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I have been trying to use the Fourier transform in recognizing images of the same size 200x400.
I have tried many different ways to do that such as:
Performing the Fourier on the full image and then try to match it with the ones in the database. the accuracy rate was very bad.
Performing the Fourier on the full image ... |
I've seen in practice taking an FFT of a signal, then transforming it by the 2nd, 4th, etc. power (depending on signal type) to determine the baud rate. I'm trying to implement this in my code, but am lost as to what a transform of the 2nd power is. It appears to be some sort of non linear transform and not simply squa... |
The SS formulation of DT system is given by
$$x[(k+1)T] = Ax(kT) + Bu(kT)$$
$$y(kT) = Cx(kT) + Du(kT)$$
Note: T is the sampling period and often omited
Can someone explain to me why the state equation $x[(k+1)T] = Ax(kT) + Bu(kT)$ is only between the currently sampling period $kT$ and the next sampling period $(k+1)T$?... |
Newbie question here.
I'm working on a system that is running a 32khz sampling rate, audio, 16 bit DAC.
Previously, our system had a very hard latency requirement of 1 sample. So no problem, we just read 1 sample in, did some processing within the sampling rate, and then read 1 sample out.
Now that this requirement ... |
How can I make sure to map, for example, 7% of the pixels to pure black (0) and pure white (255) in a grayscale image?
|
I was hoping that you can help me understand how to find poles and zeros in this transfer function.
$$
H(s)=\frac{1}{(s-s_{\alpha1})(s-s_{\alpha2})}
$$
I know that this function does not have any zeros, because of the 1.
From the solutions I can see that the poles are $s_{\alpha1}=-1+j$ and $s_{\alpha2}=-1-j$ and to te... |
I learned in school that any real-valued, even-symmetric sequence can be expressed as the convolution of a minimum-phase sequence and its time-reverse, which is maximum-phase. In my case, the real-valued, even-symmetric sequence is $sinc(x)$. What causal, real-valued, minimum-phase sequence convolved with its time-re... |
I am working on a project that uses EEG signals of the brain to identify emotional states. While surveying the literature, I came across several references where "derived features of bispectrum" are used as features for the purpose of classifying motor and emotional signals.
Although I have a list of some these "derive... |
I am using Emgu C#.
I acquire images from my cameras.
I know when there is no saturation (ie a grey-tone image) by looking at the average hue channel of the image. If zero then pretty sure picture taken at night time.
I can also detect how bright an image is by checking the average Luminescence channel.
What I would no... |
I am trying to downsample from $44100Hz$ to $8000Hz$, and I am not sure what I am doing wrong here. $44100 / 8000$ is $5.5125$, so I am getting hung up a little on the fractional remainder which is causing my implementation to play back slightly slower than it is supposed to. It seems that I need to somehow use the f... |
I am acquiring time-varying data with unequal sampling (nature of the source). When building a spectrogram, I have the algorithm choose sample blocks that are are -nearly- the same length -but, they are never equal. Since the peak widths are a function of the sample block length, this means that although two sample blo... |
how to apply wavelet transform method to extract alpha waveform( higher and lower band frequency known) from a given known signal ?
|
Hi guys I have a really tough signal processing question here.
How do you detect and distinguish two very very similar looking waves?
I need to distinguish between these two signals for an online application and the techniques so far have all failed. These two signals have very similar and often unpredictable amplitud... |
I am currently reviewing the Nyquist criterion which says I need to sample the signal at 2 times the maximum frequency in order to avoid aliasing in the reconstructed signal.
My question is that in all the applications I've done, I rarely ever remember having to reconstruct the signal after sampling it.
For example, i... |
Claim:
If $\lim_{k\rightarrow\infty} x[k]$ exists and is finite then $X(z)$, the Z-transform
of $x[k]$, has no poles in the region $|z|>1$ and at most 1 pole at $z = 1$.
Attempt:
\begin{align*}
X(z) &= \sum_{k\ge 0} x[k]z^{-k}\\\
H(z)/G(z) &= \sum_{k\ge 0} x[k]z^{-k}\\\
\end{align*}
First prove that no pole ... |
I've tried to implement STFT in functional way in Python. I've got code such as below:
def genSpectrums_dft(x, w, N, dft_func = fp.fft):
hN = N / 2
M = len(x)
hM1 = int(math.floor((M + 1) / 2))
hM2 = int(math.floor(M / 2))
wM = w(M)
w_sum = sum(wM)
xw = x * wM / w_sum
dft_buffer = np.con... |
I have some unusual question. I have searched online and couldn't find something similar to what I want to achieve.
I have an image, and I want to create a new image from it (in the same size), so the value of each pixel in the new image will be an indication for the texture of the pixel's close environment. By that I ... |
I've recently been studying wavelet analysis with a view to differentiating certain areas of texture images where the texture differs from the background pattern (which is quite random); for example a small ink smudge on a photo of sand or similar.
I've seen a lot of applications of Gabor wavelets used to pick out text... |
Is it possible to implement a moving average in C without the need for a window of samples?
I've found that I can optimize a bit, by choosing a window size that's a power of two to allow for bit-shifting instead of dividing, but not needing a buffer would be nice. Is there a way to express a new moving average result ... |
I was able to recorded an audio signal through the MIC and i applied FFT and Hanning window function to it. Now I want to know how do I identify CUTOFF frequency from it to apply the High Pass Filter.
my sample rate = $8000 Hz$, FFT block size = $256$
Can anyone help me to identify this ? I would really appreciate it !... |
I am working in image segmentation and I would like to ask you something about my problem. I have a image such as bellow. I want to segment leopard from background. However, intensity information is not useful for my case because the bough (background) whose intensity distribution is similar with leopard's. Could you s... |
I'm working on integral transforms for a science initiation project and i got to do a work on the Hilbert-Huang transform.
I've seen on the internet that, after one found the IMFs with the EMD method, you can do a Hilbert Spectrum plot of the absolute value of the componentes $H(\omega,t)$ where $t$ is for time, and $\... |
I have a map (in image format) describing the power grid of a continent.
Power plants have flags next to them, indicating their type (hydro, gas, oil, etc.). The power lines have a color indicating their tensions (different voltages). The cities are marked as black dots.
Here's a piece of the map, courtesy of the ENTSO... |
I'm trying to convert musicg Spectrogram output to dBFS.
With 16-bit signed integer PCM audio, and an FFT length of 2048, I'm trying to analyze the spectrogram for an audio file to determine things like "Was a particular frequency notched out by equalization" or "Was the audio high-passed or low-passed" by looking for ... |
It should be obvious that if there is no interference but only zero-mean random noise, as it is discussed in many textbooks. When there is known deterministic interference, what is the capacity now?
In details, the discrete channel model is as follows:
$$\mathbf{y}(n) = \mathbf{H}\mathbf{x}(n) + \mathbf{i}(n) +\mathbf... |
I am using SIFT features for detecting logos in clothes. SIFT is quite powerful, as it is scale invariant, but how do I deal with the problem of occlusion and warping?
More specifically, the logos in clothes might be partially occluded, and can also be warped when the clothes are stretched or squeezed.
Any suggestion a... |
Given a document image (i.e. newspaper), how to extract photos in it or remove text region?
I think traditional OCR methods may not be suitable here, as I don't need to recognize the text, and OCR is not accurate and slow. I believe text region (i.e. text blocks) and image region should be distinguishable by some thres... |
I would like to know how the output sequence from a fractionally spaced equalizer, with a non-integer oversampled input signal, is generated.
For example, for $T=T_{sym}/2$, my actual code is something like:
for ktime=1:2:L
nindex = ktime+(Ntaps:-1:1);
inputequalizer_block ... |
I want to train a cascade classifier to face detect. I read this page. But I wont use trainingImageLabeler app, because I already have face and nonface database sized 24x24. How I use trainCascadeObjectDetector function with my own database?
Is there any example except this you know?
|
I am a math major and have knowledge of Calculus, Real and Complex Analysis,PDEs and probability theory. I would like to get started with DSP and need a book suitable for math majors. Please give your suggestions. Thank you! :)
|
The OFDM MMSE channel estimator seems to require a-priori knowledge of the channel to calculate the MMSE estimate. See equation 8 here: http://cache.freescale.com/files/dsp/doc/app_note/AN3059.pdf. The autocovariance matrix explicitly includes the actual channel H or g.
However, you presumably don't have this informa... |
Signal
x(t) = | cos(2πft)|, f != 0
is the input of an ideal band-pass filter with bandwidth B = 3f/2.
How can i Find the Output of the y(t) of the signal.
|
I have a signal given as an expression $x(t)$. In frequency domain most of the information is around 0 and higher frequencies progressively get smaller and smaller compared to DC component.
I was wondering how to determine the sampling rate I should use if I wanted to compute discrete samples and pass them through som... |
After considering a couple of advices and suggestions for upsampling techniques here, I finally converged to use the cubic interpolation technique to estimate the voltage values corresponding to intermediate samples present between the original or previous samples. I know that spline interpolation is basically used for... |
According to this link, the waveforms of clarinets do not have even-numbered components in their harmonic series:
A closed cylindrical air column will produce resonant standing waves at a fundamental frequency and at odd harmonics... As can be seen from a sample waveform, the even harmonics missing from the tone
Is t... |
I am currently reading the 'Coding' chapter on Rabiner & Schafer's Book on speech processing.
In one of its exercises, the reader is given a simple A/D converter using 16-bit uniform quantization. The converter uses a sampling rate of $Fs = 8000 Hz$. Then it asks what is the effect on $SNR_Q$ (quantization signal-to-n... |
img = rgb2gray(imread('lena.bmp'));
imgFirstHalf = img(:,1:2:end);
imgSecondHalf= img(:,2:2:end);
implay(cat(3,imgFirstHalf,imgSecondHalf))
Now the question I have is, relative to the first frame, how should the second frame look like as in moving left or to its right?
I think the second frame should move to the r... |
I was given a WSS ergodic process $x(t)$ with power spectrum :
$$
\begin{array}{rcl}
G_x(f) &=&1−\left|\frac{f}{B}\right| &\mbox{for } |f|<B\\
G_x(f) &=& 0 & \mbox{ elsewhere}
\end{array}
$$
and first order probability density function is uniform in the range $[−A, A]$.
How do I evaluate $A$?
It's not a ... |
R (sampling rate)
fs (signal being sampled
fN (the Nyquist frequency)
fa (aliased frequency)
I was hoping someone could explain to me why this is true with a more mathematical proof. it seems reasonable for the aliased frequency to be related to these parameters, but I would like a more solid rationale.
|
I am studying HOG. I have find the code code1 and code2 about HOG. However, both of them don't implement trilinear interpolation. I have also read some websites, including web1 and web2. I still don't know how to write the HOG code with trilinear interpolation. Is anyone who can help me and provide me Matlab sample cod... |
This doesn't make sense to me, because the Heisenberg inequality states that $\Delta t\Delta \omega$ ~ 1.
Therefore when you have something perfectly localized in time, you get something completely distributed in frequency. Hence the basic relationship $\mathfrak{F}\{\delta(t)\} = 1$ where $\mathfrak{F}$ is the Fourier... |
My intuition about the scaling (x,y) of the 2d representation of the 3d object generated by our native visual processing system tells me it accelerates as it approaches the visual sensor (our eye).
Is this true? What is the rate of expansion of objects within our visual field?
|
Let suppose
x(t)=$\sum\limits_{k=-∞}^∞ R(t-kT)$
$R(t) = \begin{cases}1 &[0,2T] \\ 0 & \text{otherwise} \end{cases}$
x(t) is the input to an ideal bandpass filter with $\text{BandWidth} = \dfrac{1}{(2T)}$
and $\text{Center Frequency} = \dfrac{L}{(T)}$
How can i find the output y(t).
any help will be appreciated.
|
I am learning wavelet theory for image processing. To understand the theory, I write one Matlab program to decompose one black-white image. The program is as follows
Image = zeros(256, 256, 'uint8');
Image(101:200, 101:200) = 255;
figure; imshow(Image);
[cA1, cH1, cV1, cD1] = dwt2(Image, 'db1');
Image1 = [cA1, cH1... |
I need to extract information about the typical distance between the black patches in an image like the one I attached here. Typical distance would be the the most frequent separation between two patches. For example, if the photo was parallel black stripes, the algorithm would give me the typical width of the white st... |
I'm implementing a variable fractional delay element for use in online audio processing. Applications include ie. Karplus-Strong synthesis, flanger, chorus, echo, vibrato. I'm not oversampling, so drop-sample and linear interpolation are not really acceptable for interpolation.
Could a low order sinc FIR work as an alt... |
I am extremely new to this and I'm learning by building stuff myself so please let me know if this is too vague and Ill elaborate if I can. Im sure this is something very simple, but cant figure out how to do it.
I have built radios before and know how to modulate a signal as ASK but now I'm trying to send a simple bit... |
i'm writing a batch script in MATLAB to flange.
i'm getting some periodic noise, and i'm having trouble tracking down the source. it's definitely in the algorithm, because soundsc() will scale values larger than 1. and theres no memory or computing time issue, because it's running as a batch process.
any mp3 or wave f... |
Input: A video with a digital timer, possibly several hours long, such as this video. The timer might use any font or color, and might be located anywhere on the video, but it probably won't fill the entire screen.
Output: A list of time indices when the timer starts and stops, it might start and stop multiple times. F... |
Seems both will produce another step. there is no difference? Thanks
|
DCT, what is the benefit of using it for image processing?
I noticed that it is used in JPEG compression.
Can i use it for something else?
Is it useful for motion detection?
Is it useful for compressing further? If I convert an image to its DCT I could remove the higher frequencies to zero, then convert back to image. ... |
$w(n)= 0.54 + 0.46\cos(2n \pi/(M-1))$ is Hamming window and we have say $f_{s_1}$,$f_{p_1}$,$f_{p_2}$,$f_{s_2}$ with pass and stopband tolerance specifications of the desired filter. From this specification can we get mathematical corresponding frequency response?
|
I am stuck with a case where I need to get rid of a portion of sinusoidal signal that suddenly appears in my main signal (sine wave).
my total signal will look like:
$
s(n) =
\begin{cases}
A\sin(\frac{2\pi}{8000}*n + \theta) + b\sin(\omega*n) & \text{if } 4500 \leq n \leq 5500 \\
A\sin(\frac{2\pi}{8000}*n + \theta) & \... |
Couldn't decide whether the question belongs on Mathematics or here, but I guess I'll ask it here.
I've got a discrete - valued function defined on a finite segment of a line that looks like this:
Then the task is, given a set of other functions, find a function in this set that is the closest - in some way that I'm a... |
In DSP textbooks a system is stable in the BIBO (Bounded-Input, Bounded Output) sense if and only if every bounded input sequence produces a bounded output sequence. After stating this definition stable always means BIBO-stable.
I'd like to know if there exists other form of stability for a system?
|
I'm looking for books or resources that cover the following in detail:
implementing mathematical functions (e.g., logarithm, exponential, sine, cosine, inverse) in fixed point arithmetic for DSP purposes.
techniques like using lookup tables, Taylor series, etc.
I am fairly familiar with C programming and am more inte... |
I'm trying to distinguish by code between a real 3D object and its picture - a 2D object, based on depth information.
However the picture (= the 2D image) might be captured from noisy background, so I need something more sophisticated than just having diversified depth information; also, the depth camera's output itsel... |
I'm using MATLAB, and have experience with it but not with this kind of problem. I'm trying to identify white lines in noisy 2D images such as the one below. I can separate the brighter ones just by thresholding, but the dimmer ones (like in the bottom left) are tricky. Any suggestions? I guess I need some kind of ridg... |
Many windowing functions are listed here in the Mathematica documentation. I tried using a few to reduce leakage when computing a Discrete Fourier Transform. From what I could tell it made little difference which windowing function is used. Two of them that are very dissimilar are the BartlettHannWindow and BlackmanHar... |
I forgot a very simple fact and I am now struggling to find reference that proves this basic property?
How would you prove that for a single in single out system, the system output is the impulse response convoluted with the input?
|
I am working on some algorithm implementation, however being new to image processing, I have some questions about some of the definitions used.
UPDATE: for those asking for more information, this is the RELEVANT information stated in the paper.
"Step 4: Centerline Computation
Our implementation of the centerline extrac... |
If I have a signal x(t) as follow
x(t)=$\sum\limits_{k=-∞}^∞ R_{T}(t-2kT)$
$R_{T}(t) = \begin{cases}1 ;&[\dfrac{-T}{2},\dfrac{T}{2}] \\ 0; & \text{otherwise} \end{cases}$
$\mathfrak{F}\{R_{T}(t)\}=Tsinc(\pi fT)$
$H(f)= \begin{cases}1 ;&|f| \le \dfrac{3}{4T} \\ 0; & |f| \ge \dfrac{3}{4T} \end{cases} $
$Y(f)=\dfrac{1}{2}... |
Is this possible to direct trans modulate DVB-S/S2 -> QI into -> DVB-C/C2 signals without doing it the way DVB-S/S2->Demodulator.ic-Transport Stream -> Modulator.ic-Transport Stream -> DVB-C/C2 ? Qpsk and Qam are similar, rf tuners the same, trouble within IQ. Direct conversion should be multichannel and cheaper within... |
I have been trying to find a solution to my FFT convolution problem but everything that I have found while searching hasn't been helping me.
I have a working forward and backward FFT function, that I have tested with perfect results. A wav file that I ran through the forward FFT came out with a result of a frequency do... |
I'm studying some variances ($\sigma^2$), that in my case, they must depend by velocity squared $v^2$.
So, in my experimental proofs, I have plotted a graph of $\sigma^2/v^2$, and I was hoping to find a horizontal line.
But, my data seem to be constants in $\sigma^2/v$, and now I find myself in times of trouble: I have... |
Telecom companies offer different data rates for home/office purposes depending on the money they pay.
How are the telecom people able to control the flow of data of different cables?
Say supposing a cable can be used till $20\textrm{ MBps}$. But he paid only for $5\textrm{ MBps}$ scheme, why is the user not able to ... |
At present, I am learning the theory of operation of resampling for bandlimited periodic discrete signals using $\mathrm{sinc}$ interpolation. I am developing a design flow and having difficulty in understanding a particular expression/equation, hence I am stuck! Here I go:
Suppose we have a samples $x(nT_s)$ of a cont... |
I'm trying to test my ear frequency range by using MATLAB. The thing I could not understand is that I can hear the frequencies above 20 kHz. My sampling frequency is enough to satisfy the Nyquist criteria (80 kHz which is limit for MATLAB). So there is no possibility to have an aliasing. What can be the problem? Thank ... |
This is a conceptual question I am having difficulty to understand due to my limited knowledge of computer vision: If a pinhole calibration or any calibration is a mapping from world coordinates to image coordinate, is it possible to invert this mapping? I understand most of the times camera matrix is 3x4 so non invert... |
Papers use wireless device-dependent radio-metrics as fingerprints. A radio-metric is a component of radio signal, amplitude, frequency and bandwidth. Each device creates a unique set of radio-metrics in its emitted signal due to hardware variability during the production of the antennas, power amplifiers, ADC and DAC ... |
I have a pretty complex signal flow graph with all the blocks and the branches completely describing an analog filter, in the Laplace complex variable s. The signal $X(s)$ is the input and $Y(s)$ is the output.
Is there any (free) tool which can analyze such a graph and provide the overall transfer function $H(s) = Y(s... |
I'm going over an exercise of designing an simple FIR filter, I have the solution in front of me, but I struggle to understand some parts of it.
I'm asked to have an FIR filter with only 3 coefficients.
I have reached this form:
$$ H(\theta ) = (2\alpha_0 \cos(\theta)+\alpha_1)e^{-j\theta} $$
where $\theta$ is the freq... |
Let $f:\left(-\frac T2,\frac T2\right)\to\mathbb{R}$ for some $T>0$. The Fourier coefficients of $f$ are $$\left\{\begin{matrix}a_0&=&\displaystyle\frac 1T\int_{-T/2}^{T/2}g(t)\;dt\\a_k&=&\displaystyle\frac 2T\int_{-T/2}^{T/2}g(t)\cos\left(k\frac{2\pi}Tt\right)\;dt\\b_k&=&\displaystyle\frac 2T\int_{-T/2}^{T/2}g(t)\sin\... |
I try to describe a simple signal in the frequency domain with the use of FFT function:
from scipy.fftpack import fftfreq, rfft
def spectrum(sig, t):
"""
:param sig: signal.
:param t: time scale.
:return:
"""
f = fftfreq(sig.size, d=t[1]-t[0])
y = rfft(sig)
return f, y
Signal:
...and ... |
Edited.
Previously this question was named "Segmentation of overlapping pulses in a binary spectrogram" and it was stated in slightly different way. I'm apologise to those users, who were affected by reformulation of the question.
Problem.
There are a set of binary images, that contain arbitrary set of noisy parallelog... |
I'm trying to calculate the power of a signal and my tutor has given me this formula to do it
I've spent the past while building a program and now the foundations are there it's time to implement the maths side of it. The problem is I can't actually read it. Would someone be able to transcribe it and explain it to me?... |
I am fairly new to the topic of DSP and FFT and I have hit a mental block. For a project, I am trying to pick out frequency's with amplitude peaks in a 47-53 MHz signal. This signal is being put through a 24 bit ADC with a sample rate of 96000 Hz. In order to successfully measure a sample, don't you have to have a samp... |
Let $y:\left(-\frac T2,\frac T2\right)\to\mathbb{C}$ be a square integrable function. The Fourier coefficients of $y$ are $$\underline{Y}(k):=\frac 1T\int_{-T/2}^{T/2}y(t)e^{-i\omega_kt}\;dt\;\;\;\text{with }\omega_k:=k\frac{2\pi}T$$
for $k\in\mathbb{Z}$. The Fourier polynom of degree $n\in\mathbb{N}$ of $y$ is $$\math... |
When designing an FIR filter using the windowing method, how can one estimate the filter order ? It's obvious that the type of window and the transitions band's width has some effect on the order.
|
I want to implement Fourier Descriptor of an object. I have read link. However, I have some questions about normalizing Fourier Descriptor.
First, if I want to normalize the position of the starting point, according to the above link, This is done by subtracting the phase of the second Fourier descriptor $\phi_1$ from... |
I have a function of $j\Omega$ and $v$ (velocity), i.e.:
$$A(j\Omega,v)=\frac{(j\Omega)^2}{p + \frac{j\Omega}{v}}$$
where $p$ is the pole.
I want know how $A(j\Omega,v)$ modify its behavior, when I insert another cascade filter $F(j\Omega)$.
In this case I would like study the power of this system via Parseval's theore... |
I am new to signal processing, and I am a bit confused by the use of coherence in academic literature. In several articles in neuroscience, coherence between signals (eg. EEG signals) is determined at a very high temporal resolution. See for an example this figure, from Bosman et al, 2012:
That article refers to the '... |
I am measuring acoustic emission signals. The a.e. frequency range is 20kHz to 1 MHz. The sampling frequency that I,set was 100kHz
Samples per second. I must be able to detect a maximum of 50 kHz signal using it. But when I do fft I get a maximum of only 300Hz.
Can anyone tell me where I would have gone wrong?
|
I want to implement one of the following mappings in MATLAB and verify its performance on an image, but I couldn't. Please help me with the implementation
|
A hold operation can be modeled using a step function over one sampling period i.e.
$R(t) = 1/T * (h(t) - h(t-T))$, $h(t)$ the step function
In frequency domain this is equivalent to
$R(jw) = e^{-jwT/2}*sinc(wT/2)$
We see there exists a phase distortion of $T/2$ and a magnitude distortion from the $ sinc(wT/2)$ term.
... |
Refer to diagram above, in Ogata's text on discrete time control, he showed that you can map a curve in the S plane, namely curve 1,2,3,4,5 onto a circle in the Z plane through the complex mapping $e^{Ts}$
What I do not understand is why are we missing the negative branch? This is curious because we must have poles i... |
Lets assume we have a simple audio processing flow with preprocessing, feature-extraction and classification.
Where and why do we normalize the data?
I know the purpose of normalizing the data in the preprocession-step. But as I implemented some feature-extracrion methods like spectral flux, I have read about normaliz... |
A signal $x=\sin(\pi t/4)$
sampled at every $t=1$ sec.
so $T=1$ sec
Sampled signal is then $x=\sin(\pi n/4)$,
What is the sampling rate in this case?,
And according to Nyquist sampling rate what should be the minimum sampling rate to sample this signal?
|
I'm trying to do frequency analysis on signal of a rotating shaft. The signal is generated in two measurement planes i,e X-position and Y-Position. I was able to use fft and transform into frequency domain for individual planes. The plot I get for each place is only Half spectra. What I'm looking for is a full spectra ... |
I want to measure a reverberation time in the room. What is a best way to do that? What kind of signal should be used? I know about balloon and pink noise, but are there any better methods?
|
I have to do a project for college. The project consists in writing a paper about some application of digital signal processing and then implement the solution in MATLAB. It doesn't have to be the original.
We're supposed to check papers to come with ideas but I thought that perhaps someone here could give some ideas.
|
Given a signal with a list of discrete values
1,2,3 (t=0),0,1,
Whether the signal is causal when the arrow is in 3 and why? I know the definition of causal is that the output will not depend on future input, but how to apply the definition in this question?
|
I got this explenation:
"It is well-known that an image’s histogram is essentially
the probability mass function (pmf) of the image (only
differing by a scalar). Multiplying each component of the
pmf by a correspondingly shifted unit impulse results in the probability density function (pdf). Obviously, in the context
o... |
I see two notions that describe the relationship between poles and system stability. But they are not the same from my understanding
The system is BIBO stable if and only if all the poles are in the
left half of the complex plane
A LTI system with a rational system function H(z) is stable if and only if all of the pol... |
I got the time domain signal from experimental work as per below. The blue is x-direction,green is z-direction and red is y-direction.
When i convert the signal into FFT using MATLAB, I got as per below.
.
The problem is, the peak should happen in z-direction(Ch3) but happen in x-direction(ch1). The coding as per bel... |
I need to know if a certain audio file is real lossless and not a transcode (i.e. lossy converted in lossless, but lossy at the end). I was told there was a way to do this by creating a spectrogram of the file and then checking something else. The problem is that, since I am not well versed in audio processing, I don't... |
I was reading this thread: How to get Instantaneous Magnitude for a Instantaneous Frequency From FFT?
I have basically the same question, but I'm curious about more detail about the Hann window kernel. ederwander said that once you know the frequency offset from the nearest bin then the instantaneous magnitude is a the... |
I have some microscopy data that is contaminated by a heartbeat artifact that I'd like to remove. The data consists of a large time series of images captured at ~60Hz.
Here's a small example clip in GIF form:
I have taken the average pixel intensity over time, and computed the periodogram using Welch's method:
As you... |
I have a pulse signal from which I sample N times of level changes (e.g. high->low).
At undefined times the pulses in the original signal are completely missing. This leads to wrong number of measured original samples (N+m, m: count of lost samples).
I have implemented a naive detection algorithm:
prev_time = x[n-1] - ... |
I have some Bode plot (only in amplitude) as these:
Now, I must to find their transfer functions, in particular the exact value of their zeros and poles.
It is clear that their are a low pass filter and a high pass filter.
I'm looking for a method for extract the numerical value of their transfer function.
Thank you a... |
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