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Questions tagged [adaptive-algorithms]

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Adaptive Clip Limit on CLAHE

I am working on CLAHE algorithm in order to contrast enhancement. I try to find best clip value to get best result image. However, each input image desires different clip value. Therefore, I need an ...
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27 views

Adaptive frequency discovery of binary signal

First of all, I'm not a signal processing expert. Actually, I'm trying to benefit from some concepts of signal processing theory in my computer science research. My problem is that, I have to find ...
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49 views

Noise cancellation using RLS Algorithm [closed]

I am trying to do Noise cancellation using RLS algorithm at a software level, as part of my M.Tech Project work. Here, the error strength is continuously increasing, instead of decreasing as time ...
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1answer
39 views

Is CMA equalization applicable for OFDM

I have a question regarding the constant modulus algorithm (CMA), as you know it's one of the known algorithms used for blind equalization. The cost function of the CMA is build blindly, it means ...
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45 views

How general are adaptive-filtering techniques? [closed]

How often do problems arise that let you use adaptive filters? Unless I am understanding something incorrectly it seems the requirement that the input signal be stationary(or even WSS) is too strong ...
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Are the update equations for LMS in Real Time System Identification being handled correctly

Question: Are the Least Mean Squares (LMS) coefficient update equations and step size being handled correctly? Some background information: This algorithm is implemented on the ezdsp5535 on which ...
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1answer
85 views

Block LMS with overlapping blocks

In the Block LMS algorithm, the input is partitioned into nonoverlapping blocks of size $L$ and the filter coefficients are updated once every $L$ samples. Would convergence improve if we used more ...
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202 views

What is adaptive noise reduction algorithm in Adobe Audition

I have a noisy audio clip and when I use adaptive noise reduction option in Adobe Audition, with raising signal threshold (to around 11 dB), the noise is really reduced. I want to know what is ...
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Constructing Contour for Star QAM Equalization

I am trying to equalize the 16 Star QAM using known blind channel algorithms such as CMA,MMA,SCA,RCA,IRCA,CXA,SCXA.I now need to contruct a new contour for equalizing the 16 Star QAM.As it is in ...
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1answer
119 views

RLS Algorithm (Memoryless)

I have been studying the adaptive filters lately and now when I am at RLS (Recursive Least Squar) Algorithm I came across the term used in the weighting function of the RLS called forgetting factor ($\...
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44 views

Applications for adaptive and non adaptive histogram equalization

I have a question regarding histogram equalization and adaptive histogram equalization. In which circumstance would it be preferable to use adaptive histogram equalization over histogram equalization ...
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1answer
56 views

Is document image binarization a closed research field [closed]

A lot of work has been done in the field of document image binarization. Is it a closed research field or still an interesting challenge area? I am new in the field, and just curious.
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Signal chain for voice calls including adaptive noise cancellation, adaptive echo cancellation, and automatic gain control and their algorithms

I am trying to understand the entire signal chain and all the algorithms associated with adaptive filtering as mentioned in the case above. From my understanding: Adaptive noise filtering (ANF)- can ...
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0answers
447 views

Noise cancellation using RLS filter

I am trying to create an adaptive noise canceller using the RLS algorithm. The dsp toolbox from matlab offers the RLS adaptive filter already implemented, so this saved me some trouble. My goal is to ...
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2answers
49 views

Stochastic approximation algorithm

The goal is to find the FIR filter coefficients $\mathbf{h} = [5;3]$ with the help of the adaptive FIR filter $\mathbf{w}$ of order $p = 2$. I have implemented the Stochastic approximation algorithm ...
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31 views

What are the methods of optimizing the well known Stochastic Gradient Tap Update Algorithm Performance?

As the Stochastic Gradient Algorithm tap update equation is: $$ w[n+1]=w[n]-\mu \bigtriangledown J(w) $$ $w$ are the filter tap weights So what are the methods for optimizing the performance of this ...
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1answer
534 views

Adaptive filtering: Optimum filter length and delay

I'm trying to find the optimum filter length for an Adaptive Filtering, using RLS Algorithm. I'm using this design: So the "error" signal is the signal without noise (and that's the signal that I ...
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2answers
176 views

Regression vector size for prediction, reconstruction and filtration with adaptive filters

I am working with adaptive filters and similar adaptive models (mainly with gradient adaptation) for a few years. I and my colleagues always struggle to find out the correct size of regression vector. ...
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97 views

Transient and steady-state analysis for adaptive filter

I have got review for my work saying, that my work (adaptive filter variant) should be analyzed in transient and steady-state before claiming it improves performance. I have done common (in my ...
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2answers
63 views

Upsampled input to an Adaptive filter?

I will try to explain the issue I am having as clearly as possible without going into my coding or maths. I have my own and a MATLAB Central implementation pf standard LMS in MATLAB. Fixed step size. ...
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2answers
84 views

How the gain term k(n) is assumed to be the equation in RHS. And why is it called gain?

In "adaptive filter theory" and "advance signal processing and Noise reduction" they have directly come up with the term gain without stating how they got it. In adaptive filter theory they have ...
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30 views

Unknown parameters in adaptive observer

For a project I'm designing an adaptive observer. The observer has 2 states of which 1 is measured and 1 is unmeasured. To estimate the unmeasured state, I need to estimate some other unknown ...
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1answer
198 views

Regarding the choice of cost function in adaptive control - squared error vs absolute error

I did search the question database regarding this question, and although one or two questions came close, they didn't really address my specific question. In adaptive control based on minimizing ...
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1answer
64 views

Control theory: how do you initialize input for a model predictive controller?

Although I think this is a pretty popular algorithm, I posted this question on electronics stacksexchange but received no response. I am posting it here to see if there are many signal/control experts ...
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1answer
77 views

What is usual independence assumptions on adaptive filters

In this paper stands: The derivation and analysis of NLMS rest upon the usual independence assumptions. It has a footnote: The independence assumptions used in the analysis of adaptive filters ...
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111 views

Instability problem in NLMS adaptive algorithm

I have been used NLMS algorithm to equalize 4x4 MIMO signals, but the bit-error-rate (BER) after equalization is unstable with iterations. I don't know if it is the normal behavior of the adaptive ...
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1answer
457 views

Are the RLS filter and Kalman filter gradient methods?

I would like to extend my previous question What is difference between LMS and gradient-descent adaptation? with this other question. I found out, that RLS and Kalman filter learning seems to be ...
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1answer
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What's the Difference Between LMS and Gradient Descent Adaptation?

I found algorithms that seems the same to me, but they are described with different names (in field of adaptive filtering). For example: LMS - least-mean-squares seems to be GD - stochastic gradient ...
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1answer
264 views

Best DSP algoritms for ultrasonic background noise cancellation

I am looking into detection of pressurized gas leaks by means of the broadband hissing sound (white noise) generated from pressurized leaking gas. The instrument will have a broadband microphone ...
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1answer
173 views

Cost function for adaptive algorithms

I am having little difficulty to understand that why most of the adaptive algorithms use error power or addition of error power as cost function/minimization criterion. I have read that minimization ...
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1answer
94 views

Estimate $s$ from $y=s+n$

Now I receive $y=s+n$, $s$ is the signal and $n$ is the white guassion noise. Everytime $s$ will be change irregularly, have some methods to get a estimation of $s$ namely $\hat s$? Namely $s$ is ...
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2answers
421 views

Modeling ADC in Active Noise Cancellation

I'm tinkering in Matlab with a problem that's very similar to active noise cancellation. In the literature, the secondary path is described as the transfer function from the output of the adaptive ...
3
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1answer
232 views

Echo cancellation supporting long delays and without frequency domain processing

AEC algorithms mostly rely on LMS adaptive filtering, i.e. you update FIR filter coefficients then perform the filtering. Theoretically, the FIR must be as long as the maximum echo length you want to ...
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1answer
2k views

MATLAB : Proper estimation of weights and how to calculate MSE for QPSK signal for Constant Modulus Algorithm

I had asked conceptual Question about Constant Modulus Algorithm. I am implementing the simple steps of the algorithm, as I do not have the cma() built in module. ...
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1answer
127 views

Beginner level : Help with terminologies : smooting length, length of channel, channel equalization delay, blind system identification, equalization

Say the channel model is an univariate FIR filter with true coefficients $h=[1,a_1, a_2 ]$. I am learning algorithms for system identification and channel equalization. For this, I am implementing ...
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1answer
846 views

Constant Modulus Algorithm and the gradient operation

CMA is a blind channel equalization algorithm with the details presented above. I am facing 3 difficulties and shall appreciate help Q1: Does $H$ and the bar over $\bar{y_k}$ represent the Transpose ...
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0answers
53 views

non-standard error function for adaptive filter

I want to create an adaptive filter. Its coefficients have this general shape: When the input signal for the filter is a sine wave, the filter behaves the desired way if the look-back window is set ...
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1answer
189 views

Auto/cross correlation of a cosine in the context of an adaptive beamformer

I am currently reading chapter 13 of 'Adaptive Signal Processing' by Widrow and Stearns, so if anyone happens to have a copy of the book to hand it could be helpful. I am reading the chapter on "...
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2answers
1k views

Questions about Active Noise Cancellation

Being new to ANC, this is my understanding of how ANC works: Ambient noise (n) is entering a geographically small zone. To suppress the noise, an interfering (corrective) sound is injected ...
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1answer
384 views

Adaptive equalizer for IIR channel?

I am quite new to the idea of equalization. I have a few queries regarding the same. In my application I require to equalize a channel whose impulse response is an IIR response. Is it possible to ...
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1answer
157 views

Adaptive filter weight adjustment

I have 3 sensor inputs: $a(t)$, $b(t)$ and $c(t)$. I want to design a filter such that the weighted linear combination of the three is always a constant. Kind of like: $$w_1(t)a(t) + w_2(t)b(t) + w_3(...
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4answers
220 views

Best signal processing method for this application?

I have a signal I'm getting from a sensor (shown below in the photo of an excel plot) and I need to process it to get it to look something like the red line I've overdrawn on it. Sort of a moving ...
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181 views

Need a fast algorithm of adaptive convolution

I have to apply some kind of adaptive filter to my function $f(x).$ I present each point of my signal as a Gaussian, whose bandwidth depends on its location (not the point of observation $\textbf{x}$) ...
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1answer
94 views

What could an algorithm look like that iterates through all combinations of two variables to aim at a certain number of entries? [closed]

For background information, see "Some background" further down. I have a list that looks like this: Start-Time-In-Seconds;End-Time-In-Seconds 1;2 4;6 12;15 ... ...
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1answer
1k views

Difference between 'conventional' and 'adaptive' beamformers?

This might be a terminology question but I am not sure. Basically, what is the difference between conventional beamformers, and adaptive beamformers? I thought that all beamformers were inherently ...
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2answers
2k views

Applying Photoshop's “Shadow / Highlight” Correction Using Standard Image Processing Algorithms

Adobe's Photoshop has an excelent filter called "Shadow/Highlight" used to correct, in one step, dark areas AND overexposed areas of a photo. By simple analysis, I suppose it uses some radius-...
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1answer
6k views

Kalman filter in practice

I have read the description of the Kalman filter, but I am not clear on how it comes together in practice. It appears to be primarily targeted at mechanical or electrical systems since it wants linear ...
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1answer
274 views

Convolution involving turning each pixel value to the most represented pixel value of the neighbourhood

In order to correct gradual changes of intensities in the background of grey-scales images, I have been blurring them and then subtracting the original images from the convolved one. In some cases, I ...
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1answer
495 views

Genetic or evolutionary algorithms for filter design?

For what types of filter design problems might genetic or evolutionary algorithms be useful? What kinds of genetic or evolutionary algorithms are used for DSP problems? Edit: I expanded the question ...
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750 views

How do I implement an adaptive thresholding algorithm for underwater sonar

I want to implement an adaptive thresholding algorithm in MATLAB for filtering data received by an underwater sonar receiver. The data received has an interactive noise component resulting from ...