Questions tagged [image-registration]
Image registration is the process of transforming different sets of images to one common coordinate system.
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Numerical computation of the derivative of a curve valued in $\operatorname{Diff}(\mathbb{R}^2)$
Assume we have a (discretized) sufficiently smooth curve $\alpha : [0, 1] \to \operatorname{Diff}(\mathbb{R}^2)$. Further assume that this curve is generated via a large deformation diffeomorphic ...
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Registration of segemented medical images
I’m looking to register images based on probability maps (or possibly the binary images) resulting from segmentation of medical images of blood vessels with a circular FOV using python.
Are there any ...
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22 views
Calculation of eigendecomposition of a signal in its Fourier domain?
I want to find the eigendecomposition of a 3-dimensional discretely sampled signal $X$, where each sample $X_{i,j,k}$ is treated as a vector $\langle i, j, k\rangle$ (with the origin at the middle of ...
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1answer
76 views
Derivative of mutual information in EMMA algorithm for image alignment
This question refers to the paper 'Alignment by Maximization of Mutual Information' by Paul Viola and William M. Wells III, published by International Journal of Computer Vision, 24(2) pg 137–154, ...
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How does PIL.QUAD work internally?
I am working on a computer vision problem involving some basic transformations and could use your help.
Input image:
Transformed image
I understand that we take this quadrilateral and tilt it and ...
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1answer
61 views
Whats the difference between spatial and temporal resolution?
Iam trying to understand how super-resolution works. But i think i have not understood correctly the difference between the optical resolution (spatial resolution?) and the resolution i know from a ...
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2answers
82 views
Digital Image Processing Textbook with Specific Topics
I am looking for a Digital Image Processing and analysis textbook, but there are specific topics that I would like the book to cover. Among other topics, I would like it to include a discussion of:
(...
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77 views
Understanding performance of Lucas Kanade Iterative Image Registration Technique
I am reading the paper:
Lucas, B. D., & Kanade, T. (1981). An iterative image registration technique with an application to stereo vision.
I am having some trouble understanding section 4.3 ...
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103 views
What does “invariant to bias and gain changes” mean?
Reading this paper, about the ECC criterion (which is included in opencv3), In section 3, the following is stated, with regard to the following equation:
(4) $\left\|\frac{i_r}{\left\|i_r\right\|} - \...
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1answer
76 views
Homography for (small baseline) Stereo Image Registration
If the distance between two stereo cameras (baseline) is much smaller than the distance to the geometry, is it possible to align the resulting two stereo images using a homography?
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30 views
Does Mutual information utilize spatial information to calculate image similarity?
To calculate images similarity based on Mutual Information (MI), histogram and join histogram is required. In the literature, there are 2 contradict opinions about MI operation. 1. MI does not utilize ...
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1answer
89 views
Transforming Non-Uniformly Sampled Image onto Rectangular Grid
I have an image and associated latitude and longitude matrices. So I know the latitude and longitude of every pixel. However, due to the camera orientation, the image is skewed and thus the latitude ...
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434 views
Affine Transformation for matching 2D point sets
I have two sets of 18 corresponding 2D points. These coordinates represent the main joint points of a human body, describing the "human pose".
I want to decide if these two poses are similar/have the ...
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97 views
Obtaining Subpixel Resolution for Video Processing in Python
I am working on a video processing application to calculate distance between two points using opencv
Specs :
Linear Pixels - 1600.
FOV - 100 mm
Resolution per pixel using above data : 62 micron
...
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1answer
1k views
Affine transformation without imwarp
I program function to calculate the overlap area between 2 images (which is called fixed and floating) after transformation but it takes much time and it's complex for me to combine more than one ...
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0answers
60 views
Images similarity measure using j-divergence
I need to reproduce the result of Xu, Xiaocong, et al, 2016 paper . Mutual information code already was done and work fine. can anyone help me to write Jeffrey’s divergence code? because the I use ...
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1answer
97 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 ...
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1answer
488 views
Finding the four corners of each quadrilateral shapes in an image
I am working on some image processing application using Matlab. The image after segmentation will look (more or less) like the figure below.
Now I want to find the four corners of each shape to crop ...
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1answer
320 views
Parallel Processing Gigapixel Images
Parallel programming is often used to accelerate image processing methods (e.g. Eklund et al., 2013); however, there doesn't appear to be the same level of discussion about using parallel processing ...
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1answer
578 views
Estimates sub-pixel shift directly in phase region
I try to estimates shift estimation directly in phase region, by following the proposed method in this Sub-pixel Shift Estimation of Image based on
the Least Squares Approximation in Phase Region by ...
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46 views
Get slopes of integer shift of an image in radians
I tried to reproduce the result from this paper, However I'm stuck at the Section III of the paper which involve integer shift. Two images which their phase correlation $\theta(k_1,k_2)$ was ...
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1answer
558 views
Estimating scaling and translation between two consecutive temporal images
I have two camera images taken from a camera mounted over a vehicle at time $t$ and $t+1$. I need to estimate the scaling and translation in the images in spatial domain itself so that information ...
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1answer
137 views
How is “Joint class histogram” algorithm deploy using Matlab?
Image registration and image retrieval depend on image similarity measure to find mutual information between 2 images. Using histogram, joint histogram, and joint class histogram we can find the ...
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1answer
154 views
Using Local Binary Pattern for finding Homography between two Image
Can LBP be used to find the homography between two images with similar field of view for Image Registration?
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2answers
600 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 ...
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1answer
619 views
Best way of segmenting veins from arm?
I have done fews researches and found out approach such as
multiscale and
region growing,
that could be used of extracting forearm veins.
However, I tried to use frangi filter and Figure 1 is the ...
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2answers
3k views
Practical advices for applying phase correlation in image registration task
I'm using OpenCV to detect shift between 2 images, here is sample code (based on cv::phaseCorrelate function):
...
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1answer
121 views
Feature matching of images without corners
I am trying to stitch aerial images using feature-based registration. Most image pairs are matched well, such as this:
Others are not matched due to lack of common features:
As you can see, the ...
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1answer
91 views
Automatic landmarks on images of hands
Problem statement
I am starting a project soon where I need to create a method to automatically create landmarks on a set of images of human hands. I do not have a sample image but the images are ...
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1answer
3k views
How to achieve image straightening as cam scanner does?
Is it possible to achieve image straightening as cam scanner does
I mean selecting a non-rectangular region and converting it to a rectangular region as an image. I can only do re sizing and crop of ...
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1answer
429 views
Are there any template matching / optical flow algorithms for large image displacement?
I had some success with feature-based methods for image registration, but these methods are sometimes unsuitable (e.g. images containing repetitive patterns, very low contrast, low texture, no edges/...
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2answers
830 views
Is there a difference between Image Alignment and Stereo Rectification for stereo correspondence or matching?
As far as I know,
Image alignment just finds the best fit given two images of the same scene.
Whereas Image rectification, with regards to stereo vision, warps the images so that the epipolar lines ...
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264 views
Image registration dataset
I am searching for global purpose Dataset to test some image registration algorithm.. May you please give advice?
I am looking for color or gray-scale dataset. I prefer it not to be medical or ...
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1answer
845 views
Camera calibration vs. registration
Suppose I have two cameras, c1 and c2 that are securely installed and do not move. What I want is a matrix T, that takes a pixel of an image from camera c1 and calculates the according pixel in an ...
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1answer
259 views
Image Registration
I am trying to register two images of daily objects from different viewpoints (5 to 20 degrees angle). I have been reading about image registration and I feel like the best way to go is using Feature-...
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76 views
Understand about registration between spatial prior and original image
I am working in level set/active contour method using spatial prior information . The main papers that I am focusing:"Automatic segmentation of neonatal images using convex optimization and coupled ...
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1answer
100 views
mathematical transfer for different camera attributes
Suppose I have two camera shoots(Image1,Image2) for the exactly same scene (each pixel is alignment correctly) but from different cameras and different light conditions. I want to remove this light ...
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2answers
158 views
Transformation of coordinate set
I have a problem in which i have a video that was taken from the side of the subject, something like this
and i need to transform the coordinates of the subject to be as if the photo was taken from ...
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2answers
640 views
How to transform or distort or skew a rectangular image to fit arbitrary quad
I have a rectangular image which need to transform so the image fits an arbitrary convex quad. Easy? Except I have an important constraint, the features on the original image must maintain their ...
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1answer
270 views
Image registration / fusion optimal similarity metrics
I have a theoretical question about optimal similarity metrics for comparing data sets.
In reading this linked paper, pp. 488-489 [1], I read the following 2 interesting statements. On page 488:
...
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2answers
158 views
How does 3D Time-of-Flight (TOF) camera work?
This is my first post in this forum! So Point me if anything is not clear!
I want to know how TOF camera works? So I've done Google & read some nice explanation about How Phase difference between ...
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2answers
188 views
Background Removal and Object Tracking - Track Fish Jumping Out of the Water
0 down vote favorite
I am totally new to Image processing. I just started my Master thesis in the area of Computer vision and Machine learning. My background is Informatics. Now, my first task is to ...
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2answers
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What exactly do we do in non-rigid registration?
I found many readings on Non rigid registration, also saw some videos but didn't find a clear explanation anywhere.
What I understood is the following
Rigid ...
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0answers
995 views
Image Registration C#
I'm trying to fuse different images of the same scene which each image have a different focus. I've been told that first I have to perform an image registration to the images.
Right now, the result ...
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0answers
165 views
Detecting blades of a wind turbine
I have many close-range images of a single wind turbine blade (taken from different positions, same angle):
I need to separate the blade image from background like this:
The problem arises in image ...
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1answer
3k views
Base line detection of text lines
I came across various works in the literature of document analysis addressing the problem of detecting base lines in multi-oriented texts. But no amount of search could give me satisfactory answer to ...
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1answer
2k views
Image Registration and optical flow
Image registration algorithms can be classified into intensity-based and feature-based algorithms, I want to know When and Why should i choose intensity or feature based algorithm?
another question ...
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1answer
813 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 ...
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1answer
584 views
Normalized cross correlation via FHT - how can I get correlation score?
I'm using the 2D Fast Hartley Transform to do fast correlation of two images in the frequency domain, which is the equivalent of NCC (normalized cross correlation) in the spatial domain.
However, ...
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2answers
234 views
image correlation without fft
I want to stitch 2 images by crosscorrelation measure, but I don't want to use fft.
I tryed this but something seems to be wrong.any suggestions?
...
