# All Questions

3 views

### Using morphological operations for color images processing

Have you ever seen any articles about using morphological-like technique for denoising color images?
16 views

### What part of complex number of inverse discrete Fourier transform?

Ok, so we have an image that is a Fourier inverse of the original picture. We want to get the original picture back. We use Matlab to get that job done. We import the image and then we invert it with ...
23 views

### Basic sampling problem - could use some advice

I have a problem in my DSP class that I could use some advice with. An analog signal of length 2.5s is sampled with a Nyquist frequency and the sampled sequence has 5001 values. What is the highest ...
17 views

### why LTE doesn't use DC subcarrier in the downlink?

I know LTE doesn't use the DC subcarrier for OFDM/OFDMA modulation for the downlink, but no author gives a detailed explanation to this stuff. Can you tell me the reason behind it? Thank you!
24 views

### Overlapping with flat-top window MATLAB

I am applying a flat-top window to signal because I am very interested in its actual amplitude in the time-domain. I have read that overlapping will improve results. I am using MATLAB and the ...
25 views

### Flat-Top Window

I am calculating the velocity of a moving table (Vs) whose motion is sinusoidal by using an encoder connected to a motor shaft. On this moving table I have a lattice tower on which are mounted a ...
13 views

### PAPR in the SC-FDMA system

in wireless communication,compared to the OFDM system , why does the SC-FDMA (single carrier FDMA) system has a lower PAPR (peak to average power ratio)? regards, phani tej
14 views

### what is the significance of DFT in SC- FDMA system?

in the SC-FDMA system, prior to applying the IFFT , there is a DFT block and sub carrier mapping. what is the significance of DFT and sub carrier mapping?. And how these blocks make the system single ...
15 views

### how to choose a mic and make sure not to overcahrge it

I'm not sure that's the right forum to ask this question but I'll do it anyway . in my project, I've to listen to different machines using an MEMS mic by fixing the mic directly on the machine , the ...
49 views

### Solution to Cross-correlation problem of 2 audio signals

There are 2 audio signals, X & Y. X is of 15 second duration. The duration of Y is not given. Y is a part of signal X (ie a small part of audio X is extracted & made into audio Y) I have to ...
12 views

### any in built function to read a part of an image in malab? [on hold]

i am dealing with images with size 6000x9000 (16 bit). if i want to perform any mathematical operations on whole image it takes lot of time,at the same time it consumes a lot of working memory.i want ...
23 views

### How is LMS/FXLMS noise cancelling different than simple polarity inversion?

Consider a noise-cancelling headphone: If I have a noise signal from the outside world, mic it, flip the polarity by multiplying by -1 (with an op-amp or digitally), delay by the appropriate amount, ...
23 views

### Why does my overlap-add integrator in frequency domain result in distorted signals?

With help from the dsp guide and DSP-Related, I tried to implement a leaky integrator in octave/matlab. It seems to work in general, but there are a few problems. So that's what I do: Calculate the ...
43 views

### Spectrum of a signal

We are given this signal m(t)= sin(400pi*t)/pi*t , which is modulated successively using the system in the shape below. Triangles are amplifiers of gain=2 . (sorry for the bad quality, it's a pic ...
18 views

### Linear prediction filter for loudspeaker equalization

does anybody know the usage of linear prediction filters for equalization of loudspeakers? Thanks in advance.
39 views

### Appying a Filter Several Times on Data

I have data from an experiment and apply a lowpass filter (Butterworth filter, in Matlab). My question ist what happens if I apply the same filter e. g. 2 times on the data? What is changing? Is it ...
21 views

### Avoid saturated pixels in cross-correlation computation

I am doing template maching using Normalized Cross-Correlation for measuring similarity between template and image. However, some images from my dataset contain saturated pixels (overshoot) which ...
10 views

### Process Noise “Q” covarience matrix in a kalman filter

I am trying to implement a Kalman filter on a Phasor Measurement Unit (PMU) values. I meaured the signal from PMU and give those meaurement as input to Kalman filter to get best estimate. I do not ...
28 views

### Spectral Content of two waveforms

I have found this interesting question here: Which of these two waveforms has a richer spectral content, and why? Intuitively speaking, I think that the first one is richer, but I cant really ...
30 views

Weighed overlap add Filterbank structure is often used in speech coding. (https://www.onsemi.com/site/pdf/Filtering_Hearing_Ai.pdf) I have basic question with respect to analysis. what is the ...
20 views

### Can uneven sampled points generate valid PSD and spectrogram?

My recording device samples signal at 100 Hz. At each sampling point, it generates 512 values (I assume due to non-ideal impulse in practice, so each impulse is actually a window with certain width ...
20 views

### Detecting white noise signal and narrowing the frequency in matlab

I created a white noise that is played in 2 channels. While the left channel is active the right is silent and vice versa. I am trying to detect the signal arrival time after it has run through the ...
85 views

### Is this a new or existing FFT approach?

Wanted to run this past you to know if it's been done before (and also whether my mention of resonator makes much sense) ... I basically perform FFT by factorising calculations, resulting in O(n log ...
25 views

### Image Processing - Identifing/locating Random Solid Blocks of Colour

I am not overly familiar with image processing. I know a little about it from University, but I have not really done any for a while and I have found myself with a problem that requires it. What I ...
33 views

### Checking linearity/time-invariance etc. for recursive system

I'm familiar with the general methodology for checking if a system is linear: Define output $y_1[n]$ for input $x_1[n]$, define output $y_2[n]$ for input $x_2[n]$ Define $x_3[n] = ax_1[n] + bx_2[n]$ ...
33 views

### How is a realtime BiQuad/IIR possible?

I was thinking, if a realtime system is one in which the processing time is shorter than the sampling period, how does a feedback filter such as a biquad perform the computation without waiting for, ...
26 views

### Window function applied to frequency domain signal - why not to time domain signal? [on hold]

How to apply the Hamming window function to FM signal to generate a sweep signal? Here I have wrote the MATLAB program without using chirp function.
45 views

### Recursive version of DFT as presented in Cooley-Tukey paper

The seminal paper of Cooley and Tukey provides an iterative method for computing the DFT for a sequence of length $N$. Specifically, they mention a method which utilizes the fact that $N$ can be ...
41 views

### Segmenting a sound file before each of its attacks

Like the title says... I want to split audio file where a single instrument is played (not so fast)... I just need to detect the attack phase of the waveform to know where a played note begins. Can ...
14 views

### Python module request: Spectral density estimation for multivariate time series

I have worked with scipy.signal.welch and spectrum.pptm to calculate power spectral density with Welch and Multitaper methods. However as far as I can see these functions are meant for one dimensional ...
72 views

### Compare Overlapping FFTs to a longer FFT

How would you compare the SNR gain from a longer FFT (more samples) to overlapping FFTs? Given the choice, which one would you pick and why? Update: Suppose you have 2048 samples of a signal. ...
53 views

### Determining whether or not a system is BIBO stable

I'm trying to determine whether or not a system with impulse response $$h(t) = \sum_{n=-\infty}^{\infty} \delta(t-2n)$$ is BIBO stable. I haven't touched this material for a very long time -- ...
18 views

### Saving satellite signal data to file on a predefined time interval in GNU Radio Companion [on hold]

THE QUESTION: In GNU Radio Companion, I need to save signal data only for predefined time intervals into differently named files. How can I have the file sink check that condition before saving? I am ...
19 views

### Determining effect of powers of DFT matrix conjugate on input without multiplying

Suppose I have a DFT matrix $F$ of dimensions $N \times N$ where $N$ is a power of $2$. I convert it into a unitary matrix $\displaystyle U = \frac{F}{\sqrt{N}}$ and compute $S = U^* U^*$. $S$ ...
13 views

### Texture segmentation [closed]

I would like to ask you something about texture segmentation. Please give me some common method to segment texture image and what is basic idea of texure segmentation?
19 views

### Research work for the thesis [closed]

i want to do work in the the field of optimization of FIR filter .give me suggestion about the latest advancement in which i can do my work. i am also interested in multirate signalling processing. ...
24 views

### The error between the theoretical value and the simulation value of imaginary part of the FFT results

As we know, a complex analytic signal can be obtained through Fourier transformation of a real value function, and the imaginary part can be reconstructed by Hilbert transform of real part. But I have ...
25 views

### Error tolerance for MUSIC (Multiple Signal Classification)

I would like to know if there is rule about how much can a matrix X-hat deviate from original matrix X $$\epsilon \le ||X -\hat{X}||_2$$ for MUSIC algorithm to still work. $$\hat{X} = X + Noise$$ I ...
13 views

### Detecting inset images/videos from a video

I want to detect multiple rectangles in a video, each of which features a different content, but running simultaneously. This is typically seen during debates on news channels. For example, in the ...
23 views

### which one is the most appropriate approximation way between legendre polynomial and taylor polynomial?

I trying to implement such as $$f(x)=\log\left(\frac{\tanh(1+x)}{\tanh(\delta+x)}\right),\quad x\in (0,1),\quad\delta\in (0,1)$$ equation to Hardware logic. So i think i need some way to ...
20 views

### Do DCT each output coefficients have to be orthogonal?

I have a question: Do DCT each output coefficients have to be orthogonal? Here DCT is DCT-II type. It is used by the jpeg compression algorithm.
11 views

### Image Registration Accuracy

I am doing image registration of aerial images with ground reference image. To extract the accuracy measure, one would have to obtain some sort of ground truth manually via selecting tie-points ...
60 views

### Filtering data so that only rising edge is left

I have data that looks like this: Sometimes the data has a higher point in the middle of the shallow slope I want to find a way to filter the data such that it smooths it and leaves the first ...
29 views

### intuitive interpretation Fourier Transform of two different Rectangular pulses

From my understanding of Fourier transform, a Fourier transform of a signal in time domain will give the different frequency components of the signal in frequency domain, specified by their ...
27 views

### Power of a square wave signal

I have a signal with half-amplitude $A$ and period $T$ and I want to calculate the average power of the signal. I think I remember the power of a signal $x(t)$ to be ...
79 views

### Is it customary to correct for the gain of a window?

Consider how the Hanning window is defined: 0.5 - 0.5 * cos(n*2*Pi/(N-1)) By this definition, it has a gain of 0.5, which is simply the average value of the ...
10 views

### choose correct variant of signal/noise ratio calculation

let us consider following sinusoidal model ...
38 views

### Algorithms for deformable image registration

I need to perform a deformable image registration (DIR) for delineation of the different brain parts on the brain MRI 3D image. I faced with a problem that there are a lot of different approaches for ...
I am having difficulty in developing an algorithm for checking if a given system is time invariant or not. For example, let there be 2 systems with input output relation given as: $$y(t)=x(t-2)$$ ...