Questions tagged [normalization]

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Spectrogram normalizaion to train a Fully Convolutional Model for Audio dereverberation

I'm trying to implement a deep learning based dereverberation algorithm. The network I am using is inspired by the U-net. The idea is to supply the reverberated spectrogram as input and 'clean' it ...
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1answer
24 views

0/1 dB normalization using clamp function

I would like to perform dB normalization on audio data to make less loud sound louder and to make unusually loud sound less loud, before feeding them into neural networks. I came across this function: ...
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1answer
28 views

How to normalise 3D time-frequency sound intensity vector

I've got a 3D time-frequency sound intensity vector that I've derived from Ambisonic b-format signals. W acts as the sound pressure ...
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1answer
37 views

sensor data windowing and normalization

I am getting up to speed with working with sensor accelerometer data. I am looking to conduct a FFT on this signal. I found that the signal being non periodic is causing issues so I have tried to look ...
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1answer
76 views

simple explanation of rank transform and its relation to normal distribution

I tried to understand the rank transform, but I couldn't. The first step common to all histogram remapping techniques is the transformation of the pixel intensity values of the given image via the ...
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23 views

Z-score normalization

I have extracted the wavelet features from an image and then applied z score normalization on the extracted features. I noticed that the z score normalization step has a noticeable effect on ...
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27 views

Modern method for feature Gaussianization

Suppose non-negative feature vectors $X = [x_0, x_1, ..., x_{N-1}]$. Existing methods include: BoxCox Lambert Iterative, rotations Log-median: $$ \hat X[n, p] = \log \left(1 + \frac{X[n, p]}{C \mu[p]...
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1answer
107 views

how to normalize DCT (or FFT) coefficients to compare different signals

I have signals that have a broad range of values. I want to compare them in a meaningful way. Just as an example, two of those signals might be: $$f(t)=100\cos(50t)+40\cos(60t) \quad g(t)=2\cos(50t)+0....
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2answers
70 views

What's a Normalized function?

I'm studing Representations of Random Processes and the book talks about Orthonormal functions, but doesn't make it clear what is it. I was able to realize that a set of functions are orthonormal if ...
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1answer
41 views

How to validate that an audio algorithm result is independent of microphone device?

I have a machine learning algorithm that takes speech sample audio recordings collected from mechanical Turk. During processing it was shown that some audio from certain OS/microphone devices have ...
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23 views

Phase-vocoder normalization for different speed factors

Question in short: How can I normalize audio from a block-based phase-vocoder system without knowing the global minimum and maximum during runtime? Longer version: Hey! I am very new to DSP and need ...
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2answers
346 views

Normalization factor in the convolution theorem

Maybe it's a trivial question, but I couldn't find any explanation for this. According to the convolution theorem, in the continues case we add normalization factor, i.e. $$ \mathcal F\left\{h\star g\...
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1answer
61 views

How do you normalize a sample-by-sample processed signal?

I am writing an audio effect based on a second-order filter that adds two samples. The resulting output is clipped. So I multiplied the signal by 0.5, which results in an output that is too low. Since ...
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38 views

Audio RMS normalization prior to a DNN classification

I want to normalize my data prior to a deep neural network model (DNN). It was recommended to me to use real mean square (RMS) normalization for audio, though I am not sure this is the best for a DNN. ...
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45 views

Is it possible to normalize an un-normalized cross-correlation vector after computation

I have a C++ code that computes cross-correlation for a given 2 vectors as input. It doesn't have an implicit normalization or normalized implementation of cross-correlation. But I would prefer a ...
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37 views

The normalized cross-correlation of two signals

I wanted to calculate the normalized cross-correlation function of two signals. I use the command ...
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25 views

How to Normalize the ideal Tx and Equalized Waveforms in LMS algorithm

Below mentioned steps has been done but I don't know if I am doing the right way of Normalizing the 2 signals. Ref_1 = load('Tx_16QAM_25_New.txt'); % transmitted data Tx(:,1)=Ref_1(:,1)+1i*Ref_1(:,2); ...
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1answer
655 views

audio reprocessing for machine learning

I have a bunch of phone interviews where there is large sound volume difference between two voices in some of the interview audios, because they were recorded only on one side of the phone. May I ask ...
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2answers
6k views

Am I supposed to normalize FFT in Python?

I'm sorry if this question is posed often, I can't seem to understand the answers already out there. I'm working with several forms of the Fourier transform, including the FFT, PSD, and spectrograms. ...
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1answer
146 views

Autocorrelation - Understanding reduced correlation at periodic time shifts using np.correlate (versus statistical autocorrelation)?

I'm going through the Think DSP by Allen B. Downey, and I'm struggling to understand a specific aspect of np.correlate and how it differs from statistic autocorrelation. The question is at the bottom, ...
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2answers
55 views

Amplitude of a signal. [-1, 1] vs variants and MFCC implications

I've seen two sort of audio signals, one where the y-axis takes values between -1 and +1. I'd think this means 1 means loudest? Not really sure And the second one I saw goes between $-10 000$ and $+...
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2answers
1k views

MFCCs and mean normalization

I'm reading a blog about extracting MFCCs features for Machine Learning applications, but I didn't understand the following points about the mean normalization: To balance the spectrum and improve ...
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1answer
427 views

How do I normalize a predesigned IIR filter?

Obviously my question here is very similar to this previously asked question: How to normalize predesigned IIR filter coefficients to have unity gain? Unfortunately, in the responses available to ...
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277 views

Removing DC Offset (via removing mean) of input and output signals affects their coherence

I have input $x$ and output $y$ signals (fs=10 Hz, length N=10800). I have removed DC offset via the following equation: $x_{normalized} = 100 \frac{(x-\bar x)} {\bar x }$ where $\bar x$ is the mean ...
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1answer
711 views

Spectrogram power/magnitude normalization in analogy with image intensity normalization

In analogy with the 8-bit grayscale image color depth, in which the intensity of a sample pixel is normalized to a value between 0 and 255 by taking into account the minimum and maximum intensities ...
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93 views

How enhance amplitude of audio signal without distortion?

After FFT I've set to zero some frequencies and I'd like to enhance the amplitude in order to recover the leak. I'd like to do a normalization in order to avoid distortion. I've done in this way but ...
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0answers
1k views

Basics of Normalizing Cross-Correlation with a View to Comparing Signals

I'm trying to understand how cross-correlation is used determine the similarity of two signals. This tutorial offers a very clear explanation of the basics, but I still don't understand how to use ...
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1answer
2k views

What is the relationship between angular frequency and normalized angular frequency

This is a slide from my lecture notes: My professor used the following words " We denote digital frequencies with capital letters and analogue frequencies with lower case letters" The problem I have ...
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1answer
355 views

Why do we use normalized angular frequency?

Let's say we want to generate a signal in MATLAB, using sin, representing the A-major chord (440 Hz, 550 Hz, 660 Hz, each with amplitude 0.1). I know we have to use the normalized angular frequency. ...
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1answer
985 views

Overlap/add time-domain audio frames: How does normalization/scaling work with overlap greater than 50%?

I am attempting to overlap-add time-domain audio frames in a real-time context (with a continuous stream of data coming-in). Each frames consist of 1024 samples and have been previously "Hann" ...
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1answer
833 views

why multiply grayscale images by 256

I am a newbie in image processing. in an open source code for convolution neural networks, the author is multiplying a gray scale image from MNIST dataset by 256. Please can any one tell me why? ...
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0answers
277 views

Correctly scaling Power Spectrum and Correlation Function of Galaxies from Mock Catalogues

I'm currently writing a code to compute the two-point correlation function of a set of galaxies. As I work with a loooot of galaxies, it was suggested to me not to do it in real space, but to compute ...
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1answer
969 views

The concept of normalized frequency

This question has already been asked and answered, but the motivation behind the use of normalized frequency units still evades me. The Discrete Time Fourier Transform $$X(\tilde{ \omega }) = \sum_{n=...
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1answer
90 views

What information does the abs(normalized_image - normalized_quantised_image) carry?

Given a grayscale image X2 And its (under)quantised version with 3 bits depth X3 What information does the abs(X2_normalized - X3_normalized) carry?As an example ...
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1answer
515 views

Pole zero plot, normalizing frequency response plot?

I'm asked to plot the frequency response (amplitude) given a specific pole-zero diagram. $$ H(z) = H_0 \frac{\prod\limits_{m=1}^{M} (z - q_m)}{\prod\limits_{m=1}^{M} (z - p_m)}$$ $$ H(e^{i\omega}) =...
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2answers
2k views

Normalization of a signal with respect to another signal

Imagine that I gave one signal (call it master signal) with respect to which I would like to normalize all the others. How should I treat it mathematically? Any ideas?
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1answer
126 views

Design a filter which passes all frequencies except $\omega=\pm\frac{\pi}{2}$ and plot its pole-zero diagram

Also draw its normalized frequency response. What is the ROC? This has to be done in z-plane so there must be two poles at $+i$ and $-i$ since they cannot be included in region of convergence. Is my ...
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1answer
471 views

Making audio clips comparable in terms of RMS

I have a challenging question on how to normalize several audio clips so that they are comparable (similar) in RMS but without the clips clipping (having values over -1 and 1). Is there a systematic ...
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1answer
316 views

Methods of scaling FFT power

I wanted to know what are the well-known methods of scaling the FFT power of a signal? I am referring to EEG signal but this should apply to all signals I guess. I need to plot the powerspectrum/PSD ...
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1answer
974 views

Normalizing audio waveforms code implementation (Peak, RMS)

I have some audio data (array of floats) which I use to plot a simple waveform. When plotted, the waveform doesn't max out at the edges. No problem - the data just needs to be normalized. I iterate ...
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1answer
170 views

Normalization of signal against reference

I am trying to figure out if there is any standard way of normalizing a sequence such as a time series against a reference sequence. I am not an expert on signal processing but I was hoping someone ...
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1answer
1k views

FIR filter Gain of 0dB at Passband Frequency

I have designed a FIR pass band filter. The impulse response looks good and on applying this on my input data, the filter works as desired. Now I have a requirement in my system to have exact $0$ dB ...
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1answer
4k views

normalized sum of squared differences

I want to search for a patch in a region of image, and I will use the normalized sum of squared differences. I know that the sum of the squared differences is: $SSD = \sum {\left(F - I\right)^2}$ ...
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2answers
88 views

Factor $|a|^{-1/2}$ in definition of mother wavelets

The mother wavelet is defined as $$\Psi_{a,\tau}(t) = \lvert a\rvert^{-1/2}\Psi\left(\frac{t-\tau}{a}\right)\tag{1}$$ in which the factor $$ \lvert a\rvert^{-1/2}\tag{2}$$ is supposed to serve ...
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1answer
1k views

Magnitude response and DFT normalization

Suppose I have an FIR denoted h that represents the impulse response of a system. Using MATLAB syntax (for convenience and brevity), What does ...
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1answer
1k views

Normalization of an image in MATLAB [closed]

If I have an image whose range is from $-18.3667\cdot10^{-5}$ to $9.3127$, how could I normalize it on the same gradient so that they fall between a specific range, say fro $0$ to $255$?
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1answer
3k views

Signal normalization

I have some questions about what is normalization. The obvious way to do that is x_max = max([max(x), abs(min(x))]); x=x-mean(x); x_norm=x./x_max; Can somebody ...
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2answers
232 views

How to choose the "best" measurment (from a given set) as input for a kalman filter?

Problem: For an object tracking scenario with multiple objects and multiple tracks, I want to choose the "best" assignment object<->track. Therefore, I need a parameter indicating how suitable an ...
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1answer
1k views

Obtaining normalized matrix for the Haar Wavelet Transform

I've been reading this article: http://aix1.uottawa.ca/~jkhoury/haar.htm which explains the Haar Wavelet Transform. At a certain point, the author says: ... Since the transformation matrix $W$ is ...
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1answer
3k views

How can I sample a signal at 4 samples per cycle?

I am in Chapter 5 of "Understanding Digital signal processing" 3rd edition by Richard G. Lyons. I am stuck with Section 5.4. In order to get the bandpass filter centred at $F_s/4 \mathrm{Hz}$, I need ...