9
votes
Factor $|a|^{-1/2}$ in definition of mother wavelets
My answer is for real scale $a$ and the fact that wavelet transform is usually defined in $L_2$ with norm
$$||\Psi(\tau)|| = \int_\mathbb{R} \Psi(\tau)\Psi^*(\tau)\mathrm{d}\tau $$
So
$$||\Psi_{a,t}...
- 6,020
6
votes
FIR filter Gain of 0dB at Passband Frequency
FIR coefficients are $h[n]$, the same as the impulse response. there are $N$ non-zero taps.
$$ h[n] = 0 \qquad \text{for } n<0, n \ge N $$
frequency response is
$$\begin{align}
H(e^{j \omega}) &...
- 19.8k
5
votes
Accepted
Normalization of a signal in MATLAB
Assuming that $N$ is the length of your signal $s$, the normalized signal $s_n$ is given by:
$$s_n = \dfrac{s}{\sqrt{\dfrac{\sum_{i=1}^{N}\left|s_i^2\right|}{N}}} $$
The denominator is nothing else ...
- 11.1k
4
votes
Accepted
How to choose the "best" measurment (from a given set) as input for a kalman filter?
Question: Which parameter is suitable to indicate how "good" the
measurement fits to the Kalman filter?
To estimate a quality of association you can use likelihood function. The likelihood ...
- 388
4
votes
Accepted
Overlap/add time-domain audio frames: How does normalization/scaling work with overlap greater than 50%?
Let's assume continuous time (rather than discrete time).
If you do not process the windowed data at all, you would like the output (the sum of the windowed frames) to be equal to the original signal....
- 13.5k
4
votes
Accepted
What is the relationship between angular frequency and normalized angular frequency
Again there is no wrong or right here. In the Alan Oppenheim's Discrete-Time Signal Processing book, the notation is as follows:
when there are only continuous-time signals we use $\omega$ for ...
- 27.9k
4
votes
Accepted
Am I supposed to normalize FFT in Python?
Your decision to normalize or not does not change the accuracy of your answer, as it is simply a scaling factor. If you use the common scaling of $1/N$, then the output for each DFT bin will represent ...
- 48.3k
3
votes
Accepted
Signal normalization
[EDIT] After a second read, the proposed normalization looks non standard. Suppose that $m\le x \le M$ ($m$ and $M$ denote the min and max). The scaling factor will be, depending on the situation:
if ...
- 31.6k
3
votes
Accepted
How do I normalize a predesigned IIR filter?
As mentioned in the comments, you have to choose a frequency $\omega_0$ at which you want to normalize the gain. This could be DC (i.e., $\omega_0=0$) or any other frequency, depending on the filter's ...
- 87.4k
3
votes
Accepted
Design a filter which passes all frequencies except $\omega=\pm\frac{\pi}{2}$ and plot its pole-zero diagram
The kind of filter you are looking for is a notch filter. Using filter design toolbox in Matlab you can get it as I'm showing you in the following picture:
This has to be done in z-plane so there ...
- 1,048
3
votes
Dynamic range compression - Need pseudo algorithm for normalizing a signal
from your posted waveform, i am assuming that this is a unipolar signal. that is
$$ x[n] \ge 0 $$
in audio, it would be the same, except that we would be working on $|x[n]|$ instead.
so first you ...
- 19.8k
2
votes
Dynamic range compression - Need pseudo algorithm for normalizing a signal
here's an efficient sliding maximum algorithm that has cost that is $O(\log_2(L))$. below window_width is $L$.
comes from
Brookes: "Algorithms for Max and Min ...
- 19.8k
2
votes
Accepted
Obtaining normalized matrix for the Haar Wavelet Transform
After a few quick calculations, it seems to me that the trouble comes from poor notations for the root in your reference. If you read, in the final normalized matrix, $\sqrt{8/64}$ and $\sqrt{2/4}$ ...
- 31.6k
2
votes
Accepted
normalized sum of squared differences
In an attempt to solve the question on why to normalize, and implicitly how to normalize:
$F$ is your reference patch, $I$ is the patch under inspection.
So make $I$ only consist of the maximum ...
- 29.1k
2
votes
Factor $|a|^{-1/2}$ in definition of mother wavelets
Wavelets play differents role in functional spaces, especially as unconditional bases (see What are unconditional bases and which wavelets have this property?). In $L_p$ spaces, if $|\psi|^p$ is ...
- 31.6k
2
votes
The concept of normalized frequency
Consider a continuous signal $$ x(t) = \sin ( 2\pi f t) \ $$
of which we have the following measurent points: $$x_n = x(n T_s) = \sin \bigg(2\pi \frac{f}{f_s} n \bigg) \ . $$
We note that $\frac{f}{...
- 127
2
votes
Normalization of a signal with respect to another signal
I have had the same problem. My signals are coming from the MRI machine. In my case, the scaling is one of my options; in a way, I divided the signal A and B to the maximum of signal A, but I could ...
- 21
2
votes
MFCCs and mean normalization
Why did he add the epsilon value 1e-8
This is so you don't end up taking log of zero later, although since the first operation isn't guaranteed to be >=0, I'm not sure if it's necessary or helpful
- 21
2
votes
Accepted
Normalization factor in the convolution theorem
The choice of the normalization factor is just a matter of convention. Note that the specific correspondence between convolution in the time domain and multiplication in the frequency domain with a ...
- 87.4k
2
votes
Accepted
Why is scaling of images / pixels into `[0, 1]` range performed before SIFT (Scale Invariant Feature Transform) algorithm?
Scaling images into the [0, 1] range makes many operations more natural when using images.
It also normalizes hyper parameters such as threshold independently of ...
- 19k
1
vote
Autocorrelation - Understanding reduced correlation at periodic time shifts using np.correlate (versus statistical autocorrelation)?
The difference here is that statistical autocorrelation assumes a stationary power signal (so basically an infinite periodic signal) and does a normalisation to $[-1,1]$ and that autocorrelation just ...
- 2,175
1
vote
Accepted
Why do we use normalized angular frequency?
We use normalized frequency units in DSP mainly for convenience-- most DSP textbooks are written this way so that the theory can be presented in terms of essentially unitless quantities.
For ...
- 2,202
1
vote
Accepted
why multiply grayscale images by 256
Grayscale images are typically stored as 8 bits per pixel in files. Perhaps the network was trained to work with such data. $2^8 = 256,$ so 8 bits can represent any number from 0 to 255. It may well ...
- 13.5k
1
vote
Normalization of a signal with respect to another signal
I think I understand what Vasilis is after with this question, so I will attempt to clarify for all, and answer.
Let x(0...N-1) be a predetermined reference signal.
Let y(0...N-1) be another signal. ...
- 11
1
vote
Making audio clips comparable in terms of RMS
I wrote this simple Matlab function a while back, it operates on dBFS:
...
- 139
1
vote
Accepted
Normalizing audio waveforms code implementation (Peak, RMS)
What is the best method to solve this?
Intuitively, it seems I might need to calculate a local max or average based on a moving window (rather than the entire set) but I'm not entirely sure. Help?
...
- 10.5k
1
vote
Normalization of signal against reference
I assume your reference image data y_reference is acquired when there is no light on the image sensor - that's the standard thing to do. Then the usual normalized ...
- 191
1
vote
Accepted
Normalization of an image in MATLAB
First, shift: put the minimum to $0$, by compensating the actual minimum $m=−18.3667⋅10^5$ for every pixel: $p\to p - m$. Now your pixels are between $0$ and a new maximum $M = 9.3127 - m$. Finally ...
- 31.6k
1
vote
How to choose the "best" measurment (from a given set) as input for a kalman filter?
Search for radar plot to track association. There's a lot of algorithms on this subject. To your question:
The residual itself will not give you information without its associated covariance matrix
...
- 620
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