# All Questions

16,591 questions
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 ...
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.
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 ...
55 views

### Convolution of Two Impulse Signals

I have encountered convolution of two different impulse signals. ...
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 ...
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 ...
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 ...
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) ...
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 ...
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 ...
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. ...
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)...
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 ...
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 ...
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. ...
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 ...
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 ...
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 ...
39 views

### Filtering on time or frequency domain?

I'm applying an ideal filter on the frequency domain. My code below: ...
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 ...
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 ...
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 ...
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....
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 $n<0$?
26 views

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 ...
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 ...
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 (...
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 ...
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 ...
17 views

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 ...
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 ...
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:
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 ...
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 $\mathbf{A}\sigma^2$. ...
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 ...
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.
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). ...
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: ...
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 ...
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 ...
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 ...
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 ...
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?
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 ...
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 ...
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 ...
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 ...