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Questions tagged [shape-analysis]

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Dynamic Time Warping in Matlab

I want to find specific shape in accelerometer data. I have specific shape signal and accelerometer data, I want to see if they are similar. I was thinking of using DTW algorithm, to see how similar ...
Dominykas's user avatar
  • 111
0 votes
0 answers
31 views

Algorithms for signal shape detection

I have a discrete signal shape which I am trying to find in accelerometer data. I want to compare at least two methods. First one is of course correlation, I calculate peak value of 10 experiments ...
Dominykas's user avatar
  • 111
0 votes
1 answer
32 views

How to detect faint, dense grains on an image?

I have a bunch of images similar to the following: As you can see, there are faint grains in a roughly ellipse-shaped area, along with a few bright ones. I need to identify the location and density ...
Neinstein's user avatar
  • 101
-1 votes
1 answer
60 views

How to determine the shape along which an object is moving [closed]

The object moves as it pleases and receives its GPS coordinates. How to determine which shape the object is moving along? For example, we accumulated 10 points, processed them and produced the result: ...
Natal04ka's user avatar
1 vote
0 answers
49 views

How to create a single variable describing these peaks?

First, I would like to point out that I am a complete outsider to the field of signal processing, so please bear with me and go easy on the jargon :) I nevertheless decided to post here, because I ...
Rumi P.'s user avatar
  • 111
1 vote
1 answer
1k views

Need a similarity metric that describes these two curve as highly similar

I have a large number of time series data and I need to be able to compare the similarity of the curves to a reference curve. The reference curve in question is shown in red in the figure, and I'd ...
gammapoint's user avatar
0 votes
0 answers
23 views

Sampling points on a face of a human body mesh

Is there a known shape analysis technique to sample points of a not necessarily naked human body mesh (more specifically the head part). The goal would be to randomly sample (uniform distribution) ...
user8469759's user avatar
1 vote
2 answers
399 views

Typical shape detection algorithms

Here is my target, given a set of consecutive discrete 1-d data points within a window. I want to know whether there are good algorithms to detect certain typical shapes of the signal in the window. ...
Adam's user avatar
  • 11
1 vote
2 answers
1k views

How to find position, scale and rotation of a known shape/contour in an image?

I have an image of an object. The image shows a high contrast outline of the object. It is guaranteed that the image shows exactly one object. The shape/contour of that outline is known. It is not ...
user11398730's user avatar
0 votes
1 answer
267 views

morphological processing : Hit or Miss shape detection

I am currently looking at shape detection for Hit or Miss. I am having a bit of trouble with the concept of the window that they have you to detect the shape. Up till now reading about hit or miss ...
james2018's user avatar
  • 173
0 votes
1 answer
39 views

How to change the shape of a function generator keeping the rate?

I'm making a sort of Envelope Function Generator. At the moment, I'm calculating only the the "rise" stage, which goes from 0 to 10 V; than, brutally, I back it to ...
markzzz's user avatar
  • 45
0 votes
2 answers
680 views

Selecting gradient orientation for Generalized Hough Transform while scaling and rotation is present

I am using this link to study Generalized Hough Transform. I will explain it briefly. In order to detect a shape, an R-table is created for the shape with $\phi$ indicating gradient orientation for ...
skr's user avatar
  • 283
1 vote
0 answers
79 views

Estimating the deformation of a printed label in an image

For a university honours project, I am developing an algorithm to read the text on nutrition labels. One difficulty I have encountered is how to 'flatten' the text in images of labels that are very ...
machfour's user avatar
  • 131
1 vote
0 answers
37 views

What is the most reliable shape representation for the purpose of detecting humans shapes?

The requirement of the algorithm is to detect human shapes. While the standard HoG or Harr cascade can be used, I am exploring whether the human shape - which primarily includes face+neck+upper-torso ...
Dipan Mehta's user avatar
  • 5,597
3 votes
0 answers
103 views

Video: Who crossed the finishline first?

Okey, so there was a boat race during the weekend. It was a very tight race, but a few minutes after the race, the green boat was declared winner. Given only this video images, how can they ...
user2453780's user avatar
1 vote
1 answer
68 views

How to recognise different symbols from their slope ? like (<,>,^) etc

i am trying to build a program in which user input a symbol with mouse and program recognise the symbol by saving mouse coordinates in array ,for this i have followed following steps: Firstly check ...
Chetan Pant's user avatar
1 vote
0 answers
215 views

What is a good algorithm, and framework, to calculate centres of gravity or mass (cog)? [closed]

I'd like to take an photograph, subdivide it into a tesselation, either of squares, or (ideally), hexagons, and then find the centre of gravity (or, if you prefer, centre of mass) of each cell of the ...
Peter Brooks's user avatar
1 vote
3 answers
292 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-...
Ben's user avatar
  • 220
0 votes
1 answer
821 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 (...
user6321's user avatar
  • 111
3 votes
1 answer
870 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 used?...
e.tadeu's user avatar
  • 33
0 votes
1 answer
380 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 ...
TheStrangeQuark's user avatar
1 vote
1 answer
348 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 (...
Il'ya Zhenin's user avatar
2 votes
1 answer
2k views

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 ...
Dole's user avatar
  • 348
2 votes
1 answer
159 views

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 ...
Laurent Duval's user avatar
1 vote
1 answer
3k 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 ...
Rafael Ruiz Muñoz's user avatar
0 votes
1 answer
1k 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-...
Rafael Ruiz Muñoz's user avatar
2 votes
1 answer
5k 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 ...
γιάννης's user avatar
2 votes
0 answers
2k 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 ...
γιάννης's user avatar
0 votes
0 answers
201 views

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 ...
user2069136's user avatar
0 votes
0 answers
165 views

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 ...
compephys's user avatar
  • 101
2 votes
1 answer
220 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 ...
Dzung Nguyen's user avatar
7 votes
2 answers
5k 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, \...
Hooked's user avatar
  • 509
4 votes
1 answer
1k 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? ...
krzych's user avatar
  • 317
2 votes
1 answer
139 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., ...
Karl's user avatar
  • 837