# Santhana Raj

### Path Partner Technology

https://sites.google.com/site/santhanarajarunachalam/

Professional Interests: Signal Processing, Automotive Radar, Condition Monitoring of rotating equipment.

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**Content Feed**

FFT of sensor data

You are getting mirror images. except that matlab's FFT results are different from what you have read in your books. Normally FF...

5 years ago | 2

find commun neighbor of matrix

From my understanding of nodes, A =[0 1 0 1; 1 0 0 0; 0 1 0 0; 1 0 1 0;] h=zeros(4); for i=1:4 [~,H]=find(A(i,...

5 years ago | 0

Find the maximum value on each color dimension (red, green, or blue) and plot a circle using that color. There may be more than one pixel with a maximum value; if so, pick one pixel at random.

The property color in plot function takes input between 0 to 1. While your max color values are >1 usually. Try the below one: ...

5 years ago | 0

How to set different y limits for multiple subplots?

Your mistake is to use the function name as a variable. "min" The first loop will work. where you use the min function to get...

5 years ago | 2

How to display the name of my ODE used, as figure title?

The below code works in 2017a: figure('Name','SolverName','NumberTitle','off')

5 years ago | 0

Sum of elements per hour

try this: sum(M(find(M(:,1)=='1-Oct-13' & M(:,2)==1),3)) Repeat this in a for loop, and you can generate N.

5 years ago | 0

What is internal math of the pointsToWorld() function?

PointstoWorld function does the conversion of image points to the real world representation. The real world is some times called...

5 years ago | 0

When I use matlab neural network toolbox, what is the cost function of the training?

The default cost function is Cross Entropy, if am not wrong. You can check doc patternnet to get more details

5 years ago | 0

Data not being filtered out by threshold

If you see the help of diff, it says: diff(X), for a vector X, is [X(2)-X(1) X(3)-X(2) ... X(n)-X(n-1)]. So, in your case, ...

5 years ago | 0

Is there a way to plot a confusion matrix of the cross validation results?

I am not aware of any method to plot confusion matrix. But usually I calculate the precision and recall from the true positives...

5 years ago | 0

How create string like this: word+number+word with number=num2str(x)

x=2; y= ['I have' num2str(x) 'dogs'];

6 years ago | 2

| accepted

2d plot of a function with two variables

No.You need not. generate vectors of x and t. Then implement the function for y. Use mesh to plot result. Remember to use the...

6 years ago | 0

how to calculate the classification accuracy in neural network toolbox?

There are various parameters that can and are used in different classification algorithms. Take a look at this wiki page: <ht...

6 years ago | 0

Error using xlsread (line 260)

<https://in.mathworks.com/matlabcentral/answers/305976-error-using-xlsread-line-249-excel-worksheet-could-not-be-activated>

6 years ago | 1

| accepted

Problem subtracting and adding a value to a textbox using a popupmenu and push buttons

The GUI workspace handles variables differently than a normal function. The function subtract_callback has its own workspace and...

6 years ago | 0

GUI with guide, statements around the functions

U can use statements 'around' callback functions. You have to be more clear on this. Since you are new to GUIDE, I would advi...

6 years ago | 0

Loading in png file that is black

By saying that the image appears in black, do you mean that the image is still visible but the image is in grey scale?? The belo...

6 years ago | 1

| accepted

Loading in png file that is black

The problem might be due to improper scaling or the type of image. Use imagesc

6 years ago | 0

why we need scale in implementations of FFT?

This is because the FFT equation implmented by Matlab is little different from your textbook equation. Usually in a engineeri...

6 years ago | 1

I want to solve this equation and plot it but lot of errors are coming kindly help

Matrices multiplication can be element by element or vector multiplication. For element by element, which I assume you want, th...

6 years ago | 0

How can I create the matrix in the photo?

Try making BNdog=[4 7]; instead of [4 4]

6 years ago | 0

Help with a for-loop of an array of iterative matrices

Consider one set of your code: col1 = rep1(:,1)'; col2 = rep1(:,2)'; col3 = rep1(:,3)'; col4 = rep1(:,4)'; col5...

6 years ago | 0

how to do curve smoothing in real time?

Try applying a moving average filter or otherwise called a box filter.

6 years ago | 0

numbers in random positions on a zero matrix

Start with the function randi(4). it generates random integers. It doesnt give 0, so you can generate with a max of 4 and subtra...

6 years ago | 0

Time shifting property DTFT

I suppose this is what you want to do: clc, clear all, close all; x=rand(1,21);n=0:20; k=0:20;w=(pi/20)*k; X=x...

6 years ago | 0

matlab 2017a takes 10 minutes+ to initialise

I had a similar problem. The reason in my case was because Matlab, due to some unknown reason, was taking too much time to locat...

6 years ago | 0

Importing / Xlsread: How to replace unknown character?

Instead of using xlsread, use readtable. one of its options is fileEncoding. I am sure it can read Swedish, but you can explo...

6 years ago | 0

How to design a position control in C using Matlab

For PID equation, you have to find the previous error values also. Foe example, for integral action, sum of all previous errors...

6 years ago | 0

Performance comparison plotting for different Back propagation algorithms

You have to calculate the mean square error and time taken. You can use (t-y) to calculate the error and tic/toc to calculate th...

6 years ago | 0

| accepted