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2answers
50 views

Undoing a filter operation in MATLAB

Out of curiosity, is it possible to actually reverse a filtering on MATLAB. For example, if I have ...
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0answers
54 views

remove static noise from audio

I have a recording with a static noise added throughout the audio. the longest silence period I could extract was this: audio_file however, it contains some moments of new sounds of flipping pages. ...
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1answer
44 views

Adaptive filter with two inputs

I have general theoretical questions: Is it true that an adaptive filter with two inputs (one normal and one delayed by the single time increment) can completely get rid of any single frequency ...
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1answer
26 views

What are the advantages of higher order Kalman Filters like EKF, UKF?

Kalman Filter provides the optimal estimate of the states of a stochastic dynamical system if the system is linear, the measurements are also linear functions of states and the errors in system ...
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0answers
14 views

identification of a parameter in a state-space model

let's assume $$x(t+1)= \Biggl( \begin{matrix} 1 & 1 \\ 0 & \theta\\ \end{matrix} \Biggr) *x(t)+ \Biggl( \begin{matrix} 0 \\1 \end{matrix} \Biggl) m(t)$$ $$ z(t)= \Biggl( \begin{matrix} 1 ...
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1answer
87 views

Causal and Non-causal filtering. Strange behavior

I'm trying to understand the behavior of a causal filtering exemplified by figure below. This behavior is making LDA (Linear Discriminant Analysis) misclassify our data, by clearly reverse the ...
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2answers
54 views

What criteria should be used for smoothing

Actually I have some measurement which I want to get rid of noise I want to use different filter techniques but I am wondering what criteria I should use to check if I am removing noise or not or if ...
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0answers
21 views

Choosing modulation frequencies

A square wave $s(t)$ is modulated by two functions, $y_{1}(t) = \sin (2\pi f_{1}t)$ and $y_{2}(t) = \sin (2\pi f_{2}t)$, which are combined into a single function $x(t) = y_{1}(t)s(t) + y_{2}(t)s(t)$. ...
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1answer
56 views

How can a signal have two maximum frequency components?

$x(t)$ can be exactly reconstructed from its samples at $\omega_s = 10 \textrm{ rad/sec}$. My conclusion is that the maximum frequency component in $x(t)$ is $5\textrm{ rad/sec}$. But I'm being told ...
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0answers
50 views

Question if FIR Filter is implemented correctly?(ECG Application)

I am working on using the TMS320C5535 ezDSP to implement signal processing algorithms for an ECG application. My main issue right now is that it seems the digital filters are not being implemented ...
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1answer
78 views

Choosing correct filter parameters for IMU sensor datas

I have a IMU sensor breakoutboard using ITG3701, LSM303D LinkProduct. This involves accelerometer, gyroscope and magnetometer. I have connected the sensors to a Arduino and sending the datas to ...
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2answers
35 views

In fourier space, how to apply transfer function with n frequencies to input data with m>>n frequencies

I have a transfer function in Fourier space with $N=2028$ frequencies $(\frac {0, 1}{(N\cdot dx)} \dots ) $ Where $dx = 0.1m$. I need to apply this transfer function to a signal with 20000 samples (...
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1answer
43 views

iZotope RX's FFT processing?

How does iZotope RX handle the FFT (i.e. how does it manage to perform those processes in the frequency domain without creating glitches) since its able to e.g. Apply another DSP process (even time-...
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0answers
32 views

Apply cuts in frequency bins before doing an FFT

I have a complex function $d(k)$ which is given to me after a simulation in a box of side L. It is in frequency/momentum domain and I would like to use FFTW to go to the space domain. The fundamental ...
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3answers
102 views

Filtering Frequency Bands Out of a Signal

Let's say I have a 2 second data set taken at 220Hz sample rate and I would like to filter out the frequency bands associated with the EEG Spectrum: $$\begin{align} \Delta:& [1,3]\text{ Hz}\\ \...
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0answers
53 views

maching convolution filters to results

I am practicing for an exam and I need help in the following question (it is just for me- no grade...) we get an input image, 6 convolution filters and 6 results. we need to find the matches between ...
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0answers
54 views

Best beamforming algorithm for audio cocktail party

I have read some texts about different types of beamformers. They all seem to have pros and cons. So I was trying to figure out which type of beamformer to implement, when the goal is to get best ...
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0answers
24 views

Research help on BM3D

I am working on BM3D (Block-matching and 3D filtering). I extract all reference patches and target patches and find out distances between them. But now how to group them according to reference patch (...
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0answers
17 views

Proximal operator of image Laplacian

Let $\alpha, \beta > 0$ and $\Delta := \nabla^T \nabla$ be the discrete laplacian operator, $$\nabla: \mathbb{R}^{n_x \times n_y \times n_z} \rightarrow \mathbb{R}^{3 \times n_x \times n_y \times ...
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2answers
88 views

Filtering noise from FFT, where noise is known to be shifted delta function

I have an input sequence $x=\{x_1, x_2 , ... x_n\}$ of reals, where $n=2^m$ for some $m$. I wish to calculate FFT of $x$. $X=FFT(x)$ However, before I calculate the FFT, the signal $x$ gets ...
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1answer
20 views

Pulse shaping and Baseband filtering

I'm slightly confused about baseband pulse shaping. Let's assume I have a complex data vector in an arbitrary complex constellation (QAM for example). I would like to pass this complex vector through ...
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2answers
173 views

How to filter almost periodic noise?

I have signal that looks like this: As you can see there are some almost periodic pulses at the background with amplitude about 1000. I am saying almost, because, if you zoom in, you may see that ...
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0answers
38 views

Open source GPS+IMU sensor fusion?

Are there any Open source implementations of GPS+IMU sensor fusion (loosely coupled; i.e. using GPS module output and 9 degree of freedom IMU sensors)? -- kalman filtering based or otherwise I see a ...
2
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2answers
94 views

Removing Bounded Noise from an Audio Signal

I'm currently trying to remove some noise from a "contaminated" audio file. From what's given, I know that the noise is isolated to a specific frequency band - that is, from ~1400 Hz - ~1800 Hz. The ...
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0answers
52 views

Median Filter for salt and pepper noise removal

Why median filter is considered as good for removal of salt and pepper noise? What are the other filters used for the same?
1
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1answer
58 views

Overlap/Chunk processing possible with Zero-phase?

I'm relatively new to DSP and I'm currently investigating FIR filter and IIR filters. From what I've found FIR filters can be implemented efficiently using the overlap-save method, but I was wondering ...
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0answers
163 views

Implementing a 2d butterworth filter for image processing?

I am at the moment trying to implement a bandpass butter worth filter which i then can use to apply on my original image. Problem is though My implementation of it using OpenCV doesn't seem to be ...
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0answers
10 views

Why would prefiltering measurement data affect the least squares estimate?

In estimating parameters in a discrete time model I've often seen the use of filters applied to the input data, before its applied to least squares processing. I've been told that the filters are ...
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1answer
137 views

Derive velocity and acceleration from position

I generate random spike data that represent the ouput from a rotary encoder. Here the output of my algorithm: The first plot is position, then velocity and then acceleration. Even though I downsample ...
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1answer
53 views

Filtering performance on Poisson noise with quadratic data-fidelity

We recently performed a work on signal filtering/component separation (sparse signal/trend/noise). The cost function contains: A quadratic data fidelity term, Some smoothed $\ell_1$ terms for ...
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1answer
90 views

How is the ends of a bandpass filtered signal reliable after applying the cosine taper?

A taper function decaying to zero at ends such as a cosine window is routinely applied to the signal before bandpass filtering to reduce end effects. Obviously the window alters the waveform. So, as ...
3
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1answer
106 views

Optimal windowing strategy for filtering live signal

I have a stream of 250 samples per second arriving at a pipeline stage which looks something like this simplified example. ...
1
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1answer
63 views

What is a 'notch' in image processing?

I cannot find out what does "notch" means in image processing? We have selective filters that one of the best of them is Notch filters. but what does the concept of "Notch"? why they are called "...
1
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1answer
32 views

How to reconstruct the signal if there were some temporary offsets

I am not a signal processing expert. I have data like this: where the red is what I have and the black is what I want to have. Any idea how to reconstruct this? The code for generating the data is ...
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0answers
59 views

Numerical noise in Butterworth filter

I am testing a digital Butterworth filter. This first example is a bandpass filter with a centre frequency of about 824 Hz. I generated this plot by calculating the Fourier transform of the filter ...
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0answers
34 views

Accurate Noisy Signal Filtering

I'm looking for some ideas to filter a noisy signal. my sampling Condition is : ...
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2answers
27 views

Adding channel effects to a signal

I have a a channel matrix "H" that is circulant. I have data blocks. I want to add the channel effects to the signal. When H was only a vector of channel coefficients I would say: ...
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0answers
22 views

Common spatial patterns explanation

Can anyone provide a lay explanation of what common spatial patterns are designed to do in EEG/BCI work? From what I understand, it is similar to PCA in that given 2 classes, it attempts to find a ...
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0answers
21 views

What is a Thresh filter?

I was looking at this site and saw the term. While I'm a bit familiar with some DSP terminology, I have never heard of this before. Google did not really help at all. From what the site explores, it ...
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0answers
82 views

What is Single pole filter?

Can anybody tell me why do we use single pole filter? And may be an example of Single pole filter in matlab. Good literature recommendations are also welcomed.Moreover, that would be good if anyone ...
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0answers
20 views

If a signal is added to another in the freq. domain, how to filter it out?

I have two signals, $x$ and $y$. I know that $F(x)=F(s)+F(n)$ and $F(y)=F(n)$, where $s$ is the 'clean' signal, $n$ is the added noise and $F$ donate Fourier Transform. To obtain the clean signal, I ...
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2answers
44 views

Can filter “depth” be adjusted by mixing dry and wet signals?

Can filter "depth" be adjusted by mixing dry and wet signals? I.e. can I simulate e.g. a +6dB bandshelf/peak filter at 1kHz by mixing in some of the dry unequalized signal and some of a wet signal ...
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2answers
204 views

MATLAB : How to filter a data signal

I have a data signal (column vector) with N values taken over at specific sample rate (dx) at a fixed frequency. After taking the Fourrier transform of this signal and representing it in the Fourier ...
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2answers
170 views

Filtering out a specific frequency in an analog signal

I'm wondering how I would go about filtering out a regular sine-wave signal with a constant frequency and voltage. I'm really new to the whole DSP-area but imagine I would have a regular sinewave at ...
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0answers
29 views

Understand the assumption of the ideal bright line in this paper

hope I ask my question on the right place. I am a student and my favorit subject is computer vision. I try to understand some apects of the paper "Three-dimensional multi-scale line filter for ...
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0answers
148 views

What is pulse train filter?

I have recently seen some code written in modelling tool like Simulink, ASCET which uses PT1 filter? Why do we use a pulse train filter? What is the difference between FIR, IIR, Chebyschev, ...
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3answers
31 views

Texture-like measures for quantifying density of data in binary images

Consider the following black-and-white image. It depicts a freehand sketch. I wish to characterize the "density" of sketch strokes. For e.g. the hair strokes are densely grouped together. So are ...
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1answer
44 views

Contour based blurring

Suppose I have an image of a cat and a binary mask image corresponding to cat's location as shown I would like to blur the image region surrounding the cat but as a function of distance from the ...
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4answers
472 views

difference between mean filter and order statistic filter

I am working on my paper about comparing between mean filter and ordering statistics filter, The mean filter is contraharmonic mean filter and the ordering statistic filter is alphatrimmed mean filter....
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1answer
91 views

Discrete sinusoidal to state space

I'm looking to apply an optimal LQR filter to a discrete signal of the form $x[n]=A\sin[\omega_0n + \phi]+ v[n]$ The amplitude $A$ and the phase $\phi$ are unknown variables I want to estimate using ...