Forums Search for: Deconvolution
deconvolution problem
inHi, I have a problem with vector deconvolution. This is what I do in Matlab: > > vect1=[1 2 3 4 5 6 7 8 9]; > > vect2=[1 2 3 4 0 0 0 0 0...
Hi, I have a problem with vector deconvolution. This is what I do in Matlab: > > vect1=[1 2 3 4 5 6 7 8 9]; > > vect2=[1 2 3 4 0 0 0 0 0 0 0 0 0 0]; %I want to find w with conv(w,vect1)=vect2 > > Lx=length(vect2)-length(vect1)+1; > > Lx2=pow2(nextpow2(Lx)); > > VECT1=fft(vect1,Lx2); > > VECT2=fft(vect2,Lx2); > > W=VECT2 ./ VECT1; > > w=real(ifft(W,Lx2)); > > w=w(1:1:Lx); > > w=w/max(abs(w));
deconvolution problem
inHi, I have a problem with vector deconvolution. This is what I do in Matlab: > > vect1=[1 2 3 4 5 6 7 8 9]; > > vect2=[1 2 3 4 0 0 0 0 0...
Hi, I have a problem with vector deconvolution. This is what I do in Matlab: > > vect1=[1 2 3 4 5 6 7 8 9]; > > vect2=[1 2 3 4 0 0 0 0 0 0 0 0 0 0]; %I want to find w with conv(w,vect1)=vect2 > > Lx=length(vect2)-length(vect1)+1; > > Lx2=pow2(nextpow2(Lx)); > > VECT1=fft(vect1,Lx2); > > VECT2=fft(vect2,Lx2); > > W=VECT2 ./ VECT1; > > w=real(ifft(W,Lx2)); > > w=w(1:1:Lx); > > w=w/max(abs(w));
Design of a deconvolution filter
inHi, I am really new to this so bear with me. I got a homework assignment for a course called analytical topics and I was wondering if anybody...
Hi, I am really new to this so bear with me. I got a homework assignment for a course called analytical topics and I was wondering if anybody could help me figure it out. I don't need a complete answer but just some pointers of where to begin with this problem and how to proceed. Thank you very much for any information. The setup is as follows: I am given an fir filter: y(k)=sum[u(k-i)h(k)] ...
Deconvolution
inIf I have a random signal u(k) and a (known) transfer function H then y(k)=Hu(k) and if I know H and H is minimum phase then I ca neasily find...
If I have a random signal u(k) and a (known) transfer function H then y(k)=Hu(k) and if I know H and H is minimum phase then I ca neasily find u(k). Suppose H is nonminimum phase eg y(k)=u(k)-2u(k-1) how to get at u(k)? Can I run time backwards in some way so the H is stable in reverse time? hardy
deconvolution in time?
inHello! I have a output signal y(k) and a plant P(z). The signal y(k) contains some noise and I know the PSD of the noise. But lets assume that...
Hello! I have a output signal y(k) and a plant P(z). The signal y(k) contains some noise and I know the PSD of the noise. But lets assume that for now that the noise is qhite and the system looks like this: Y(z)=U(z)P(z)+E(z) u(k) y(k) ----------> [P(z)]--> [+]---> | e(k) | -------| I want to restore the sig
Prewhitening....how to explain?
inHi All, Is there a book or source that explains what prewhitening is, in relatively simple terms? Or would any of you like to explain it to...
Hi All, Is there a book or source that explains what prewhitening is, in relatively simple terms? Or would any of you like to explain it to me, please? I have a blood flow signal and I want to prewhiten it and then do some blind deconvolution on it to see what happens. As the prewhitener it has been suggested to use a predictor as the signals I have are quite short. (Some form of stocha...
Deconvolution by Fourier method
inIn order to convolve two functions 'a' and 'b', we can take their Fourier Transform(FT) and multiply them in Fourier domain i.e. C= FT(a) *...
In order to convolve two functions 'a' and 'b', we can take their Fourier Transform(FT) and multiply them in Fourier domain i.e. C= FT(a) * FT(b) c = IFT(C) and then Inverse Ft(IFT) of 'C' gives us the convolution of 'a' and 'b'. Now if we want to deconvolve 'a' from 'c' to get 'b' we can do B = FT(c)/FT(a) b = IFT(B) Now if 'a' is a square wave i face the problem of 'DIVIDE by ZERO', a...
Deconvolution of two gamma variates
inHi! I'm busy with a project to determine cerebral blood flow using MRI. At two places in the brain the concentration of a contrast solution...
Hi! I'm busy with a project to determine cerebral blood flow using MRI. At two places in the brain the concentration of a contrast solution is measured every 1 second (or so.) The points are then fitted to a gamma variate of the form: f(t) = a (t-to)^b exp[ -(t-t0)/c ] for t=> t0 f(t) = 0 t
how to minimize ringing
inHello, I am trying to restore a one dimentional signal using wiener deconvolution with a PSF. Because it's important for me to restore sharpness,...
Hello, I am trying to restore a one dimentional signal using wiener deconvolution with a PSF. Because it's important for me to restore sharpness, but more important, the shape at the transient edges- the ringing is getting in my way. I understand that ringing to some extent is unavoidable, but how can I miminize it? Thank you, Keren
"Repairing" an out-of- focus picture
inHi, My question might be simplistic as neither optics nor image processing is my field. Firstly, I was wondering if it is possible to...
Hi, My question might be simplistic as neither optics nor image processing is my field. Firstly, I was wondering if it is possible to compensate for a picture taken by an out-of-focus digital camera by doing a 2D deconvolution on it (MMSE filtering or something like that), in order to recover the in-focus picture Secondly, can the optical transfer function between a properly focused pi...
Deconvolution problem
inHi guys, I have a theoretical relationship that variable z = convolution(x, y ). I now have vectors of z and x and I am trying to deconvolute...
Hi guys, I have a theoretical relationship that variable z = convolution(x, y ). I now have vectors of z and x and I am trying to deconvolute them to get vector y. I tried to to FFT to solve for y. The problem is that I also got some oscillation in the y vector while there should be none. The shape of the vectors z and x all look like bell shape and they look pretty smooth. They are close to z...
Problem with image deconvolution
inHullo All, I recently posted to this group on this question but I never saw it appear, so please excuse my posting again. I have two...
Hullo All, I recently posted to this group on this question but I never saw it appear, so please excuse my posting again. I have two overlapping images (apprx. 30% overlap) which are part of a series to be stitched into a panorama. One image is blurred by motion blur, the other is sharp. As I effectively have the blurred and the 'latent' images it seemed like there was a fair chance I could...
Lytro
inAfter seeing discussino of the Lytro light-field camera, the first thought I had was that DSP would be pretty important in making it work. Yet I...
After seeing discussino of the Lytro light-field camera, the first thought I had was that DSP would be pretty important in making it work. Yet I don't remember seeing any discussion of it. The article describing the technology is: http://graphics.stanford.edu/papers/lfcamera/lfcamera-150dpi.pdf it would seem to me that deconvolution would be related to the technology, though so far, (a...
Re: deconvolution in time?
inGordon Sande wrote: > On 2005-11-08 09:41:43 -0400, abariska@student.ethz.ch said: .=2E. > There are two common usages of adjoint. > > ...
Gordon Sande wrote: > On 2005-11-08 09:41:43 -0400, abariska@student.ethz.ch said: .=2E. > There are two common usages of adjoint. > > One is in matrix theory where it is the transpose of the matrix of cofact= ors > as one would find near the definition of determinants and how to solve > equations using determinants. I just looked through all my pure linear algebra books (Lang, J=E4nich
Deconvolution question
inSuppose I have an acoustic guitar with a (relatively good-sounding) peizo pickup (a K&K, for those interested). I can mic the guitar and...
Suppose I have an acoustic guitar with a (relatively good-sounding) peizo pickup (a K&K, for those interested). I can mic the guitar and record the peizo simultaneously. But when I deconvolve the miked signal against the peizo, the resulting convolution signature isn't very coherent. Most convolution signatures of this nature have a "spike" where the dominant bucket is - this has just a ...
vibroseis deconvolution without the reference sweep
inI have a vibroseis dataset which has been collected in the field. To my knowledge, the recorded signal s'[t] is the convolution of the...
I have a vibroseis dataset which has been collected in the field. To my knowledge, the recorded signal s'[t] is the convolution of the original sweep s[t] and the reflection response r[t] of the layered earth. Thus, the relationship is expressed in its simplest form as s'[t] = s[t]*r[t], neglecting the effects of earth attenuation and noise. However, I do not have the reference sweep s[t] since...
deconvolution using known set of filters
ini have lot of filters impulse responses and signal 'x' that i got by convolving original signal 's' with one of the filter...
i have lot of filters impulse responses and signal 'x' that i got by convolving original signal 's' with one of the filter impulse response.Also,the signal 'x' contains noise. Now i want to recover the original signal 's'. 1)Which techniques are most feasible and effective to solve this problem 2)which technique is more real time
Discrete Deconvolution
inHello, all. I have a dilemma. I'm analyzing some time signals for periodicities, and I was wondering about a seemingly basic method of doing...
Hello, all. I have a dilemma. I'm analyzing some time signals for periodicities, and I was wondering about a seemingly basic method of doing it. I hope you'll forgive my ignorance, as my specialty is physics and not signal processing :P So, we have a time-series that is the product of a source signal and a window function : c(t_i) = w(t_i)s(t_i) where t_i represents the i_th time...
Which algorithm would you choose?
inSay you have two signals, x and y, where y is the output of an unknown FIR filter. The only thing which is "known" about the FIR filter is that...
Say you have two signals, x and y, where y is the output of an unknown FIR filter. The only thing which is "known" about the FIR filter is that it has N filter coefficients. The above relates to acoustic echo cancellation for speech signals sampled at 8kHz. I guess you can call it a channel estimation problem? Or a deconvolution problem? I don't know.... Anyways....As a pre-liminary expe...
Mixed phase deconvolution
inHello all DSP gurus, I am struggling with some (seismic) DSP theory and need some help! In seismic the convolutional model states that the...
Hello all DSP gurus, I am struggling with some (seismic) DSP theory and need some help! In seismic the convolutional model states that the observed signal as a function of time, st (seismic trace), equals the convolution between the seismic shot signal, s, and the earth response function, e: st=s*e. Given a known st and s I want to calculate the unknown e. We introduce a pulse shaping fi...