Anton Semechko

128 total contributions since 2012

Professional Interests: Signal/medical image processing, computational anatomy and biomechanics

Anton Semechko's Badges

Submitted

Suite of functions to perform uniform sampling of a sphere
Toolbox for generating uniform sampling patterns and decompositions of a unit sphere

2 maanden ago | 22 downloads |

Submitted

Fast fuzzy c-means image segmentation
Segment N-dimensional grayscale images into c classes using efficient c-means or fuzzy c-means clustering algorithm

3 maanden ago | 46 downloads |

Submitted

Rigid body parameters of closed surface meshes
Fast computation of exact rigid body parameters of closed triangular surface meshes using divergence theorem

3 maanden ago | 4 downloads |

Submitted

Detect outliers in multivaraite datasets
Compute robust estimates of mean and covariance, and flag potential multivariate outliers

3 maanden ago | 33 downloads |

Submitted

Exact minimum bounding spheres and circles
Compute exact and approximate minimum bounding spheres/circles of 3D/2D point sets

4 maanden ago | 21 downloads |

Submitted

DecimatePoly
Simplify a 2D closed contour/polygon to within user-defined boundary offset tolerance

4 maanden ago | 4 downloads |

Submitted

Exact histogram equalization and specification
Perform exact histogram specification or equalization of 2D grayscale images

4 maanden ago | 11 downloads |

Answered
PCA on high dimensional data
A 13952736-by-104 data matrix (with observations along rows and variables along columns) will take up 13952736*104*8/2^30 =...

ongeveer een jaar ago | 0

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Fitting scattered data to multiple cosine functions
Below is an example where I use brute-force search to find an optimal set of sinusoid parameters that best fit an unorganized da...

ongeveer een jaar ago | 1

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imshow() not working
Use syntax: imshow(im,[]) when im has non-integer format. Or just do this: im = imread('/MATLAB Drive/My Project/ima...

ongeveer een jaar ago | 0

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Answered
distance of points to points calculation
Use <https://www.mathworks.com/help/stats/knnsearch.html#namevaluepairarguments 'knnsearch' function>. For example: [idxA,D_...

ongeveer een jaar ago | 0

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Answered
How is the number of bins chosen with the auto binning algorithm in histcounts?
'histcounts' first estimates width of the histogram bins using 'scottsrule': rawBinWidth = 3.5*std(data)/(numel(data)^(1/3...

ongeveer een jaar ago | 0

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Barycentric Coordinates of a spherical triangle
This can be done in four steps: 1) Compute linear transformation (T) that maps triangle A to its counterpart B on the sphere....

ongeveer een jaar ago | 0

Answered
How do I use a .lut file (or the equivalent in MATLAB) to reference pixels in a grayscale image and assign them new values for pseudocoloring based on the LUT?
There is a Matlab function that maps gray values to RGB values using custom made look-up-tables. Its called 'ind2rgb': <https://...

ongeveer een jaar ago | 0

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Transformation of the complex plan: Conformal Mapping
Modified code ('conformal_map_demo') is attached below. In principle, this piece of code should should allow you to visualize an...

ongeveer een jaar ago | 1

Answered
How to sum each column element of one matrix with all column elements of another matrix?
Do kron([a b;c d],[1;1]) + kron([1;1],[i j;k l]) Here is an example using symbolic expressions syms a b c d i j k l...

ongeveer een jaar ago | 0

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Answered
Generating sets of non repeating random numbers
Here is an example: S=reshape(randperm(40),[],4); All elements in S will be in the range [1 40] and unique. From this it...

ongeveer een jaar ago | 1

Answered
3D plane plotting restricted by 3 points
Equation of a plane is determined uniquely by any 3 (noncollinear) points lying on the plane. Based on your question, it sounds ...

ongeveer een jaar ago | 0

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Could anyone help me with extracting similar features( to be used as corresponding points)in two images which need to be registered together?
Hey, Poupack, here is <https://drive.google.com/open?id=1SRXAVFkbHPfQ9jLjsFL-fkfWz2KrKJAO link> to a function ('pairwise_his...

ongeveer een jaar ago | 0

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Answered
How can I extract the slices of a 3D matrix in x-direction from a 3D matrix?
Suppose you have G, which is a Y-by-X-by-Z 3D array, then i-th xy slice: G_yx=G(:,:,i); % Y-by-X array i-th xz slice...

ongeveer een jaar ago | 1

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Multivariate nonlinear regression model fitting
If the function you are trying to fit is linear in terms of model parameters, you can estimate these parameters using linear lea...

ongeveer een jaar ago | 1

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How to export 3D spheres (3D plot) generated in Matlab to ANSYS or Abaqus. ?
The builtin 'ellipsoid' and 'sphere' functions produce bad quality meshes (in terms of element shapes and connectivity of the ve...

ongeveer een jaar ago | 0

Answered
Is there a way to open music and play it?
Yeah, there is a way. Here is an example: % Get sample audio file from the web [y,Fs]=webread('http://www.worldnationala...

ongeveer een jaar ago | 0

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Answered
How do I compute the maxpool of a image? Let us say stride of 2,2 on a mxn matrix?
Here is an example: % Sample image im=imread('cameraman.tif'); % sample image % 4 pixels comprising non-overlappi...

ongeveer een jaar ago | 0

Answered
How do I plot a plane that has points of different values?
Actually, based on the sample picture you provided, you have a total of 17x21 grid points, and total number of cells in the g...

ongeveer een jaar ago | 2

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Answered
Obtain Number of Pixels in Area Around Binary Image Object
To distinguish between points/pixels inside the ellipse vs. those outside, you need to know parameters of the ellipse. Here is a...

ongeveer een jaar ago | 0

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Answered
subplot with multiple images - Pulling images from API into one figure
Hey, Vincent. Here is an example: [IM,IM_all]=PubChem_compound_image_stacking_demo; <</matlabcentral/answers/uploaded_fi...

ongeveer een jaar ago | 0

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How do you generate a Cumulative Histogram on R2014a?
Here is an example of how to use 'histcounts' and estimate percentiles: % Simulate data; N samples from standard Guassian P...

ongeveer een jaar ago | 0

Answered
I want to plot a numerical integral in a mesh which is dependent of x and y. How can I do this?
The integrals in your equation can be evaluated analytically. Here how you can visualize C(z1,z2) and C(z1,z1): L = 20...

ongeveer een jaar ago | 0

Answered
Interpolating scattered 3 dimensional data
Hi, Markus, here is a demo of how to perform linear interpolation of vector fields on a unit half-sphere: half_sphere_inter...

ongeveer een jaar ago | 1