## MMSE

Started by in comp.dsp15 years ago 1 reply

Dear all, Using Matlab I was trying to find unknown vector 'omega' using Minimum Mean Square Error method given...

Dear all, Using Matlab I was trying to find unknown vector 'omega' using Minimum Mean Square Error method given by omega_cap=C_omegaY*(C_YY)^(-1)*Y in the above equation the only known vector is Y. where C_omegaY = cross correlation between omega and Y and C_YY = auto correlation of Y when my task is to estimate the vector omega, how could I find the cross correlation between...

## Autocorrelation versus Cross-correlation

Started by in comp.dsp15 years ago 3 replies

Hello, I am trying to determine the frequency of a signal. Samples of the signal are taken from 2 channels at a time. After some filtering, I...

Hello, I am trying to determine the frequency of a signal. Samples of the signal are taken from 2 channels at a time. After some filtering, I perform the autocorrelation of each channel, and the cross-correlation of the 2 channels. The autocorrelations, as expected, yield almost identical results, from which we can easily work out the frequency of the measured signal. However, the cross-cor...

## Accuracy of channel identification based on finite data record

Started by in comp.dsp15 years ago 8 replies

I have an FIR channel that I would like to identify, say h[n]. To do this, I create a test signal x[n] of length N as an input to the channel,...

I have an FIR channel that I would like to identify, say h[n]. To do this, I create a test signal x[n] of length N as an input to the channel, and I measure the output of the channel y[n]. Let's say that I obtain N samples of y[n] for simplicity. Then I estimate the autocorrelation rxx[m] of x[n], and the cross-correlation rxy[m] between x[n] and y[n]. Since I have finite N, then the q...

## Digital Waveform comparision question

Started by in comp.dsp15 years ago 4 replies

when trying to determine the correlation between a waveform contained in two asynchronously sampled series, either through cross correlation or...

when trying to determine the correlation between a waveform contained in two asynchronously sampled series, either through cross correlation or other techniques, is it common to perform some type of signal reconstruction beforehand? It would seem if I am sampling at 4x the max bandwidth, the max possible phase difference would yield huge errors if I just compared sample to sample (take tw...

## Help, plots of autocorrelation and cross correlation

Started by in comp.dsp14 years ago

Hello, I'm trying to work my way through a few introductory courses that I taped two years ago. I've been listening to them during the weekends...

Hello, I'm trying to work my way through a few introductory courses that I taped two years ago. I've been listening to them during the weekends and have to get straight on things! I've struggled through the material many years ago and am keeping my fingers crossed. Basically, I'm hoping for a tuturial from you directed to my specific questions below. If the input to the below functions i...

## Cross correlation applicable?

Started by in comp.dsp14 years ago 1 reply

In deciding whether an athlete has recovered from a concussion, his performance in cognitive tests taken after injury is compared to those taken...

In deciding whether an athlete has recovered from a concussion, his performance in cognitive tests taken after injury is compared to those taken before injury. The test results consist of around 100 data points which measure reaction times under various conditions. The usual method for answering the question as to whether an athlete has recovered from a concussion is to compare the means of the ...

## not a descrete case but a simple question about signal processing

Started by in comp.dsp14 years ago 1 reply

Hi all I am reading the Papoulis's book on Random Variable and getting confused with the following formula: X(t) is input of a linear...

Hi all I am reading the Papoulis's book on Random Variable and getting confused with the following formula: X(t) is input of a linear system with impulse response h(t), Y(t) is its output. X(t) is a WSS Random Process ===> the Cross Correlation: Rxy(to)= Rxx(to) * h*(-to). where * is convolution, and h*(-to) is conjugate of h(-to). Now the density spectrum Sxy(omega)= Sxx(omega)H*(

## Cross Correlation Function

Started by in comp.dsp14 years ago 1 reply

Dear Sir, I need to calculate the cross correlation of left and right channel of stereo audio signals. And I need to get and output when it...

Dear Sir, I need to calculate the cross correlation of left and right channel of stereo audio signals. And I need to get and output when it is -1. I try to find a C++ program for above purpose. But i couldn't find that. Therefore please help me or direct me to correct way Asoka Colambage

## Cross Correlation Query

Started by in comp.dsp14 years ago 6 replies

> From Wikipedia: http://en.wikipedia.org/wiki/Cross_correlation "The cross-correlation is similar in nature to the convolution of...

> From Wikipedia: http://en.wikipedia.org/wiki/Cross_correlation "The cross-correlation is similar in nature to the convolution of two functions. Whereas convolution involves reversing a signal, then shifting it and multiplying by another signal, correlation only involves shifting it and multiplying (no reversing)." This seems wrong to me because cross correlation is the one with the comp

## Cross Correlation Definition

Started by in comp.dsp14 years ago 4 replies

I have read about cross correlation in several places and I think I understand it but there is this particular definition of correlation...

I have read about cross correlation in several places and I think I understand it but there is this particular definition of correlation that keeps me thinking. In a probabilistic framework I have seen the cross correlation of an stochastic process x(n) defined as: Rxx = E{x(n)x'(n)} where E denotes expectation operator and ' denotes conjugate transpose. (hermitian transpose) This defi...

## Fast Normalized Cross-Correlation

Started by in comp.dsp14 years ago

Hi. All, I'm working on Image processing and using Fast Normalized Cross- Correlatino method to compare the template image with the...

Hi. All, I'm working on Image processing and using Fast Normalized Cross- Correlatino method to compare the template image with the Sample image. Fot the theory I use, I need to undestand two terms. 1) Weighted sum and 2) Rectangulare basis function. How should I apply this two the template image ? If anyone knows, reply asap. Thanks & Regards, Chauhan P.D

## Cross Power Spectrum Estimation

Started by in comp.dsp13 years ago 7 replies

The only way I have seen documented to estimate the cross spectrum density is by obtaining the DTFT of the cross correlation of the two signals...

The only way I have seen documented to estimate the cross spectrum density is by obtaining the DTFT of the cross correlation of the two signals of interest. With so many spectrum estimation methods available I was wondering if it is possible to estimate cross spectrum using those methods. For example using the MEM (aka Burg), MUSIC, ESPRIT, CAPON, APES, Yulk-Walker, etc. Even in Matlab the o...

## Question about Cross-Correlation in Frequency-domain

Started by in comp.dsp14 years ago 6 replies

Greetings, I am currently writing my diploma-thesis on new spectroscopic methods, and one of them (2D-Correlation-Spectroscopy) involves...

Greetings, I am currently writing my diploma-thesis on new spectroscopic methods, and one of them (2D-Correlation-Spectroscopy) involves cross-correlation of fourier-transforms. I have encountered a strange issue, for which even my professor could not supply me with a satisfying answer: When the cross-correlation of two Fourier-transformed signals is to be calculated, why do I have to take the ...

## 2D FFT cross correlation problem

Started by in comp.dsp14 years ago 4 replies

I'm doing 2D image cross correlation on the c6400 TI DSP. I'm using the FFT functions in the DSP library to do this. I high pass filter...

I'm doing 2D image cross correlation on the c6400 TI DSP. I'm using the FFT functions in the DSP library to do this. I high pass filter my images before correlating them using a 3x3 convolution mask. The result seems to be correct giving a target peak in the correct position but there is always an erroneous peak at the very centre which does not change. Here's an image of the correlation plan...

## Barrel Distortion correction algorithm

Started by in comp.dsp14 years ago 7 replies

Hi..All, I have started to work on Image processing. I have used Cross- correlation to find the match between two images. Now, I want...

Hi..All, I have started to work on Image processing. I have used Cross- correlation to find the match between two images. Now, I want to remove barrel distortion from the sample image. But I don't know the algorithm to remove barrel distortion. Does any one have any idea of the same ? Thanks in advance..

## funding fundamental frequency(pitch)

Started by in comp.dsp14 years ago 26 replies

HI, We re working on a project dealing with south Indian music signals. We re right now stuck with finding out the fundamental frequency of...

HI, We re working on a project dealing with south Indian music signals. We re right now stuck with finding out the fundamental frequency of the signal. Wat we ve done so far: 1)Segmented the signal and store it in an array 2)Find out DFT of the segments and store. 3)Find the cross correlation between adjacent elements from the DFT values and store. 4) Take the maximum value from the cr...

## About range estimation for fixed point implementation

Started by in comp.dsp14 years ago 1 reply

I am reading a paper about fixed point implementation. The author has given an example for input range estimation for multi user detection. It...

I am reading a paper about fixed point implementation. The author has given an example for input range estimation for multi user detection. It is said "From the characteristic of the Gold code, we know that the maximum value of cross-correlation coefficients is the auto correlation of any particular spreading sequence,i.e., rang R is R=2x(2^r-1), where the spreading gain is 2^r-1". I can unde...

## cross correlation

Started by in comp.dsp14 years ago 3 replies

Hi, i'm relatively new to dsp and matlab.I currently have 2 waveforms read into Matlab from my oscilloscope,for example waveform A and waveform...

Hi, i'm relatively new to dsp and matlab.I currently have 2 waveforms read into Matlab from my oscilloscope,for example waveform A and waveform B. I want to to perform a search for a similiar match of waveform A in waveform B. I believe its poossible to do this using the xcorr function in matlab but I'm having difficulties in getting this to work. I want to plot my results so that a "correlation...

## cross correlation vs FFT

Started by in comp.dsp14 years ago

Dear all, I have two signals which I want to test the correlation of the image by comparing two procedures, the cross correlation and fast...

Dear all, I have two signals which I want to test the correlation of the image by comparing two procedures, the cross correlation and fast fourier transform. I do that in matlab, but I have a problem that I don't know how to use a function correctly. Here is my code; xt = 2*(rand (1024,1)-0.5); yt = rand (1024,1); for i=1:1024; yt(i)=0; end; i=1; for hh=501:532; ...

## cross correlation

Started by in comp.dsp14 years ago 4 replies

I have a problem doing cross corrlation in matlab. The problem is I don't know how to use the 'xcorr' function correctly. For example, if I...

I have a problem doing cross corrlation in matlab. The problem is I don't know how to use the 'xcorr' function correctly. For example, if I have x=1024 numbers do the crosscorrelation with y= 1024 numbers, the result I have will be around 2048 numbers with half left of the result is zero, as it suppost to be only 1024 numbers and give me the peak where I expect it. If I do the FFT correlation, ...