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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.

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Algorithm to interpolate any view from individual view mapped on a sphere

I'm trying to create a graphics engine to show point cloud data (in first person for now). My idea is to precalculate individual views from different points in the space we are viewing and mapping them into a sphere. Is it possible to interpolate…
user11615
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MATLAB: projective transformations

I have a picture and I want to get projective transformation by shifting it back like this: but the only result I can see is this: and I cannot find my mistake. My code (A - picture I want to transform): p=0.25; a=p*rows(A); U = @(m, n) ([1 1; 1…
myname
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How can I find a matching between two independent sets of features extracted from two images of the same scene captured by two different cameras?

I need to find matching between two independent sets of features extracted from two images of the same scene captured by two different cameras. I'm using the HumanEvaI data set, so I have the calibration matrices of the cameras (in this particular…
user1400151
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Spherical Coordinates from a non centered location

Assuming a pinhole camera centered at (cx,cy,cz) != (0,0,0) is there a more efficient way to compute it's projection in a spherical coordinate system centered at the origin other than performing a ray-sphere intersection for each pixel? If the…
memecs
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How to efficiently implement "point-on-heightmap" picking in OpenGL?

I want to track the mouse coordinates in my OpenGL scene on the ground surface of the world which is modeled as a height map. Currently there is no fancy stuff like hardware tessellation. Note that this question is not about object…
leemes
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Project points from a plane to the camera plane

Let's say I know the (x,y) coordinates of the 4 corners of the cameras view. Is there a way to calculate the pixel coordinate of a point given its (x,y) coordinate in the world? I've looked into cv2.projectPoints() but I couldn't figure out how to…
Brayden Rudisill
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How to get new homography (between camera POV and a map) when camera is translated?

I'm new to computer vision and confused about how homography works. I have a homography matrix computed between a camera's point of view and a map which it uses to track people on the floor. If I rotate and translate the camera to a new position…
fliptrail
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Alignment of depth and color image on an oak-d camera

I'm trying to create an RGB-D dataset and I'm having some troubles in aligning the color and depth images from the oak-d camera. The depth image is aligned with the right camera of the stereo rig and the objective is to align it with the color…
Tiago Rodrigues
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Bad Essential Matrix With OpenCV

Overview I'm writing a simple Python program to calculate the distance to a chosen target from a pair of two arbitrarily located stereo images. Both images are taken from a single camera with known intrinsics K, and although the camera locations and…
Evan
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Using a Projection matrix to project grid

I'm trying to project a grid using a projection matrix creating a grid. I generate some lines given two points. Then, I found a projection matrix and find the point images but when I'm trying to plot the result, I obtain weird things def…
Esteban
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Determine adjustment factor for projecting 2D image with FOV from 3D point cloud which is constructed using different FOV

I am trying to project a 2D image from a 3D point cloud. Herein, the 3D point cloud is constructed using RGB and Depth images whose FOV is 120 degree. Once the 3D point cloud is constructed, I wanted to reproject a 2D image from it using a FOV 80…
Vinod prime
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Depth to world registration hololens2 unity

I'm working on a program on hololens2 research mode on unity. Hololens give us a depth image that is distance from depth sensor to object in front, for every pixel. What I do is for every pixel I project pixel to image plane, then backproject it…
mahdi bagheri
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The reason for the half integer coordinates

I am reading some projective geometry image warping code from Google def WarpCoordinatesWithHomography(homography, rect, cfg): """Computes the warped coordinates from rect through homography. Computes the corresponding coordinates on the image…
Brans
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Python- Projecting a circle with camera.Camera class

I am currently projecting a circle with the camera.Camera class and different viewing angles. Specifications: Circle center -> [0 , 0, 1] Camera center -> [0, 0, 0] (looking up the z-axis) I used the camera.Camera class and it all seems fine, but…
TecK97
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Finding inner common tangent to a pair of conics

I have been trying to get the common tangents to two rotated ellipse. I was following the method given by Edward Doolittle in the following thread. The two ellipses are given as the equation given in Wiki. In the Matrix form the ellipse can be shown…
Kashish Dhal
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