0
votes
0answers
8 views

Sliding Windows, Global Image, Clustering and …?

Imagine that you have an algorithm that must detect some feature in an image. Right now, I know three "families" of search algorithms. Sliding Windows: You take a patch of some size (e.g. 15x15 ...
0
votes
2answers
17 views

Re-recording audio vs. convoluting old audio data - differences?

I want to transform a studio audio dataset into a smartphone audio dataset (used for a speech recognition application). Would there be any difference in the resulting audio files using one of the ...
0
votes
0answers
7 views

Is there a 3-dimensional correlate to phase residues?

In 2D phase unwrapping problems, the presence of a "phase residue" indicates that the answer obtained from a path-following unwrapping algorithm is dependent upon the path taken. A phase residue is a ...
0
votes
0answers
15 views

Extracing IQ samples from a composite signal?

I'm writing a modulator in matlab to simulate IQ data that I would get from my radio to test my demodulator. I've read that I = x(t) * cos(wt) and Q = x(t) * cos(wt). What is the omega (w) term? If ...
0
votes
2answers
31 views

why the number of filter coefficients in FIR filter has to be an odd number?

I calculated the order of the FIR filter to be 31(N). so, the number of coefficients has to be 32 (N+1). so, I have to increase it to 33 to make it an odd number. Why the number of filter ...
0
votes
1answer
20 views

Comparing signals recorded using diffrent methods

Suppose we have two signals( focus to audio) recorded with different methods, or more simply, suppose we have two audio signals recorded with different microphone, and we want to confirm that these ...
0
votes
1answer
24 views

Convolution of h(n) & x(n)

can anyone please help me with finding Convolution for following problem ..... 1) $h(n) = \delta[\sin(1 + |n|)]\quad \text{and}\quad x(n) = \sin(n^2)$ 2) $h(n) = \delta[\sin(2\pi n/N)] \quad ...
0
votes
0answers
19 views

How to obtain Power Spectral Density (difference between RMS)?

I did a fft but i need to do the PSD of certain frequency range, how can I do it and whats the difference between this and RMS?
-1
votes
0answers
16 views

piano detection and comparing two sounds file

I am pretty new for DSP. After studying some DSP knowledge and reading posts here, my algorithm is able to detect monophonic pitch accurately. However I want to detect simple music pieces in piano, ...
-1
votes
1answer
20 views

how to detect signal noise

I have data from a power transformer that has a frequency of 60 hz. Sometimes there are faults in the system and causes a large spike in the reading of the transformer. What I want to do is run the ...
-1
votes
1answer
31 views

Can all pass filers have a pole/zero at the origin of the root locus

I came across this root locus diagram in my DSP class. It has a pole at the origin, another pole within the unit circle and a zero just outside the unit circle. I understand that the poles and zeros ...
-1
votes
1answer
21 views

Overlap frames in short term fourier transform

I'm trying to understand the aim of overlapping frames in the short term fourier transform. Why is it important to do it? I have been told that it's to avoid "problems" at the frontiers of frames. But ...
-1
votes
1answer
29 views

Accumulator with decay?

I am using an accumulator in the form of X + [Y-1], X plus the unit delay of the output. Is there an accumulator that follows this form, but will fall to 0 over time, similar to a differentiator?
-1
votes
0answers
14 views

is there a specific band for noise in eeg

i want to know is there any specific band in eeg signal for noise? i have read all the related posts on this forum . one of them make me know that there is noise with 50 hz in eeg. some suggest to use ...
-2
votes
1answer
37 views

fft of a complex signal

I am new to dsp and just have a vague understanding of fft process. i know fft is used to convert time to freq domain.... i need to generate a sequence of frequencies such that F=[F1,F2,.....Fn-1] ...
0
votes
0answers
17 views

MFCC gives poor results for speaker identification

I trained my program by using 2 GMM algorithms for speaker identification. I used 32 MFCC features for the first GMM and the f0 feature for the second GMM. There are 6 speakers . And for each speaker ...
0
votes
1answer
25 views

Discrete approximation to Gaussian filter

One method of producing a discrete approximation kernel to a Gaussian filter of variance $\sigma^2$ is to assume a cutoff of $5\sigma$. This seems to suggest the following procedure: Create a ...
0
votes
1answer
41 views

Explain Shift property of DFT

Please check the link What effect does a delay in the time domain have in the frequency domain? Here it is said that if you delay your input signal by D samples, then each complex value in ...
0
votes
2answers
45 views

What do you get appling FFT to Music?

I am trying to take a section of a song (approx 1.5 seconds) 44100 sample rate equals sample size of 65536 which is 2**16. I want to find the frequency of the piano note that is played in the window ...
0
votes
0answers
45 views

Simplest approach to classify signal based on its 'smoothness'?

First of all, I have no experience with signal processing whatsoever and I may not even use proper terms so please bare with me. I am just humble software developer trying to find the simplest and the ...
-1
votes
2answers
22 views

Implementing image chroma keying with FIR filter in MATLAB

Is there any way I can apply the concept of FIR filters in chroma key composition, where I will remove a green background to focus on a subject and replace a different image on the removed part, sort ...
0
votes
1answer
23 views

Confusion about speech being piecewise stationary

From wikipedia: "Modern general-purpose speech recognition systems are based on Hidden Markov Models. These are statistical models that output a sequence of symbols or quantities. HMMs are used in ...
0
votes
2answers
22 views

How does using DCT help in image compression

I once learnt that the Huffman Encoding is used to rid of redundant information, thus reducing file size. I am not sure how using a DCT, or FFT on an image can help in reducing file size. It does not ...
-1
votes
1answer
38 views

Can someone please help me out with audio, sampling frequency question

I really having a hard time to tackle the following question. It is asked to load a ".mat" file using load file.mat. And the result is two variables: Fs varaible ...
0
votes
0answers
11 views

Python implementation of multidimensional power spectral density with Welch method

I have done my best to write Welch method implementation for python for multidimensional time series and still in the case of one dimensional time series I am getting inconsistent response compared to ...
0
votes
0answers
9 views

Getting low accuracy with deep convolutional NN trained on Imagenet 2011

I've downloaded the Imagenet2011 dataset and tried to train the Caffe imagenet network on it using the instructions here. I used about 500K images for training and 70K images for validation. I've ...
1
vote
1answer
33 views

Rectangle detection in “real life” images

I have seen a lot of posts here and on SO and on various websites, using Matlab, OpenCV, name it, on how to detect rectangles in an image. I have done it myself too, using Matlab. My usual steps were: ...
0
votes
0answers
19 views

Learning fundamentals of OFDM (Theory & Simulation)

Will you please suggest me some basic fundamental reference to learn OFDM techniques. I am looking for underneath theory with some basic mathematical explanations of CP, Subcarrier, FFT Size, Pilot ...
0
votes
0answers
14 views

Wavelet Transform: Terms and Definitions

I have some doubts in respect to terms and definitions in the domain of wavelet transform/analysis. I analyse a signal by correlating each time my original time samples with different scaled and ...
0
votes
1answer
22 views

Stopping Viola Jones Face Detection early

I want to try to improve an image processing technique for finding faces in images. I want to stop the Viola Jones face detector before it finds all faces, and do histogram equalization and other ...
0
votes
0answers
7 views

Response to spatially varying impulse response

From this 2003 question paper: Is the following answer to part (a) correct: $$ g(x,y) = \{f*g\}(x,y) \\ = \int_m \int_n f(m,n) h(x-m,y-n) dm dn \\ = \int_n f(a,n) h(x-a,y-n) dn \\ = \int_n f(a,n) ...
1
vote
1answer
38 views

Solving for impulse response

I'm working on some problems that instruct me to find the impulse response of a given system. For example $$y(n)=4y(n-1)-4y(n-2)+x(n)-x(n-1)$$ The first step I take is to find the homogeneous ...
0
votes
1answer
59 views

Picking out a signal that appears to be noise inside a large signal

I have a signal from a photodiode sensor that has two types of noise. One type of noise is ambient light white noise that gets introduced just from the surrounding environemnt. The other type of noise ...
0
votes
2answers
26 views

What is a translation property in DFT

Hi someone please explain me the translation property of DFT. I am not able to understand it neither from Gonzalez nor from internet. I have done extensive study on this but not able to get it. Really ...
1
vote
1answer
25 views

Characterising a system from its input and output

I have 2 data sets sampled at regular intervals which represent the input and the output of a system. A quick analysis of the plots shows the following: There is a proportional factor between the ...
1
vote
1answer
45 views

How to learn MUSIC algorithm?

I was actually preparing for my semester project and decided to take up Frequecncy estimation.I ll directly come to the point that I want to know how should I learn MUSIC algorithm. How do I start it? ...
0
votes
0answers
6 views

OFDM intra-block multipath interference

We know that OFDM eliminates the inter-block intereference. But there are still multipath interference in a single OFDM block(symbol). How does LTE handle this intra-block interference induced by ...
0
votes
2answers
32 views

Convolving Room Impulse Response with a Wav File (python)

I have written the following code which is supposed to put echo over an available sound file. Unfortunately the output is a very noisy result which I don't exactly understand. Can anybody help me with ...
0
votes
1answer
22 views

Available Online Recordings for Acoustic Echo Identifiablity

I am trying to add a few samples for a publication on identification of clean signal from the one which has echo on it. For this purpose I need data set that includes playback of an already available ...
2
votes
2answers
41 views

Would the locations of SIFT features generally agree with features detected by Shi-Tomasi method?

I am having a comparison of different feature detection methods. So if we compare the SIFT (Scale-invariant feature transform) and Shi-Tomasi method, will their feature locations agree and why? Are ...
0
votes
0answers
5 views

State Space model of a differential eqn. for use in Least Squares

The code in this page solves the Least Squares problem for the following dynamic model: $\dot{y}=ay+bu$ where $a$ and $b$ are constants, $u$ is an input. The code is as follow: ...
0
votes
0answers
22 views

Creating a digital filter, from laplace to z transformation(zero order hold) to code?

I'm trying to create a digital filter in code(C) but any languge is fine. Now I've got an analogue filter that i have represented by an equation in the Laplace domain and I want to try and implement ...
0
votes
1answer
51 views

Looking for integral-free DSP textbooks

I am looking for a treatment of fundamental DSP theory where only discrete/finite signal models are used. To make a concrete example, every time standard textbooks write a convolution as a continuous ...
0
votes
1answer
28 views

Implementing digital filter by padding with zeros

I am making a 9th order digital bandpass filter with lower and upper corners of 200 kHz and 40 MHz respectively. I am using this filter to filter a 1D time domain signal which is 64k samples long ...
0
votes
1answer
37 views

Instantaneous phase calculation problems

I am currently struggling with a problem when calculating the instantaneous phase of a wavefield using a 1D Hilbert transformation. The scheme is as follows. 1D Hilbert transformation of wave field ...
0
votes
0answers
25 views

Welch's Overlapped Method

I am measuring wind speed using a number of different anemometers. These anemometers are placed on a structure which exhibits sinusoidal motion. Thus, the signal of the anemometers contains both the ...
0
votes
0answers
10 views

.ptw Video conversion

On Video recording with IR camera, a file in .ptw is obtained. I want to analyze the file using standard software, like MATLAB. However, video processing in MATLAB requires the file to be converted to ...
0
votes
1answer
29 views

What does “warp” mean in DSP?

I hear the word warp a lot, but cannot quite get a feel for what it really means I suppose it's literal meaning would be to change in shape, but what does it mean with respect to DSP? More ...
3
votes
4answers
239 views
+300

“cascaded” cross-correlation

so, first let's do this for the circular correlation case (it might be easier). let's say we have three real and periodic functions or signals $x(t)$, $y(t)$, $z(t)$ all with period $2 \pi$: $$ ...
1
vote
1answer
49 views

How to constrain the object detection problem?

How to constrain the object detection problem? It would be tempting to ask for precision such as: "It depends, does it have to be viewpoint invariant, is there going to be viewpoint changes, etc.?" ...

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