128 total contributions since 2010

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

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 =...

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 =...

25 days ago | 0

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Answered

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...

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...

1 month ago | 1

| accepted

Answered

imshow() not working

Use syntax: imshow(im,[]) when im has non-integer format. Or just do this: im = imread('/MATLAB Drive/My Project/ima...

imshow() not working

Use syntax: imshow(im,[]) when im has non-integer format. Or just do this: im = imread('/MATLAB Drive/My Project/ima...

1 month 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_...

distance of points to points calculation

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

1 month 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...

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...

1 month ago | 0

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Answered

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....

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....

1 month 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://...

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://...

1 month ago | 0

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Answered

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...

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...

1 month ago | 0

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...

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...

1 month 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...

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...

1 month 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 ...

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 ...

1 month ago | 0

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Answered

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...

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...

1 month 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...

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...

2 months ago | 0

| accepted

Answered

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...

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...

2 months ago | 1

| accepted

Answered

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...

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...

2 months 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...

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...

2 months 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...

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...

2 months 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...

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...

2 months ago | 2

| accepted

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...

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...

2 months 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...

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...

2 months ago | 0

| accepted

Answered

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...

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...

2 months 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...

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...

2 months 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...

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...

2 months ago | 1

Answered

Taylor expansion with 2 variables

Taylor's theorem generalizes to multivariate functions. Formula for third order approximation of a bivariate function can be fou...

Taylor expansion with 2 variables

Taylor's theorem generalizes to multivariate functions. Formula for third order approximation of a bivariate function can be fou...

2 months ago | 0

Answered

Troubleshooting Isosurface Rendering Code

Make sure that your 'Image' variable is cast as a double and actually has a zero level-set. Here is an example: % Samp...

Troubleshooting Isosurface Rendering Code

Make sure that your 'Image' variable is cast as a double and actually has a zero level-set. Here is an example: % Samp...

2 months ago | 0

Answered

How to find distance between two nodes? including the nodes.

Download <https://www.mathworks.com/matlabcentral/fileexchange/5355-toolbox-graph graph processing toolbox> from FEX. Use Dijks...

How to find distance between two nodes? including the nodes.

Download <https://www.mathworks.com/matlabcentral/fileexchange/5355-toolbox-graph graph processing toolbox> from FEX. Use Dijks...

2 months ago | 0

Answered

how to deal with large polygons ?

Check out 'DecimatePoly' function on FEX: <https://www.mathworks.com/matlabcentral/fileexchange/34639-decimate-polygon> Inclu...

how to deal with large polygons ?

Check out 'DecimatePoly' function on FEX: <https://www.mathworks.com/matlabcentral/fileexchange/34639-decimate-polygon> Inclu...

2 months ago | 1

Answered

Detection of line segments and length

It doesn't look very clear to me, and is maybe the reason why the Hough transform isn't generating the output you want. For exam...

Detection of line segments and length

It doesn't look very clear to me, and is maybe the reason why the Hough transform isn't generating the output you want. For exam...

2 months ago | 0

| accepted

Answered

Can I recover only the diagonal elements of A' * B with SVD vectors of A and B?

i-th diagonal of A'*B equals dot product of the i-th columns of A and B. Here is a demo showing how to recover only the diagonal...

Can I recover only the diagonal elements of A' * B with SVD vectors of A and B?

i-th diagonal of A'*B equals dot product of the i-th columns of A and B. Here is a demo showing how to recover only the diagonal...

2 months ago | 0

Answered

How to have automated thresholding to deal with disparities between images

Here is a demo that uses automatic multi-level thresholding to isolate the disks: im_files={'https://www.mathworks.com/matl...

How to have automated thresholding to deal with disparities between images

Here is a demo that uses automatic multi-level thresholding to isolate the disks: im_files={'https://www.mathworks.com/matl...

2 months ago | 1

| accepted