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Questions tagged [quantization]

Use this tag for questions related to quantization of any kind, such as vector quantization.

Quantization, in mathematics and digital signal processing, is the process of mapping a large set of input values to a (countable) smaller set.

For more, please read the Wikipedia article for more.

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JPEG source-code and quantization mode change - C language

I'm assigned to do a project that consists in changing the quantization in the JPEG source-code, from the quantization tables to Lloyd-Max quantization. The problem is not knowing what to do (I know how to change the quantization), but where to find…
André Monteiro
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Synchronise to beats per minute / Send quantised messages

I'm getting periodic signals (beats per minute) from a Transmitter and now want to call methods in a fraction of the period, e.g. send 1/1, 1/2, 1/4, 1/8, 1/16,.. notes. My solution for this is to create a thread, do a busy wait and then execute the…
user
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Image quantization in matlab

I created a method in Matlab for quantizing an Image. But I don't seem to get a good quantization of the image. (For example, when I quantize the image after using DWT and then use IDWT, the image is filled with squares). what is wrong with the…
greg phillip
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MPEG-1 Video Compression Quantization

MPEG-1 quantizes both inter-frames and intra-frames, however I am curious why the quantization table for inter-frames are all constants, whereas the default quantization table for intra-frames is not.
Petrov
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How to quantize signal (to k levels) in MATLAB

I have a continuous signal which I want to convert to a step-like function (I'm not sure what the correct term is) So every sample in the lower part of the signal should be replaced by 1, middle ones 2 and high ones 3. And I want to control the size…
jeff
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What is the best way to quantize a float to a byte

I have a single-precision float value, and no information about the distribution of the samples from which this value was generated, so I can't apply a sigmoid or perform some kind of normalization. Also, I know the value will always be…
Sau
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Companding and uniform quantizaton in Matlab

I hava a function for quantization and decrease the bit depth of images and then increase it and compare with original image.As result I need a table like this:(MSE:mean square error) but I don't know a much about companding and uniform…
Sinapcs
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D3js-Get the first and the last decile

I have some data in a csv. I want to get the first and the last decile of all the numbers. I think I might need to use d3.scale.quantize() but I do not know how... Thanks for your help I'm stuck since a while.
Melki
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Quantization Step Size or Quantization factor

About non-linear Quantization techniques: we have the "QIM" (Quantization Index Modulation). This technique use some quantizers of step size (quantization factor) delta in order to quantize samples of original signal. That i noticed after my…
Liszt
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ppmtogiff: to many colors workaround

I'm working on a script that takes an .xwd image, runs wxdtopnm on it then pipes that to ppmtogif. Basically: exec wxdtopnm < file.xwd | ppmtogif > file.gif However, sometimes I get an error ppmtogiff: to many colors - try doing a 'ppmquant…
Daniel
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Finding duration of a song

This was a midterm question and I do not know how to calculate this. A CD quality stereo song has been saved on your computer, occupying 35.28 MBytes of storage. The CD quality mandates that we have 16-bit quantization as well as a uniform…
Semih Altaş
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Matlab Error: The covariance matrix of each group in TRAINING must be positive definite

I am currently looking at the effects of sampling rate and quantization on tumour signals during classification. I get the error 'The pooled covariance matrix of TRAINING must be positive definite.' ONLY when I try to classify the quantised signal…
user2173297
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Is "color quantization" the right name for color quantization in OpenCV?

I'm looking for a way to get a complete list of all the RGB values for each pixel in a given image using OpenCV, now i call this "color quantization". The problem is that according to what I have found online, at least at this point, this "color…
user2128456
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Star / half star rating function without if/then logic?

The question is, is there a straightforward mechanistic way to know which stars (gold, 1/2 gold, grey) to draw without using conditional logic, for example using a pointer to the correct star based on the result of a simple math function to generate…
alphablender
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Quantization in JPEG Image Compression

In JPEG Compression, loss takes place during quantization and during the DCT Transformation. Why do we get many 0's after quantization after DCT transformation IN JPEG image Compression.
Luv
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