MATLAB (MATrix LABoratory) is a numerical computing environment and a fourth-generation programming language. Use this tag with care.. see excerpt.

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Find Chessboard Corners using RANSAC in Matlab

I have a question: I want to implement an algorithm to find chessboardcorners out of set of given points. I have an image where I already have all the chessboardcorners there are, but also some ...
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45 views

Created Matlab echo signal: Is it an actual “echo?” Or am I just manipulating the signal to make it seem like an echo?

This is just an outline of what I did (assume that all my dimensions fit): ...
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18 views

how to down convert an LFM signal in a simple way? [closed]

I'm learning about LFM signals. How do i down convert LFM in simple way and display on MatLab.
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11 views

how to visualize image segmentation using matlab

After clustering in image, I want to visualize the result. To do so, I first reshape an RGB image to 3*size. The result of BSMC is the set of indices after clustering. So I change the value at the ...
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32 views

What is purpose of correlation kernel? IIs it high pass filter or low pass filter?

I am research about correlation kernel and I have some questions that need your help. Let see the pp. 3302-3303 in the paper: Changyang Li, et al., Robust Model for Segmenting Images With/Without ...
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15 views

object detection in image in matlab

I have two images ; 1. Penstand with pens. 2. Penstand with no pen is there. Now my issue is, there is any code in matlab to know: There is no pen in Penstand OR There are pens in the Penstand. ...
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39 views

Train a Cascade Object Detector in MATLAB

I am trying to train a cascade object detector in MATLAB using the built in functionality from the Computer Vision Toolbox. I’ve taken 500 photo’s of the sole of my shoe. Every photo is taken from ...
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1answer
50 views

Finding phase angle via FFT

I am using the FFT to calculate the amplitude and phase of AC cos signal. Regarding amplitude it gives me an accurate result but I get wrong result for a phase: 6 degrees instead of 36 degrees. My ...
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2answers
54 views

Verifying channel response identity

If $x[n]$ is input signal, $y[m]$ is output signal, $h[m]$ is impulse response of the channel, then the following relation holds $\lvert Y(\omega)\rvert = \lvert H(\omega)\rvert^2 . \lvert ...
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1answer
82 views

What is correlation kernel and compare with gaussian kernel

I read a paper that said about correlation kernel that defined: $$W(x-y)=(α/1+d(|y − x|))$$ where $α = (\int(1+d(y − x)dy)^{-1}$, $(d(|y − x|))$ is spatial Euclidean distance from the central pixel. ...
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2answers
34 views

shifting sequences using Matlab

I'm reading this book and I came across a function to shift sequences. Mathematically, $$ y(n) = \{x(n-k) \} $$ if $m = n-k$, then $$ y(m+k) = \{ x(m) \} $$ ...
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50 views

Deriving finite impulse response for polylogarithm

As a part of my research i have to use the following z-transform in matlab 'filter' function so as to derive the convoluted signal from the original one. $$\frac{1}{{\rm Li}_{k}(z^{-1}e^{-b})}$$ ...
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11 views

Region splitting and merge

I am currently working on an image trying to apply split and merge technique. My main problem is selecting the best predicate for my image. Furthermore, because the objects in the image are quite ...
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1answer
54 views

Find B given A and impulse response of B/A

Here is a small MATLAB function that computes B in B/A given A and the impulse response h of B/A ...
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2answers
57 views

Denosing signal using soft and hard thresholding

Let us consider following code: fs=100; N=1000; t=0:1/fs:N-1; y=10*sin(2*pi*100*t)+0.5*randn(size(t)); plot(y) plot(t,y) I have applied following threshold ...
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1answer
65 views

how can I analyze a basic sine wave for its frequency phase and amplitude at a particular point in time in matlab

How can I analyze a basic sine wave for its frequency phase and amplitude at a particular point in time in MATLAB? Are there any tools to do that? I am trying to do additive synthesis of inharmonic ...
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3answers
93 views

Measuring audio Signal Similarities

i have recorded samples of lungs sound (person breath) signals from electronic stethoscope. how can i measure(in percentage) the similarity between two audio signals (lung sound), the general idea is ...
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21 views

denoising signal using DWT

let us consider following program for denosing signal using DWT ...
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1answer
42 views

I have run an FFT now want to get the mean value in the 8hz - 13hz range?

I have a matrix [66 x 100,000] (it's some EEG data, across 66 electrodes) and want to find the mean power in the 8-13hz range. How can I do this? I have so far: ...
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17 views

What data of images are given to kmeans clustering in matlab?

I am having 100 images in my database. I am using those 100 images as both training set and also test images. I have to make 5 clusters. I am using eigen faces (PCA) for feature extraction. What data ...
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1answer
50 views

An alternative algorithm for blob detection

Here's a sample image of my experiment which is to be processed for finding the information of all the blobs (centre, dimension etc.). Basically the image contains some noise, few bold lines, and of ...
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2answers
86 views

Image Reconstruction:Phase vs. Magnitude

Figure 1.(c) shows the Test image reconstructed from MAGNITUDE spectrum only. We can say that the intensity values of LOW frequency pixels are comparatively more than HIGH frequency pixels. Figure ...
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1answer
25 views

How can I run this MATLAB code snippet for the waveform synthesis? [closed]

Can you give me an example for this MATLAB snippet to generate sine wav with specified phase? ...
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1answer
24 views

How to find the frequency response of a communication channel from input and output symbols' functions in MATLAB?

I want to find the channel frequency response of a digital communications system. I have the functions of the input symbol (a triangle) and the output symbol - a distorted triangle: $$\dfrac{1}{1 + ...
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2answers
90 views

How to calculate step and impulse response at multiple sampling rates

I'm struggling with a basic concept. Suppose I have a system $y(t)=e^{-at}u(t)\ast x(t)$ and I want to plot impulse response and step response using Matlab conv() function at various sampling rates. ...
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1answer
47 views

Simulate a pulse of specific power

Suppose you produce a pulse x in discrete samples of duration dt each (e.g. in Matlab) according to a function. I was given some ...
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1answer
95 views

How do you change pitch with wavelet transforms in MATLAB?

I'm trying to increase the pitch of a wav file using MATLAB. (I don't expect it to sound very good, but I'm trying to figure out how wavelets in MATLAB work.) Here's what I'm doing: ...
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1answer
33 views

How are phase values able to capture motion from video?

I know that the phase spectrum contains most of the structural information about the image importance of phase. But I want to know more about importance of phase spectrum related to video signals. I ...
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1answer
51 views

Improve spectrogram appearance using windowing functions MATLAB

I have a program which plots data obtained in a NI USB DAQ realtime to a spectrogram plot using the surf function. I'd like to improve the appearance of the plot using some sort of windowing function. ...
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36 views

Is it possible to decompose an image into basis images using MATLAB?

I have read that: Using Fourier decomposition any arbitrary image can be represented as summation of orthogonal basis images. I want to see the basis images for any image say Lena or ...
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2answers
91 views

How do I manually plot the frequency response of a bandpass Butterworth filter in MATLAB?

I have code like below that applies a bandpass filter onto a signal. I am quite a noob at DSP and I want to understand what is going on behind the scenes before I proceed. To do this, I want to know ...
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1answer
45 views

FIR-Decimation and Low-pass filter (taps vs number of input points vs number of decimation stages)

I am new to digital filters and trying to understand parameters behind them. Scenario I am trying to get DC value from signals sampled at 100kHz sampling rate. such high frequency is used due to ...
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32 views

Rejecting a particular frequency band using DWT

My problem is as follows: I decompose the 4th level detail coefficient of an ECG signal further up to the fourth level and I want to reject the approx. coeff. at this level, which corresponds to the ...
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2answers
165 views

Removing transients in highpass filtering with MATLAB

I've made a simple first order IIR highpass filter with a zero at z = 1 and a pole at z = 0.9. Its frequency response looks like this: Now, I filter a DC signal using this filter. Here's the MATLAB ...
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1answer
63 views

How do I generate sound using MATLAB?

I want to generate and play sound for tones with frequency 100 Hz and 200 Hz for 10 sec and 5 sec respectively using MATLAB with sampling frequency equal to 20500 Hz. Also I want to plot their ...
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1answer
53 views

How do we distinguish between Image Recognition,Detection and Segmentation?

I am reading image processing book.while reading i am getting terms like image detection,image recognition and image segmentation. it seems that all above terms are one and the same.i am totally ...
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1answer
80 views

How can I load a wav file, split it in frames, apply different filters do different frames and then recombine the filtered frames into a single file?

I'm working on a wav audio file using MATLAB. What i would like to do is: load a wav file and divide it into frames of the same dimension filter these frames (with a different filter for each ...
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1answer
49 views

MATLAB rand and C++ rand() [closed]

I am trying to port a MATLAB code into C++ and found the usage of rand in MATLAB. Is MATLAB's rand function and C++ ...
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1answer
58 views

how to read full input signal with STFT in matlab

Please help! I am trying to figure out why in the code i have below my input signal is being cropped but in the code I have a full signal created. The white noise created is 5000 samples for the right ...
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2answers
76 views

Detecting and isolating part of an image

I'm working with cross-sectional CT scans of the leg using matlab's image processing toolbox. Part of what I'm attempting to do is to automatically isolate the leg in any image, which requires ...
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27 views

Why does the Stationary Wavelet Transform shift this image?

I am running a stationary wavelet transformation on a brain image. I can't understand why it shifts with each level so that the image is no longer centered. You can see that the X component shifts to ...
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2answers
114 views

How to design a filter with a certain magnitude response

I am trying to design a filter whose magnitude is the same as that of a given signal. The given signal is wind turbine noise, so it has significant low-frequency content. After designing the filter, I ...
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2answers
161 views

Is it possible to convert from 2D to 3D form?

I have captured car positions at different frames from the video. Suppose car's(e.g.left side car which is coming towards us in the images) centroid at video frame1 is P(x1,y1) and Q(x2,y2) at video ...
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1answer
26 views

How to get the conjugate symmetry of the complex matrix using MATLAB? [closed]

How to get the conjugate symmetric of the complex matrix using matlab
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1answer
86 views

MATLAB filter not attenuating enough

Currently, I'm working on removing 50 Hz power line interference from an ECG signal. Before trying out notch filters, I decided to try out a simple lowpass filter with a cutoff less than 50 Hz. Here's ...
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14 views

Identifiability for Time Invariant State Space Models

Kevin Murphy's Kalman Filter toolbox (for Matlab) contains an example where it's the fact that the state space system in not identifiable causes problems. I include the example in it's entirety but ...
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36 views

Calculate cutoff frequency of filtered data

I am processing data which was put through a low pass filter at some point. Looking at the FFT, I can see that it is less than the Nyquist rate. I am trying to filter another set of data so that the ...
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2answers
62 views

Gaussian Blur In Matlab and Connection to Image Resolution

I am calling fspecial in matlab to create a Guassian blur of an image. For example, ...
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1answer
74 views

Segmentation and Labeling of White Blood Cells

I am trying to segment and label white blood cells from this image: Using K-Means I managed to segment most of what I wanted: But as you can see, there are some cells connected to each other which ...
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59 views

No proper kmeans clustering of images in matlab

I am having 1200 face images in my training set.There are 2989 test face images. I am using eigen faces (PCA) for feature extraction. I am using kmeans clustering. I even tried all 2989 test face ...