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According to this page, the Baudline software tool implements
...the uHz-rotator algorithm that operates in the complex domain to
calculate an extremely accurate estimate of the frequency.
Furthermore
Under good conditions (strong signal and low noise) the frequency
accuracy can exceed 8 significant digits (~.00... |
I have a feedback loop with transfer $L(z)= \frac{H(z)C(z)}{1+H(z)C(z)}$.
$$H(z) = h\quad \text{and} \quad C(z) = \frac{K}{z-\alpha}.$$
If I manually calculate the transfer function, I get:
$$L(z) = \frac{Kh}{z-\alpha + Kh}$$
But if I let MATLAB do the calculation I get:
$$L(z) = \frac{z-\alpha}{z-\alpha}\frac{Kh}{z-\a... |
Can any one suggest me a Bandpass filter in java which I would like to apply on generated sine wave of a particular frequency
|
For OFDM synchronisation, we are using two training symbols according to the Schmidl and Cox method of frequency synchronization and timing synchronization. The paper says:
The first OFDM training symbol has only even numbered subcarriers applying a PN sequence.The result is two identical half symbols in time domain e... |
Is it possible to break out the i and q of a complex WiFi signal? If I have a laptop with a standard WiFi card in it, could I break out the i and q in analog, or upon sampling in an FPGA via digital means?
It must be possible since it is being done on a WiFi receiver, right?
|
I am creating a system (modulator and demodulator) for broadcasting binary data through an analog signal. I'm using BPSK with great success – at least, I'm generating great graphs.
Green is input signal, red is carrier phase, pink is digital zeroes and ones.
My question is – now that I have that pink stream of binary ... |
The following binary maps are the results of a measurement I've carried out. I'm looking for a quantifiable measure of the red areas. I could trace rectangles manually (the green rectangle on the upper-right image), but it's hard to motivate their shapes.
Is there a natural (and well-used) method to detect the shapes ... |
Using a signal of three joined sinus of equal length at different frequencies (40 Hz, 50 Hz, 80 Hz) I calculate a scalogram of it (scale vertical, time horizontal, The steps of variing the scale parameter are equidistant):
Plot of the Scalogram:
In contrast to my expection that lower frequencies (i.e. higher values f... |
We know that DFT (discrete Fourier transform) breaks down a signal into multiple frequencies of sine waves. Does there exist a transform that does the same thing, but for triangle waves?
For my purposes, im only talking about 1-d signals (like voltages, etc). I'm studying historical stock market data, and I just want t... |
I'm writing a C++ application to extract four modulated carrier signals at four separate frequencies, from a single input signal. I've designed four FIR filters at t-filter.appspot.com but they run very slowly, even when I reduce # of taps to 80.
Is there a better option? People seem to point to biquad filters – are th... |
In a baseband complex signal, I need to generate a BSPK modulated signal at a given frequency. If I generate a CW at this frequency, all is good. However, when I then BPSK modulate the CW, I get a signal at both the positive and negative frequencies.
Is there a way of implementing BPSK modulation without this negativ... |
I was wondering if anyone had run into the problem of trying to estimate errors in their signal processing on spectroscopic data. I know that many people use spectroscopic techniques to estimate concentrations of different materials, but I would like to know how accurate these measurements can be (i.e. I would like to... |
EDIT
The first version of my question has not worked as I expected, so that I will try to be a little bit more specific.
The final goal I am trying to achieve is the generation of a ten minutes time series: to achieve this I have to perform an FFT operation, and it's the point I have been stumbling upon.
Generally the ... |
This may be a very straightforward question but I've been trying to understand this for a long time and can't wrap my head around it.
How would one go about discretizing the following continuous time signal:
signal_continuous = 1/6 * sin(880*pi*t) + 1/15*sin(1760*pi*t);
As far as I understand, if I wanted to sample th... |
I am working on a image processing application which uses a discrete fourier transform to implement blurring/sharpening. The application is more or less working, but something about the mechanics is still confusing to me.
In particular, it is how the process of centering the zero frequencies is being done.
The exampl... |
Suppose I have a $4x4$ image with the following values as its grey-level intensity for each pixel like this:
I want to get its Fourier spectrum. Usually, I would just punch into Matlab and run a fft for everything to be calculated automatically. Now, if I don't have Matlab, and I have to do it by hand and with just an... |
I am looking for theory on whether compressed sensing reconstruction via ℓ1-minimization is unique and under which conditions.
I have looked through:
Tropp, J. A., "Just relax: convex programming methods for identifying sparse signals in noise," IEEE Transactions on Information Theory, 2006, 52, 1030-1051.
This pape... |
What is the meaning of $Ta_k$ of fourier series or transform?
I am taking a course on signal and systems.
In 286 page of my textbook, it says that as T becomes arbitrarily large the original periodic square wave approaches a rectangular pulse.
Also it says that all that remains in the time domain is an aperiodic signal... |
i have to estimate a process which changes over time, not with respect to the system-evolution or the measurement-function, but regarding the number of objects that have to be estimated. So every iteration I have to estimate e.g. 5 more state variables of a new object. Do you know method to do this with a Kalman or Par... |
I'm trying to remove noise from an audio file. This audio file contains speech as well as constant pink noise. I know that I have to use the Fourier transform to convert to the frequency domain then use a filter to filter out the frequencies of the pink noise, but I really don't know where to start with that. It also s... |
Before anyone yells at me I fully realize that this question has been asked numerous times. I assure you that I've read through the existing questions and answers but I am still confused about part of the problem.
I have a sound source that plays music (A) in a closed environment. I have a mic that I'm using to record... |
I'm writing an app that recognizes Sudoku puzzles from a camera input. I'd like to remove camera blur from the images to improve recognition. Here is an example image:
Since I'm processing a continuous camera feed, I'm concerned about speed, since slow algorithms will degrade my frame rate. On the other hand, the t... |
We're trying to implement a "simple" speech recognition application in MATLAB (isolated words from a very limited dictionary). We've been trying the following methods:
Extract MFCC coefficients for each frame of the word, and then compare to templates that we have recorded previously using DTW, and take the template t... |
I want to ask about this scheme:
$u_0$ should be something as input in specific point given by the initial conditions and $y_0$ output. Block State Spase represented linearized system by A, B, C, D state metrices.
And I'm wondering why there is "-" by $u_0$ and "+" by $y_0$. Is this scheme universal? Why does it look ... |
It is well known that the DFT can be interpreted as a filter bank. The same can be done for the DCT, for instance Fig. 3.29, pag. 129 in [1] shows a plot of the frequency response of a DCT filter bank. I am wondering how this plot (and similar plots for other transforms like DST, etc.) was obtained. For the DFT, we hav... |
I am having trouble with zero-padding. As I understand it, in theory, zero-padding in the time-domain should 'sinc-interpolate' the FFT of the signal in the frequency domain.
This would mean, that 1) none of the values of the original signal change. 2) the overall profile of the FFT doesnt change- aka the peaks remain... |
I am working in digital image processing field, i have set of mammogram images in .bmp format, when i am opening anyone image using MATLAB then i am getting intensity value as 0 for a particular location (i,j), but when i am opening this image from java program using BufferedImage then i am getting intensity value as 5... |
I have a block of audio and I have performed an FFT on it. Now what I want to do is convert this FFT into a set of MFCCs, however while I know I need to do something with weighting the FFT samples based upon a set f triangular filters I haven't really got a clue what this involves.
Can anyone go into some good detail ... |
Is there any way to control per-pixel contrast? E.g., a way to set an upper or lower limit on the contrast between pixels?
The closest thing I've found is a high-pass filter of an n-pixel radius, inverted and applied as an overlay layer in Photoshop. Other kinds of filters, such as median, blurs, and traditional contra... |
I started studying DSP and the first things that came out were the differences between continuous and discrete time signals. So, I was wondering if I understood well these concepts before I keep going into more difficult topics.
The first thing I realized is that discrete-time signals replace the continuous parameter $... |
I have a question about matched filtering. Does the matched filter maximise the SNR at the moment of decision only? As far as I understand, if you put, say, NRZ through a matched filter, the SNR will be maximised at the decision point only and that is the advantage of the matched filter. Does it maximise the SNR any... |
I have a question concerning BPSK and the bandpass filter that seems to be sometimes placed before the receiver circuit (the receiver is a mixer and lowpass filter).
Basically, from what I've noticed, there is sometimes a bandpass filter before the receiver of BPSK (and other types of receivers too I think). Is the on... |
I'm trying to find out why digital systems are stable iff poles oh their transfer function are inside the unit circle (or are there any others conditions?).
I understand analogous systems are stable iff all poles of their transfer function are negative 'cause of inverse Laplace transform, where $\mathcal{L}^{-1} \left ... |
I've been sent here from this question in stackoverflow, please excuse me if the question comes too specific and it's not in the manners in here:)
The task is to find a glass with specific liquid in it. Let me show you the pictures and then describe what i'm trying to achieve and how i was trying to achieve so far in t... |
I have as a homework to determine the line rate and frame rate for a system described above:
Heigh of monitor: 40cm
Screen Aspect Ratio: 16:9
Pixel Aspect Ratio: 4:3
Progressive scan
Viewing distance from screen: 0.6m
Active line period: 15μs
Horizontal Blanking: 5μs
... |
I would like to ask, cuz I don't know much from that, how we can find the BER at a GSM network (uplink & downlink separately of course), while we are using FSK modulation? I mean the equations precisely, cuz I searched the Internet and there's nothing clear. Most cases where about MFSK, QFSK etc., but not specific for ... |
I've been trying to do some research on audio watermarking and what i wanted is to insert string into audio file in the transform domain (DWT), i've read some literature of DWT especially HAAR transform and try to implement it. So far i can embedd and extract watermark from the audio which is wav file beacuse i followi... |
I have these values,
m2 = 1 -1 -1 1
w2 =-1 -1 1 1 -1 -1 1 1 -1 -1 1 1 -1 -1 1 1
Im about to multiply m2 with w2
Should i multiply m2 with all of w2
(1 * -1 -1 1 1 -1 -1 1 1 -1 -1 1 1 -1 -1 1 1)
(-1 * -1 -1 1 1 -1 -1 1 1 -1 -1 1 1 -1 -1 1 1)
(-1 * -1 -1 1 1 -1 -1 1 1 -1 -1 1 1 -1 -1 1... |
I'm an electronics engineering student with high inclination to analysis and pure mathematics. I was just wondering if there was any book ( or any resource ) that treats signal and systems and signal processing with a lot of mathematics rigour ( actually doing proper complex analysis, using functional analysis and lin... |
I'm trying to intuitively understand why a windowing function of a signal is a low-pass filter.
I know its DTFT is a sinc function, making it mathematically a low-pass filter, but my logic says truncating a signal with a windowing function would preserve high frequencies better than low frequencies, since high frequenc... |
I'm processing audio data for voice input from a mic. The data arrives in 32 bit floats [-1 ~ +1].
My first filter is to remove DC:
// x = new input value, y = filtered output value
m_x += ( 0.01 * ( x - m_x ) );
y = ( x - m_x );
When I feed it audio that is close to clipping (but not actually hitting -1 or +1), I'll... |
I'm sure there must be an easy way to do this, but given the Fourier transform of an isotropic filter kernel, $\hat{f}(\mathbf{u}) = \mathcal{F}f(\mathbf{z})$, can one calculate the value of the kernel at $\mathbf{z} = 0$?
|
I have a image and I want calculate fft2 of it, after it I want recover image only by magnitude of it. how can I achieve this work?
I=imread('1.bmp');
I = rgb2gray(I);
imafft = fft2(double(I));
% Gets magnitude and phase.
mag = abs(imafft);
% Generates the modified spectrum
newfft = mag.*exp(0*angle(imafft));
im... |
I'm pretty new on signal processing and I've been reading a lot the last days in order to understand a little about it. But still there are things that I'm not sure if I got well. Sorry if I don't use the terms well.
I'm developing an application that detects onsets using a frequency spectrum, using KissFFT. Basically ... |
Here we have the basic formula of a Proportional Integral Derivative controller. This is the formula from the Wikipedia page on the subject
I want to implement this type of controller in my system. Currently the system (function in the software) is fed a psi value and told to set an analog output to a value so that th... |
I have a discrete function that represents a 1d position in space over time. I have a motion system that would like to achieve this curve, but, due to constraints on jerk (3rd derivative) and acceleration (2nd derivative), it cannot actually achieve the motion. This occurs due to a discontinuity in the function, wher... |
I am software engineer studying DSP on my own. I came across this question in a graduate textbook and am not sure how to proceed.
Determine the frequency response for the filter:
H(z) = 1.5 / (1 + 3z^-1)
Clearly, this is a z-domain transfer function. How do I get the frequency response? I am thinking of converting it ... |
Take the simple frequency-domain band-pass filtering operation below . . .
NFFT = 128;
x = randn(NFFT,1);
H = zeros(NFFT,1);
H(10:20) = 1;
y = ifft(H.*fft(x), 'symmetric');
This gives a real output because I'm using the conjugate symmetric flag to the ifft operation.
I want a function that returns the conjugate symmet... |
I want to calculate the total bit rate of a video system.
In order to calculate the total bit rate for a 1080/50p video system(4:2:2) we need:
• Luminance sampling rate:Fs=13.5MHz (standard for 4:2:2)
• Number of bits: N=8
• Number of components per PEL: M=3 (Y,Cb,Cr)
• Number of lines: L=1080
• Line durat... |
I have to use image processing for quality control of a cookie manufacturer (as a part of my project). The program must be able to detect oversized, undersized, distorted cookies, cookies having cracks, etc. I am new to opencv. Can you please suggest which all functions would help me?
|
What does $|H(j\omega)|^2$ in $20 \log_{10}|H(j\omega)|$ mean?
Is it some ratio of energy or power? And why? How to derive it?
I'm sorry for curtness of my questin.
|
While going through FFT I came to know that, shifting of phase in frequency domain results on shifting of time in time domain.
According to this, in wireless communications, from the transmitter side having 2 antennas,signal s1 transmitted from Ant 1 and phase shifted version of sig2 in frequency domain transmitted fro... |
Is there an analytic expression by which it is possible to calculate overshoot of step-response of second order IIR digital filter? I have tried to search through Mitra's signal processing book and through some other materials, but wasn't able to find it.
|
Suppose there is a DFT vector $\mathbf{X}$ with length N, which presents complex conjugate symmetry around its middle point, i.e., $X(1) = X(N-1)^*$, $X(2) = X(N - 2)^*$ and so forth. $X(0)$ and $X(N/2)$ are the DC and Nyquist frequency respectively, therefore are real numbers. The remaining elements are complex.
Now,... |
I'm processing audio signal sampled at 44.1 kHz. After some other processing, I need to filter the signal between ~5-50 Hz. Achieving this for a signal with such a high sampling frequency appears to be difficult. I would like the magnitude response to be nicely flat within the bass-band. No phase distortion is allowed.... |
Adobe Acrobat has this as a feature called ClearScan. While doing OCR it allows image enhancement, by smoothing irregularities on font outlines.
For example, this source:
turns to this:
Are there other tools with such feature, or public algorithms (Matlab/Python) that can smooth contours of arbitrary font-like object... |
I want to select a random sub-block of 8x8 out of an image 256x256. Is there an instruction that do this thing or i need to calculate it with a different approach. I found how to choose a galois field array out of a matrix but i think this is not in my case what i need.
|
I am trying to track small object in videos using LK
but the problem is, some time the object does not appear in the frames !
How can I track an object that does not appear in few frames ??
how can I approximate it is place automatically ,,,
I am trying to find the object using Optical flow LK ... but this techniqu... |
What does the spectrum of a sampled signal look like if one uses a zero-order-hold?
There is some information in:
Sampling theorem and Dirac comb, but I am wondering, how to apply this in practice.
Starting with an analytic spectrum I generated a time signal and recalculated the spectrum and it fits quite well. In a n... |
I have DSP in my curriculum. I kindly request suggestions on alternatives to MATLAB. Ideally, alternatives that are not as "heavy", megabyte-wise.
|
I'm a student studying communications engineering. I'm trying to understand why this particular laser diode is made for 155 Mbps and 622 Mbps. I'm thinking that the bitrate is entirely dependent upon the bandwidth of the photodiode. I can see from the datasheet that $f_c = 2 \text{ GHz}$ and so what I'm thinking is ... |
How I can approximate the signal $x(t)=0.001\,t^3 \exp(-0.1t)$ in the interval $[0,100]$ using a linear combination of the following functions:
$f_1(t)=A_1$
$f_2(t)=A_2\cos(0.05t)$
$f_3(t)=A_3\cos(0.1t)$
$f_4(t)=A_4\cos(0.2t+1)\exp(-0.2t)$
$f_5(t)=A_5\,t^3$
I try to write a matlab code. Is this correct?
t=[0:100];
x_t=... |
When we perform DCT transform using matlab:
number_of_sample_data = 100;
f=0.1; %frequency
fs=1; %sampling rate
phi_0=0
t=0:1/fs:((number_of_sample_data-1)*1/fs); %generate 100 samples
x=sin(2*pi*f*t+phi_0);
dct_transform=dct(x); %perform discrete cosine transform
figure(1), stem(dct_transform);
this piece of c... |
Suppose there is a DFT vector $\mathbf{X}$ with length N, which presents complex conjugate symmetry around its middle point, i.e., $X(1) = X(N-1)^*$, $X(2) = X(N - 2)^*$ and so forth. $X(0)$ and $X(N/2)$ are the DC and Nyquist frequency respectively, therefore are real numbers. The remaining elements are complex.
Now,... |
I want to found how many elements in an array is not equal to zero. I use this code:
y=sum(img_dct~=0);
z=sum(y);
Can i make this with a different way? Is there a matlab instruction like 'numel' that can do the job?
|
I would like to start learning audio signal processing. There are numerous books online and academic papers all of which seem to skip the fundamentals of the topic.
I would like to know a rough roadmap, so to speak, to follow in order to successfully learn audio signal processing.
I have read that calculus is the first... |
I am doing 1D wavelet decomposition and I am particularly interested in parts at the border of the signal. These parts are affected by boundary effects.
I know that some of the methods to extend the signal are periodic and reflexion, but none of these solutions are acceptable in my case.
I would like to extend the sig... |
I have this assignment that I can't figure how to solve.
I have a sound.wav human-voice file, and use matlab add-random-noise (monotonic)
Goal: to remove the noise from the sound (and the sound from the noise)
What I've done so far is to read the file and then add the noise.
I then do an fft.
Now I need to analyze the ... |
I am working on a board that has no antialisaing filter at the input of the ADC. I have option to I implement my own filter using RC + Opamp circuit. But is it also possible to implement Anti Aliasing filter after sampling by ADC and processing in Digital domain: a digital Anti aliasing filter?
|
I have DSP in my academics and while going through the video lectures i am stuck regarding power of periodic signal.
Its mentioned as
$$P_{\text{avg}}= \frac{1}{N}\sum_{n=0}^{N-1}|x(n)|^2$$
my doubt is why we have to mention $|x(n)|$ as square ?
Note: I am having format issues please edit my Question and put it in for... |
So if I have an image of the size: 1920×1080 and I want to apply a convolution filter of 3x3. Take the formula for DFT $N^2$ and FFT $N \log N$. What should I fill in for N in this case?
|
I am approaching to the Oxford Buildings dataset which contains already computed SIFT descriptors from affine detected keypoint locations.
Usually SIFT detector provides to its detected keypoints with scale and orientation information.
In the case of affine keypoints is clear that they don't have a single scale paramet... |
Suppose that I have a sensor that can acquire samples $X[k]$ of the Fourier transform of an unknown signal $Y[t]$. An example is MRI, where the acquired data is in $k-$space. Now suppose that the unknown signal $Y[t]$ is known to be real and non-negative. My question is: is there a principled way to incorporate this kn... |
I would like to ask about this function in OpenCV:
cvTermCriteria( CV_TERMCRIT_ITER | CV_TERMCRIT_EPS, 20, .3 )
How do I get more accurate results - do I need to increase the value of epsilon or decrease it?
|
I have been looking at trying to use wavelets for multichannel audio dynamic range processor. I am in the very early stages of trying to get decomposition and reconstruction working. In this thesis, it is suggested that a multiresolution dwt can be calculated using a tree of complementary filters. Being a hands-on pers... |
I am aware of the common types of windows, (Hamming, Hanning, Kaiser, Tukey, etc etc). However while many books describe them - almost none tell me just how exactly they were derived.
What is so holy about the hamming window? What about the hanning? I understand that they all play on the ratio of mainlobe width VS sid... |
In DTFT of a signal, the spectrum of a sequence is periodic with period $2\pi$ and all the information needed for derivation of the original signal from its spectrum is contained in $\pi <\omega <\pi$.
But , why do they integrate over $2\pi$ and not from $-\infty$ to $+\infty$ , as in continuous Fourier transform in in... |
I recently realized that FFT's aren't perfect. Meaning if I take a signal and then take it's FFT, and then do an inverse FFT, the resulting output isn't exactly the same as the input. Here's an image to show you what I mean :
I think the image is fairly self explanatory. The IFFT signal is just an inverse transform of ... |
What useful information i can take from the coefficient intensity maping after performing DCT transform?
|
Is it true that convolving a 3x3 matrix and a Full HD (1920×1080) image is slower with FFT, than with normal for-loops? Because you have to do zeropadding to get to a power of 2? (with the traditional Cooley-Tukey FFT for example)
Because when using the FFT, you have to zeropad the 3x3 kernel as well...
log(1920*1080)/... |
This question is a continuation of the discussion at How can a linear operator on DFT vector produce the same vector using only half of the DFT vector?, where the higher level motivation is better explained, in case there is interest.
Question:
How to take the positive frequencies from an hermitian symmetric DFT vector... |
I know this question has been asked to hell and back from many people, and that it will probably get downvoted until it's deleted, but please bear with me.
I am designing a sound engine for one of my projects, which needs to support low-pass filtering (no other filtering required, so no need for extremely robust equali... |
I would like to convert a signal to frequency domain. The desired frequency range is 0.1 Hz to 1 Hz and the frequency resolution is 0.01 Hz.
With the sampling rate of 30 Hz, FFT gives the frequency components up to 15 Hz.
Raising the sampling rate gives better frequency resolution. However, FFT gives wider frequency ... |
There is a statement regarding the Nyquist frequency in one of my textbooks which I don't quite follow. I would appreciate it if someone could clarify it for me.
Now, the way I understand it - if we sample a signal with frequency $f_{s}$, then the highest possible signal frequency which we can reconstruct without any ... |
Right now I simply do this (pseudocode)
for freq in freqs:
for i in len(samples):
samples[i] += sin(...)
Is there a better way? This is for outputting to a 16-bit WAV file, using C on an ARM7 device. The frequencies are actually the centers of FFT bins for a particular bin size.
|
Calculate the amount of operations you need for the Fast Fourier Transform.
Take $N=2048 \times 2048$
$N\dfrac{\log(N)}{\log(2)}$
$\dfrac{\log(2048 \times 2048)}{\log(2)}$ is 22.
$(2048 \times 2048) \dfrac{\log(2048 \times 2048)}{\log(2)}$ is 92274688.
But does $92274688$ stand for total operations or $92274688$ adds A... |
I would like to estimate the impulse response of a simple environment (room, two speakers, one microphone). I am aware of the issues/limitations of working with "near" LTI systems. That said, I have a rather basic question regarding the mechanics of performing cross-correlation using audio which has been recorded in my... |
I'm looking for some suggestions and wondered if anyone had any ideas.
I have just completed a project in Speech Recognition using MFCC, Dynamic Time Warping and Hidden Markov Models etc.. (Some of you will probably remember me, and, how annoying I was!!) But I managed to complete it.
It's the summer now and I'm lookin... |
I would like to ask a theoretical question concerning the Dirac function. The Fourier Transform of the Dirac function is the value 1 (DC) for every frequency. If we consider the Sampling Theorem, we have to find a maximum frequency in the signal $ \ f_{max} $, so that we can sample with $ \ f_s \ge \ 2f_{max}$. But as ... |
What are the salient differences between Lumped and Distributed systems? In what contexts are distributed systems the appropriate model and in what are lumped systems the appropriate model?
Also, Lumped systems are said to be described by ordinary differential equations while the latter is said to be described by parti... |
I have a really simple question regarding this tutorial I found on Gabor filters.
Check the very beginning section, equations (1), (2), (3) and (4). Is there any chance that equation (4) is missing an = and should be written as follows?
e^jθ * s(t) = e^j(2πfot+θ) = [sin(2πfot + θ), j cos(2πfot + θ)]
^
... |
I'm having a trouble here. I'm supposed to learn Frobenius canonical representation form for finding statespace matrices, but I found many different forms.
Let's suppose we have a system with this transfer function: $$H(s) = \frac {b_ns^n + b_{n-1}s^{n-1}+ \cdots + b_1s+b_0}{a_ns^n+a_{n-1}s^{s-1}+ \dots + a_1 s +a_0}$$... |
Define moving average process $y_t := 0.5 x_t + 0.5 x_{t-1}$ where $x_t := e^{i2 \pi t}$. Its frequency response is then:
$$H(f) = 0.5 + 0.5 e^{-i2\pi f}$$
Recall that the frequency response in polar notation is:
$$H(f) = G(f)e^{i \theta}$$
where $G(f)$ is the gain function. We then have that:
$$ H(f) = 0.5 \big( e^{-i... |
I am looking for Lossless compression algorithm for hyperspectral imaging. The only one that I found was LPVQ.
Do you know other algorithms? I am looking for pseudocode or matlab code.
Thanks
|
I found out today about Google +'s image search feature. It allows users to perform a text-based search for objects within their picture library. I was instantly curious to know how this feature works. Does anyone know? Are Google using anonymous usage patterns from Google Images to build a computer vision library of C... |
The Nyquist formula for digitally sampling and recovering a continuous waveform is well known. Are there any mathematical formulas that show that it is computationally infeasible (or impossible) to reconstruct a waveform if you go below a certain sampling frequency?
|
I have a signal sampled from a hardware, s. I would like to compute the coherence of the sampled signal given a single frequency, f. Below are the approaches I can think of.
Base on f generate a synthetic signal and compute the coherence of s and the synthetic signal.
Use SNR similar approach with frequency range [f ... |
I'm writing program (Qt widgets/c++) for removing noise from images. As denoising method, i selected non local means method. This method has incredible quality of restored images (that's why it's the only denoising method in OpenCV), but has huge computation cost, so i made a lot of modified variants of this method (so... |
I do understand the mathematics behind digital beamforming but I am not sure how such systems are practically implemented. For example, in a typical wideband FMCW radar operating in S-band, the (baseband) pulse bandwidth can be as large as 500MHz. To digitize this signal, you need high-speed ADCs, typically 1GHz sampli... |
Sorry for the long question, but I'm struggling to implement something related to this question. Your help would be appreciated.
Background
Notation: In the sequel, the uppercase letters represent frequency domain vectors, while lowercase represent time-domain.
Suppose I have two $N$-length hermitian symmetric DFT vect... |
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