# Questions tagged [geometry]

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### Understanding and Resolving Singularities in Stereo Rectification using Multiple View Geometry

I am currently working on implementing a stereo rectification algorithm based on the method described in the book "Multiple View Geometry in Computer Vision (MVG)," specifically in Section ...
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1 vote
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### Understanding difference in rotation and translation

Hi I am a newbie to the field so please don't mind a rookie question. I have read multiple articles and want to ensure my understanding is correct. I have following two images. In the second image, ...
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• 283
1 vote
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### Can an untilted perspective of an object be obtained from a 2D image of a tilted object using angular transformations?

I'm trying to make a height estimation algorithm that works in tandem with a bounding box object detector. The object detector can recognise the objects in images taken at pitch/yaw angular offsets. ...
240 views

### Derivation of range migration algorithm

Problem: In Walter G.Carrara's book on synthetic aperture radar, the equation is presented: $\Phi(K_X, K_R) = -K_XX_t - R_B\sqrt(K_R^2 - K_X^2) +K_RR_S$ (10.30) And this is said to come from ...
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### Are there analogues to orthogonal transformations in non-orientable surfaces?

I am working on extremely large, symmetric matrices of counts, and attempting to identify patterns/shapes within them. Wavelets are a popular tool in image processing, and have some nice statistical ...
• 193
1 vote
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### Finding angles from an IMU (Quaternions to Eulers)

Greetings and apologies if this has already been answered, but I haven't been able to get a clear answer from looking on Stack Exchange so-far. I have Quaternions coming from two different IMU's ...
• 11
1 vote
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### Would it be possible to reconstruct 3d trajectory of ball projectile using only monocular video

Assume ball location on the image frame in each timestamp is given. Would it be possible to reconstruct the ball's 3d trajectory in the camera's coordinate frame? The ball should be able to ...
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507 views

### How to triangulate 2 sources on a 2d plane formed by 4 sensors?

I have 4 sensors capturing signal data. Signal distribution speed is constant and known. I have sensors positions in 3d space. Also, I have an amplitude/frequency decomposition for data received by ...
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### Subsampling property of wavelet transform

One of the properties I have seen for isotropic tight wavelet frames is $$\sum_{i\in\mathbb{Z}} \left|h(2^i\omega)\right|^2 = 1$$ where $h(\omega)$ is the frequency spectrum of the original wavelet. ...
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### Algorithm to effectively find perspective transform in motion estimation

I've shot a series of photographs in a sort of stop-motion fashion, and although the camera was mounted on a tripod, there are tiny motions between each two successive photos. After some ...
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### Why is this projection wrong?

I am trying to figure out why a 3D cube doesn't project in the right place in the image. I start with the camera at origin and the cube centered at (0,0,1) world ...
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### How to generate realistic echo to sounds?

I guess the most straightforward way of adding an artificial echo to a sound signal is to add its time-delayed version to the original signal. However, I am not sure how realistic that would sound ...
963 views

### 3D point cloud to 2.5D graycale image (metric) [Halcon?]

I have a problem ragarding transferring a point cloud to a 2.5D metric grayscale image (gray value gives depth information). I start with a three channel image of 32bit floats with each pixel ...
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### Ground plane estimation from a single image (was: confusion about homography and calibration camera parameters)

I'm new to this multiple view geometry issues and I'm a little bit lost, and some concept are not clear at all. I have a calibrated camera ( = I have distortion coefficents, field of view, and with ...
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### Ideal Geometric Arrangement of Microphone Array

I'm going to have to give a bit of context for this question to make sense. I am working on a project which includes audio source localisation in 3-D space through TDoA (Time Difference of Arrival - ...
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### Intuition of Location on the Conic Axis TDOA solution

In an old paper "A New Approach to Geometry of Range Difference Location", there is a mathematical derivation that does not include any mention of the relationship to the underlying problem. In the ...
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### Automatic Cropping of Arbitrary Shapes

I have an arbitrary shape defined by a binary mask (gray = shape, black = background). I would like to find a largest possible rectangle containing only gray pixels (such rectangle is pictured in ...
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### Is it always necessary to use two cameras to find the distance between camera and object?

I am working on finding the distance between a camera and an object using image processing. In many places, it's written that we have to use a stereo pair, but my project allows only one camera. ...
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