Questions tagged [3d]

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24
votes
3answers
2k views

How can I reconstruct a 3D structure from a set of images?

I have a set of contours (set of line segments) grouped in the following way: $S_i = \{I^0, I^\frac{\pi}{4}, I^\frac{2\pi}{4}, \ldots, I^\frac{7\pi}{4} \}$ where $S_i$ denote sequence of photos of ...
13
votes
2answers
20k views

How to compute camera pose from Homography matrix?

Say I use only one calibrated camera. From this camera, I get images A and B. I know the homography between A and B, computed through OpenCV's findHomography(). I know the pose (rotation matrix R and ...
12
votes
2answers
10k views

Analytical expression for the eigenvectors of a 3x3 real, symmetric matrix?

I am writing an algorithm that process 3D images based on the local moment of inertia. I have a 3x3 real symmetric matrix, from which I need to find the eigenvalues. I have found a variety of ...
11
votes
1answer
312 views

Image Processing method for spiky selection

I have an input as a 3D binary image and the preferred output below: Input: Preferred Output: What image processing methods should I look for if I am to have only the spiky object(s) remain, just ...
10
votes
3answers
3k views

Camera calibration/pin hole camera model and working out 3d position

I have a calibrated camera and have the intrinsic parameters. I also have the extrinsic parameters relative to a point (the world origin) on a planar surface in the real world. This point I have set ...
10
votes
1answer
302 views

Advise on detecting anatomical landmarks in a CT reconstructed volume

I'm trying to automatically detect some medical defined anatomical landmarks in a CT reconstructed volume. Medical doctors use these landmarks to measure some patient specific parameters. I have ...
9
votes
2answers
509 views

Finding radius r of the overlappable sphere(s) in 3D image

My current problem: I have an input 3D binary image (a 3D matrix that has only 0 and 1) that consists of random numbers of sphere with radius r. We do not know how many spheres are there in the ...
9
votes
2answers
2k views

How to measure a lung nodule in a CT Scan DICOM image?

In this question, I would like to focus on intensity value of the CT Scan. First, take a look at the image below: The upper image is the original image, while the lower image is the thresholded ...
8
votes
3answers
3k views

Is it possible to convert from 2D to 3D form?

I have captured car positions at different frames from the video. Suppose car's(e.g.left side car which is coming towards us in the images) centroid at video frame1 is P(x1,y1) and Q(x2,y2) at video ...
7
votes
3answers
2k views

Eigenvalues and eigenvectors of a 3D image Laplacian

I need to compute the eigenvalues and eigenvectors of a 3D image Laplacian. I'm trying to evaluate the heat kernel on the 3D uniform grid (the uniform structure generated by the voxelized image) at ...
7
votes
1answer
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, ...
6
votes
3answers
4k views

The fastest way to “fill holes” in 3D?

I have a 3D binary image that I must fill all of the holes in the image. "Fill holes 3D" in this case, is basically a 3D version of BW2 = imfill(BW,'holes') from ...
5
votes
2answers
292 views

I'm looking to do my senior capstone project in the field of medical tomography, what is a good book to get acquainted with the field?

I'm a junior currently pursuing a mathematics degree with aspirations toward medical school. I have a senior project I have my entire last year to devote time to, and I've decided that I want to ...
5
votes
1answer
804 views

How to blend images on a spherical surface / cube map

I already have an algorithm for making panoramic image mosaics by image registration and then blending images in the overlap regions. The following image from Wikipedia illustrates several images ...
4
votes
2answers
2k views

Shortest geometric distance from surface in 3d dataset?

I have a three-dimensional binary image of a collection of discrete, individual voxels ("seeds") contained in a connected 3-dimensional surface ("skin"). (Like a small fruit, with a surface delineated ...
4
votes
3answers
187 views

What is temporal neighborhood?

I read in a paper http://tcts.fpms.ac.be/publications/regpapers/2011/nrmmbgtd_icvs_LNCS.pdf about spatio-temporal filters, which is applied to frames of the videos. I could not understand these terms ...
4
votes
1answer
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 ...
4
votes
1answer
360 views

Smoothing 3D Data for the Second Derivative

I am not a signal processing expert and my feeble attempts at solving this problem have come up short. I have a C++ application which is being fed regularly-spaced (in time) 3D position samples. The ...
4
votes
2answers
1k views

Software to register a 2D image to a 3D volume

I have been searching for software that can handle the task of registering a 2D image to a 3D volume. The 3D volume is a microCT scan, while the 2D image is taken from a plane passing through the ...
4
votes
3answers
709 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, ...
3
votes
2answers
43 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 ...
3
votes
2answers
1k views

filling holes of a 3D image in Matlab

I want to use morphology operator for filling holes of a 3d image. The 3d image consists of 116 2-D image slices of the same size (512*512 pixels). I tried using imfill in Matlab for the 3d image but ...
2
votes
2answers
48 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 ...
2
votes
2answers
81 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 ...
2
votes
4answers
2k views

Extending 1D window functions to 3D (or higher)

(cross post of SO: https://stackoverflow.com/questions/27345861/extending-1d-function-across-3-dimensions-for-data-windowing ) For the sake of image (volume) registration, I'd like to apply a ...
2
votes
1answer
2k 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 ...
2
votes
1answer
2k views

How to relocate face points in opencv / face distortion?

I have to simulate facial expressions on a face image ( say open mouth ). For this I first extracted the facial feature points and found the corners of the lips. Now I need to deform the image by ...
2
votes
1answer
129 views

Tools for 3D shape analysis

I have a 3D shape in a 3D binary image. Therefore, I have a list of all of the x,y,z points. If I am to analyze this shape for various identification, such as "sphericity", volume, surface area, etc., ...
2
votes
1answer
2k views

Texture mapping on a 3D face from 2D face image

I have 3D points (xyz) of a face image and I have 2D face image of the same person. The 3D points of the face are such that If I project the points to 2D plane, it matches with the 2D face image. I ...
2
votes
0answers
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 ...
2
votes
0answers
136 views

Upsampling Methods for Computed-Tomography

I have two sets of data of given Field of view, one of them only covers a subset of the FOV of the other. I therefore want to upsample the one with the larger FOV to combine it with the other one. So ...
2
votes
0answers
106 views

Phong Reflection Model Parameters

Question: Can anyone refer me the Phong reflection model parameters for a face image taken for web-cam? Details: I am doing 3D reconstruction of 2D images using 3D Morphable Model as in this paper ...
1
vote
2answers
1k views

Getting HRTF from 3-D scan + acoustic simulation

This question follows from Modelling propagation of sound wave by particle simulation This last fortnight I have started experimenting with Binaural audio; it really blows everything else out of the ...
1
vote
2answers
3k 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 ...
1
vote
1answer
472 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 ...
1
vote
1answer
688 views

Decomposition of **3D** structuring elements for morphological operations

I am struggling to implement a mathematical morphology toolset in an image processing package. I base my implementation on what I saw in MATLAB, and on several papers on the subject. There seems to ...
1
vote
1answer
23 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 ...
1
vote
1answer
36 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 ...
1
vote
1answer
770 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 ...
1
vote
1answer
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 ...
1
vote
1answer
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 ...
1
vote
1answer
178 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 ...
1
vote
1answer
255 views

3d CT segmentation

It's my first attempt at 3D analysis. I am trying to segment a 3D CT data. My case study is very simple: trying to segment circular objects in my data. Do you have any suggestions on how to achieve ...
1
vote
0answers
17 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 ...
1
vote
0answers
38 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 ...
1
vote
0answers
30 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 ...
1
vote
0answers
53 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 ...
1
vote
0answers
98 views

Sensor Data Fusion with Orientation Sensors in 3D Euclidian Space

Preconditions For measuring the position of a mobile device in 3D space, I utilize two sensors with different characteristics that measure device orientation. Sensor A (a combined sensor of ...
1
vote
1answer
312 views

What are the keywords to find an algorithm that detects embossed text from a 3d model?

Currently I am doing an acadmic research about an idea which came into my mind lately. I have a 3d model and I want to extract embossed text .. anyone knows any papers? or if it is already proposed? ....
1
vote
1answer
175 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 ...