All Questions

0
votes
1answer
14 views

Fresnel transform over image

You can recommend the literature or tell you what the Fresnel Transform does to the image. I realized that this describes the passage of a light wave through an optical element, but I need to ...
-1
votes
0answers
14 views

fourier descriptor in matlab

My instructor provide me coordinates (see here) of a hysteresis curve and asked me to find fourier coefficient of the curve. How can do that please help me. please provide source.
1
vote
2answers
73 views

Why isn't bilateral filtering shift-invariant?

I have a source (that I can't share) that states that bilateral filtering isn't shift-invariant (that is, it depends on the input signal), hence we cannot use convolution and the Fourier convolution ...
0
votes
2answers
55 views

Convolution of Two Impulse Signals

I have encountered convolution of two different impulse signals. ...
0
votes
1answer
63 views

Term for integral multiples of fundamental period?

As we know that a signal has fundamental frequency and integral multiples of fundamental frequency are known as harmonics I am curious about the term that will be used for integral multiples of ...
0
votes
1answer
32 views

Phase differences between DFT and FFT (in MatLab)

I have implemented a (direct) DFT in MatLab (following script) and compared it to the built-in FFT routine. The magnitude response seems to be identical (excluding some possibly round-off errors), but ...
1
vote
0answers
35 views

persist state of digitalFilter

Suppose I created a digitalFilter using designfilt (in matlab). I am interested in using it to filter windows (I dont have the whole data set offline). When I call filter() with this filter and a ...
0
votes
0answers
20 views

Strange phase for gaussian beam 2D

I have a 2D Gaussian beam : After doing FFT2 and angle I get strange results: This is the code I'm using (Python 3) ...
0
votes
1answer
16 views

Higher side lobe levels in linear array beam pattern

I am working on beam forming of high frequency (>400 KHz) linear array for imaging sonar. I have gathered sensor data of 80 channel linear array sub merged halfway in 8 m deep water tank with a ...
0
votes
1answer
23 views

Randomized prefix code

An input symbol is randomly chosen from a set of symbols with known associated probabilities and encoded using a prefix code that minimizes the expected codeword length. Is it possible to further ...
0
votes
0answers
21 views

Non Linear Recursive/Online Least Squares

I am searching for a recursive or online non linear least squares algorithm. I want to spread the computation out as new data is sampled like in the linear Recursive Least Squares or the LMS. ...
0
votes
0answers
29 views

how can I know this system is Time invarient?

y(t) = 0 (t<0); x(t) + x(t-2) (t>=0); y(t) = 0 (x(t) < 0); x(t) - x(t-2) (x(t) >= 0); y[n] = x[n] (n>=1)...
0
votes
0answers
35 views

Why does power spectral density of OFDM signal changes with number of zero subcarriers

I am trying to plot the power spectral density (PSD) of an OFDM signal with $N_{dsc}$ subcarriers and $N_{zeros} = N_{fft}-N_{dsc}$ zero subcarriers. I am using the matlab function pwelch() to plot ...
1
vote
0answers
10 views

Frequency warping while creating filter coefficients

If I have an audio signal at 16kHz with frequencies band-limited to 8kHz. I want to low-pass filter this signal such that fc=4000Hz. Meaning when I reconstruct the signal I do not want any content ...
0
votes
1answer
22 views

BER vs Eb/N0 (db) Curve

So, I was trying to plot BER (Bit Error Rate) vs. Eb/No (in dB) curve using Python. Here is what I get, Eb/N0 is in dB on the x-axis But I know that this is not the correct graph. Here is my code. ...
0
votes
0answers
20 views

How to implement separable bilateral filter?

I’m trying to optimize my naively implemented O(n^2) bilateral filter for 2D images. I googled and found a lot of theoretical explanations about the separate one. However, it seems there are things ...
0
votes
1answer
22 views

What does "noise power is assumed to be the same at all nodes

I was reading a paper about communications between nodes, and in the simulation section they gave the condition of the simulation as follow : "...The noise power is assumed to be the same at all ...
0
votes
1answer
25 views

confused in practical example of shift invariance?

I am reading book of w smith ,"The scientist and engineer guide to digital signal processing" 2 edition I am trying to understand topic of shift invariance from theory given on pg 92 I have attached ...
0
votes
1answer
39 views

Filtering on time or frequency domain?

I'm applying an ideal filter on the frequency domain. My code below: ...
0
votes
0answers
18 views

Problem with calculating PLP coefficients

I am trying to make a programme that will calculate PLP coefficients. The process is described in this paper. However, I am unsure about some of the procedures. Namely, in the IA should I use ...
2
votes
1answer
22 views

Microscopy crystal particle object length detection

Hi I try to detect the particle length size from this image and I'd like to get the length size of the particle Like this below. and get the histogram of the size of the particle using centroid and ...
0
votes
0answers
36 views

Finding time-varying coefficients for a VAR model by using the Kalman Filter

I'm posting this again, since after my last post i've been able to advance the code quite alot. I'm still trying to write some code in R to reproduce the model i found in this article. The idea is to ...
0
votes
0answers
19 views

What is the derivative of Radon Transformation?

We have the Radon transformation, in the most common form: $g(\phi,r)=\int\int f(x,y)\delta(x\sin\phi-y\cos\phi-r)dxdy$ Question 1: So what is the closed form of the derivative of Radon transform w....
1
vote
1answer
28 views

How do I initialize the state of a digital filter in Direct From II?

Suppose I have a digital filter implemented in Direct Form II. How do I initialize the state of the filter as if the input $x[n]$ had a fixed value $x_0$ for all $n<0$?
0
votes
1answer
26 views

Please help me understand this paper about Discrete Wavelet Transform!

I am trying to understand this paper says. I have found this paragraph to be vague: (a) Preprocessing Stage. The first step in this stage was to apply the Discrete Wavelet Transform (DWT). This ...
0
votes
0answers
16 views

relation between Nyquist sampling theory and regression

Regression is mainly about estimating a function when only a finite number of samples of the function are available. Theories usually care about asymptotic performance as the number of samples tends ...
6
votes
3answers
534 views

Compress a signal by storing signal diff instead of actual samples - is there such a thing?

I am working with EMG signals sampled at 2kHz and 16 bits, and noticed that they "look smooth", that is, the signals are differentiable, and if I apply a "diff" function (...
1
vote
1answer
29 views

Normalizing vectors to be the same size to retain PSD data

Context: PSD=periodogram(y) in MATLAB gives the PSD (power spectral density) estimate of a sound-source signal. I want to find the local maximum within 3 different ...
0
votes
0answers
12 views

Use FOV or camera deprojection to find position of pixel in world coordinates relative to my camera?

A teammate and I were discussing how best to get a 3D coordinate point (X, Y, Z) in world units from an RGB-D depth image. I'm using an intel real sense D435. From how I have researched it using the ...
0
votes
1answer
17 views

Biquad Filter Non-Linearity

I'm using a biquad filter algorithm in my project. I got 3, 16 size variable arrays summing into one and then gets filtered. Now i want to filter each array seperately and sum after that, which if ...
0
votes
1answer
43 views

Time delay estimation between two complex signals(IQ)

I need to time align two complex signals. The two signals obtained were at different RF frequency before digitisation. So,I have two complex signals(IQ) and I need to do delay estimation and apply ...
0
votes
0answers
15 views

Need help with detecting onset of audio in wav file

I'm new to DSP and I'm learning as I go. I have an audio file with a chirp signal(2kHz). I played and recorded this chirp signal and the recording has a lot of environmental sounds. Here is my code:
1
vote
2answers
34 views

What exactly is captured in a Sample of the Nyquist-Theorem variety?

I'm new to DSP and was thinking of sampling in the traditional music creation way, in that you capture a sound and play it back, warp it, etc., but when I thought about the Nyquist theorem, I realized ...
0
votes
1answer
29 views

How to characterize this whitening filter?

A little bit of background: I am interested in whitening in the least-square estimation. In this sense, consider a univariate signal $y$. Assuming the covariance of $y$ is $\mathbf{A}\sigma^2$. ...
1
vote
0answers
32 views

Help in identifying low speed image transmission protocol over RF

In the seventies I worked for Muirhead on press fax machines that used to transmit pictures over radio and landline as I recall two FM systems were used a carrier 800 Hz modulated +- 150 Hz and 1900Hz ...
0
votes
0answers
20 views

Is there a software/application that shows the FM base stations nearby us?

I want to collect a list of FM base stations near me. I have found apps/software for finding LTE base station but found no success in finding an app for FM base station.
1
vote
1answer
26 views

Length of padding for multiple samples stored in a single MP3 file

I have 20 short audio samples of a piano playing a single note. Due to internal limitations of my application, I need to concatenate and combine these into a single lossy file (either MP3 or AAC). ...
1
vote
1answer
36 views

Sum of Squared Intensity Difference for block matching with ORB features, c++

I am trying to implement feature matching algorithm between image reference and image current. The pipeline is as follows: ...
0
votes
0answers
22 views

Chirp resolution as a function of bandwidth

My question concerns about the Chirp resolution during the crosscorrelation as a function of the sampling rate and available bandwidth. Suppose at a transmitter a chirp signal is transmitted (ranging ...
0
votes
0answers
7 views

I want to calculate two parameters related to Bone characterization namely BUA or Broadband ultrasound attenuation and Speed of Sound in MATLAB

I am using Simsonic software(http://www.simsonic.fr/) to generate 2 signals 1) for plane water(2D) width 45mm, and 2)for bone specimen 30mm width in the above vat. I am centering my source at 5mm and ...
1
vote
1answer
25 views

Deriving vector paths from pen strokes

I want to calculate vector paths that approximate pen strokes from handwritten documents. My tool needs to run in batch mode, unlike hand tracing or Illustrator's "Image Trace" feature. The potrace ...
2
votes
0answers
37 views

Help obtaining the variance of a signal from a power spectrum?

I have been reading this. The paper presents a power spectrum (attached). The power spectrum shows the power spectrum of velocity perturbations, $v$, in the solar atmosphere. If I want to obtain the ...
0
votes
1answer
25 views

What is the difference between domain and range filtering?

In the context of image processing, I have heard the expressions "domain filtering" and "range filtering". What do these terms refer to? What is the difference between them?
1
vote
1answer
32 views

What is a periodic signal in image processing?

In the context of image processing (and computer vision), the concept of convolution comes up a lot. Convolution is quite related to the concept of Fourier transform and DFT. In the context of image ...
0
votes
1answer
29 views

Calculating DTFT

When calculating DTFT of (1/2)^n u[n]. We evaluate the sum as follows: Please correct statements and answer questions below: 1) So to go from STEP 1 to STEP 2, the limits of the series are changed ...
1
vote
0answers
16 views

Simple Impulse Response DSP Hardware

I developed some complex chains of filters and crossovers. After that I have created IRs from the entire chains. Applying these IRs in software works perfectly. Now I wonder what is the easiest (and ...
0
votes
0answers
13 views

Block diagram reduction with multiple inputs

I need to reduce the diagram, when each input is 0, I can do when d=0, however i'm finding it a little difficult when r=0. I have solved the exercise using a signal flow diagram and the solution is ...
0
votes
0answers
15 views

Error with simple Extended Kalman Filter simulation in Python

I am trying to write a Python simulation for a bearing-only EKF tracking problem. I wish to estimate the $x$ and $y$ position and velocity vectors for an object, so my state vector is $$\mathbf{x} = [...
0
votes
1answer
35 views

DTFT frequency range

$$X(e^{j\omega}) = \sum_{n=-\infty}^\infty x[n] e^{-j\omega n} $$ The frequency term $\omega$ in DTFT is normalized as $\omega = \frac{\Omega}{f_\mathrm{s}}$ $\Omega= 2 \pi f$ is the angular ...
0
votes
0answers
13 views

Restoration problem with numpy fft function and self-made high-pass filter

Hi, I am using numpy.fft functions to do CV assignments in univ. But while implementing the high-pass and low-pass filter, I found something wrong during the process. The difference should converge ...

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