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What this relation on picture mean? Why response for a digital low-pass filter exists on "-" side of x axis? Impulse starts at 0 as i can understand and goes to infinity...
Please use phrases starting with "think of it this way..." or "it's like..."?
|
In this answer, Jim Clay writes:
... use the fact that $\mathcal F\{\cos(x)\} = \frac{\delta(w - 1) + \delta(w + 1)}{2}$ ...
The expression above is not too different from $\mathcal F\{{\cos(2\pi f_0t)\}=\frac{1}{2}(\delta(f-f_0)+\delta(f+f_0))}$.
I have been trying to obtain the later expression by using the standar... |
I am trying to implement the symbol timing recovery loop and for that I have chosen two algorithm to compare my results one is feedforward and Gardner TED. One thing that is confusing me is smoothing of error after finding timing error and finding the right sampler.
Should I use the sampler after matched filter or bef... |
I am studying wavelets in image processing. I would like to learn how to downsample a matrix in columns using MATLAB. I have used the downsample(x,n) command to downsample the given matrix in rows. But how to do the same in columns?
x =
1 2 3
4 5 6
7 8 9
10 11 12
y = downsample(x,2)
y... |
Here is a sinusoid of frequency f = 236.4 Hz (it is 10 milliseconds long; it has N=441 points at sampling rate fs=44100Hz) and its DFT, without zero-padding :
The only conclusion we can give by looking at the DFT is: "The frequency is approximatively 200Hz".
Here is the signal and its DFT, with a large zero-padding :
... |
I need to record sound using 2 (or 4, eventually) microphones and then calculate the time delay of arrival of sound at the different microphone pairs. But first, I need a microphone array. And since I'm just starting out, I would like to connect just 2 mics first and calculate the time at which sound arrives at them.
C... |
Please help me understand the following MATLAB code for Ideal Low pass filter. I am unable to understand the Part2 in the below code. Please explain me why we are doing like this.
I have read the Rafael C. Gonzalez's Digital Image Processing Using Matlab 2E which explains my question but I couldn't understand properly.... |
Some methods
#1
YData = YData / max(abs(YData));
#2
maxYdataAbs = abs(max(YData));
minYdataAbs = abs(min(YData));
YData = YData / (0.5*(maxYdataAbs + minYdataAbs));
I am not happy with neither one.
Assume that you have the following data.
Only one or two sharp peaks.
I am not happy with #1 or #2.
I am not sure anymo... |
I am on a project of vehicle type Identification (MUV,jeep,Sedan,etc) from images and Here is what I have done up-to now on matlab.
I am working only on the sideview of images.
Input Image : Masked image
Then I detected the corners easily
Now I got a matrix C with 40 corner coordinates thus I got a matrix of C=[... |
I am not very good at mathematics
I was doing some image processing so I came to know about FFT and IFFT
I was learning about them but the mathematics involved seems to be too dense
So can someone tell me about what are FFT and IFFT and their general application in short in LayMan's Language
So that again when I go to ... |
I want to write continuous wavelet transform codes manually by matlab. And I want to use complex morlet function. Here are some background:
Continuous wavelet transform definition: $C(S,T;f(t),\psi (t))=\frac{1}{\sqrt{S}}\int_{S}^{b}f(t)\psi^{\ast }(\frac{t-T}{S})$
S is scale vector.for example 1:60;$T$ is time slid. ... |
I'm trying to find the fundamental frequencies present in a piano recording using MATLAB. These are the steps I've followed;
Find the envelop of the signal
Find the note onsets
perform FFT between each onset
Harmonic product spectrum.
It's when I try to implement the HPS algorithm that I face a "dimensions don't agre... |
Please suppose the following:
The frequency of a signal's fundamental has been estimated using FFT
and some frequency estimation methods and is lying between two bin
centers
The sampling frequency is fixed
Computational effort is not an issue
Knowing the frequency, what is the most accurate way to estimate the corres... |
I've often seen i my DSP book, that when they record a sound, they use a sample rate at 10khz or 8 khz, which makes sense since the fs is 2 times bigger than the sampling signals max freq.
What i don't understand is why they only take 205 samples, rather than 10000 samples or 8000 samples, wouldn't each sample be "unpe... |
Can you please explain in simple terms what do the input parameters indicate in the ordfilt2 function in matlab?
B=ordfilt2(A,Order,Domain)
I have seen people use this function as J = ordfilt2(I, 9, true(5)) or J=ordfilt2(I,25,ones(3,3))
But I do not understand what each input does to the image I to give J as output..... |
I need to convert 150 Frequency domain samples to the time domain. The problem is, I have been provided with 250 time domain samples for comparing my results. How am I supposed to relate the 150 samples to 250 samples? I can't find any relationship like interpolation/decimation between the two.
Does this have anything... |
I have researched a bit into DSP filters for the problem of finding the angular velocity from X/Y acceleration measured by a rotating accelerometer. Essentially I need more help in picking the best type of filter.
An example of the type of data I can measure can be seen in this image (ignore the y-axis as values are s... |
Text present in captured images is high frequency or low frequency component?Why?
|
I'm building my own MIDI synth.
I have to create a decent sounding tone for every note on the piano keyboard (A-1 through C7, or MIDI 21 through 21+88=109)
I've been using a basic ring resonator, where I create a ring of the right size (for example, sampling at 44.1 kHz the ring for A440 a.k.a. concert pitch would be 4... |
Is there an example of an eigenfunction of a linear time invariant (LTI) system that is not a complex exponential? Justin Romberg's Eigenfunctions of LTI Systems says such eigenfuctions do exist, but I am not able to find one.
|
I'm trying to combine two filters into a single filter command for a homework problem and was looking for advice. I don't necessarily need an explicit answer as long as someone can point me in the right direction.
In the following code, assume that 'y' is a sound file that has been pre-loaded (10kHz). Also, both the h... |
In a problem I'm working on, I have a signal that is sampled 256 times for 3.5 microseconds.
After performing a Discrete Fourier Transform on the data, what is the frequency step between the calculated values of Cn? The prompt states that this is also called the bandwidth of each point in the power spectrum.
How can I ... |
How do you calculate the noise equivalent bandwidth for an IIR or FIR filter?
|
I am doing a project on image classification and I don't know where to get the data-set collection for cars and bikes.Any suggestions to sites for this purpose is welcome.Also please suggest the general size of images to act as a database.
Thanks and regards in advance.
|
I was reading about active sonar and couldn't quite understand how the echos are recognized.
My doubt is, when the sound signal is reflected back, it is greatly attenuated and distorted due to many factors.
Do they use MFCC(which I think is only good for audible range) for identifying the echo or are there any other be... |
I'm working on my own implementation of the discrete Haar wavelet transform, I understand the wavelet theory and how to construct the Haar matrix of size N to perform the transform, but obviously there is a problem using the Haar matrix in application - it's simply too big.
I am working on an application that applies t... |
Here I have a MATLAB code for Ideal Low pass filtering an Image. In the below code they have used D=sqrt(U.^2+V.^2); which finds some distances. Then this distance matrix D is compared with the cut-off frequency to create a filter function H ( H=double(D<=P); ) that has be multiplied with the fourier transformed image ... |
I have a device (whose behaviour I can't change) which does the following signal processing:
The incomming signal contains two frequencies $f_1$ and $f_2$. One has a huge amplitude, the other a smaller one:
$x_1 = X_{01} \cdot cos(2\pi f_1 \cdot t)$
$x_2 = X_{02} \cdot cos(2\pi f_2 \cdot t)$
with (for example):
$f_1 = ... |
We can often read that Hilbert transform is useful for envelope detection (e.g.
Hilbert transform to compute signal envelope?)
I have done some tests with various soundfiles, and
x[n] -> absolue value -> 1-pole low pass filter -> envelope
or
x[n] -> Hilbert transform -> absolute value -> 1-pole low pass filter -> enve... |
Given a an IIR lowpass-filter in z-space:
$ H(z) = \frac{\sum_{i=0}^P b_{i} z^{-i}}{1+\sum_{j=1}^Q a_{j} z^{-j}} $
How to calculate it's 3dB cut-off frequency?
I about evaluating it's fourier transform (as long it exits) and take it's magnitude:
$\frac{1}{\sqrt{2}} = \frac{|H(e^{j\omega_c)}|}{|H(e^{j0})|}$
This is then... |
When I calculate the cross correlation between two vectors with the following code
a = [1 2 3 4 5];
b = [6 9 8 9 10];
% correlation using convolution
conv(a,conj(flipdim(b,2)))
% correlation using FFT
ifft(fft(a,9).*conj(fft(b,9)))
fftshift(ans)
when I use the FFT i need to fftshift the output in order to get the cor... |
My knowledge of wavelets is less than epsilon. Bear with me.
If I have a signal of two well separated sinusoids (15 and 48 Hz) plus some random noise, I can clearly make out the two in a spectrogram (the two stripes in my picture);
t=0:0.002:1; % fs = 500 Hz
x=4*sin(2*pi*15*t)+2*cos(2*pi*48*t);
xn = x + randn(size(x)... |
I'd like to do a fade out of a sound in a few seconds, but in a "spectral way", with a special curve :
(here x-axis is time, y-axis is frequency from a few hz to 20khz).
All the part "to be removed" has to be removed !
Do you know how to do this ? (an EQ / simple IIR/FIR filter won't work for this, etc.)
|
This question follows from: Synthesizing harmonic tones with Karplus Strong
I am attempting to generate a full soundbank of 88 notes.
As far as I can see my three options are:
Using samples
Using something like Karplus Strong (as linked above)
Synthesising each harmonic and combining them
(1) does not give much flexi... |
I've been googling for a while and came across the audio cookbook and Bjorn's blog explaining it further Link Here.
Background info: I've modified the rtl-sdr open source code to tune to a VOR station (transmits heading, typically used for aircraft). I tune to 113.1 MHz which is the the frequency the nearby VOR station... |
I want to model a "negative dispersion" in waveguides.
Is it possible to design an all pass filter with inverted phase response? (e.g. -pi at 0 and pi at Nyquist)?
I feel :) this could be possible in complex domain (but don't know how). I could use a Hilbert transformer to complexity real signal at first.
|
I have a guitar music signal and I want to detect the onset points via energy.
This is the signal example:
This is the energy plot:
My question is what would be the best method defining the threshold and consequently finding the peaks. I reckon I will have to set a window length and a window step (I am thinking 1000 ... |
What is currently the most accurate Voice Activity Detection algorithm with high levels of background noise? I would also appreciate if it does not require any manual calibration. Bonus points for examples.
EDIT: I am referring to accuracy as yielding the lowest amount of false positives and negatives.
|
I am working on a project that requires me to detect and track a human in a live video from a webcam connected to a Beagleboard xm. I have completed this task using Opencv in pixel domain. The results on the board are very accurate but extremely slow. Many people have suggested me to leave pixel domain and do the same ... |
Does some have an example of what a Wiener filter (that can be used directly with scipy.signal.wiener) can be useful for, in sound processing (it seems that such adaptive filters can be useful for noise reduction, etc.) ?
I tried with various (noisy + sinusoids) soundfiles (read into an array x) with the command
y = wi... |
I am working and researching on Image watermarking/steganography and I'm stuck at a point and want to know which technique is better in image processing for data hiding.
Bit Plane Complexity Segmentation OR CDMA Spread spectrum.
Can some experts give their opinion on both techniques and which one is better and why? lik... |
I am new to the field of image compression. While going through various texts, I read about how transforming the image to another domain using, for example, the wavelet transform, or the DCT, makes it suitable for lossy compression.
I have been trying to play around with wavelet transforms on a sample bmp in MATLAB. Us... |
Given the signal shown below, what is the best way to remove the steps and local maximas it contains. The signal contains some steps which can last up to 100 Samples before they return to about the same value as before the step (Marked with red circles). There are also some peaks which last only for one sample which sh... |
I am struggling to implement a mathematical morphology toolset in an image processing package. I base my implementation on what I saw in MATLAB, and on several papers on the subject.
There seems to be abundant literature on morphological operation optimization through structuring element (strel) decomposition. For ins... |
If i have two images of the same scene, reference image and a shifted image, the shift can be in x or y directions, i want to estimate the shift using the shift property of the fourier transform.
S1 = fftshift(fft2(im1)); % Fourier transform of the reference image
S2 = fftshift(fft2(im2)); % Fourier transform of the i... |
My question here is in regards to implicit information/terminology.
Basically, whenever we say that "a shift in time means a change of phase in fourier space", is it implicit that the shift is always circular? Are there any exceptions to this? Caveats? etc?
|
Could you please clearly explain what is the difference between correlation and convolution that is done by a filter on an image?
I mean in terms of signal processing definition I know that convolution describes the output of an LTI system, that is if an LTI system produces an output due to convolution with an input s... |
I have a question regarding Discrete Fourier Transform and Discrete Time Fourier Transform.
Suppose that we have a sequence $x(n)= \{1,2,3,3,2,1\}$.
So is it possible to reconstruct the Discrete Time Fourier Transform $X(e^{j\omega})$ from the Discrete Fourier Transform $X(k)$ ? And how?
In my opinion , it is possible,... |
Question 3.1 d from Chapter 3 of Oppenheim's Signals & Systems
I have
$$x[n]=(-1)^n{u[-n]-u[-n-8]}$$
$$h[n]=u[n]-u[n-8]$$
and the question asks for $y[n]$ which is the convolution of $x[n]$ and $h[n]$ namely
$$y[n]=x[n]\star h[n]$$
I'm stuck with the limits on the sum
$$\sum_{k=-\infty}^{\infty}{\left((-1)^{k}(u[-k]... |
As I understand, the overall colour average can be obtained by summing the individual r, g, b values of all pixels within and image and dividing by the number of pixels to produce a new tri-vector.
What are the applications of such techniques?
|
I have to compute an HSV histogram of a colored image. Is it same as an H-S histogram?
I have found H-S histogram computation code everywhere. What is the method to change an H-S histogram to an HSV?
|
I have a blurred and noisy image $X$, I want to apply the Wiener filter on it and get a deblurred and denoised image $Y$ (i.e apply inverse of blurring filter while at the same time reducing some noise, if not accentuating it). I'd like to measure the SNR in both in order to evaluate the quantity of noise deleted.
I kn... |
STFT can be successfully used on sound data (with a .wav soundfile for example) in order to do some frequency-domain modifications (example : noise removal).
With N=441000 (i.e. 10 seconds at sampling rate fs=44100), windowsize=4096, overlap=4, STFT produces approximatively a 430x4096 array (first coordinate : time fra... |
I'm studying for a test and I can't really explain this question very well.
What will happen If we convolve a discrete signal signal with itself?
(Output signal )
I'll appreciate it if someone can explain this concept to me. Thanks in advance.
|
We used to classify signals as 1D and 2D etc ie one dimensional and two dimensional. For example a periodic square wave signal is 1D and an image is a 2D signal etc (reference - Signals and systems by Simon Haykin and Barry Van Veen, 2nd edition , page 2).
But the same periodic square wave signal can be decomposed usin... |
I'm trying to add up a few black & white images of the same object in order to amplify the SNR. I'm working on relatively low SNR images (about 1.1) and I wish to amplify it somehow.
My first try was to add up the images grey-levels while removing the noise through a simple threshold but this isn't really working since... |
I recently was studying gabor filters and came to know that they have a shortcoming that they do have a minimum but some reasonable dc component.
now my question is why is it necessary to remove the dc component (using log gabor).
If there are any other limitation of gabor filters then please do tell me.
thanks..
|
I have read in many papers that time complexity of WPT is $O(N \log(N))$, but I would like to know what is the effect of Levels in the time complexity.
Must it be one of the following ?
$O(2^{L} ~N~ \log(N))$
$O(2^{L+1} ~N~ \log(N))$
$O(L ~N ~\log(N))$
$ L$ is the number of decomposition levels
Can anyone helps wh... |
I have an array $A$ having the next 145 values
I would like to calculate the $\frac{dA}{dX}$, having a 1D grid, $x$: 1:286:41468
I use the function gradient:
DA_DX = gradient(A, 41468/145)
I am trying to understand why the $\frac{dA}{dX}$ output graph has peaks which cause problems to my code. Please, do you see some... |
Let's say that a stochastic process is defined as
$$X(t) = \sum_{n = -\infty}^{+\infty} X_n * f(t- nT)$$
where $X_n$ is the $n$-th symbol among independent random symbols. I have proved that $\mathbb E[X(t)] = 0$. But, I want to prove that this stochastic process is Wide Sense Stationary(WSS) which means by definiti... |
I'm reading a biology article (full text here) that analyzed the variation of a cell parameter over time at different stimulus intensities (calcium concentration). The frequency of peaks increases at increasing calcium concentrations, while their duration remains constant, fitting a gamma distribution. Here are the bur... |
I want to build a detector of sorts. Say I have a bunch of signals and they all share some patterns, like some peaks in frequency or something more complicated that I can't bother to calculate by hand. I do however have plenty of these signals, so maybe I could "model" statistically, and more importantly, numerically t... |
When we are do a discrete Gabor transform on a 1D signal, we apply a Gaussian window on a segment of the signal. However, due to the tapering ends of the Gaussian window, the magnitude of the data points will be reduced more towards the ends, This implies that the the frequency components of the segment of the signal w... |
What does the term spatial correlation and spatial convolution mean with respect to digital image processing ?
|
In my final year project, we are using a SIFT feature descriptor to classify and recognize objects, but I have never come across segmentation in the process of image classification/categorization.
Isn't this step necessary?
|
I am working different types of filters to remove speckle noise in ultrasound image. I have taken the below paper as my base paper and trying to reproduce the results of this paper:
My Base Paper
I designed all the filters and tested with the default matlab images. I was happy with the results. The Mean Square Error (M... |
I am just trying to classify images using kNN algorithm with the aid of MATLAB. So now I am in need of some collection of images of peoples' faces. Where can I get some open database of faces (both females and males).
|
I have a project in which I have to recognize 2 lines in different "position", the lines are orthogonal but can be projected on different surfaces. I'm using opencv.
I'm not asking for code, but only for hints about how can I solve this? I tried houghlines function but it works only for straight surfaces.
thanks i... |
A graylevel reference image is transformed displacing each pixel. The magnitude of the displacement follows a bidimensional gaussian distribution. When two pixels in the reference image fall in the same pixel in the transformed image, the resulting graylevel of the transformed image is the sum of graylevels of both pix... |
I always wondered why transmission capacity depends on bandwidth. For example, let us say that there is an isolated island. In this island, people decide that all wireless networks use frequencies that are positive integer multiples of one base frequency. Then when we do Fourier transform, we can just use least common ... |
I've done research and could not find any resources on this topic.
I have message signal composed of more sinusoids. Then I preform amplitude modulation, that is multiply that signal with higher frequency carrier signal, and obtain modulated signal. Then to demodulate that signal, I multiply the signal with same carri... |
Let's say I have a signal sampled at 976 Hz and I want to remove network interference noise, i.e. 50 Hz and all the harmonics. Is it possible theoretically to design a comb filter to do that?
I have looked at how to do this in MATLAB but the problem is that the order of the comb filter -which defines the fundamental f... |
The topic of zeroing frequency bins before IFFT has been discussed here : Why is it a bad idea to filter by zeroing out FFT bins?
It was very helpful to understand why it is a bad idea.
What do you think about, instead of zeroing, multiplying by a window (in the frequency domain!) which is 0 at the centre and smoothly ... |
I'm trying to create a simple NFC/RFID software simulator and am having a hard time understanding the math fully. I know that NFC tags respond by load modulating the 13.56 MHz wave that the reader is sending it. I'm pretty sure NFC tags use a subcarrier wave with a frequency of ~847 kHz. Where I'm getting confused is h... |
i need to find the frequency response of the following equations:
$$h(t) = e^{-3t} u(t)$$
$$x(t) = 1+\cos\left(\frac{4\pi}{3}t\right)$$
find $y(t)$
However i am quite confused on how to do this, please explain and show every step so i can learn
|
Does there exist a discrete low-pass filter algorithm that is greatly more computationally efficient for high-order (e.g. greater than 10) low-pass filters than straightforward methods like series of IIR Butterworth filters?
|
For a classification sort of experiment using Matlab, I am in need of a database of male and female voices. So where can I get links of such open databases.
|
In case a symbol encodes a non-integer number of bits, how is done the bit-symbol pairing?
For example, we have a 3-levels FSK with bit rate of 1Mbps and a sequence 01011001. What is the symbol period? What is the sequence of symbols?
Note: My guess is that the actual bit period and symbol period are the same. Hence, t... |
from my DSP book,i am reading that exponential signal $x(t)=e^{-a*t}$ has some time constant value $c$ let say if $e^{-a*t}=e^{-t/c}$ which means that $a=1/c$,but i want to understand what is general formula to find time constant for other signals and also what does it express?i meant what is real mining of time co... |
I would like to make an acoustic measure of one room, so I can compare it with a acoustic measure of some other room. Then compare these data. So when I take an acoustic measure of the first room again, I could recognize that i am in the first room again. Next downside is that I would try to use my iPhone's microphone ... |
I have set of HRIR( Head related impulse response) downloaded. I want to convolve it with an audio signal to generate 3D signal in Matlab.
I am new to this field. Is there any tutorials or can any one help me how to start
|
By reading some books about wavelets, it seems that Discretized CWT is not the same thing as DWT.
Can we give a classification of Discretized CWT vs DWT vs FWT etc. ?
A few remarks :
All I read about DWT or MRA (multi-resolution analysis) involves a dyadic factor (2) for $a$ in $\frac{1}{\sqrt{a}} \Psi(\frac{t-b}{a})... |
Now I', wondering how to best implement a control algorithm for it. I tried using a PID controler but started with a simple P-control first. The problem is, that when using the equation delta_exposure = k*e whereas e = mean_grey_is - mean_grey_want = mean_grey_is - 127 and with k as a fixed value it is hard to define a... |
I am wondering why is the linear phase property of filters with symmetric coefficients important for some practical applications of short time fourier transform, such as image processing? I have read that the linear phase property will ensure that there will be no phase distortion of the signal by the filter? Can anyon... |
In the LSH Tutorial by Slaney, it is written that
Increasing the quantization bucket width w will increase the number of
points that fall into each bucket. To obtain our final nearest
neighbor result we will have to perform a linear search through all
the points that fall into the same bucket as the query, so v... |
i need to find the frequency response of the following equations:
$$h(t) = \delta(t) +e^{-2(t-1)} u(t-1)$$
$$x(t) = \cos\left(\frac{pi}{4}t\right)+2\cos\left(\frac{pi}{2}t\right)$$
find $y(t)$
However i am quite confused on how to do this, please explain and show every step so i can learn
|
I would like to ask if I should use 2-PAM modulation or 4-PAM modulationif I want to send data as fast as possible given that in each case I have the same frequency spectrum available.
|
I have a signal in Malab, and I need a matrix, probably transposed specgram matrix without using specgram tool. Is it possible?
|
This question must be basic for this forum, but I'm only start working with DWT recently, and I was working with CWT before.
I think I can decompose my signal to L level and then get the scalogram with the following scripts.
my question is how can I reconstruct the signal for each details{cD1,cD2,cD3} and approximatio... |
I read somewhere the below two line and got confused what is the actual difference between the two line. These two lines are related to CAN
1.Maximum Signal frequency used is 1 Mbit/sec
2.Typical maximum data rate achievable is 40KBytes/sec.
If anyone knows about it please share the answer.
|
We know that the signal attenuates out with distance and according to the channel transfer function or frequency response, the signal frequency components attenuate to different values based on frequency.
The effect of distance is widely acknowledged & used in practice as a path-loss model which is exponentially decre... |
I'm working on a DSP-based senior project, and we'd like to allow the user to provide a 20-20kHz cutoff specification for IIR/FIR high and low-pass filters on the fly. This would be a simple problem on a desktop, but we're working on a TI 5535 DSP chip. So we're looking for a C library for generating coefficients. W... |
I've got a project and need to calculate MFCCs. I tried to read some tutorials and then make a MATLAB function but I seem to have wrong answers. I'd like to feed MFCCs to one of the classification model--my choice would probably be NN or SVM. I am going to classify sound samples that either belong to one of many catego... |
I am trying to understand panorama stitching. I've come to a conclusion that homography is one of the fundamental parts in the process. Now I am trying to make sense of all the information from literature across the web concerning about solving for homography.
I've read about Direct Linear Transform, Least Squares met... |
I'm developing an audio watermarking algorithm which embeds text (binary form) in DWT-DCT coefficients. The goal of the algorithm is to hide song information (like artist, song, album,...). Everything works fine the text is recovered using another algorithm which extracts the hidden text. However my algorithm doesn't r... |
I heard that it is important to have all oscillator clocks at different places be synchronized for example in a geographically distributed system such a telecommunication network. Of course to some error margin.
They fix GPS receivers in the base stations to synchronize the oscillators. I know GPS transmits time, as in... |
How would I detect an edge oriented at 22.5° using a spatial filter?
|
I am implementing visual bag of words through these steps:
Find interest points using SIFT
Calculate SIFT descriptor
Build codebook through kmeans clustering of SIFT descriptors.
How can I visualize these visual words? For example in the following lecture, how do they get those patches?
|
I am very much interested in pattern classification experiments and its theory etc. So I am trying some home brew experiments using MATLAB. As a first major experiment, I would like to classify persons based on sex from facial images. My doubt is basically is it worth attempting it, because right now I don't have idea ... |
I want to estimate sampling clock offset. I am currently referring this paper
" CRAMER-RAO BOUNDS FOR DATA-AIDED SAMPLING CLOCK OFFSET AND CHANNEL ESTIMATION ". Is there any other method to estimate? I also referred Lee's method, but it gives symbol timing. Is there a way to estimate sampling clock offset from timing e... |
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