolele12
  • 111
  • 1
  • 10
2
votes
1 answer

Project coordinate system onto angled planar surface in image

I want to define a coordinate system projected onto some planar surface within the image. I just need some hints and ideas for how to implement this, not necessarily code, but everything is appreciated! If code is provided, it would be preferred in…
Yuki
  • 59
  • 6
1
2
3 4 5 6 7