Specification and design of image pixel interpolation filters?

Started by Chris Bore in comp.dsp10 years ago 1 reply

I want to design interpolation filters for a grid of 3D data. I need to interpolate new voxels at varying positions between...

I want to design interpolation filters for a grid of 3D data. I need to interpolate new voxels at varying positions between original voxels. (The original data are from 3D ultrasound where voxels are uniformly spaced out along the spokes of a fan-shaped grid, and my new pixels are to be uniform on a rectangular cartesian grid. But I dont have a problem handling this aspect, I'm interested in...


Frequency Interpolation - Grandke's Method

Started by creekmor in comp.dsp8 years ago 4 replies

I have a question about Grandke's method of frequency interpolation. (I suspect this question has been asked before). Using the Hanning window...

I have a question about Grandke's method of frequency interpolation. (I suspect this question has been asked before). Using the Hanning window (and Schoukens, 1991 notation), he derives f_interp = (i + delta) * fo, where delta = (2*alpha - 1) / (alpha + 1), and alpha = abs(X(i+1) / X(i)), and {X(i), X(i+1)} includes the peak. By definition, 0 < delta < 1, which implies 1/2 < alpha < 2. W


Timing Error Detection using Gardner and other methods

Started by Rajenish_jain in comp.dsp13 years ago 2 replies

Hi, I simulated a QPSK Symbol Rrror Recovery mechanism using interpolation menthod. I used a gardner TED which works only for the case where...

Hi, I simulated a QPSK Symbol Rrror Recovery mechanism using interpolation menthod. I used a gardner TED which works only for the case where there is a symbol trensition. I would like to know of any algorithm which works for the case even without trnsition. (I didnt find Muller-Muller method very good). What if I want to simulate Symbol recovery using the same interpolation method for 16-Q...


Questions regarding polyphase filter

Started by bcarmaint in comp.dsp10 years ago 9 replies

I am try to get a better understand of polyphae filter. There are several questions I wonder if I can get some help: 1) Relationship of...

I am try to get a better understand of polyphae filter. There are several questions I wonder if I can get some help: 1) Relationship of polyphase filter and Different signal interpolation/decimation methods. One thing I am a bit confused about is the relationship between different curve fitting type interpolation methods (i.e., cubic bspline, cubic polynomial, linear etc.) and polyphase filter....


just like half band filters are ther 1/3 band filters too?

Started by bharat pathak in comp.dsp8 years ago 5 replies

Hello, Half band filters are good for interpolation and decimation by 2 as they have alternating 0's as their coefficients. ...

Hello, Half band filters are good for interpolation and decimation by 2 as they have alternating 0's as their coefficients. Is there something like 1/3rd band filters for doing interpolation and decimation by 3 with in-between 2 coeffcients being 0? Regards Bharat


2D sinc

Started by alexryu in comp.dsp10 years ago 3 replies

I've always seen 2D sinc interpolation done in a separable fashion - interpolate along the x axis to the correct x-coordinate, and...

I've always seen 2D sinc interpolation done in a separable fashion - interpolate along the x axis to the correct x-coordinate, and then interpolate the new values down the y axis to the correct y-coordinate. So if you have data defined on a grid, D(m,n), and you want to interpolate D(m1,n1+eps), you only need to do one sinc interpolation. This is well and good (Nyquist's theorem is Nyquist's t...


Changing interpolated delay line size

Started by jungledmnc in comp.dsp9 years ago

Hi there, I'm using an interpolated delay line size for audio effects such as flanger or vibrato. The trouble comes, when I want to change the...

Hi there, I'm using an interpolated delay line size for audio effects such as flanger or vibrato. The trouble comes, when I want to change the delay line size. So far it seems the only way is to "stretch" the entire delay line to avoid abrupt edges that would be caused by jumping allover the line. But this works with cubic interpolation, but not with sinc interpolation, which generates the abrupt ...


ADC Interpolation Gain

Started by pacman101 in comp.dsp8 years ago 11 replies

Hello, I've been reading a lot about increasing ADC quantization gain through oversampling and then applying an interpolation filter. I...

Hello, I've been reading a lot about increasing ADC quantization gain through oversampling and then applying an interpolation filter. I understand that for every 4x oversampling you can increase the SNR by 6 dB or 1-Bit and that lowers the quantization noise floor. However, say my ADC is sampling two tones at 1 kHz and 2 kHz using a 14-bit theoretical ADC. Theoretically my SNR is 6 dB * ...


Sampling frequency offset correction (resampling) - help needed

Started by kobem in comp.dsp9 years ago 5 replies

hi, Can someone explain how I can compensate for sampling clock frequency offset (SCO) using fractional-delay interpolation? In OFDM...

hi, Can someone explain how I can compensate for sampling clock frequency offset (SCO) using fractional-delay interpolation? In OFDM basebnad receiver design book they said that you can use fractional-delay interpolation filter to compensate SCO but of course they forgot to write about. Let's say I have a ramp signal (it will be easier for me to explain what my doubts are as it has amplitude...


Sampling frequency correction by Interpolation/Decimation technique?

Started by nqh in comp.dsp12 years ago

Dear all, In OFDM system, we difine T is the sampling period at the output of IFFT (at transmiter), T' is sampling period at receiver,...

Dear all, In OFDM system, we difine T is the sampling period at the output of IFFT (at transmiter), T' is sampling period at receiver, SFO=(T'-T)/T At receiver, after CP removal, the (m,n)-th sample of the time-domain received signal is r'(m,n),(include SFO). How can we use Interpolation/decimation technique to correct the r'(m,n) (to get desied signal r(m.n) without SFO) Who can help m...


interpolation at data sequence endpoints

Started by Ronald H. Nicholson Jr. in comp.dsp15 years ago 3 replies

In a previous thread, it was mentioned that polynomial spline interpolation and windowed sinc reconstruction give similar results, or may even...

In a previous thread, it was mentioned that polynomial spline interpolation and windowed sinc reconstruction give similar results, or may even converge under some conditions. In another recent thread, it was stated the a windowed sinc reconstruction filter used for upsampling would give "invalid" results near the endpoints of a data sequence until all the taps of the FIR filter were filled...


How to compensate for the passband droop of a Sinc filter with an IIR filter?

Started by daniel zuo in comp.dsp13 years ago 27 replies

Hello, I'm now designing a IIR interpolation filter. The interpolation filter consists of a IIR lowpass filter stage and a Sinc filter...

Hello, I'm now designing a IIR interpolation filter. The interpolation filter consists of a IIR lowpass filter stage and a Sinc filter stage. I dont know how to compensate for the passband droop of the Sinc filter. Can you help me? Daniel This message was sent using the Comp.DSP web interface on www.DSPRelated.com


Time delay an OFDM Signal

Started by emeto in comp.dsp7 years ago

Hi, I want to delay an OFDM signal in time domain (MATLAB): sig= signal ipIndex = interpolation...

Hi, I want to delay an OFDM signal in time domain (MATLAB): sig= signal ipIndex = interpolation index -------------------------------------------------------------------- % Interpolation iq_ip = interp(sig,ipIndex); % Delay the signal delayed_iq_ip = [iq_ip(end-delayIndex+1:end); iq_ip(1:end-delayIndex)]; % Reduce the sampling rate r=1; for sample = 1:ipIndex:length(delayed_...


Interpolation

Started by j in comp.dsp8 years ago 5 replies

What is the most economical way to inplement an interpoaltion by 5 on an FPGA. is it 2 x 2 x 1.25 ? Thanks Tom

What is the most economical way to inplement an interpoaltion by 5 on an FPGA. is it 2 x 2 x 1.25 ? Thanks Tom


Filterbanks Basics

Started by thomas in comp.dsp13 years ago 2 replies

Hi All, Could any one please explian the theory behind decimation and interpolation?. Thanks. Thomas.

Hi All, Could any one please explian the theory behind decimation and interpolation?. Thanks. Thomas.


Interpolation by rational factor

Started by Jens in comp.dsp8 years ago 12 replies

When you interpolate a signal by an integer M you stuff M-1 zero between each sample and send the upsampled sequence though a low-pass...

When you interpolate a signal by an integer M you stuff M-1 zero between each sample and send the upsampled sequence though a low-pass filter. What do you do if M is a rational number > 1 ???


Re: Sampling, Again -- Updates

Started by Jerry Avins in comp.dsp8 years ago 4 replies

T see neither interpolation nor extrapolation when a CD player replace a missed with the previous one to fill in the time. I see it as just...

T see neither interpolation nor extrapolation when a CD player replace a missed with the previous one to fill in the time. I see it as just filling time with what is most likely a better value than one chosen at random. Is that too simplistic? Jerry


Re: Interpolation

Started by robert bristow-johnson in comp.dsp11 years ago

On Apr 2, 3:55 pm, jim wrote: > Eric Jacobsen wrote: > > ... > > > Jeebuz, no wonder this conversation has been difficult. You...

On Apr 2, 3:55 pm, jim wrote: > Eric Jacobsen wrote: > > ... > > > Jeebuz, no wonder this conversation has been difficult. You might > > want to re-read the thread and see who's really said what. You now > > seem to be criticising me for being confused about points I made! > > I have no way of knowing whether you are confused or not. But you have > said


Interpolation response overshoot, why?

Started by Laron in comp.dsp9 years ago 21 replies

Hi, When simulate the FIR filter response, run interp(Matrix,n) in matlab, the maximum of Matrix is 1,but the response is larger than 1? ...

Hi, When simulate the FIR filter response, run interp(Matrix,n) in matlab, the maximum of Matrix is 1,but the response is larger than 1? I wonder know why this could be happen and how to degrade this effect? B. R. Thanks.


Re: Interpolation

Started by Eric Jacobsen in comp.dsp11 years ago 6 replies

On Mon, 31 Mar 2008 16:03:42 -0600, jim wrote: > Jerry Avins wrote: > > > > It's all semantics, then. The alteration comes about not...

On Mon, 31 Mar 2008 16:03:42 -0600, jim wrote: > Jerry Avins wrote: > > > > It's all semantics, then. The alteration comes about not from the > > downsampling, but from the filtering that precedes it. > > > > When there is no > > energy above the new Fs/2, there will be no change in the samples. > > The statement was when a anti-alias filter was "required". Bu