Hello, In the following A is a real constant value signal and the symbol * denotes the convolution operation. We know...

Hello, In the following A is a real constant value signal and the symbol * denotes the convolution operation. We know that: A*x(n)----Fourier----> A.&(f).X(f), where &(f) denotes Dirac function. however, A.X(0)

I am using 5X5 and 3X3 kernels to convolve with Image. As I know convolution is computational Intensive and I have to convolve many kernels with...

I am using 5X5 and 3X3 kernels to convolve with Image. As I know convolution is computational Intensive and I have to convolve many kernels with my image to achieve the result, the execution takes 2 seconds. I would like to reduce the processing time. When I sequentially convolve kernel with image, the values difference between two sequentially convolution is very less in many places, beca...

hi.. here i m sending correct convolution code for matlab...%************************************************************************* % ...

hi.. here i m sending correct convolution code for matlab...%************************************************************************* % Convolution of Two signals %************************************************************************** %DKV clc; close all; clear all; x=[1,2,3,4]; %first signal h=[1,2,3,4,5]; %second signal N1=length(x); N2=length(h); X=[x,zero...

In terms of understanding the convolution theorem i've created the following MatLab code: [ BEGIN CODE] function...

In terms of understanding the convolution theorem i've created the following MatLab code: [ BEGIN CODE] function checkconvolutiontheorem [data Fs] = wavread('pop.wav'); % a 5 second sample of pop-music signal = data(1:453); % Signal consists of 453 non-zero elements. kernel = data(1:60); % Kernel consists of 60 non-zero elements. timesignal = conv(signal,kernel); % Convolution in...

I'm looking for a simple (need not be very efficient) VC++/C++ library that does the image (png) convolution, 2D FFT. I would like to develop a...

I'm looking for a simple (need not be very efficient) VC++/C++ library that does the image (png) convolution, 2D FFT. I would like to develop a image search feature (http://www.dspguide.com/ch24/6.htm) with a VC+ + based GUI around it. http://www.codeproject.com/KB/graphics/ImageConvolution.aspx does have the convolution feature but not FFT. Anybody gone through the same requirement? Thank...

Hi to all, I've been writing an application in JAVA that uses the Fourier Transform, and performs several operations, such as the...

Hi to all, I've been writing an application in JAVA that uses the Fourier Transform, and performs several operations, such as the convolution. The convolution is being processed in the time domain, so when signals lenths are big (i.e. 1000 values or more), it takes very long to process the convolution. So the best way to do this is by working in the frequency domain. Does anybody know ...

Hi, all, I am new to DSP. I try to verify the convolution in time domain equal to the mulitplication in freq domain. I have a input signal of...

Hi, all, I am new to DSP. I try to verify the convolution in time domain equal to the mulitplication in freq domain. I have a input signal of 128 points and a filter of 30 points. I do FFT of the input signal and filter(pad zero). end up with 128 points of both signal in freq domain. I then do multiplication of the two. In time domain, I do convolution of the input signal and the filter, which en...

Hi, I have created a three flash program that demonstrate: Discrete convolution Low Pass FIR filters Band Pass FIR filters. It is...

Hi, I have created a three flash program that demonstrate: Discrete convolution Low Pass FIR filters Band Pass FIR filters. It is located here: http://www.fourier-series.com/fourierseries2/convolution.html Brent

Hi, I am new to this programming world, and i really need some serious help. I have done a program in which i design a filter in frequency...

Hi, I am new to this programming world, and i really need some serious help. I have done a program in which i design a filter in frequency domain, then i take a CT image, which is a 3d image, read each voxel and make a 1d array. then i equal the number of samples for both the data set. so i have equal samples. then i do convolution using fftw3 library. but what happens is that i am doing circula...

Hello group We know that the use of cyclic prefix (CP) in an OFDM turns the linear convolution (between the channel and the transmitted...

Hello group We know that the use of cyclic prefix (CP) in an OFDM turns the linear convolution (between the channel and the transmitted signal) into a circular convolution. This is efficient to do because then we can easily equalize the channel. In most books it is referred that CP combats ISI and ICI. With ISI i am fine. I know that a circular conv between the channel (L points ) and...

Hello, I know this may sound a common or even a basic question to many, however I will appreciate if someone can give me insight on this....

Hello, I know this may sound a common or even a basic question to many, however I will appreciate if someone can give me insight on this. I read some of the older posts on related topics but a fraction of doubt still remains. I am trying to find the correct scaling factor for the output of convolution (in MATLAB). I have a signal x[n] of length N. I have a unit-amplitide discrete-time r...

hello everybody!! can anyone tell me in calculating circular convolution using DFT what will happen if i use two different length...

hello everybody!! can anyone tell me in calculating circular convolution using DFT what will happen if i use two different length signal? suppose one is of 4 point and the other is of 3 point then what will be the system?i have to do both 4 point DFT?or 4+3-1 or 6 point DFT as like linear convolution... plz help me out.. shatila

It seems to me that cepstral mean subtraction (CMS), which is commonly performed in computer speech recognition system, corresponds to...

It seems to me that cepstral mean subtraction (CMS), which is commonly performed in computer speech recognition system, corresponds to a circular convolution. I am curious what people think about how I'm viewing this and about the possible effects of changing CMS to use a linear convolution. This post turned out very long, so if you're in a hurry please just read from the fourth paragraph...

I am somewhat new to DSP and have some general questions about convolution in regards to FIR filtering. First, when it is desired to filter a...

I am somewhat new to DSP and have some general questions about convolution in regards to FIR filtering. First, when it is desired to filter a signal and convolution is to be used, how do I interpret the fact that the output sequence is longer than the input? I guess it never occured to me that whenever you filter a signal you get more out than you put in. For example, if my data is x...

I did a decimator FIR filter simply by doing the convolution only once every M' input sample. for example M=3: feed x0,feed x1, feed x2,...

I did a decimator FIR filter simply by doing the convolution only once every M' input sample. for example M=3: feed x0,feed x1, feed x2, convolution, feed x3,feed x4, feed x5, convolution, feed x6,.... Then I find many people talk about polyphase decimation filter, I wonder if it is more efficient than what I'm doing? What is the differrence? thanks mary

Hi all, As the subject suggest, I would like to know if anyone know how to perform convolution in excel? In excel only have the Fourier...

Hi all, As the subject suggest, I would like to know if anyone know how to perform convolution in excel? In excel only have the Fourier analysis, but no convolution Function. Thanks in advance. Sulphox

Hello, I have a gaussian kernel of size [192,192] to be convoluted with an image of size [512,512] for smoothing. Using the FFT property that...

Hello, I have a gaussian kernel of size [192,192] to be convoluted with an image of size [512,512] for smoothing. Using the FFT property that fft of a convolution is the product of the fft of the individual terms (fft(f(t) * g(t))) = f(w)g(w), i could say that smoothedimage = fftinverse(fft(image) fft(kernel)) the problem i am encountering is this: straightforward convolution is easy b...

Guys: I'm brushing up the mathematical side of my DSP brain. It's a bit dusty having spent the last few years doing implementation and device...

Guys: I'm brushing up the mathematical side of my DSP brain. It's a bit dusty having spent the last few years doing implementation and device control without regard for the underlying math. I'm trying to satisfy myself that vectors are a group under convolution. I've determined that there's an identity element: For any vector V, V*[1] = V (where * is convolution rather than multipl...

Hi all, I am trying to evaluate some expressions consisting of: fg*hx*y where all letters denote function of time t. ie. f is f(t), y...

Hi all, I am trying to evaluate some expressions consisting of: fg*hx*y where all letters denote function of time t. ie. f is f(t), y is y(t), x is x(t), ... fg denotes function multiplication. g*h denotes function convolution. I want to figure out is the "convolution" the same priority as "multiplication"? ie. can I evaluate the above expression from left to right, or from...

Hi, I was reading up on older threads, and I was wondering if everyone could post their experiences with fast convolution crossover points?...

Hi, I was reading up on older threads, and I was wondering if everyone could post their experiences with fast convolution crossover points? I know that theoretically, if you have a FIR filter with 30-60 taps (depending on the source), it is more efficient resource wise to perform convolution in the frequency domain using overlap add/save. However, can people post what they have learned in ...