# Tagged Questions

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13 views

### Non-symmetrical lemniscate curve parameterization

I'm trying to fit a function to data points. The data generally resembles a butterfly/lemniscate shape, see drawing. The problem is that the shape in my data can be rotated, skewed and/or non-...
36 views

### Poster detection in OpenCV?

I'm really new in image processing, so please sorry I'm a newbie. I tried to use the squares.cpp for detecting posters (since they usually are rectangles) without using expensive feature detectors (...
72 views

### How to calculate particles sizes for spheric particles with overlapping and superposition? (Example image included)

I'm trying to automatically calculate particles sizes histogram for images like this one: Common threshold and segmentation doesn't seem to work. What filters and algorithms do you suggest to be ...
23 views

### 2D Procrustes transformation

I have 2 sets of point that belong to 2 different images. These points are defined as: $(x_i, y_i)_{_i=1,...,N}$ and $(x_i', y_i')_{_i=1,...,N}$ All these points are located on their corresponding ...
47 views

### Shape of Kaiser windowing function FFT response

I'm trying to determine the shape of the FFT response of a signal which had a kaiser windowing function applied to it. What I mean by this is if the shape is a normal bell curve or a Lorentzian ...
40 views

### How to efficiently calculate points of intersection of a straight line and a contour?

Ex. I have an image, let's say 100x100 pixels with some shape on it. And a set of straight lines that are passing through origin located at some point of image, for example origin located at point (...
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### Possibilties of chebyshev polynomial waveshaping

When talking about harmonic distortion, or more specifically waveshaping, we say the order of distortion, can be solved from the equation: $x^n$ Where n is the order of distortion. To my knowledge ...
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### Processing and feature extraction from very short signals

I recently have encountered very short time signals (from three to 12 samples, typically). They appeared for instance in small time frames in engine simulation that should be extrapolated in a robust ...
499 views

### Fourier descriptors: trying to classify objects

Describing my background: I have around 33 items labeled. For example, 3 pictures of the contour of a basil plant, 4 pictures of the contour of earphones, 7 of a mug, etcetera. I'm trying to ...
404 views

### Shape recognition, hough transform

I'm trying to match a picture saying "this is ducks, this is towers" by giving votes from the hough transform of a picture. I've found this article http://ttic.uchicago.edu/~smaji/papers/hough-...
2k views

### Zernike Moments' implementation in OpenCV

The reason why Hu moments were implemented in OpenCV and why Zernike moments were not implemented is looking like their performance similar as stated in this paper. As stated in the paper Zernike ...
699 views

### MPEG-7 descriptors' implementation in OpenCV

I'm looking for implementation of MPEG-7 descriptors which are compatible with OpenCV's recent versions and containing "region-based shape descriptor ART(Angular Radial Transformation)". I ...
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### Optimal way for curve detection

I am totally new to image recognition and image analysis and have a project concerning detecting a smooth curve on a uniform background (white/black/any color) and then be able to follow this curve ...
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### How to estimate gradient orientation?

I have a general task of discriminating images of shaded cylinders that significantly vary in 3d orientation, and almost insignificantly in size and shape. I have treated it as a regression problem ...
101 views

### Classifying 2D shapes by the smoothness of their boundaries

I'm doing image analysis, and I want to classify smooth objects (has smooth boundaries) from non-smooth objects (has zigzag-like boundaries). Which feature should be fed into ML framework? What are ...
2k views

### How to fit an ellipse to 2D data

I'd like to find the "best" fit of an ellipse to contiguous, possibly concave shapes such as: What have I tried? I thought that one could assign the direction of the major and minor axes \$\vec a, \...
635 views

### Topological skeleton matching techniques

What are the most common and best topological skeleton matching techniques? Suppose I have skeletonized object and corresponding 2D model of this object. What are the next steps to match pattern? ...
108 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., ...