Questions tagged [homework]

Homework means the asker is requesting help with school homework. This lets potential answerers know that they should guide the student in solving the problem, rather than simply showing the complete answer.

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3
votes
1answer
102 views

Erosion in image

I don't if I am posting my question in the correct place. I have tried hard to solved it but I am unsuccessful. I have an structuring element shown below: ...
3
votes
1answer
297 views

Filtering $ n \times n $ Images by Separable $ m \times m $ Filters. Computation Time for Filtering Using FFT, 2D Convolution and Two 1D Convolutions

Consider filtering square $n\times n$ images by square, separable $m\times m$ filters. Give general equations for the computation time for the following approaches to this: Filtering using FFT 2-D ...
2
votes
0answers
282 views

Proving a cyclostationary processes signal

Suppose a random signal $x(t)=\sum\limits_{n=-\infty}^\infty Z_n \delta(t-n\tau)$, where $ z_n = Z$ and $Z$ is a random variable with equal probability to be $+-1$, is passing through a low pass ...
3
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0answers
1k views

How do I check controllability and observability using Gramian matrixes?

I have a pending exam and this is one of the must-know questions. It will be about checking controllability/observability of a simple MIMO linear system, using Controlability Gramian/Observability ...
2
votes
1answer
3k views

IIR filter design in matlab

I have to design 2 IIR bandpass filter with the following specifications: Sampling frequency 1000 Hz Pass-band 50 Hz to 200 Hz Order 6 using bilinear transform and impulse invariance with Butterworth ...
2
votes
2answers
1k views

Finding the frequencies given in a wav file

I have a wav file containing a series of chords, each containing 3 or 4 notes, played concurrently. I need to find the frequencies of each note in each chord, and I can use matlab to do any ...
1
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0answers
761 views

Local histogram equalization

I want to learn computer vision and so I downloaded image processing slides from my university archive. I'm on histogram equalization. Learning about local histogram equalization points me out to this ...
8
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3answers
382 views

Gesture recognition using only simple techniques

I'm following a computer vision course and I have this exercise: write a program that, given an hand image, it can recognize if the hand is open, closed, in a punch, or holding an "ok" posture, using ...
10
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2answers
3k views

How to Deduce a Linear System's Impulse Response from a Set of Input and Output Signals?

I want to know how to solve those types of problems.. is it by inspection ? Consider the linear system below. When the inputs to the system $x_1[n]$, $x_2[n]$ and $x_3[n]$, the responses of the ...
1
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0answers
107 views

The transmitted signal of DPSK

I am very confused about how to get the transmit sequence of the DPSK signal. In my lecture notes, teacher give as the following example. ...
2
votes
3answers
983 views

Obtaining the Impulse response from the frequency of a discrete system

I have the following discrete system's transfer function (Z domain): $$h[z] = {z \over z - \frac{1}{2} }$$ I need to obtain the following: The frequency response. The impulse response. The fourier ...
5
votes
2answers
255 views

Find the frequency response of a system

I'm trying to find the frequency response $$H(\omega) = Y(\omega)/X(\omega)$$ for this system- the signal equations are given: $$y[n] = v[n - M] - g * v[n]$$ $$v[n] = x[n] + g * v[n - M]$$ I've tried ...
3
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3answers
2k views

LPF and HPF Confusion - Rectangular and Circular Cut-Offs

Interpreting some homework, I'm a little confused on what it's asking for. I'm asked to filter in the frequency domain (easy enough, just a fft2 and ifft2 when I'm done) a 256x256 8bit grayscale tiff ...
0
votes
0answers
253 views

calculate frequency at -6 db

I have to do an exercise. Given this signal: $H(f)=\frac{\frac{T}{2}}{1+(\pi f\frac{T}{2})^2}$ calculate the frequency at $-6 db$. How can I resolve this exercise? I tried this: $\frac{\frac{T}{2}}{1+...
1
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2answers
2k views

period of this signal

it could be a donkey question but I'm a little confused. I have this signal $w(t)=sin({\pi}0.1f)$. I have to calculate the period of this signal. $w(t)=sin(2{\pi}\frac{1}{20}f)$ the period of this ...
3
votes
2answers
340 views

Given the Graph of a Fourier Series $\sum c_k e^{2\pi ikx}$ Find the Graphs of $\sum c_{3k} e^{2\pi ikx}$ and $\sum (c_k)^2 e^{2\pi ikx}$

Define a 1-periodic function on $\mathbb{R}$ by: $f(x) :=$ $\left\{\begin{matrix} 1 & if & 0<x<\frac{1}{10}\\ 0 & if & \frac{1}{10}<x<1 \end{matrix}\right.$ with ...
9
votes
1answer
663 views

Solving a Convolution Problem of a 1D Signal

I'm finding in trouble trying to resolve this exercise. I have to calculate the convolution of this signal: $y(t)=e^{-kt}u(t)*\frac{\sin\left(\frac{{\pi}t}{10}\right)}{({\pi}t)} $ where $u(t)$ is ...
2
votes
1answer
65 views

Conversion between primary colours

Heads up, this is homework. Just a little stumped :) I have some arbitrary primaries, A, B, ...
2
votes
1answer
516 views

Interpolation algorithms in computer graphics

I'm looking for an image-processing algorithm that uses interpolation (polynomial, spline, doesn't matter). I have to implement such algorithm to process a bitmap for my labs. It can't be image ...
3
votes
0answers
106 views

Finding the output for an input sequence

So I think I have the answer I just want to make sure I'm doing things correctly. Let a be in the open unit disk, $F_s > 0$, and $0<f_0 < \frac{F_s}{2}$. Let $h[n]=0$ for $n < 0$ and $h[...
7
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3answers
552 views

Fourier series representation

Conceptually when we want to represent a peroidic series, for example a pulse train, we find the Fourier coefficients and get a representation in the time domain. However what is conceptually wrong ...
1
vote
1answer
275 views

Need help finding the frequency response

So I have this system: $$ y(n) = \frac{1}{N+1}\sum_{k=-N}^{N}\left(1-\frac{|k|}{N+1}\right)x(n-k) $$ Now for the impulse response I'm getting: \begin{cases}\frac{1}{N+1}\left(1-\frac{|k|}{N+1}\...
3
votes
1answer
499 views

How to 'interpret' the Fourier Transform (specifically, of a convolution kernel)

As part of a homework assignment, I had to take the Fourier transform of the kernel I was using to convolve a signal. The kernel was a constant rectangular function, that was 1 within the square $(-1,...
6
votes
1answer
541 views

How to combine a rotation matrix and a stretch matrix into a single matrix for easy Fourier Transform

For full disclosure, this is related to homework. I have to find the Fourier Transform of a function that I've boiled down to the following. I have a function $f(x,y)$ that I can think of as another ...
5
votes
1answer
3k views

When convolving two functions that are constants in a region and 0 everywhere else, where does the integration start?

Heads up, this is for homework. I never took a signals and systems course, so I'm behind on this stuff. I want to compute the convolution of two rectangular regions. I know the standard equation ...
4
votes
2answers
6k views

Polyphase Decomposition in Matlab

I created the lowpass filter h = firls(100, [0 .2 .25 1], [ 1 1 0 0],[.001 60]); My goal is to get four filters $H_{k}(z) = H(W_{4}^{k}z) k =0,1,2,3$ From my ...
3
votes
0answers
133 views

Find $Y(\omega)$ as a function of $X(\omega)$ [closed]

I have a question regarding my homework. Let's assume that the transform of $x[n]$ is $X(\omega)$. Find $Y(\omega)$ as a function of $X(\omega)$: $$ y[n] =\cases{x[n/2],&\text{if } n \...
2
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2answers
2k views

Find h[n] using DTFT properties

Using the DTFT property, find h[n] of a system where: Is it an FIR or IIR system?
3
votes
1answer
149 views

What transformations have been applied to this image to yield four derivatives?

In a few days I have an exam of image processing. I'm currently having a look at the example exam and I came across this question. "Which transformation of this image is being done here. Explain the ...
6
votes
1answer
9k views

How to find frequency response, stability, and causality of a linear system?

I have the following transfer function: $$H(s)=\frac{s}{(s+1)(s+2)}$$ How can I find the gain and phase response of the above system? I know the first step has something to do with substituting $s = ...
10
votes
1answer
6k views

Roberts Edge Detector how to use?

I am trying to use Roberts edge detection to process an image. Do I just apply both of the masks to the image and perform convolution as normal? Could someone give me the breakdown of how to use this ...
0
votes
1answer
737 views

1-D discrete cosine transform(DCT)

This was a past year paper question. Not sure how to answer it. Question: The 1-D discrete cosine transform(DCT) of a sequence f(x), x =0,1,...,N-1 is F(u) = c(u)* Summation of f(x) cos ( (2x+1)u*pi/...
3
votes
2answers
279 views

Question on 2-D Convolution

This was a question on one of my past year paper questions. Question: Prove $$f(m,n)*g(m-r,n-s) = f(m-r,n-s) *g(m,n)$$ where $f(m,n)$ and $g(m,n)$ are 2-D discrete functions, $r$ and $s$ ...
7
votes
1answer
213 views

Deriving 2-D discrete Fourier transforms

I have a problem in DFT. It was one of my past-year exam papers questions. Question: Let $F(u,v)$ be the 2-D Fourier transform of a 2-D continuous function $f(x,y)$. Derive in terms of $F(:,:)$ ...