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What is the Fourier Transform integral equation for a 1D signal and how can it be expanded into 2D, 3D, and 4D?

I know that is the 1D Fourier Transform (FT), and the 2D FT is and 3D FT is , but I am not sure whether these expressions are in fact Fourier transform integral equations for a 1D signal, expanded ...
LiuXiu's user avatar
  • 13
1 vote
0 answers
29 views

Depth estimation using phase shifted sine waves

For 3 phase shifted sine waves using the projected pattern: I = sin(x + δi) where δ ∈ [-2pi/3, 0, +2pi/3] which is then projected onto a scene. The resulting image is captured with a camera. I am ...
Arun's user avatar
  • 111
3 votes
3 answers
1k views

How to understand the basis sinusoids of 3D FFT?

I understand intuitively the concept of Fourier transforms of 1D signals and 2D images. In the case of a 1D signal, an FFT gives the relative contribution of sinusoids with different frequencies and ...
quantumflash's user avatar
1 vote
0 answers
122 views

calibrating camera using 3d objects such as rubik's cube?

Hello all hope everyone is doing fine. I have a vision related problem where I want to calibrate my camera using a 3d object such as rubik's cube with known dimensions. I have a cube with 60mm length, ...
umar anjum's user avatar
0 votes
1 answer
37 views

Tracking vectors in 3D

A 3D object with smooth surface is given as in the figure. There exist two vectors $v_1$ and $v_2$ on different points on the surface. These vectors represent velocity vectors on different moments in ...
Monotros's user avatar
  • 101
0 votes
1 answer
42 views

3D-to-3D pose estimation

Given a set of 3D points with their coordinates in 2 different coordinate systems, what is the correct algorithm to use in order to estimate the relative rotation and translation of the coordinate ...
Ahmed's user avatar
  • 11
0 votes
0 answers
57 views

Get Length, Breadth and Width using Intel Real Sense Camera

I want to find 3d dimensions of an object in an image. With mobile phone camera and using the code here I can compute dimensions of an object within an image using a reference object. Following are ...
user avatar
1 vote
0 answers
17 views

Finding optimal translation & rotation to place a 3d model into its visual hull

The title already sums up my question pretty well: I've got a pretty accurate 3d model of some object. This object is usually non-convex and it also may have some holes etc. This object is placed (...
Nils's user avatar
  • 11
0 votes
0 answers
497 views

Filter 3D volumetric image with a Butterworth filter in Python

I have been looking for a way to filter a 3D volumetric image in python with a Butterworth filter, but I haven't found any good solution. I have tried this: ...
Malte Jensen's user avatar
2 votes
0 answers
21 views

What is the name of the filter or technique to reduce depth aliasing around object edges when working with camera depth?

I'm working with a point cloud, created by sampling a 2D camera texture and a depth map. The color is combined with the depth and is projected onto a 3D scene to create a "point cloud". The ...
Alex Stone's user avatar
2 votes
2 answers
485 views

HRIR interpolation using VBAP

1) Problem description I am trying to implement a 3D audio simulator in Python. I am using the HUTUBS dataset as HRIR database (more informations here: https://depositonce.tu-berlin.de/handle/11303/...
Mattia Surricchio's user avatar
1 vote
1 answer
49 views

Why not use synthetic datasets for training machine vision (deep learning) algorithms?

I am studying some examples of how to perform 3D instance segmentation in indoor scenes, and I have noticed many of the available datasets are from real environments. I was wondering with the ...
KFkf's user avatar
  • 111
0 votes
1 answer
2k views

Making a 3D point cloud from multiple RGB-D images

I have multiple (4 kinect) cameras that give RGB-D (color and depth) information of the same scene from different points of view. I want to make a 3D point cloud out of these depth maps. I can get a ...
Kiarash Farivar's user avatar
3 votes
2 answers
121 views

2D to 3D view conversion

I came across this demo by Fox sports: https://youtu.be/N9SxFf5WCb0 Where they show a player's view in a 360 space. Very smooth and nice. I was wondering how do they achieve it without any cameras ...
Tina J's user avatar
  • 193
1 vote
0 answers
316 views

Projecting 3D point to 2D image coordinates

I am trying to replicate the projections of a 3D point to 2D using the pinhole camera model and the formula $x = K * [R|-RC] * X$, where $x = s\begin{bmatrix} u\\ v\\ 1 \end{bmatrix}$, $K$ is the ...
oezguensi's user avatar
0 votes
0 answers
849 views

Mapping ring asteroids in Elite Dangerous by image processing

In the game Elite Dangerous, which is an online spaceflight-based sandbox game set in a procedurally-generated galaxy, one of the most profitable in-game occupations is mining commodities from ...
Monty Wild's user avatar
2 votes
1 answer
170 views

3D reconstruction of moving object

I am pretty new to the field of 3D reconstruction and overwhelmed by the large amounts of different methods. I am trying to find the correct method for my use case: Setting: I have a stationary ...
oezguensi's user avatar
0 votes
0 answers
31 views

Compute $d^2$ entries of a 3D convolution faster than $O(d^3)$

Let $A,B\in \mathbb{R}^{d\times d\times d}$. The 3D circular convolution $\text{conv}(A,B)$ can then be computed as $F^{-1}(F(A)\odot F(B))$ where $F(\cdot)$ denotes the 3D discrete Fourier transform ...
Alexander Mathiasen's user avatar
2 votes
2 answers
189 views

Is there any simple algorithm to convert a sound source in 3d to volume and panning

I'm looking for a simple algorithm which calculates an approximation of volume and pan at the position of the camera from the following 3d data: Camera (position and look direction) An item which ...
Viktor Sehr's user avatar
0 votes
1 answer
97 views

why is it so hard to simulate up and down position on headphones?

i'm wondering how come simulating front,back,left and right source position on headphones is easy but up and down is not ? (maybe even impossible ?) is it due to the shape of the ear ? but should we ...
Jeff's user avatar
  • 89
1 vote
0 answers
66 views

How to create 3D signed distance function?

I am trying to segment a 3D shape using levelset. I want to track shape movement in consecutive frames. Now I want to create a signed distance function matrix for ...
MJay's user avatar
  • 467
1 vote
1 answer
85 views

Is there any way to do 3D (Voxel Data) feature detection?

In the 2D image processing, there are ways to find and match features of the image (like corner of the edges). However, I could not find the equivalent of that in the 3D-voxel data (Here voxel means a ...
Allosteric's user avatar
2 votes
1 answer
37 views

Switching camera angle based on several images

Given a number (3 or 4) of different images of a given subject from different angles, how do I interpolate to an angle that isn't available on any of the photos? What is this technique called and is ...
Michael Zedeler's user avatar
1 vote
0 answers
48 views

Bundle adjustment optimization parameters

While reading the Wikipedia article on Bundle adjustment, I came across the following objective function used to represent the bundle adjustment problem. I have two questions regarding this objective ...
Carpetfizz's user avatar
0 votes
1 answer
948 views

Isosurfaces from three dimensional column data: methods

I have just been asked the following question, and I somehow felt short of smart answers. You are given a series of $N$ triplets of values ($P_1$, $P_2$, $P_3$), pertaining to physical measurements. ...
Laurent Duval's user avatar
0 votes
1 answer
732 views

Multiple-image dense point cloud reconstruction with camera extrinsics/intrinsics

I have the following data available: Images from different angles X, Y, Z, pitch, yaw, and roll for each camera/image, together with the timestamp Lens distortion parameters and intrinsic camera ...
chris's user avatar
  • 111
0 votes
1 answer
379 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 (...
Oct F's user avatar
  • 1
0 votes
0 answers
125 views

How to filter a sequence of frames?

I'm have a sequence of 2-dimensional MxN frames. I have concatenated these frames to form a 3-dimensional MxNxT matrix. Now i want to filter this 3D volume by 2 types of filters (a 2D log-Gabor in xy-...
MJay's user avatar
  • 467
0 votes
2 answers
293 views

1D as a 3D FFT - what’s wrong here?

I implemented the algorithm to calculate 2D DFT derived from 1D DFT. It works great, and makes my calculations much more efficiency then regular 1D DFT. But now I want to make 3D DFT derived from 1D ...
pajczur's user avatar
  • 359
1 vote
2 answers
8k views

Camera calibration and extrinsic parameters for perspective transformation

I'm working in a photogrammetry camera and laser application where I need to measure a displacement in a specific plane, this is a quick diagram of the setup: In order to get proper measurements I'm ...
joe's user avatar
  • 137
0 votes
1 answer
49 views

How left out down-sampling in 3D-DWT just on the Z direction

I am working on image processing by a 3D wavelet transform. I have a problem with the classification size of the wavelet coefficients. As you know, when we apply 3D_DWT on the image (for example: ...
Mehdi's user avatar
  • 3
2 votes
0 answers
2k views

3D image segmentation

Re-written more specific question For the details of my segmentation algorithm, see the original question below. I have managed to improve the segmentation considerably by using a different strategy ...
Phlya's user avatar
  • 121
0 votes
1 answer
121 views

Estimating exterior camera parameters by matching lines using least square estimations (Lowe, 1991)

I'm new to computer vision and graphics. I want to estimate exterior camera parameters using non-linear least square estimation as suggested by "Lowe, David G. "Fitting parameterized three-dimensional ...
Debaditya's user avatar
  • 103
2 votes
1 answer
4k views

Triaxial accelerometer to single signal

I have some smartphone recorded accelerometer data, so I have acceleration along 3 axes: $$a_{x}, a_{y}, a_{z}$$ The accelerometer data was collected by securing a phone to a walking subject. I'm ...
Simon's user avatar
  • 315
0 votes
1 answer
57 views

A PID that can handle 2 inputs for my application

I am currently working on a Drone that navigates to different points that it detects on the ground. To go from one point to another in a smooth manner, I am employing a PID looks at the error between ...
SDG's user avatar
  • 201
0 votes
1 answer
580 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 cameras’ optical axes. I take this setup for granted. One idea came ...
Jogging Song's user avatar
1 vote
1 answer
862 views

Sensor fusion with accelerometer and gyroscope only

I need to track an object in 3D-space and I can use only accelerometer and gyroscope. I can't use a magnetometer because the object itself has a strong magnet. I need to know the orientation of the ...
tipo1000's user avatar
0 votes
1 answer
965 views

Two-View 3D reconstruction using the sparse Levenberg–Marquardt algorithm

I have trouble implementing the Levenberg-Marguardt algorithm as described in the book Multi View Geometry in Computer Vision. To be more specific I have trouble calculating the partial derivatives ...
johny's user avatar
  • 15
0 votes
1 answer
2k views

the position of image plane in optical imaging

In the book Learning OpenCV, there is one figure that show the image plane always is focal image. The description of the figure from the book is as follow. We begin by looking at the simplest model ...
Jogging Song's user avatar
0 votes
4 answers
128 views

What algorithms can automatically determine a 3D scene from one or a few 2D images?

For a project I'm doing, I'm trying to model a scene based on a phone camera's video input, and then insert arrows into it that indicate direction in three dimensions. I've looked around, and the ...
oink's user avatar
  • 101
1 vote
1 answer
1k views

Backprojection of 2D image on 3D model

I am trying to implement the paper "Face Reconstruction in the Wild". In that I use a template 3D model and rotate it to align it with the orientation of the face in the 2D image. Now I want to ...
malreddysid's user avatar
0 votes
2 answers
1k views

How can we combine 2D image with 3D image for the same sense?

We have 3D point cloud data captured by a laser scanner and need to register it with 2D images to get further information. In our case, the 2D image and 3D points are not overlapping and therefore we ...
Mohammad nagdawi's user avatar
1 vote
1 answer
499 views

Point cloud comparison

Let me preface this question with the fact that two hours ago I had no idea what a cloud point was. I do however have a solid mathematical background although geometry has never been my focus. I do ...
Jan van der Vegt's user avatar
0 votes
2 answers
177 views

Generate 3D image from Multiple 2D Images

If we're to capture an image of a body using four (4) WebCam with a 16 megapixel (1 in the front, 1 in the back and 2 sides(left and right)). Is it possible to make a 3D out of it using image ...
cydi's user avatar
  • 1
2 votes
2 answers
100 views

How does google automatically create 3D cityscapes?

In the last years, Google models not only are major cities, but also suburban and rural areas (google video) I read that there are some tridimensional model building algorithm here. How could such ...
Rowandish's user avatar
  • 123
1 vote
1 answer
1k views

Accelerometer - coordinate system transformation

I'm getting some accelerometer readings from an Android phone, but it comes in on the phone's coordinate system. I want to apply a transformation to put the acceleration in the world coordinate system ...
Simon's user avatar
  • 315
1 vote
0 answers
106 views

How to reconstruct 2D flat image from a series of pictures of a tube

I have pictures of an oesophagus (ie a tube) taken under standard white light looking down the tube. I have about 10 images taken over 20cm in series. The image looks forward down into the tube and ...
Sebastian Zeki's user avatar
0 votes
2 answers
825 views

Image distortion and alignment on 3D mesh / pointcloud

Currently I have a fairly accurate (50 µm) and large dataset from a 3D scanner and a set of high resolution pictures. Sadly the 3D scanner (a Nikon/Metris arm-based CMM that was hanging around the lab)...
Bart Plovie's user avatar
4 votes
1 answer
2k views

How Can Convolution and Deconvolution be Defined for 3D Images?

I am trying to understand how convolution and deconvolution can be represented for 3D images/ stacks of data. I would prefer it, if you built the these concepts from 1D vectors to 3D matrices in terms ...
SDG's user avatar
  • 201
2 votes
1 answer
253 views

Essential Matrix from line correspondences

I'm looking for some library with a function to compute an essential matrix from line correspondences in multiple images. All the computer vision libraries I know use point correspondences to compute ...
martinako's user avatar
  • 121