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I've been looking around and found some great C/C++/Java libraries like CMU Sphinx or Windows SAPI. I did not like SAPI, and CMU Sphinx is way too complicated... would need months to understand how it works.
So I would like to start writing my own library, even it would be crap, but to understand all the parts how to r... |
i want to know more about brief descriptor algorithm and matlab code for this.
the points copmare with another what choice them. e.g. 128 point at patch how are choose.?
thanks
|
When a sum of sine waves is passed through a non linear process, harmonics and intermodulation distortion products are created, which are visible when applying an FFT to the signal. This causes potential problems when figuring out which sine waves were present in the signal originally.
Does something similar happen wh... |
How can I detect a quadrilateral in a point cloud that looks almost like a rectangle? How do I set the criteria (i.e orientation, size etc) to get the shape for example in the image below?
|
I am working on a spectrum analyzing simulator, which is meant to compute and plot the FFT of a sine wave carrier signal of $16 Hz$.
From my practicals with a spectrum analyzer, I know that the spike shows up on the $16Hz$ mark. But after computing my own FFT and passing the magnitude of the FFT to a plotter in Matlab,... |
My problem is essentially a 'blind source separation' problem. I have 3 non-orthogonal sources (or basis functions) and $N$ random linear combinations (mixes) of said sources. My problem is to obtain the sources from the mixes.
Figure A shows the sources, B shows the mixes.
Approaches taken:
$\textbf{PCA}$ - I tried ... |
In idea of buying an SPL meter i have drawn the specifications out in them very first and important spec is sensitivity of microphone many high priced microphones have their sensitivity arround 50mV/Pa where as some other with less cost have it arround 1V/Pa,
so what actually i want to know is, what is the actual role ... |
I would like to resample an audio signal.
Sampling frequency of an original audio signal is 50k Hz.
What I want to down sampling frequency is 30k Hz.
In this case, I followed the procedures as below using LabVIEW.
'1. IIR low pass filter
Butterworth / 6th / Lowpass / up to 15k Hz
'2. Resample to 30kHz
Why I used LPF ... |
suppose I have a 4 seconds signal captured at $f_s$ = 1024Hz, which gives 4,096 data array. What is the different between these 2 FFT methods (MATLAB code)
[1] FFT the entire input with 4096-points FFT
N = length(input);
Y = fft(input)/N;
[2] Divide the input into 8 segments (4096/8=512 data point each), and feed each... |
I want to set the precision to 24 bits while using matlab. Is this possible without using vpa?
because vpa is consuming lot of time since I am calling vpa more than 8000 times.
Please help
|
I am reading a text on discrete signal processing, which states that the frequency response of a signal can be obtained by plugging the value $e^{jω}$ into the z-domain transfer function $H(z)$. In other words:
$H_{IIR}(ω) = H(z)|_{z=e^{jω}}$
In the example given in the text, it is given that:
$H(z) = (\frac{1}{1 - \fr... |
How can I find this all pass filter's phase?
$$H(e^{jw}) =\frac{−a* + e^{-jw}}{1 - a(e^{-jw})}$$
where $a = ρe^{jϴ}$ is the pole.
Then I want to find group delay, I know that the group delay is the derivative of the phase with respect to w but i don't know how to find the phase
|
I often see examples in textbooks where someone constructs a 2D Fourier spectrum of an image by fixing two (symmetric) pixels to a given value, and computes the inverse DFT to get a nice waveform image. I want to know how these images are created. It seems to me that they pick one pixel that would give them the desired... |
there.
Let me have a noisy speech signal $y(k)$ as below.
$$ y(k) = x(k) + v(k) $$
where, $k$ is the discrete-time index, $x(k)$ is clean speech signal, $v(k)$ is a zero-mean random process, uncorrelated with $x(k)$ e.g. white noise.
If we put into this as a vector form:
$$ \textbf{y} (k) = \textbf{x}(k)+\textbf{v}(k)... |
It has been said a picture is worth a thousand words!
There have been a large number of softwares to write dsp codes and analyze signals and algorithms. It will be good to share on data plotting tools, that is - given a data set (1-d, 2-d, 3-d, ..higher dimensions (creative ways to visualize this)) what are the differe... |
I'm a bit confused with some details about frequency domain or studying systems with Laplace and Fourier analysis.
Let's say we have a system with a transfer function $H(s)$ with no poles and zero's at origin. We know that the transfer function is a ratio between output and input. Also, an input of $X(s)=1$ represents ... |
Matlab documentation says things like:
For high order filters, the state-space form is the most numerically accurate, followed by the zero-pole-gain form. The transfer function coefficient form is the least accurate; numerical problems can arise for filter orders as low as 15.
http://www.mathworks.com/help/signal/ref... |
I have this linear system that is defined by the differential equation
$$
y''(t) + 4y'(t) + 5y(t) = 2x(t) + 3x'(t)
$$
with x(t) the input and y(t) the output. I'm asked to find two things: The output when x(t) = cos(t), and the impulse response
This is what I did: First, I found the frequency response,H(f)... |
I have no background in telecommunication. Could anyone please explain to me what is the IQ data in telecommunication? It will be best to explain it with some basic analogies. Many thanks!!
|
If we have an Image I and a Gabor filter created at specific size and orientation, assume that is 11x11.
I saw some persons who normalize the size of the filter, but i didn't understand what was meant by "precalculate the normalization of the filter size". And within the normalization, they square the image, for exampl... |
I am trying to understand the equivalence of convolution through polynomial (coefficient) multiplication, Fast Fourier Transforms, and matrix multiplication. I am using octave with the octave-signal package, and part of this question may possibly related to their implementation (which I believe would be the same for MA... |
I red this link, but unfortunately i still don't understand the process...
By the way, Dilation process is performed by laying the structuring element H on the image I and sliding it across the image in a manner similar to convolution.
The grayscale morphological dilation formula is written as follows :
$[I ⊕ H](u,v) =... |
Doing excersies from Richard Hammings book about digital filters I've got two questions about them:
1) Fourier expansion of $g(x) = \sin^5(x)$. Provided answer is: $\sin^5(x)=5\sin(x)-20 \sin(3 x)+16\sin(5 x)$. Which is obviously contradicts well-known solution. Is it mistake in a book or author meant something another... |
In image processing, why do we always use odd square kernels(3x3, 5x5, 7x7, etc.) for filters?
Why can't we use kernels of size 3x1, 5x3, etc. that are rectangular kernels? Also, why do we not prefer even kernels (2x2, 4x4, 6x6, etc.)?
|
Mercury's distance from the solar system's barycenter (in kilometers)
can be approximated as:
5.9115960588705115e7 + 1.1573608483842954e7*Cos(2.086944367456105 - 0.0029751428085695573*t)
based on 8 years worth of hourly "samples" from HORIZONS. (t is in
hours; I forget what value corresponds to t=0, but it should ... |
I have some samples that are read from a square pulse wave and I'm looking for a way to find the characteristics of this wave.
It's a pulse wave, let $T_1$ be the non-pulse duration and $T_2$ to be the pulse duration, usually $T_1$ is bigger than $T_2$.
I would like to know the base frequency, e.g., the frequency that ... |
I'm looking at last year's exams, and I found an exercise I can't solve:
(Roughly translated)
Consider $x(t)=\sum\limits_{k=1}^{+\infty}\left(\frac{1}{2}\right)^k \cos(k2\pi t)$ the input to a LTI system, with the transfer function shown in the picture below
a) Determine (and sketch) the Fourier transform of x(t) and ... |
I am doing a time series change detection experiment. One of the experiments includes generating some artificial data for model evaluation.
I came across a problem in generating noise data with some arbitrary covariance at every 100 time steps.
While randn from Matlab allows me to generate the value, I am never able ... |
On Wikipedia there is quite a list of window functions. However, when you are doing a lot of STFTs, you often have to have some overlap to get better results.
Generally an overlap factor of 2 (i.e., 50% overlap) works fine (I'm doing analysis & resynthesis), but for some windows it isn't good (I currently have this ex... |
I'm doing EEG data collection and my amp forces use of an analog lowpass filter before the ADC. I'm fairly sure that I won't be interested in phenomena associated with frequencies of 30Hz or higher, so it strikes me that the most disk-space efficient thing to do is to analog lowpass at 30Hz (it uses a Bessel filter) an... |
The original Microsoft Kinect device IR projected a spacially encoded dot field and looked for distortion in the dot field with a single IR camera to create a depth map. But there were thousands of dots.
I've seen a few devices however, usually in motion capture, that only use a few dots. The one pictued below for exam... |
When you are transforming a signal in to a frequency domain using both DFT and DCT, say for a function sin(x), how the spectrum will be? will both frequency values (of DCT and DFT) same? Can anyone explain the values of the frequencies for the function sin(x) (obviously the frequency should be 1/2π)
|
I have difficulty in understanding what is Hue and Saturation. please explain what is hue and saturation to me with an example or analogy.
|
Thanks for reading my question. Please refer good books(links, if possible) for the following topics in Image processing. Your help is very much appreciated.
UNIT II SEGMENTATION
Fuzzy clustering, Watershed algorithm, Active contour methods, Texture feature based segmentation, Model based segmentation, Atlas based segm... |
I have the following problem, that I ran into recently, when calculating the spectra of data that I obtain from a measurement technique, we are using in our group.
In short what we do in the technique, is record a movie of a fluctuating, nearly circular object and determine the contour in each frame of the movie. We th... |
If I have a measured signal $\mathbf{y}$ which is the result of the true signal $\mathbf{x}$ convolved with another function (linear and not circular convolution), I always seem to get an underdetermined system. Convolution expressed as a matrix equation:
\begin{equation}
\mathbf{y} = \mathbf{A} \mathbf{x}
\end{equatio... |
can someone please help me? I have a project to implement a superheterodyne transmitter and receiver without using matlab functions that modulate. The first part which I can't seem to get right is the RF filter, which the my doctor said should just be a bandpass filter centered around Wc. I am supposed to get two sound... |
I'm not sure if this is possible, but let's say you had access to the original raw sampled digital pixels from a sensor, captured with nothing between the sensor and the lenses, i.e. Anti aliasing filter, colour filter array etc etc removed. Would it be possible to filter the raw pixels in relation to the original wav... |
What should the energy, pitch frequency, and zero crossing rate of a voice/unvoiced/silence frame in signal be?
My professor said that it is experimental, but I do not have any idea what the factors of these are and where I should begin from.
I would appreciate any guesses based on experimental data or any limits on th... |
I would just want to prove $\cos(t) + \cos(\pi t)$ is non periodic.
I don't know where to start it. Also I know that individually these signals ie $\cos(t)$ and $\cos(\pi t)$ are periodic with frequencies $1/(2 \pi)$ Hz and $1/2$ Hz respectively. But since the superpositon of these signals is not periodic should we re... |
A lot of people use imfilter to achieve a 2-D convolution between an image and a filter, but the majority of people use conv2 instead of imfilter because it is faster than imfilter by at least 20%.
Examples:
filtered_image_with_imfilter = imfilter(image,filter,'symmetric','same','corr');
filtered_image_with_conv2 = con... |
I am trying to gain a better understanding of pole locations in the $z$-plane of a given discrete transfer function, $H(z)$. I think I have a pretty good understanding of how to use the $\mathcal Z$-transforms for filter design, but there is something about the core concepts that still confuse me.
I understand that po... |
Suppose that $G(i,j)$ is a Gaussian decay function on the distance between points $i$ and $j$ of an image. In addition, $D(i,j)$ is the difference between the VALUES of the image at those points.
Now, at every point $i$ of an image I need to compute the summation of the neighboring $G(i,j) D(i,j) $ , this is, the prod... |
I am very very new to signals, and I am trying to generate sounds based on some parameters from a database. So, the database stores the following:
startFrequency
endFrequency
startAmplitude
endAmplitude
duration
I am generating a WAV file based on this information using the following code:
...
double currentFrequency... |
I am trying to estimate the Spectral Correlation Function by the FFT Accumulation Method (FAM) in Matlab. The way I understand the FAM method is as this link (see page 6 & 7 for FAM tutorial).
Here is the image again summarizing the process:
I'll summarize how I am understanding this method below:
Acquire a data chu... |
I have this differential equation
$$
y''(t) + y'(t) + y(t) = x(t) - 3x'(t)
$$
I found the system response of the system:
$$
H(f) = \frac{1 - 6\pi fj}{(2\pi fj)^2 +2\pi fj+1}
$$
which is equivalent to
$$
H(s) = \frac{1 - 3s}{s^2 +s+1}
$$
My question is: How to find the impulse response? ... |
When you use the deconvolution method to make the blurry image sharper, you will have to estimate the Point Spread Function. Is there a difference between this PSF and an image kernel?
Second question: Is the Point Spread Function in the time domain or frequency domain? Or can it be in both?
|
experts.
I have a question concern "linear sine sweep".
Here is the equation of linear sine sweep(from Wikipedia Chirp).
$$ x(t) = sin\biggl[ 2\pi( f_0 +\frac{f_1-f_0}{2T}t)t\biggr] $$
where,
$f_0$ is start frequency
$f_1$ is end frequency
$T$ is total length of excitation time.
In my case, I would like to calculate ... |
I want to learn how to go about analyzing some audio files I have acquired. Let's say the files contain some sort of repeating sound (e.g., water dripping), and I want to derive the pattern of the repeating sound. I use R for programming and analysis and have briefly introduced myself to the tuneR and seewave package... |
I am working on algorithms to separate mixtures of 'almost periodic' signals. One such example is composite ECG consisting of maternal and fetal signal.
Can anyone help with examples of such signals? The signal can also be from internet data.
|
Compressive Sensing is built on 2 properties: 1) the sparsity of the representation basis relative to the sampling basis and 2) the incoherence between the singular vectors from each of the 2 bases in a). On the surface this seems fine to me but he "incoherence" relationship is confusing me a little.
Some texts refer ... |
There have been discussions on the differences between convolution and correlation, autocorrelation, cross-correlation, et al.
In spite of looking at the visualizations, and understanding the formula for calculation of convolution and correlation, I don't understand the need for correlation - is it required for identi... |
Let us consider the following code:
function [ x ] = generate1(N,m,A3)
f1 = 100;
f2 = 200;
T = 1./f1;
t = (0:(N*T/m):(N*T))'; %'
wn = randn(length(t),1); %zero mean variance 1
x = 20.*sin(2.*pi.*f1.*t) + 30.*cos(2.*pi.*f2.*t) + A3.*wn;
%[pks,locs] = findpeaks(x);
%plot(x);
end
I know peaks in the Fourier domain are r... |
I need to implement an adaptive delta modulation encoder and decoder using matlab for my term project. How can I code a good adaptive delta modulation? How can I change delta(or sigma) to follow speech signals better? After that How can I decode it to recover original signal? I am using an algorithm which has that main... |
I wish to isolate a crosswalk from its surrounding, and I thought that as crosswalks have a repetitive pattern of thick white stripes, I might be able to isolate them by measuring their frequency range, and using a band pass filter with the right cut-off frequencies.
The problem is that I have no idea how to analyze th... |
It's well known that convolution in the spatial domain is equivalent to multiplication in the frequency domain. i have multiplied the Fourier transform of an image F with H. where H is the FT of a Gaussian function generated by the following code:
function H = gaussian_kernel(size, sigma)
half_size = floor(size/2)... |
According to my previous question, I have changed the generate command to:
y=generate1(100,1000,1);
and got the following picture:
Now I want to test a wavelet transform on the same signal, which of course exists in Matlab, but I have one thing which I should clarify: generally, as I know large scale values corres... |
I am trying to achieve a pattern matching between an image and a scene in which the image is. I am having problems with some images that does not contain corners, since SURF is not able to find keypoints.
Does anybody know any algorithm or method for retrieving keypoints in images without corners? In other words: how c... |
I am working on Speckle reduction in ultrasound images. I read a paper (snapshot of that paper is included below) where they have used a metric called beta metric which indicates the edge preserving capability of the filters. I tried to implement it using the equation (7) provided in the below snapshot.
This is the c... |
I'm implementing a spectrogram algorithm and I get the basic concepts, however, I'm struggling with something.
Let's say I have a 1D vector:
data = [0.36, 0.58, ...., 0.25]
I then compute a STFT of this data (with an overlap of say 128) this then produces a 2D array. I then compute the log of these values in order to... |
I have the following signal:
I'm trying to compute a Spectrogram algorithm, but, don't think I'm doing it right..
I have computed the following:
1) STFT (size 256 with an overlap of 128)
2) Computed the logs using: '10 * log10(sqrt(re * re + im + im)
This is the result that I get:
But when I use pylab in Python (... |
consider the classic scenario of identifying a radar frequency. You typically have a very short pulse of very high RF frequency. For example, a 50ns pulse repeating itself every 1MHz or so (PRF 1MHz and Pulse Repitition Interval 1us) and let's say there are 50 such pulses in each (radar) interrogation so that each set ... |
I would like to find the frequency spectrum by drawing magnitude and phase for the following signal:
S=sin(2*pi*100*t)+cos(pi*500*t);
X=sinc(2*pi*t);
Is there something particular to this problem that I should be noticing?
We can easily find the spectra giving a time domain like
t=0:0.01:0.1;
And using the fft comm... |
Why is this the most widely accepted model of signal sampling?
When multiplying the continuous signal value with the Dirac delta, we get an infinite value. However, if we perform convolution of our signal and the Dirac comb, we get our signal again — how is it useful?
The answer to a similar question has been given her... |
When I transform an image from the spatial domain to the frequency domain, some frequencies are negative. What is the meaning of the negative sign?
For example:
|
EDIT (after comments and subject matter review)
CS is based on a choice of a sensing basis $\Phi$ relative to a representation basis $\Psi$. Using an "Incoherence Property" $\mu$ that measures the correlation between vectors from each basis it has been shown that the CS paradigm can achieve good reconstructions if the ... |
A wavelet transform is defined for infinite length signals. Finite length signals must be extended in some way before they can be transformed. I know that periodic replication and zero padding are appropriate for signals that begin and end on the baseline, while mirror -image replication and linear extrapolation provid... |
I would like to know if it is possible to search Doppler shift of a carrier with sufficient oversampling while performing code search in the freqency domain. For instance can I selectively drop every X time domain sample bin from the fft processing? Will that not effectively change the input frequency being compared t... |
So, I was reading the paper on SURF (Bay, Ess, Tuytelaars, Van Gool: Speeded-Up Robust Features (SURF)) and I can not comprehend this paragraph below:
Due to the use of box filters and integral images, we do not have to
iteratively apply the same filter to the output of a previously filtered
layer, but instead can... |
Looking for a Basis representation:
Given a sparse or compressible image M, how would one represent this image using a basis A?
If I let m = vec(M)
m = Ax
where A is my "representation" basis and x is the vector of coefficients in the A domain, what is the method for actually getting A?
|
If I know y (samples) and x (signal), is there a practical matlab algorithm to calculate A in y = Ax?
|
Given a million data points in say 100d,
is there a way to generate an optimal filter bank of say 20 filters
from an SVD of the data ?
Call the 100d space $F$ (as in Frequency), with coordinates $[f_1, f_2 ... f_{100}]$.
There are many bases $V_i$ of $F$,
that split the 1M $\times$ 100 data array
$ A \approx \sum_{i=1}... |
Is there a good online course (with video) for Image/Signal Processing or Matrix Computations that includes a section on the principles of Compressed Sensing?
|
First, some background: The STFT is the best general-purpose tool I know of for analysing a (musical or other) signal into its component frequencies. For many purposes the STFT works fine, but there are two related problems that make it non-ideal for musical purposes -- 1) the frequency bins are evenly-spaced, not loga... |
I am looking to detect a combination of frequencies in the frequency domain. For example, here is my spectrum:
And I'm trying to detect the pilot tone. I have the FFT of the pilot tone:
which zoomed in looks like this:
I tried doing a cross-correlation in matlab:
trainingfft = fft(trainingfreq);
datafft = fft(idat);... |
All of my DSP experience is very much centred in the EM spectrum and I've only ever processed EM-type signals in the past.
I'm now doing quite a bit of work in ultrasound and the audio spectrum, but a lot of the techniques I'm using are used in the EM mainly. I'm reading a lot of EM papers about DSP at much higher fr... |
How come FIR filters are always stable?
Since they contain poles, shouldn't they be more affected by stability issues than others?
|
Why is it that spectral images appear? I know they appear for $F_s$, but why those replicas appear, I don't know.
E.g., sampling $x(t) = sin(1000 * 2\pi t)$ with a sample frequency of 230 Hz.
I know it will alias, due to spectral replicas, but why do those appear at all?
|
Why is it that we Z-transform a difference equation to get a the transfer function of an digital filter?
How come a digital filter is given in the Z-domain, and what is the Z-domain?
And for that sake, why do analog filters operate in the S-domain, and what is the S-domain?
|
How does an equalizer prevent a sample and hold effect?
Does a reconstruction filter only smooth out the output of an DAC (+S&H) or does it have another function?
|
Can anyone help me understand where the value of $2$ comes from in the following statement?
A time function t whose frequency response is white out to a bandwidth B has
about 2 · B · T independent values when measured for the time interval T.
This is in the context of a serial stream of digital (e.g. binary) data. T... |
while abs(x(i)) <0.05 % Silence detection
i = i + 1;
end
x(1 : i) = [];
x(6000 : 10000) = 0;
x1 = x.* w;
mx = fft(x1);
% Transform to frequency domain
nx = abs(mx(floor(mel(f))));
|
This is what I am doing and will be grateful for any help.
I selected 16 similar blocks to a reference block from a search block, put them in a 3D array, Wavelet Thresholded them, took inverse transform.
These 16 similar blocks belong to one 32 * 32 search block as mentioned above.
Now I should multiply each of these ... |
I have an EEG signal and it contains eye blink artifacts. I read some references and know that it is possible to detect eye blinks and remove them by using wavelet transforms, but I don't know that how do it.
How do I detect eye blinks? After transforming the EEG signal into wavelet coefficients, what should I do and ... |
I'm starting to learn about Gabor filters and Fourier series. I need to make a presentation on Gabor filters in a few months, so I need quality references for the presentation.
Does anyone have any suggestions on introductory books, useful articles or other similar literature which I may use as references for theory on... |
I am able to find out the velocities of pixels using the Lucas-Kanade method. Now I want to use it for tracking. I am using a Kalman filter taking $x$, $y$, $v_x$ and $v_y$ ($(x,y)$ is position of a particular object pixel and $(v_x,v_y)$ is velocity of a pixel) as state variables of the Kalman filter. Now the problem ... |
I want to find the partial derivative of an image with respect to its X coordinate. I read that it can be done by convolution of the image with a mask like:
fx = conv2(im1, 0.25 * [-1 1; -1 1])
I do not understand how is it calculating the partial derivative - can anyone explain?
|
I am relatively new to DSP and have been reading a lot on the internet. I have a couple of questions.
I have a signal in the form of a function
$$
f(x) = A_0 + A_1 \cos(\omega_1 x) + A_2 \cos(\omega_2 x)+...+ A_n \cos(\omega_n x).
$$
I have $f(x)$ and I know the minimum and maximum frequencies. $f(x)$ can have really... |
I have a 4096 sequence of FFT coefficient. All of which a real values. My sampling frequency is also 4096 samples per seconds. Now I want to make a plot. I know my Y axis would be my FFT magnitude values, but what would my x- axis be. Would it be my sampling frequency, that is 1,2,3,4.........4096?
|
I have This image which is basically made of sloped lines (almost horizontal and parallel)
I tried exactly the code in matlab documentation to detect those lines (except the rotation part) but I got a very strange result (vertical lines detected and no single horizontal line!):
I really can't find explanation of this... |
I am working on Speckle Noise reduction in Ultrasound Images using MATLAB R2013. I have designed 10 basic filters and trying out hybrid combination using these filters. When I run my program I get different results at different time for the same input image, no other input parameters were changed. When I ran my program... |
I am working on an implementation in which I need to apply an FFT to determine which of 4 frequencies are present in a signal.
I am doing a 64 point FFT on a buffer which only is partly filled (the remainder of the buffer is zero-ed).
When looking at the screenshots of the signal in the time domain, you will notice t... |
I've just learned about linear systems and impulse response functions. I know that in a linear system consisting of $h_1[k]$ and $h_2[k]$, the impulse response of the system is $h_1[k] \ast h_2[k]$.
In an exercise I was given the following system responses:
\begin{align*}
h_1(0) &= a \\
h_1(1) &= b \\
h_2(0) &= c \\
h_... |
When I select a part of an image and apply a negative function to it, it works 100%:
When trying to apply the same method using another function, the part of image becomes black:
What is the problem and how can I fix it?
|
I am sampling two sinusoidal analogue signals that are phase separated by $\frac{2\pi}{3}$, and there appears to be a significant amount of common mode noise in my samples. What, if any approach can I take to improve my SNR?
|
This question is in two parts, both related in some way or another.
Suppose I have a signal where the sample rate is 44100 and compute a normal 1D DFT on this signal. The size of this signal is 220500. I need to compute the Hertz for the outputted DFT.
I calculate the bins using the formula below:
sqrt(output[i].re * o... |
Could you tell me why wavelets without scaling functions can't be used for two-dimensional analysis? What is the role of scaling function?
|
I have a large collection of oversampled images (family photos of varying 'sharpness' scanned at a uniformly high dpi) and would like to downsample them to optimise storage space whilst retaining detail within some reasonable threshold.
I am hoping to find (or build) a tool that can help me identify what I (a confesse... |
Thanks for your time to read my question first. I’m new about audio, but I have to make this done:
Add a few bytes of data to a sound file and generate a new sound file.
If I convert that file to any sound format, these bytes data should still there.
When I play that file anywhere, I pick up the sound with mobile phon... |
I can understand just fine how to use 1-dimensional interpolation on data points where one coordinate is a function of the other: y = f(x). However, when we have an image, we generally have points in the image that are not given uniquely by such a function, e.g. two points (x1,y1) and (x1,y2), so how do we describe thi... |
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