The tag has no wiki summary.

learn more… | top users | synonyms

2
votes
1answer
50 views

Efficient calculation of correlation function every N_th point

I would like to calculate a long correlation function of length say, 1e6 points. I have a prior knowledge that the correlation peak will be in point k*1000. Is there an efficient way to apply this ...
0
votes
0answers
27 views

“Circular shift - invariant” distance

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: ...
0
votes
0answers
47 views

filter out an expected but not regular signal

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} ...
1
vote
1answer
59 views

Least squares and auto and cross correlation

I am trying to understand why auto and cross correlation helps find the best fit line in least squares. I have an equation as stated here: $Ax=b$ -- I have not exact solution, so I use the least ...
0
votes
1answer
27 views

Validate correlation of data

I have data from two samples of a biological process. The data consists of oscillations with noise in them. The noise is also relevant as it is characteristic of this data. I want to show that both ...
0
votes
2answers
76 views

Cross correlation peak value

I would like to measure the time delay between two signals. By applying the cross correlation I get the time delay or number of samples by the location of the cross correlation peak, however I am ...
0
votes
0answers
32 views

Auto/cross correlation of a cosine in the context of an adaptive beamformer

I am currently reading chapter 13 of 'Adaptive Signal Processing' by Widrow and Stearns, so if anyone happens to have a copy of the book to hand it could be helpful. I am reading the chapter on ...
1
vote
1answer
64 views

Efficient Marker Detection for Images

I need to detect a known number of simple markers (chessboard patterns) in a color image efficiently. I implemented normalized cross correlation (NCC) as a pixel shader via WebGL since I need this to ...
0
votes
0answers
64 views

Why Normalized Cross Correlation Score of different templates is high?

I am using OpenCv's built in template matching function to search for an object in image. I am using Normalized Cross Correlation Method.The function is returning a value which I think indication of ...
0
votes
2answers
66 views

“Perfect waveform” for cross-correlations?

I am well versed in cross-correlations, as my masters thesis heavily relied on them for music classification and beat detection. So this question focuses more on the signals that I am running an ...
1
vote
1answer
77 views

range and motion in received signals by radar

I've got two signals which are consecutive received signals by a radar system. the signals values are complex (in form x+iy). I have generated a trasmitted signal using the info available. Now, I ...
3
votes
2answers
87 views

Map time difference between two similar videos

Question: Is there any software, source-code, or well documented and easily implementable research (I am not afraid for a little bit of Python) to do the following: Take two similar videos from ...
0
votes
1answer
88 views

Cross correlation vs FFT for finding phase between 2 signals

I have been struggling with this issue for months now, trying to understand which one to pick: FFT or cross correlation. I am given a sine wave (with phase, amplitude, frequency and time vector ...
3
votes
4answers
276 views

“cascaded” cross-correlation

so, first let's do this for the circular correlation case (it might be easier). let's say we have three real and periodic functions or signals $x(t)$, $y(t)$, $z(t)$ all with period $2 \pi$: $$ ...
0
votes
1answer
141 views

Solution to Cross-correlation problem of 2 audio signals

There are 2 audio signals, X & Y. X is of 15 second duration. The duration of Y is not given. Y is a part of signal X (ie a small part of audio X is extracted & made into audio Y) I have to ...
0
votes
1answer
30 views

Avoid saturated pixels in cross-correlation computation

I am doing template maching using Normalized Cross-Correlation for measuring similarity between template and image. However, some images from my dataset contain saturated pixels (overshoot) which ...
1
vote
0answers
100 views

GCC-PHAT cross correlation

I am trying to implement GCC-PHAT in python. The approach is similar to the following two links: link1 and link2 It seems the only difference between GCC-PHAT and normal cross-correlation using FFT ...
1
vote
1answer
33 views

How to decode speaker gender from spoken transcript

I have 20 audio recordings (raw format) of people reciting the same ~50 word transcript. I would like to use audio signal analysis to decode speaker gender from audio recording. Intuitively, it ...
0
votes
1answer
86 views

Cross-Correlation : Comparing two signals or finding the location of a target

I read across places that cross-correlation of two signal (a radar sending a signal and receiving it back) one can detect the location (distance) of a target from a point and that cross-correlation ...
-1
votes
1answer
102 views

Correlation : Cross correlation why we need to multiply the samples

I understand what books states about cross-correlation of signals and their mathematical representation: For continuous functions f and g, the cross-correlation is defined as: $(f \star g)(\tau)\ ...
-1
votes
1answer
52 views

phase amplitude transform as a solution to reverberation

I am trying to use generalized cross correlation with phase transform (GCC_PHAT) on some audio processing indoor, with the existence of low noise. I ve read here that by canceling the magnitude ...
1
vote
1answer
54 views

What Information does the phase of a cross power spectra give me?

I obtain the cross power spectra by the following steps: compute the FFT of signal A and B Multiply A with the conjugate of B store it in C (cross power spectra) Now looking at the Phase of this ...
1
vote
0answers
47 views

Time delay analysis in different binary sequences

I am extracting a property of a signal which I represent with either a 0 for absent or 1 for present. This property is extracted for each data point in a time series and in the end I am left with a ...
1
vote
2answers
193 views

fast 2D cross correlation algorithm

I want to match a small template to a larger image, that the distance between the template and the subimage with the same size of the template is minimized. It can be solved directly or by applying 2D ...
0
votes
0answers
57 views

Noisy Signal auto/cross-correlation

I am trying to understand the basics of the cross/auto-correlation if the noisy signal $y(t)$ which is received from the channel at the receiver. Here at receiver we want to estimate the noise in the ...
1
vote
1answer
451 views

Correlation using FFT/IFFT (fast convolution) in Java - not centered

I try to find about the delay between two audio files using Cross Correlation in Java. I've already done this algorithm so far that i get a idea about how many samples is the delay. FFT x1 -> Zero ...
2
votes
1answer
144 views

DOA estimation 2 sources time delay estimation uniform array

I am new to signal processing, so sorry if the question is superbanal. I have been spending more days than I would admit on this and can't find the error. I have two triangle waves that are emitted ...
1
vote
1answer
57 views

Fast cross correlation with limited range

I am measuring the phase shift between two pseudorandom signals using correlation ifft(A.conjugate()*B) and picking out the maximum). That works very well, but takes a lot of time. I roughly know ...
1
vote
0answers
42 views

ACF and PACF Confidence Levels for ARMA

I'm trying to figure out where exactly to draw the confidence levels for the autocorrleation function (ACF) and the partial autocorrelation function (PACF) for an ARMA model. For PACF I found that a ...
1
vote
2answers
165 views

Subtracting Original Audio Signal

here is my scenario: one speaker is sending a chirp, and a microphone is recording it as well as all following echoes. The function of the chirp is already know. My goal: subtract the original chirp ...
0
votes
0answers
45 views

Describing a time delay at a maximum for maxima and minima but tends to 0 elsewhere

I have two force-time signals obtained from a couple of force plates, corresponding to input/output signals for some system. Plotting the two together one of the first things I noticed was a time ...
2
votes
1answer
86 views

Ultrasound Signal Processing Methods

I am sending 6.6Vpp square wave across a narrow-band, 40 kHz Transmitter to a narrow-band, 40 kHz Receiver. I want to find a very accurate distance between the two (sub millimeter). My assumption so ...
0
votes
1answer
481 views

How to compute the cross correlation of two fuctions

I am trying to implement Matlab's cross correlation function but I can't seem to replicate the results obtained when using Matlab's built in function "xcorr". Documentation for xcorr can be found ...
2
votes
2answers
154 views

Time delay estimate and sampling frequency

This is an extention to my other question. My sampling frequency is only about 2x my tone frequency. I want to estimate time delay of arrival using this signal. I am generating the tone signal so I ...
1
vote
1answer
112 views

Upsampling signal for cross correlation

I am recording a 17khz signal at a sample freq of 44.1khz. I want to perform cross-correlation between the received and transmitted signals for calculating TDOA. But when I do xcorr, the results are ...
1
vote
1answer
171 views

Time delay estimation using ultrasound

I have a sound source that generates an ultrasonic pulse. I have two microphones seperated by a distance which are at a distance from the source. I want to find the time delay of arrival of the ...
0
votes
2answers
394 views

Matching two audio inputs (signals) [duplicate]

this is for an application in which passwords are stored in the form of audio inputs . In order to provide user access , the password(in audio form) will be matched with already stored password(audio ...
2
votes
1answer
161 views

Cross-correlation of time compressed 1D signal

If I ave 2 otherwise identical 1D signals that are phase shifted from each other then cross-correlation is a perfect way to identify the time lag between the 2 signals. Now supposing I double the ...
2
votes
1answer
235 views

Normalized-cross correlation operation

According to my question about separability of Gabor filters in this link, I want now to convolve my image with this separable filter by using the normalized cross correlation operation. Assume my ...
1
vote
1answer
48 views

A special case of 2 jointly WSS stochastic processes

I know that 3 conditions must be met in order a pair of stochastic processes X(t) and Y(t) to be characterized as jointly WSS: 1. X(t) WSS 2. Y(t) WSS 3. Rxy(t1,t2) = Rxy(t1 - t2) = Rxy(t2 - t1) ...
4
votes
1answer
379 views

Ambiguous results of phase correlation in pattern recognition

We are using phase correlation to find pattern on image and what we get is 15% of results is spurious. Ours pattern has 32x32 pixels and image for research has 32x512 pixels. So we put Pattern to ...
1
vote
1answer
104 views

Detecting a frequency pattern in the frequency domain

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 ...
1
vote
2answers
777 views

Applications of Correlation in Signal Processing

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 ...
0
votes
1answer
96 views

how to calculate cross correlation of transient signal?

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, ...
1
vote
1answer
564 views

Signal compare - cross corelation in frequency domain matlab

I need compare two signals. Signals have simliar shapes but completely different values (as on picture): So I think cross corelation in frequency domain should gave me a number that shows me how ...
0
votes
2answers
144 views

Normalized cross-correlation in detail

I'm trying to implement a normalized cross-correlation algorithm but I don't get what in fact is this measure. What confuses is the wikipedia definition: $\frac{1}{n} \sum \frac{(f(x,y)- ...
1
vote
0answers
67 views

Train Pulse Recognition in Medium Voltage Networks

I just started a project in the Smart Grids area. It involves the recognition and quick extinction of earth faults in a medium voltage system. The system works automatically and pretty much gets rid ...
1
vote
1answer
1k views

How can I compute a time-frequency cross-spectrum in MATLAB?

MATLAB has a spectrogram function for the time-frequency analysis of a single signal. It also has a cpsd function for estimating the cross-frequency spectrum for two signals. However, cpsd averages ...
0
votes
1answer
184 views

Speech discrimination from animal sound

i am looking for discrimination of speech from animal sound if you take a 150ms frame of speech and bird as shown below, what feature can i extract from them so that i can effectively state the ...
0
votes
0answers
294 views

Similarity of signals

I have a question concerning methods to find different aspects of "similarity" of signals. So, first, I'd like to characterize the signals to be dealt with: We have a number of close to rectangular ...