-1
votes
0answers
38 views
Is it true that convolving a 3x3 matrix and a Full HD image is slower with FFT? [closed]
Is it true that convolving a 3x3 matrix and a Full HD (1920×1080) image is slower with FFT, than with normal for-loops? Because you have to do zeropadding to get to a power of 2? (with the traditional ...
0
votes
1answer
21 views
Information i can take from coeficient intensity map in DCT transform
What useful information i can take from the coefficient intensity maping after performing DCT transform?
5
votes
2answers
62 views
Artifacts in FFT
I recently realized that FFT's aren't perfect. Meaning if I take a signal and then take it's FFT, and then do an inverse FFT, the resulting output isn't exactly the same as the input. Here's an image ...
3
votes
2answers
56 views
Why integrate over $2\pi$ in inverse DTFT?
In DTFT of a signal, the spectrum of a sequence is periodic with period $2\pi$ and all the information needed for derivation of the original signal from its spectrum is contained in $\pi <\omega ...
8
votes
2answers
116 views
How were windows originally conceived?
I am aware of the common types of windows, (Hamming, Hanning, Kaiser, Tukey, etc etc). However while many books describe them - almost none tell me just how exactly they were derived.
What is so ...
1
vote
0answers
24 views
Multiresolution discrete wavelet transforms: First steps
I have been looking at trying to use wavelets for multichannel audio dynamic range processor. I am in the very early stages of trying to get decomposition and reconstruction working. In this thesis, ...
0
votes
0answers
20 views
Plotting the Graph against ECG Modality
ECG
I have no previous experience in plotting the Graph. I want to plot ECG Graph w.r.to their Waveform Sequence How it can be achieve and below are some points that also i need to ask....
1)I want ...
1
vote
1answer
35 views
How to get more accurate results with OpenCV
I would like to ask about this function in OpenCV:
cvTermCriteria( CV_TERMCRIT_ITER | CV_TERMCRIT_EPS, 20, .3 )
How do I get more accurate results - do I need ...
4
votes
1answer
45 views
Spectral analysis of positive signals
Suppose that I have a sensor that can acquire samples $X[k]$ of the Fourier transform of an unknown signal $Y[t]$. An example is MRI, where the acquired data is in $k-$space. Now suppose that the ...
1
vote
0answers
21 views
Affine detector + SIFT descriptor
I am approaching to the Oxford Buildings dataset which contains already computed SIFT descriptors from affine detected keypoint locations.
Usually SIFT detector provides to its detected keypoints ...
2
votes
2answers
99 views
DFT/FFT: What did N stand for again?
So if I have an image of the size: 1920×1080 and I want to apply a convolution filter of 3x3. Take the formula for DFT $N^2$ and FFT $N \log N$. What should I fill in for N in this case?
3
votes
2answers
81 views
Why the power of periodic signal is square?
I have DSP in my academics and while going through the video lectures i am stuck regarding power of periodic signal.
Its mentioned as
$$P_{\text{avg}}= \frac{1}{N}\sum_{n=0}^{N-1}|x(n)|^2$$
my ...
5
votes
3answers
204 views
Can we have a Digital Anti Aliasing filter?
I am working on a board that has no antialisaing filter at the input of the ADC. I have option to I implement my own filter using RC + Opamp circuit. But is it also possible to implement Anti ...
1
vote
0answers
43 views
voice with a random noise redction - MATLAB
I have this assignment that I can't figure how to solve.
I have a sound.wav human-voice file, and a matlab add-random-noise (monotonic)
Goal: remove the noise from the sound (and the sound from the ...
2
votes
0answers
16 views
wavelet transform boundary
I am doing 1D wavelet decomposition and I am particularly interested in parts at the border of the signal. These parts are affected by boundary effects.
I know that some of the methods to extend the ...
0
votes
0answers
41 views
what's the name for errors like phoneme deletion and phoneme substitution? [closed]
I want to know the global name for speech errors like phoneme deletion and phoneme substitution, just like there is word called "prosodic error" for stress error and intonation error.
I have viewed ...
-1
votes
0answers
19 views
Produce a 4:2:2 sub sampled Y matrix, Cr matrix, Cb matrix for an image
I have write the matlab code below for to extract Y, Cb, Cr information from the picture:
...
5
votes
1answer
60 views
Learning roadmap for the audio signal processing beginner
I would like to start learning audio signal processing. There are numerous books online and academic papers all of which seem to skip the fundamentals of the topic.
I would like to know a rough ...
-1
votes
4answers
49 views
Number of elements of an array
I want to found how many elements in an array is not equal to zero. I use this code:
y=sum(img_dct~=0);
z=sum(y);
Can i make this with a different way? Is there ...
0
votes
2answers
66 views
How can a linear operator on DFT vector produce the same vector using only half of the DFT vector?
Suppose there is a DFT vector $\mathbf{X}$ with length N, which presents complex conjugate symmetry around its middle point, i.e., $X(1) = X(N-1)^*$, $X(2) = X(N - 2)^*$ and so forth. $X(0)$ and ...
0
votes
1answer
29 views
Plot the magnitude of coefficients against frequencies of DCT transform
When we perform DCT transform using matlab:
...
1
vote
1answer
40 views
Signal approximation using linear combination of functions
How I can approximate the signal $x(t)=0.001\,t^3 \exp(-0.1t)$ in the interval $[0,100]$ using a linear combination of the following functions:
$f_1(t)=A_1$
$f_2(t)=A_2\cos(0.05t)$
...
2
votes
1answer
32 views
Laser diode bitrate datasheet
I'm a student studying communications engineering. I'm trying to understand why this particular laser diode is made for 155 Mbps and 622 Mbps. I'm thinking that the bitrate is entirely dependent ...
-3
votes
0answers
31 views
DSP MATLAB example question about notch filter!! [closed]
![this is the example question from the dsp using MAtlab edition 2, using the sources I have it was quite hard to answer it correctly. Needs you guys help!!][1]
[1]: ...
0
votes
3answers
61 views
similar tools for MATLAB ? [closed]
I have DSP in my academics , I am here to have a suggestion regarding the better alternative to MATLAB because of Its downloading size.
Thank you.
2
votes
1answer
97 views
Spectrum of a zero-order-hold signal
What does the spectrum of a sampled signal look like if one uses a zero-order-hold?
There is some information in:
Sampling theorem and Dirac comb, but I am wondering, how to apply this in practice.
...
0
votes
1answer
57 views
Tracking object that is missing in some frames
I am trying to track small object in videos using LK
but the problem is, some time the object does not appear in the frames !
How can I track an object that does not appear in few frames ??
how ...
0
votes
1answer
25 views
Random selection of sub-block in an image with matlab
I want to select a random sub-block of 8x8 out of an image 256x256. Is there an instruction that do this thing or i need to calculate it with a different approach. I found how to choose a galois field ...
0
votes
0answers
18 views
Frequency cut-offs for guitar amp tone [migrated]
I am wanting to know what the typical frequency cut-offs are for the bass/mid/treble controls on a pre-1990s guitar amp. I want to simulate them in Java. So basically I have
...
1
vote
1answer
35 views
Smoothing “font characters” outlines in bitmap image
Adobe Acrobat has this as a feature called ClearScan. While doing OCR it allows image enhancement, by smoothing irregularities on font outlines.
For example, this source:
turns to this:
Are ...
3
votes
2answers
47 views
Multiple filters or not?
I'm processing audio signal sampled at 44.1 kHz. After some other processing, I need to filter the signal between ~5-50 Hz. Achieving this for a signal with such a high sampling frequency appears to ...
4
votes
0answers
49 views
Practical impulse response estimation using NumPy
I would like to estimate the impulse response of a simple environment (room, two speakers, one microphone). I am aware of the issues/limitations of working with "near" LTI systems. That said, I have a ...
2
votes
2answers
54 views
Conditions for precoding matrix to preserve complex conjugate symmetry on DFT vector
Suppose there is a DFT vector $\mathbf{X}$ with length N, which presents complex conjugate symmetry around its middle point, i.e., $X(1) = X(N-1)^*$, $X(2) = X(N - 2)^*$ and so forth. X(0) and X(N/2) ...
1
vote
0answers
43 views
formant frequency bandwidth of LPC root
For formant estimation from LP polynomial roots, more roots amplitude shows that poles is near to unit circle in Z-domain but
Can anyone explain why the bandwidth of the formats must be small ?
I have ...
2
votes
1answer
60 views
Step response overshoot in IIR filters
Is there an analytic expression by which it is possible to calculate overshoot of step-response of second order IIR digital filter? I have tried to search through Mitra's signal processing book and ...
1
vote
1answer
60 views
frequency domain phase shift
While going through FFT I came to know that, shifting of phase in frequency domain results on shifting of time in time domain.
According to this, in wireless communications, from the transmitter side ...
0
votes
1answer
33 views
Square of Frequency characteristic of the system
What does $|H(j\omega)|^2$ in $20 \log_{10}|H(j\omega)|$ mean?
Is it some ratio of energy or power? And why? How to derive it?
I'm sorry for curtness of my questin.
0
votes
1answer
36 views
Image processing functions for quality control
I have to use image processing for quality control of a cookie manufacturer (as a part of my project). The program must be able to detect oversized, undersized, distorted cookies, cookies having ...
0
votes
0answers
29 views
Validation of Signal Pre-Processing methods?
I have to design a set of Pre-Processing methods for an acoustical signal for further neural networks classification.How can I validate my methods?
1
vote
0answers
42 views
Calculate total bit rate
I want to calculate the total bit rate of a video system.
In order to calculate the total bit rate for a 1080/50p video system(4:2:2) we need:
...
3
votes
2answers
81 views
How to make a signal conjugate symmetric?
Take the simple frequency-domain band-pass filtering operation below . . .
...
-1
votes
0answers
67 views
bandpass implementing with DWT in matlab
In matlab help in find the implementation of bandpass as following
...
3
votes
2answers
94 views
Finding the frequency response of a filter defined as a Z-domain transfer function
I am software engineer studying DSP on my own. I came across this question in a graduate textbook and am not sure how to proceed.
...
-3
votes
0answers
34 views
Want to Get Pixel Values from Mouse Pointer Location from the Mouse Click Event [closed]
I am trying to display dicom image over the picture box it works fine,
but Now When I click the mouse on the dicom image from that mouse pointer click event is fire,
I got x and y coordinate of that ...
7
votes
1answer
110 views
+50
'Best fit' motion curve for an unachievable profile
I have a discrete function that represents a 1d position in space over time. I have a motion system that would like to achieve this curve, but, due to constraints on jerk (3rd derivative) and ...
2
votes
2answers
56 views
Implement a software PID for the first time in real time software, I can find P what about I and D?
Here we have the basic formula of a Proportional Integral Derivative controller. This is the formula from the Wikipedia page on the subject
I want to implement this type of controller in my system. ...
3
votes
3answers
102 views
Basics of frequency spectrum for onset detection using FFT
I'm pretty new on signal processing and I've been reading a lot the last days in order to understand a little about it. But still there are things that I'm not sure if I got well. Sorry if I don't use ...
2
votes
2answers
59 views
recover image by only magnitude of image fourier transform
I have a image and I want calculate fft2 of it, after it I want recover image only by magnitude of it. how can I achieve this work?
...
1
vote
1answer
33 views
Calculate maximum of filter kernel
I'm sure there must be an easy way to do this, but given the Fourier transform of an isotropic filter kernel, $\hat{f}(\mathbf{u}) = \mathcal{F}f(\mathbf{z})$, can one calculate the value of the ...
4
votes
1answer
103 views
DC blocking IIR filter clipping?
I'm processing audio data for voice input from a mic. The data arrives in 32 bit floats [-1 ~ +1].
My first filter is to remove DC:
...
