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I'm trying to implement SIFT algorithm.
After I found the min/max points in DOG images I need to find the real min/max subpixels by taylor exapnsion:
$$
\begin{equation}
D(\mathbf{x}) = D + \frac{\partial D^T}{\partial \mathbf{x}}\mathbf{x} + \frac{1}{2}\mathbf{x}^T\frac{\partial^2D}{\partial \mathbf{x}^2}\mathbf{x}
\e... |
First of all excuse me for asking a seemingly vague question. But i am going nowhere in the problem i am trying to solve.
I am working on a powerline communication system where i need to upconvert in 28-56Mhz range and later downconvert it to 0-28Mhz so that it works in the coupler range.So i need to design a band pas... |
I am trying to analysis a system by Fourier Transform. my system has 3 dominant modes. (1,0.05) (0.51,0.01),(0.46,0.01) the pairs are defined as (freq,damping_ratio)
I've got those result with eigenvalue analysis.the system contains 3 signal.so these frequency[1,0.51,0.46] must be find in these three signals too. so I'... |
I have some basic understanding of signals and convolution. As far as I know it shows the similarities of two signals. Could I get some explanation in plain English of:
what are the linear and circular convolution
why they are important
practical situation where they are used
|
I'd like to have your overview if what I'm doing is OK.
I need to plot the BER vs Eb/No. So the noise power which I should generate should be related to Eb/No.
bits are encoded into 1/2 rate encoder.
the output of the encoder is converted to +1 and -1 symbols
symbols are oversampled by OS ratio.
the oversampled sym... |
I just studied about SURF and I'm going for its implementation, but I still didn't understand why we use descriptors.
I understand what keypoints are and their purpose, but when we extract the keypoints than why do we need to use descriptors ? What is their importance and role in recognition?
|
Sorry if this question is too simplistic, but I am new to image processing and after successfully writing two programs, a convolution program and a low pass filtering program, I noticed that for approximately the same output, the low pass filtering method takes 4 times the time!
Lets assume that the image is a square o... |
I'm trying to use Berchin's FDLS methods (for those that don't know what it is, it's a way to design arbitrary magnitude and phase of an IIR Eq)
I tried different things but neither gave me what i asked:
I tried to design an allpass filter with arbitrary phase response (nothing fancy just a linear phase and a short de... |
So the Gaussian function is an eigenfunction of the Fourier transform because it transforms into itself, right?
But this isn't true for the sampled Gaussian in the DFT because the tails of the function are truncated, right?
Wikipedia describes a discrete Gaussian kernel here and here (solid lines), which is different f... |
I've got a high-resolution image segmentation, which I'm downsampling (and non-linearly deforming) to fit on an ROI image. I typically blur the high-res image before downsampling with a Gaussian-fwhm related to the downsampling factor. The result is high-res and low-res images with the same mean.
I'd like now for my hi... |
Consider x(n) as input, y(n) as output & h(n) as filter coefficient. The filter is of 16 taps(N=16) from 0 to 15. The decimation factor of the filter is 4.
When I apply x(n) to this 16 tap decimation filter with decimation factor 4, what is the output that i should get?
What is the general relation(give formula) betwee... |
I'm finally making some headway in understanding data whitening, but I have a question now relating what I think of as "data-based" whitening to the situation where there are time-varying signals.
So in the "data-based" world, suppose I have a mean-centered column matrix $X$ with covariance $\Sigma = \mathbb{E}[XX^\top... |
I have two sets of MFCC coeficients which I get with fftExtract utility from two wav audio files.
How can I compare this sets (matrix 271x13 and 551x13) if they are similar ?
Probably I should use EMD distance ... But Im sligthly lost in all this math and I dont
know how to interpret its results .
How can I make fro... |
The DFT of a real signal is Hermite-symmetric, so you can roughly halve the computation time/memory by not bothering to calculate half the values of the spectrum (and complex conjugating the existing values and copying them to the second half if needed). So the rfft operation takes N samples and outputs N/2 spectrum b... |
I have a signal and from that I want to extract a specific frequency range, e.g. 10Hz to 15Hz. Now I heard that I should use Fast Fourier Transformation.
I'm going to do that in Matlab, but I have no idea where to start. Is there any good example how I can do this by passing the original signal and the frequency band ... |
There is an example of inverse filtering in my textbook which I don't fully understand.
Given the two filters v(t) = (1,-0.5) and w(t) = (-0.5,1). The inverse of these filters are given by:
for v: 1:(1,-0.5) = (1, 0.5, 0.25, . . .)
for w: 1:(-0.5,1) = (-2, -4, -8, . . .)
However, there is no mathematical illustratio... |
What is meant by Least square plus Gaussian method of estimating the parameters of an unknown system? I am aware of least squares in general but some works refer it as least square+gaussian method. What is the role of Gaussian here? Is it for some kind of assumption of the distribution of the residual errors? please ... |
I am averaging several FFT results together in an attempt to get the average frequency spectrum of a track of audio. I'm attempting to use Parseval's Relation to get the RMS of the audio from the resulting average spectrum, but i've noticed the RMS i get is wrong, usually only by a couple dB. Why does this happen? Does... |
I'm new at Fourier Transforms. I'm using AForge.Math FFT/DFT algorithm (C#). Said that I have this situation:
My signal:
$$
1.4 + sin(2\pi t) + 0.4sin(5·2\pi t)
$$
Sampling: 100 samples each second.
Here is the spectrum. The DFT finds the frequencies of my signal: 1Hz and 5Hz (and the constant component: 0Hz).
Here... |
Suppose that I have two signals $x[n] = \left\{2,4,1\right\}$ and $p[n] = \left\{5,1,8\right\}$ and I want to multiply them.
How do you do that?
How different is it from convolving two signals?
I understand that multiplication in one domain is equal to convolution in other domain. How do you choose as to what to use ... |
I'm studying the IIR filter design that is described in the book: Algorithms for the constrained design of digital filters with arbitrary phase and magnitude responses.
You can get the code at page 171 (at least the main function), and here is an example of a filter design :
M=4;
N=4;
tau=5;
om=pi*[linspace(0,0.2,20),... |
I am multiplying two sine waves with the same frequency (f), but might have a phase difference 0 <-> 90 degrees. The product is a two frequency sinusoidal wave with f1 = f-f = DC and f2 = f+f = 2f. I now want to filter out the 2f component. I am currently sampling at Fs = 32 x f. I get a 40th order equiripple FIR filte... |
I understand that digital audio has both a sample rate (time "discretization") and a bit depth ("amplitude" discretization). Also, it can have multiple channels (stereo would be 2 channels).
But things that I can't find readily in the internet:
What is the range that is discretized in the bit depth? My experience is i... |
i would like to add even harmonics from the data of FFT of a signal.
How do i do that ? do i have to search for higher magnitude frequencies then add the $2f$ then $4f$ etc ?
I understand how to do it from a sin wave for example but not from a noisier signal.
|
I need to scan an image in OpenCV and obtain the lines. For this I use the canny edge detector and then the propabilistic Hough transform, with which I actually get the lines.
The problem now is that I get many short lines instead of a few continuous ones. The image I am analyzing has the size 1024x768 and I am wonder... |
I extracted features from an image using SIFT and SURF. Then I applied few transforms on the image and again calculated the features. While matching the features, I noticed that there are some erroneous matches. For example, if using image of a face, some points on face are matched with points not on face in the transf... |
I saw the following sentence from Feature Extraction & Image Processing, 2nd Edition
$$
x = a_0 + a_x\cos(\theta)+b_x\sin(\theta)
$$ $$
y = b_0 + a_y\cos(\theta)+b_y\sin(\theta) $$
This equation corresponds to the polar representation of an ellipse.
I don't know this meaning. If you need extra information, I'll add ... |
There are several kinds of detectors and descriptors, like SIFT, SURF, FAST.
I wonder are they all eligible for real-time applications? Which is the best or better?
And furthermore, is Harris-Laplacian dectector still useful when we already have the above three? Is it better than them?
|
Does anyone know about different adaptive filtering implementations (LMS, RLS ...) in 2D or even 3D ? I have sequences of 2D images and 3D volumes with repeating patterns but small differences. I was thinking of using one as my reference input and extract differences between the pair (A simple subtraction doesn't work ... |
In scale-adapted Harris detector, the scale adapted second moment matrix is defined by:
$$\mu(x, \sigma_I, \sigma_D) = \sigma_D^2\ g(\sigma_I) *\left[ \begin{array}{cc}
L_x^2(x, \sigma_D) &L_xL_y(x, \sigma_D) \\
L_xL_y(x, \sigma_D) &L_y^2(x, \sigma_D)
\end{array} \right]$$,
while $\sigma_I$ is the integration scale, an... |
I am working with phoneme clustering. I have been using $k$-means clustering have done $k$-means on 2 different data: spectrogram vector and MFCCs. I would like to know how I can evaluate the result of clustering quality? I mean I need to know standard ways to validate the clustering. It would great if someone explains... |
I have two sets of data of given Field of view, one of them only covers a subset of the FOV of the other. I therefore want to upsample the one with the larger FOV to combine it with the other one.
So the question is: In the context of X-ray computed tomography, where the x-rays projections are backprojected to obtain a... |
i'm trying to implement an arbitrary IIR filter design. I'm decomposing all the algorithm into smaller pieces that i can test.
I currently am on the part where it designs a FIR filter from an arbitrary response.
Matlab's main function is here :
function h = lslevin (N ,om, D, W)
% Complex Least Squares FIR filter desi... |
I'm developping a people tracking with nearest neighbour data association technique and kalman filter for smoothing/predicting.
The tracker works quite good but sometimes it mismatch objects if they cross them-self.. (I think it is a common problem for a tracker).
I really believe that this tracker could be strongly im... |
I am trying to make program in matlab that counts the number of times the accelerometer was lifted up and down (a rep counter for exercise). Basically my phone is getting accelerometer data on all three axes and then i import this data into matlab. I have tried to filter the data using a simple filter a = [1 -0.9] b=0.... |
I need to create a diagonal matrix containing the Fourier coefficients of the Gaussian wavelet function, but I'm unsure of what to do.
Currently, I'm using function ConstructHaarWaveletTransformationMatrix to generate the Haar wavelet matrix and am taking the rows at dyadic scales (2, 4, 8, and 16) as the transform:
M ... |
If I have a 2D scalar image, it's trivial to display it with MATLAB or matplotlib type tools with the pixel values mapped via a color map, and there is any amount of literature (one example, another one) describing the perils of those tools' default "rainbow" colour-maps and the advantages of various other schemes (col... |
I'm trying to figure out how to convert any phase response to the corresponding group delay response.
Is there a way to do that, and vice-versa if possible?
|
could you tell me step by step the algorithm to design an arbitrary phase response IIR allpass filter design ?
I know Matlab uses a "brute force" algorithm to find an arbitrary group delay response but how do they do that?
|
Are there any good published approach for designing parametric EQs as FIR filters. The standard techniques discussed in DSP textbooks are frequency-domain-sampling or using Parks-McClellan, which this involves passband, stopband, transition band, etc. This is nice for rejecting a certain portion of the frequency spec... |
I have successfully extracts all Pitch Markers from waveforms, I used autocorrelation to find my pitch periods, The markers can be observed in the figure below:
I want change my signal (Pitch or Speed) using PSOLA, I need find the synthesized Marks, for example if I choose change my Pitch one octave UP(0.5), for it I ... |
First of all thanks for your patience: it is the first time for me posting a question in this forum. I am not a DSP expert, but I should get by if you give me in depth explanation.
This is an example of my raw data
and a link to the actual dataset (time=t0, acceleration=acc).
My problem is the following: I am measur... |
I come from Fluid Mechanics domain so pardon me for asking a naive and fundamental question.
I am trying to perform high pass filtering on a set of positive real numbers (~Energy) using FFT. However, the result I obtain has a lot of negative values. I tried to quantify how many of them are negative and it seems $\sim5... |
I'm quite new to machine learning/data mining and I'm struggling to find the correct path for my problem and would appreciate some guidance or criticism of my proposed solution i.e. is there a better/simpler algorithm for the problem?
The Problem
I have a number of features that describe a particular type (label) of wa... |
First of all I'm new to DSP so excuse my simplified words & I'm sorry if it's a duplicated question.
Now, I'm trying to filter a signal but as you all know, the filter step response overshoot the filtered signal at the beginning.
Here it's the signal. It begins with zeros then the signal comes up
Is there any accurate... |
Let $x[n]$ and $y[n]$ be two orthogonal baseband signals, with bandwidth B. Check if the following signals are orthogonal:
$u[n] = x[n]*\cos(2*\pi*f_c*n)$
$v[n] = y[n]*\cos(2*\pi*f_c*n)$
I'm not sure what the problem asks to be honest.
1) What exactly does he mean by bandwidth?? I only know the definition of a bandwi... |
Suppose we have filter $h[n]$, length $N$. If I use it to do convolution in the time domain, then there will be $N$ multiplications each time during the sliding. (Ignore border conditions for now). However if say $h[n]$ had zeros every other sample, then there would be half that number of multiplications, so ostensibly... |
My signal oscillates back and forth on the interval [-1, 1] at varying frequencies, with some added higher frequency noise components (example data shown below). I want to to estimate the phase of the slow oscillation at any given time. This means I would like to filter out some of the high frequency noise, and then ca... |
I am trying to write a connected component labelling program, I have done the first part to create a label based on the neighbours. For simplicity I am using a 4-connectivity. I am using ANSI C and to create the equivalence table I am using two linked lists with structures defined like this:
struct T2_node
{
size_t... |
I am trying to implement audio dynamic range compression in JavaScript (not using web audio API).
There is a lot of articles for sound technicians, and some high level documentation, but I couldn't find any helpful reference for actually implementing digital dynamic range compression.
From what I understand, there is a... |
I'm new to this multiple view geometry issues and I'm a little bit lost, and some concept are not clear at all.
I have a calibrated camera ( = I have distortion coefficents, field of view, and with those I can find what is called intrinsic matrix).
With this camera I'd like to make an application that can estimate the ... |
In many of my readings, whenever some author speaks about working in the frequency (transform) domain (of a digital signal), they often times take the DFT, or the DTFT, (and of course their corresponding inverses). Different authors will tend to work with one or the other.
I have not been able to really ascertain a pa... |
I have been studying about exponential average. There are enough explanations about this at Internet, but they do not explain about the time constant.
I have one channel with a $T$ seconds time signal with sampling frequency $f_s$.
If I want to do average of this time signal, we need to use either linear or exponentia... |
I have been doing some research into modelling acoustic spaces, and (with help from this site) I've managed to take the frequency response of fibrous layer model, convert it to a reflection response as a target for an IIR, and then find the polynomial coefficients for it using FDLS. All good so far.
I performed the us... |
I need to get the lines from a photographie of a sheet of paper. While recherching, I came along this, where one answer referred to this blog entry.
Now I am having trouble with this approach. I have implemented it as follows (with the c++-interface of OpenCV:
// the image has to be grayscale
if (image.channels() != 1)... |
I'm trying to compute the the interference that one OFDM user with beamforming causes to another user. The two systems are fully overlapped in frequency and time. I know how to generate an OFDM signal in MATLAB and compute its BER in AWGN and fading channels, I just don't know how to implement beamforming. The beamform... |
I would like to calculate the total SINR of a IQ modulation system in time domain.
$$ SINR = \frac{P}{N+I}$$
The blocks of the system are.
Bit generation
QAM modulation
pulse shaper (sq root raised cosine f)
IQ mod
IQ dem
filter (root raised)
QAM demodulation
I made a simulation of a IQ modulation system in time ... |
I would like to implement a HOG descriptor in C++.
I found an implementation of this code in Open Pattern Recognition Project - Histograms of Oriented Gradients (HOG) Feature Extraction.
An extract of the code follows:
//extract HOG features from a group of key points
void HOGExtractor::extract(ublas::matrix<float> &ds... |
After investigating signal analysis methods based on empirical mode decomposition (EMD), I found that recent developments are mostly related to the Hilbert Huang transform (HHT) and the Local Mean Decomposition (LMD) method.
I have been reading a few articles on the subject and I would like to have your opinion regard... |
I have to apply some kind of adaptive filter to my function $f(x).$ I present each point of my signal as a Gaussian, whose bandwidth depends on its location (not the point of observation $\textbf{x}$) as $h(t),$ which is a known pre-calculated function. The final output function $s(x)$ is a superposition of the influen... |
I am detecting the object from the live camera through feature detection with svm , and it read every frame from camera while predicting which affect its speed , i just want that it should select the frame which contain the object and ignore other frames which have no object like empty street or standing car's , it sho... |
Is a dirac comb a Linear and a shift Invariant System? I could prove the linearity, but I do not think it is shift invariant. How do do I prove it is shift variant?
|
Is it possible to make one IIR filter from various cascading IIR filters of different orders?
I know it is possible to do it from filters of the same order, but what about filters with different orders?
|
Please excuse me if this is not the proper place to ask this. I just need some general advice.
I have set up a very basic homemade motion capture system where I put three TrackIR cameras from NaturalPoint in a three fixed positions. I want to capture movement of a single object in three axis. So I laid out two of the ... |
Excuse my ignorance...
Given a digital image of a label I'd like to
Requirement: Match it to the closest pre-existing image in a datastore
Optional: OCR it, if possible (only necessary if step 1 fails)
I'm a programmer but not an engineer. I have no idea where to begin or where to look into solving this problem. I do... |
I know about Harris corner detector, and I understand the basic idea of its second moment matrix,
$$M = \left[ \begin{array}{cc}
I_x^2 & I_xI_y \\
I_xI_y & I_y^2
\end{array} \right]$$,
edges and other unstable points can be removed via $M$.
But about Hessian detector, it uses Hessian matrix to detect key points and re... |
I recently received some scanned pictures which are in a pretty good state, with OK resolution, but they are randomly spattered with a bunch of black dots. These cover everything (clothes, faces, walls, windows, and so on) except for a few very bright areas. I also have no idea how they got there. Here is a sample:
Fr... |
I am running a wavelet transform (cmor) to estimate damping and frequencies that exists in a signal.cmor has 2 parameters that I can change them to get more accurate results. center frequency(Fc) and bandwidth frequency(Fb). If I construct a signal with few freqs and damping then I can measure the error of my estimatio... |
I am starting with a typical $\ell_1$ basis pursuit problem:
$$
\min_{\mathbf{x}} \Vert \mathbf{x} \Vert_1 \quad \mathrm{s.t.} \quad \Vert \mathbf{ERx} - \mathbf{y} \Vert_2 \leq \epsilon,
$$
where $\mathbf{R}\in\mathbb{C}^{M \times P}$, and $\mathbf{E}$ is an $M' \times M$ row selection matrix that randomly chooses $M'... |
I have a time series that has been measured after convolution with a moving average filter. Knowing the parameters of the moving average filter, is it possible to reconstruct/constrain the values of the original? When considering deconvolution, there is much discussion in the literature of the form and magnitude of mea... |
what is 'parm' means when you set the name of wavelet function in cwtft or icwtft. wave = {wname,[7.6]}. also can I change Fb and Fc when I use 'morl' function in cwtft or icwtft transform? and If not, then how can I reconstruct my signal with cwt transform? cause cwt let me to select optional value for fb and fc (cmor... |
I'm trying to get an understanding of the relationship between an FIR filter designed from "first principles" using a filter kernel with convolution, and a filter designed in one of two ways using FFT (see below).
As far as I understand, the impulse response of an FIR filter is the same thing as the filter's convolutio... |
A classical technique in still images (e.g. fluorescence microscopy images) to remove uneven illumination and isolate bright blobs is to use morphological operation such as the top-hat transform.
For instance the Rolling-ball algorithm[1] uses a ball as a structuring element and performs the top-hat transform[2].
The s... |
Ok, this is leaving me increasingly frustrated. This builds on a previous question here but I am still not getting the indexing, although I learned from that question all the same.
Case 1: First convolution equation example:
$$
h[k] * h^*[-k] = \sum_{n=-\infty}^{\infty} h[n] \ h^*[n+k]
$$
The way I got the right hand s... |
For an image $I$, its first order derivatives can be computed using several oprators, such as
$$K_{sobel} = \left[ \begin{array}{ccc} -1 &0 &1 \\ -2 &0 &2 \\ -1 &0 &1 \end{array}\right]$$
$$I_{x} = I * K_{sobel},\ I_{y} = I * K_{sobel}.T$$.
And to compute the second order derivatives $(I_{xx}, I_{yy}, I_{xy})$, I can ... |
Having found some unofficial sources on Complementary Filter (Thousand Thoughts Sensor Fusion and The Balance Filter by Shane Colton), I wish to work out its rigorous mathematical proof.
The Complementary Filter,
$$y=\alpha \times y+(1-\alpha) \times x$$
where $\alpha$ is the filter parameter, usually chosen to be ~0.9... |
I know that a function $f_a\in \text{L}^2(\mathrm{R})$ is an analytic signal if its Fourier transform is 0 for negative frequencies, i.e.
$$ \hat{f_a}(\omega)=0$ if $\omega<0 $$
We can characterize an analytic function by its real part $f = \text{Re}[f_a]$, and the Fourier transform of this function is
$$ \hat{f_a}(\om... |
By using Python (numpy/sklearn/opencv) I'm trying to process images with hand-written digits, and after all my main problem turns to be connected digits. For example:
If I crop the digits by hand I get expected output, by taking advantage from NIST dataset, and sklearn SVC classifier, but segmenting the digits seems l... |
I have 6.4 sec recording of a discrete signal on 40Hz frequency (256 values).
How can I compute the variance of the signal?
Please, share an algorithm in pseudo-code or in an actual programming language.
|
Given that $|a|<1$, then which of those inverse-Z-transform equations are we to use?
I am leaning towards the first because (as I understand it), $z$ is merely a complex number that is evaluated on the unit circle, and thus $|z|$ must always equal 1? I guess my question is, when is $|z|=1$? Always?
|
I have one and only one frequency signal, a sine signal at f = 10 kHz that is sampled at Fs = 320 kHz.
I have read about applying a simple analog anti aliasing (AAA) filter then oversample, do some digital anti aliasing (DAA) and decimate to get the correct signal frequency.
I understand how this is useful if signals o... |
Sorry if this sounds elementary but I am struggling to grasp the physical idea behind ARMA (auto-regressive, moving average) process. The "AR" part is intuitive and so is "MA", but put together?
If I model my time series using "AR", I can predict the next sample using linear terms of the previous samples and the differ... |
I'm not a signal processing person at all so hopefully I'm not asking an obvious question (if I am, I'd appreciate any resources that would help give more context).
I have a 1D vector where the values give temperature at some position. I want to find out where the regions of greatest change are and then mark off those ... |
I'm trying to wrap my mind about what happens in Matlab/Octave when you compute the fft of a sine function. Theoretically, the Fourier Transform of a sine is given by two delta functions multiplied by the imaginary unit (one placed at the frequency of the sine and another at minus the frequency). I can see that in the ... |
I'm looking for advice or references on how to implement a "type I" compensation network of digitally. An analog example is shown in the following diagram:
I am familiar with the basics of digital signal processing, and have read about digital integrators. Would it be possible to use something like a first order IIR... |
I have a vector of signal x(t) with its time vector. I want to obtain a frequency representation of the signal, in particular the energy spectrum of x(t).
Can someone please show some light into obtaining the energy spectrum ?
Is energy spectrum and energy spectral density ,ESD produce the same result ?
Any help is m... |
Laplacian of Gaussian formula for 2d case is
$$\operatorname{LoG}(x,y) = \frac{1}{\pi\sigma^4}\left(\frac{x^2+y^2}{2\sigma^2} - 1\right)e^{-\frac{x^2+y^2}{2\sigma^2}},$$ in scale-space related processing of digital images, to make the Laplacian of Gaussian operator invariant to scales, it is always said to normalize $L... |
I am studying my Oppenheim and Shaffer book, (New Edition), and the last chapter deals with something called homomorphic filtering. I have read the wiki and some other websites about it, but they do not really delve into details on applications. Moreover, I have almost never heard of it be brought up in discussions or ... |
The impulse is given as a sequence: $x: {10; -3; -1}$. To determine if it is minimum-phase I compute the $Z$-transform (the geophysical case, positive powers of $z$) of it: $X(z)=10-3z-z^2$. Then I factor $X(z)$ into dipoles $(a_0+a_1 z)$: $X(z)=10-3z-z^2=(5+z)(2-z)$. Then I observe that all the dipoles satisfy the $|a... |
For the 2D discrete Gabor transform, why is it that we cannot use a set of orthonormal basis for its representation, instead we have to use frames for representing it?
|
I am trying to filter a sinusoid ($f_{sample}=50 Hz$) ,, i need to remove all frequencies above 10 Hz with accepted transition region 2 Hz (stop band freq=12 Hz)
the question is why after filtering this signal is the 20 Hz still appearing in the FFT? is there something wrong ? I know results should be the same in fre... |
For a signal sampled at $f_s$, the frequency resolution (or "bin width") for an $N$ point FFT is $f_s/N$. Does this mean that the $k$th bin will contain energy from sinusoids within $0.5f_s/N$ on either side of the center frequency of that bin (ignoring spectral leakage for now)? Is this energy averaged? Is it the same... |
I've been using Thinning recently on line-like structures in an attempt to generate skeleton-like chains of pixels connected through their Moore neighborhoods.
The description of Thinning says that the algorithm "finds the skeletons of foreground regions in image by applying morphological thinning until convergence".... |
How could I know the best size of the board for my camera?
My camera is Canon D-100 It's 18 megapix
I have created a board consist of 14*10 squares
the length of each square is 7*7cm
I need to know what the step of choosing the number of squares ?
and How could I know the best dimension for each square ?
Thank you ver... |
I'm sorry if my question might be simple, but I don't have a strong background on signal processing. I have a csv file of a 8 MHz bandwidth, sampled with a resolution bandwidth of 100 KHz. What I want to do is to compute the PSD over the 8 MHz bandwidth, but I'm not sure if I am doing this correctly.
For a "stable" sig... |
I'm trying find authoritative references for
[1] Which analyzing techniques (time/frequency domain) i should use for determining the quality of a speech signal.
[2] Which algorithms i should run for improving speech signals( As "cheaply" as possible)
There are no constraints for the first requirement as it will be don... |
I need to take the wavelet transform of an image (for reference, I will be using Debauchies wavelets, and the test image will either be Lenna or matlabs default woman image),and plot the coefficients in order of their magnitude. This is as an example for a document on compressive sensing I'm writing.
I'm a little unsur... |
I'm confused about the difference between a wavelet transform and a wavelet decomposition is. For example
load woman
[cA1,cH1,cV1,cD1] = dwt2(X,'db1');
[c,s] = wavedec2(X,2,'db1');
What's the difference between these two matlab commands, and when would you want to do one over the other?
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Actually i am in search of a Voice Activity Detection Algorithm which could distinguish between voice and non-voice
Roughly speaking it must not detect even a bullet sound,even a foot stepping and other non speech activity should only detect people conversation or any one shouting
in that search this question arises ... |
I am working on speech segeration and each source I am reading , spectograms are being made by filterbanks which uses gammatone filters . I can't find a proper c++ source code which would make me understand process behind gammafilters, completely.
Now I am curious what is its difference than 2d FFT, I mean why all sou... |
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