instruction stringlengths 31 27k |
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I am attempting to convert YV12 to RGB using the following fragment shader:
precision mediump float;
uniform sampler2D tex0, tex1, tex2;
varying vec2 v_texCoord;
void main(void) {
float r, g, b, y, u, v;
y = texture2D(tex0, v_texCoord).x;
u = texture2D(tex1, v_texCoord).x;
v = texture2D(tex2, v_texCoor... |
My question is: What mathematical model of polyphonic sound can make possible the changing (i.e. pitch shifting) of individual musical notes in a multi-voice-in-single-channel audio recording of a polyphonic acoustic musical instrument? By 'changing notes in polyphonic audio', I mean doing something like editing sound ... |
Over on the TeX stackexchange, we have been discussing how to detect "rivers" in paragraphs in this question.
In this context, rivers are bands of white space that result from accidental alignment of interword spaces in the text. Since this can be quite distracting to a reader bad rivers are considered to be a symptom... |
Assume the following first order IIR Filter:
$$ y[n] = \alpha x[n] + (1 - \alpha) y[n - 1] $$
How can I choose the parameter $ \alpha $ s.t. the IIR approximates as good as possible the FIR which is the arithmetic mean of the last $ k $ samples:
$$ z[n] = \frac{1}{k}x[n] + \frac{1}{k}x[n-1] + \ldots + \frac{1}{k}x[n-k+... |
I'm reading up on Autocorrelation, but I'm not sure I understand exactly how it works and what output I should expect. Am I right in thinking that I should input my signal to the AC function and have a sliding window input. Each window (of 1024 samples, for example) would output a coefficient between -1 and 1. The sign... |
I have an image. I find features on it using different methods. I want to quantify that which method performs the best. The creteria is how many features per unit area of the image are and how they are spread. More the features are spread, the better it is. How to visualize them.
So at the end the criteria is "how many... |
Is there any way to take advantage of the frequency domain to make a clean/nice sampling rate reduction effect ? and how ?
Basically, deducted from my tests:
if I set to 0 the magnitude uppon a certain threshold I only get a filter(quite obvious...)
if I set to 0 one sample over 2 before the buffer transfrom it's not ... |
I am working on acoustic echo cancellation which has a double talk detector. During the single talk, the ERLE (Echo Return Loss Enhancement) exceeds 100dB and during double talk around 20dB to 40 dB. I have read few papers and saw that for a good echo canceler the ERLE should be between 40-50dB. Am I going wrong anywhe... |
I'll use the Scale-invariant feature transform algorithm as an example here. SIFT creates a scale space based on scaled gaussian filtering of an image, and then computes the difference of gaussians to detect potential interest points. These points are defined as the local minima and maxima across the difference of ga... |
I have binary 160x120 images such as:
I would like to detect corners of those white blobs. They are previously closed by mathematical morphology so there shouldn't have any inner corners. In this specific case, I would want 16 corners, like:
My first attempt was using some OpenCV functions like goodFeaturesToTrack or... |
Is it possible to read a JPEG file and skip parts that are corrupt? I have three corrupt JPEG files and I can detect the first corrupt block, but can I skip it and continue with the next block?
I can already stop and convert the blocks I've processed so far, but I would like to recover as much as I can. This is not a... |
In my project, the ADC is an 16-bit unipolar type, 0 - 3.3 V. This 16-bit data we are making as bipolar ($-1.65$ to $+1.65$ range), converting as Q15 data.
The conversion is as follows.
Q31_data = (q31_t) ((16bit_ADC_data- Offset) <<15)
Here I am making it as a Q30 format, so I'll get Q30 (range is $-2$ to $+2$).
We ... |
I want to calculate the loudness of a given signal and I've come across this thread. I'm slightly confused about the A-Weighting aspect of it. I can't post images, but I think this site has the formula I need. (Wa = 10log...)
What I don't understand is how to actually use it in my program. If the f stands for frequency... |
I'm working on a simple web app that allows the user to tune his/her guitar. I'm a real beginner in signal processing, so please don't judge me too harshly if my question is inappropriate.
So, I managed to get the fundamental frequency using an FFT algorithm and at this point the application is somehow functional. Howe... |
We can use the narrowband spectrogram for finding the pitch of an utterance. But is it possible to find the pitch using the wideband spectrogram? If so, how would that be done?
|
Disclaimer: I am in NO way engaged in signal processing. Just very curious...
Ny question is, very simply: is it possible to apply software processing to an image to remove or reduce headlight glare?
It would be a picture such as this:
If this IS possible, is there a software library available for this? I don't ca... |
I was wondering what good method(s) exist for the estimation (and subsequent compensation) of doppler shift for transmitted signals, be they acoustic or RF, in the context of comms.
The question: Specifically, if the degree of doppler shift is varying over the duration of a packet, how best to estimate (track it?) and... |
I've heard that the Hilbert transform can be used to calculate the envelope of a signal. How does this work? And how is this "Hilbert envelope" different from the envelope one gets by simply rectifying a signal?
I'm interested specifically in finding a way to calculate an envelope for use in dynamic range compression ... |
What are some recommended resources (books, tutorials, lectures, etc.) on digital signal processing, and how to begin working with it on a technical level?
|
This has been one of the holes in my cheddar cheese block of understanding DSP, so what is the physical interpretation of having a negative frequency?
If you have a physical tone at some frequency and it is DFT'd, you get a result in both the positive and negative frequencies - why and how does this occur? What does it... |
I am confused by the dual concepts of time-resolution and bandwidth. Often I will hear that a pulse-compressed radar application 'doesnt have enough BW' for some specific time resolution that is sought.
Isnt the maximum time resolution simply the reciprocal of your sampling rate?
How are those concepts related?
|
When we apply the DFT operation on a real signal $x[n]$ to get $X[k]$,
then take the square magnitude of the $X[k]$, $\lvert X[k]\rvert^2$, the power spectrum is symmetrical.
You can take the positive frequencies or negative frequencies as the frequency information in $X[k]$.
However this is not true for complex valu... |
I have an audio spectrum (FFT) that looks like this:
101761.00 : *
76309.98 : ... |
Is anyone aware of any research/papers/software for identifying a trail (as a line or point-to-point curve) in an image of a forest scene (from the perspective of the camera standing somewhere along the trail)?
I'm trying to find an algorithm that could take an image like:
and produce a mask, identifying a likely "tra... |
I am trying to implement a karaoke scoring algorithm and, for a particular song, have the note information (done by a professional) that indicates what note occurs in which part of the lyric.
When I use a pitch detector and plot the pitch values for the portion of the lyric where a single note is held, the pitch vari... |
I am trying to use Octave to generate a pure sine wave. The code for the same is as follows:
x = 10.*sin(2*pi*(300/16000)*(0:1:400));
The sampling rate is 16000Hz, the sine wave is at 300 Hz. I write the above wave to a file using wavwrite like so:
wavwrite(x, 16000, 16, "temp.wav")
When I try to read it back into a... |
I am trying to make a high pass filter for electroencephalographic (EEG) datasets, in order to get rid of very slow drifts. However frequencies around 0.3 Hz are very important for the research these data serve.
I use Matlab and I tried various things. It seems that a very low dB attenuation, of 3 dB is fine with FIR ... |
I'm familiar with the Radon transform from learning about CT scans, but not the Hough transform. Wikipedia says
The (r,θ) plane is sometimes referred to as Hough space for the set of straight lines in two dimensions. This representation makes the Hough transform conceptually very close to the two-dimensional Radon tr... |
Are there some good sites or blogs where I can keep myself updated on the latest news and papers about image and signal processing research, or I should just check out "classical" providers like IEEE Transactions, Elsevier, etc?
|
Is a stochastic process completely described by its autocorrelation function?
If not, which additional properties would be needed?
|
Wavelets seem to be very useful for image processing. Assuming that I'm only ever going to study signals of time, i.e. 1D signals, should I still take a course in wavelet analysis? Are they applicable to 1D signals?
|
I have a 1D signal that is roughly periodical (but not exactly) - think of some kind of motion that someone performs repeatedly, and which is measured by some sensor.
I am looking for a way to
automatically chop up the signal into the individual cycles, and
somehow calculate an "average" that preserves the characteris... |
I'm in a biomedical engineering master's program and am mostly interested in signal processing. Unfortunately, I feel that I'd like to get deeper into the subject, and my university can't accommodate that request -- there's a limited number of courses, and the professor I've asked doesn't know of any local project that... |
It has been a long time since I studied engineering, please forgive my mistakes.
I got data sampled from a digital accelerometer. It is sampled at 20 hz, then collapsed into 1 second epochs. The data is then filtered to remove noise. The system outputs 0 at rest, a lot more during activity.
I'm looking at the fourier ... |
I have an object (orange color object) and I know its centroid/center mass C. I want program to automatically find another point ( can be point 1, point 2, point 3 or point 4 and so on) such that the line connect point C and one of those points (so as green line in figure 2) must stay inside the object. Moreover, the ... |
My problem is that I don't know the energy of the background noise, so I can't just threshold the energy. The processing is done in real time, and I have about 500msec to decide.
Ideally, I'd want quiet consonants considered non-silence.
|
If I have a signal that is time limited, say a sinusoid that only lasts for $T$ seconds, and I take the FFT of that signal, I see the frequency response. In the example this would be a spike at the sinusoid's main frequency.
Now, say I take that same time signal and delay it by some time constant and then take the FFT... |
I have a simple BPSK demodulator. Very simply, the signal comes in and is split into two branches, one for I and one for Q.
The I branch is mixed with a sin wave of the carrier, and the Q branch mixed with the cosine wave of the carrier.
Then, each of the outputs is convolved with a matched filter, (in this case a r... |
I am looking for an algorithm that adds borders to a bitmap image(very much like the photoshop stroke effect) but one that will also have antialiasing to the borders(or one that copies alpha from the original bitmap to make the border look antialiased).
If you can't answer with an algorithm a direction of creating one ... |
This question takes off from this question regarding syncronization of BPSK signals. For the sake of argument let us assume 10 samples make up 1 bit.
One method currently suggested is break up the envelope of the downmixed and matched filtered I and Q signals into multiple 10 sample bit intervals, Then, the average of... |
The definition of $\rm SNR$ seems to be somewhat of a tower of babel in industry. What definitions of $\rm SNR$ are there (feel free to site application), and how exactly can it be measured for that applications?
My specific questions on $\rm SNR$ are:
How may we measure $\rm SNR$ for a communications system, if we ha... |
Let's say I have a time series $ \{t_i, x_i\} $ where the $x_i$ are strictly increasing and the $t_i$ are not regularly spaced. I can define a differential operator as
$$ \Delta_i = \frac{x_i-x_{i-1}}{t_i-t_{i-1}} $$
but that is very noisy.
Müller et. alia define a different operator with characteristic time $\tau$ in... |
Having two different size of sets of points (2D for simplicity) dispersed within two different size squares the question are that:
1- how to find any occurrence of the the small one through the large one?
2- Any idea on how to rank the occurrences as shown on the following figure?
Here is a simple demonstration of th... |
I am trying to use the Hough transform for edge detection, and would like to use gradient images as the basis.
What I have done so far, given the image I of size [M,N] and its partial derivatives gx, gy, is to calculate the gradient angle in each pixel as thetas = atan(gy(x,y) ./ gx. Similarly I calculate the gradient... |
This probably walks a fine line between Cross Validated and this site, but I think the practical application of it lies more on the signal processing side.
I have had the occasion to record some EEG data for an experiment, and determined the mean-squared coherence between each lead:
$$ C_{xy} = \frac{\lvert{G_{xy}}\r... |
Background: The software that i use to anaylze my signals is matlab. I have two audio signals that were recorded using two magnetic sensors. Lets call one sensor A and the other one B. A and B have mutual inductance between them.
While sensors A and B are working, I would like to subtract the information that was rece... |
I am looking to create an algorithm which adds a bevel effect to a bitmap using it's alpha as a bump map.
How would I go doing something like this? I have tried specular lighting but I only get the highlight and not the shade.
Here is the effect I am talking about(made using Photoshop):
All of these were done using si... |
In my group, we have developed an algorithm which shows abstract information from quantum mechanical systems as images. This way, given a quantum system, we obtain an associated image which has the same information and makes some features visible.
One of the important features is obtained using a "cross-correlation mat... |
I'm working on a control system that measures the movement of a vibrating robot arm. Because there is some deadtime, I need to look into the future of the somewhat noisy signal. My idea was to use the frequencies in the sampled signal and produce a fourier function that could be used for extrapolation.
My question: I a... |
Can anyone state the difference between frequency response and impulse response in simple English?
|
As part of a homework assignment, we are implementing the Inverse Filter. Degrade an image then recover with an Inverse Filter.
I convolve the image in the spatial domain with a 5x5 box filter. I FFT the filter, FFT the degraded image, then divide the degraded image by the filter. Inverse FFT the result into an image a... |
I'm calculating FFT from microphone input. I notice that lower frequencies always seems to have more power (higher dB) than higher frequencies.
I cut the data into frames of 24576 bytes (4096*6).
Apply Hamming window: input[i] *= (0.54d - 0.46d*(double) Math.Cos((2d*Math.PI*i)/fs));
Run it through FFTW Process1D().
C... |
If I sample sound with a microphone and find the absolute square of the (non-normalized) DFT, I get the discrete power spectrum (correct me if I'm wrong). Which unit does it have?
|
I'm a novice in DSP and I have few doubts regarding the $\mathcal Z$-transform and its region of convergence (ROC).
I know what a $\mathcal Z$-transform is. But I'm having trouble with understanding the ROC. First of all I have some confusion with $X(z)$ and $x(z)$. I easily get caught by exchanging these terms. I kno... |
I wanted to ping the DSP hivemind for general thoughts on what would be the best modulation type to use for low frequency underwater communications. I have chosen this project since I can learn a lot from it.
Some context:
Low frequency as in < 500 Hz (for both carrier and modulated data obviously)
BPS of say, 200 Hz... |
The definitions of the Fourier transform and inverse Fourier transform I learned in college were
$$
F(j\omega) = \int_{-\infty}^{\infty} f(t) e^{-j\omega t}\ dt
$$
$$
f(t)=\frac{1}{2\pi}\int_{-\infty}^{\infty}F(j\omega)e^{j\omega t} d\omega
$$
The salient characteristics of this convention are
Non-unitary transfor... |
Is angle modulation spectrum always discrete or this property only holds for periodic modulating signal?
|
I want to help someone with a homework in signal processing, and the courses he provided are some slides, without clear definitions in them. I am required in solving a problem to represent the amplitude spectrum and the phase spectrum of a given signal. I searched the internet and didn't found the definitions of these ... |
In the scale-space theory the scale-space representation of the signal $f(x), x = (x_1, ..., x_d)$, (in case of image $d = 2$) is given as:
$L(x, y; t) = g(x, y; t) * f(x, y)$ where $g(x, y; t)$ is a gaussian kernel with parameter $t$ and $*$ is a convolution. By changing the $t$ parameter we receive a more or less smo... |
I've made a pitch detection algorithm using HPS and I'm facing a problem. I'm a beginner with signal processing and this site helped me before, so I though I should ask.
For higher pitches ( eg. >C6:1046.50hz ) I'm starting to get garbage data from the HPS. The higher the pitch the more garbage I get (by garbage I mean... |
I want to use my phone as a CCTV system to control a room in my house, and display an alert when something is moving.
For now, what I have succeeded in doing is to grab a picture every minute and upload them via a PHP script to my server. Now, I would like to compare the current picture and the picture 1 minute ago and... |
I'm working on a real-time audio processing project in which I have to downsample a 44.1 kHz to a yet-to-be-determined lower sampling rate essentially for reducing computational complexity. I'm looking for a decent downsampling filter, and I found articles suggesting both IIR (mainly elliptic) and FIR (mainly minimum p... |
Say you wanted to run a X point FFT on the last X audio samples that were played. The problem being, using a normal hann window function would place emphasis on the "middle" of the audio sample. However, the most current audio samples played (the audio samples toward the end) are of the greater importance for algorithm... |
I've got an offline signal that I want to high-pass filter. Should I use a Butterworth filter, or could I use the fact that the whole signal is known and use an ideal (step) filter?
Using a high-degree Butterworth filter is, I think, practically the same thing as using an ideal filter, and a higher degree means a bette... |
MATLAB has a butter, which constructs a Butterworth filter given an order and relative cutoff frequency. The filter created can be used to filter any finite signal.
How does MATLAB do this if the filter has an infinite impulse response? I suppose it must window the signal -- is this done by a simple rectangular window ... |
I'm writing a program to filter a 20,000-sample signal with a fifth-order Butterworth filter offline. I've got access to an FFT implementation. There seems to be two alternatives for implementing the filtering:
convolving the signal with the impulse response in the time domain, or
multiplying the signal with the impul... |
I have written my own LSE equalizer (that works on the bit level), and literature I have read says that 'fractional' based ones are much better. So how exactly does one get 'fractional' bits? Is it as simple as resampling the softbit decisions to 2x, 4x or whatever of their bit rate and applying the equalizer like that... |
I am trying to create a pitch-detection program which extracts the frequencies of peaks in a power spectrum obtained from an FFT (fftpack). I am extracting the peak frequencies from my spectrum using Quinn's First Estimator to interpolate between bin numbers. This scheme seems to work well under certain conditions. For... |
I have a set of images which consist of a fairly regular pattern - essentially a set of roughly concentric distorted ellipses - with a small area (<1% of the total image area) obscured by a circular disk. I'd like to be able, digitally, to reconstruct the part of the pattern which is hidden by the disk and produce an ... |
I've got a first-order Butterworth filter with the cutoff frequency $\omega_c$. Its transfer function is then
$$H(s) = \frac{\omega_c}{s+\omega_c}$$
Using the bilinear transform to find an $H(z)$ (what is that function called?), I get
$$H(z)=\frac{\omega_c}{\frac{2}{T}\frac{z-1}{z+1} + \omega_c}
= \frac{\omega_c z + \... |
This question is related to on How to decide what platform is best to implement real-time audio processing on?, but focusing on Windows.
I'd like to be able to take input from a data acquisition board and process it (either through Matlab or a custom program), and use the result of that program to drive an external de... |
I have discrete-time model of 2-user CDMA system with: $b_1=-1, b_2=+1, \alpha_1, \alpha_2, s_1, s_2$ and $n$ white noise.
What are the recovered infromation bits for user 1 and user 2 respectively if polarity detection is used?
If the optimum MLE is used, what are the recovered infromation bits?
I tried to solve but s... |
What are the Fourier-, Laplace- and Z-transforms of the impulse response of a filter called? I've seen $H(s)$ referred to as the system function or transfer function, what about $H(i\omega)$ and the discretized $H(z)$?
|
I'm trying to HP-filter a signal by LP-filtering it and subtracting the output from the original filter. To obtain the LP-filtered signal, I backward-forward filtered using a third-order Butterworth filter for a 16,000-sample signal. The cutoff frequency was 0.5 Hz @ 250 Hz. No window was used.
In the first 85% or so o... |
I've got an algorithm that zero pads a sequence to 4N, does an FFT, and only uses the lowest frequency N points out of the generated 4N.
This seems like a lot of wasted work, any ideas how this can be done faster?
|
Specifically, I am a tech writer working with WiFi hardware, and I need to understand why the 2.4GHz frequency band has only three channels, while the 5.0 GHz band has so many more.
I would presume that, since they're both "frequency bands", they would both have about the same bandwidth, and so would have about the sam... |
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(:,:)$ the 2-D Fourier transform of
each of the following functions
1) $f(x,-2y)$
2) $f(x+2y,y)$
I know how to do 1-D Fourier ... |
I am trying to understand how exactly to implement what is known as a 'pre-whitening' filter or simply a 'whitening' filter.
I understand that the purpose is to make it have a delta as its autocorrelation function, but I am not sure how to do this exactly.
The context here is the following: A signal is received at tw... |
I'm involved with an effort to implement an FFT algorithm, and am curious what the recommended advice is for the input test data to use -- and why! -- and what accuracy to expect.
On test inputs, I've found a little guidance in old Usenet posts that I'll post as an answer, but it's just one person's suggestions without... |
I have used both correlation and coherence as measures of correlation between signals. I was thinking that a time-frequency approach would give me the best of these worlds.
My question is whether this extra data adds enough to the overall picture of the signal to justify the increased computational cost associated w... |
I'm a masters student, preparing a seminar in computer vision. Among the topics is the Kanade-Lucas-Tomasi (KLT) tracker, as described in
J. Shi, C. Tomasi, "Good features to track". Proceedings CVPR '94.
Here's a web resource that I'm using to understand the KLT tracker. I need some help with the math, as I'm a b... |
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 $s$
are integers and $*$ is the 2-D convolution operator.
Not sure how to start on this and need some guidance on it.
|
How viable would it be to classify the texture of an image using features from a discrete cosine transform? Googling "texture classification dct" only finds a single academic paper on this topic, using a neural network.
For my application, I have a large corpus of labeled images, in which the entire image is a consiste... |
Even after having studied these for quite sometime, I tend to forget (if I'm out of touch for a while) how they are related to each other and what each stands for (since they have such similar sounding names). I'm hoping you'd come up with an explanation that is so intuitive and mathematically beautiful that they'll ge... |
The Fast Fourier Transform takes $\mathcal O(N \log N)$ operations, while the Fast Wavelet Transform takes $\mathcal O(N)$. But what, specifically, does the FWT compute?
Although they are often compared, it seems like the FFT and FWT are apples and oranges. As I understand it, it would be more appropriate to compare t... |
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/2N)
show that 1-D DCT of the sequence
g(x) = f(N-1-x), x = 0,1,...,N-1
can be expressed as G(u) = (-1)*F(u), u=0,1..., ... |
So I recently implemented a CMA equalizer in MATLAB that uses method of steepest descent to converge to the minimal cost. (Im on an equalizer implementation binge).
My questions are the following:
1) It seems to me that the CMA algorithm is only good for channels where they are relatively 'flat'. In other words, it is ... |
I have an image processing algorithm which uses Gaussian and Laplacian Pyramid Decomposition.
At each level of the pyramid the algorithm decimates the previous level by a factor of 2.
The LPF the algorithm uses is Gaussian.
I was wondering whether I could get the same results without the decimation step (By altering th... |
Would someone be able to give me some info or a link etc ... regarding haarlets aka Haar wavelet-like features. I'm reading several papers for my master dissertation and several of these papers briefly mention haarlets. I can't seem to really get what they are and how they are used. I apologize if this is a basic quest... |
I have heard anecdotaly that sampling complex signals need not follow Nyquist sampling rates but can actually be gotten away with half Nyquist sampling rates. I am wondering if there is any truth to this?
From Nyquist, we know that to unambiguously sample a signal, we need to sample at least higher than double the band... |
Here is a question for image processing experts.
I am working on a difficult computer vision problem. The task is to count the stomata (marked below) in DIC microscopy images. These images are resistant to most superficial image processing techniques like morphological operations and edge detection. It is also differ... |
A point cloud is generated using uniform random function for (x,y,z). As shown on the following figure, a flat intersecting plane (profile) is being investigated that matches as the best (even if not the exact one) a target profile i.e., given at the left-bottom corner. So the question is:
1- How to find such a match ... |
Suppose I have 4 of 300bps synchronous digital input and 1 of analogue input with a bandwidth of 500Hz. The analogue input is sampled at 4bit using PCM. All the channels are multiplexed with TDM.
As one of the input is of analogue, I need to convert that to digital input first before TDM can be carried out. Since the a... |
When converting scanned text to a 1-bit black-and-white image what are some filters that one can apply in the process to improve the result? Right now I am running into the problem where dithering errors make the image look horrible.
Update:
I think trying to undo dithering is a much harder problem. How can I convert ... |
Can someone explain the algorithm behind the "Black and White" adjustment layer in photoshop?
I have to reproduce it using C++ for an application that emphasizes non-red/magenta(ish) pixels from an image (with a percent-like configurable tolerance), and this resource showed the behavior I'm expecting.
Update: Still c... |
I found contours on two images with same object and I want to find displacement and rotation of this object. I've tried with rotated bounding boxes of this contours and then its angles and center points but rotations of bounding boxes don't tell about contour rotation correctly because it's the same for angles a+0, a+9... |
I've recorded a 2-sec pronunciation of a vowel sound. The first 0.12 or so seconds of the signal are shown below.
Now, I've constructed an auto-regressive (AR) 8th-order model to compress this signal. (Actually, I'm just modelling 160 samples or 0.02 sec at a time.) The ar function in Matlab's System Identification Too... |
What is the algorithm employed by video cards when one talks about for example 8xAA?
I thought the algorithm was about looking at neighboring pixels for correction. Yet, I hear that the implementation is just upsampling followed by downsampling.
|
I want to implement an adaptive thresholding algorithm in MATLAB for filtering data received by an underwater sonar receiver. The data received has an interactive noise component resulting from underwater noise and specular reflection. CFARD method is close, but it does not serve my purpose. I have to image the data so... |
Some unsharp algorithms (e.g. Matlab's fspecial) use a Laplacian kernel to achieve sharpening of the image.
From what I know, the image needs to be blurred first, and then the blurred image is subtracted from the original to get a sharper image. The Laplacian part comes exactly where alleged smoothing should take place... |
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