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Questions tagged [downsampling]

231 questions
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summing of submatrices of a matrix without using for loops

I have a code that sums up the 8 by 8 subcell of a 256 by 256 matrix to give a smaller matrix of the size 32 by 32. I use for loops, which make the process slow. Can this be done without using the loop? I need to use this summing code in an…
A Khan
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How to remove bias when downsampling a vector in Matlab

I have a set of vectors containing some arbitrary shape like a triangle pulse with a single maxima. I need to downsample these vectors by an integer factor. The position of the maxima relative to the length of the vector should stay the same. Below…
Mr Vinagi
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Chebyshev LPF introducing noise

I have created a simple Chebyshev low pass filter based on coefficients generated by this site: http://www-users.cs.york.ac.uk/~fisher/mkfilter/, which I am using to filter out frequencies above 4kHz in an 16kHz sample rate audio signal before…
Mark Heath
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How can get audio with sample rate of 44100 from iPhone 11 or iPhone 11 Pro Max

I am using the following code to get the audio sample of the 44100 sample rate from the iPhone 11. iPhone 11 has a 48000 sample rate by default. let audioEngine = AVAudioEngine() let inputNode = audioEngine.inputNode let main =…
Raj Aggrawal
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R-caret-plyr : how to modify downSample function to create sampled data of different proportions

Below is the downSample function of caret that I found here . downSample <- function(x, y, list = FALSE, yname = "Class") { xc <- class(x) if(!is.data.frame(x)) x <- as.data.frame(x) if(!is.factor(y)) { …
Basilique
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GridDB downsample into OHLC bars with nanosecond epoch int as row key

For a table structure e.g. containing an int key (reflecting epoch in nanoseconds accuracy which is required) and price. How can this be downsampled into groups of open high low close rows (ohlc bars) with time interval e.g. minutes?
toby185
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Anyone has any good link to documents for Compaction & Downsampling?

I have been trying to get hold of compaction & Downsampling implemented in Prometheus (And Thanos). I somewhat understood the storage based on LSM, but not finding any good documents on compactions(levelled based) that is used. Any pointers ?
swetad90
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Point cloud Downsampling and normal estimation with PCL

I am working on downsampling point cloud and normal estimation. The normal estimation is working fine with me and downsampling also; however, when they combined together they are not working, and I receive this: (core dumped). below is my code.…
Ali
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How to downsample dataframe rows uniformly based on columns distinct values?

I'm trying to downsample dataframe rows in order to create a smaller dataframe. Let's assume our dataframe has several columns and each column has predefined categorical values. How to make sure every distinct categorical value has a chance of…
Arian Shariat
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How to perform downsampling and upweighting technique?

I am referring Google's machine learning DataPrep course, in this lecture https://developers.google.com/machine-learning/data-prep/construct/sampling-splitting/imbalanced-data about solving class imbalanced problem, the technique mentioned is to…
Fariha Abbasi
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InfluxDB disable downsampling

I like some functions of influxDB that's why I would like to use it instead of just MySQL etc. In my case I need to pull from the DB exactly the same time series I pushed into it and any data change between what I put and what I got is considered a…
Jimmix
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Downsample the audio from buffer inputs from 48000 to 16000

I have the recorder.js which will record the audio and takes buffer inputs but I want to downsample the audio buffers but I am lot confused where to call it though I have written it. Please check my function and if possible please suggest where to…
Kramer
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OpenCL 1D strided convolution performance

For downsampling a signal, I use a FIR filter + decimation stage (that's practical a strided convolution). The big advantage of combining filtering and decimation is the reduced computational cost (by the decimation factor). With a straight forward…
luxderfux
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How to optimize a custom downsampling using pandas?

I have a large set of measurment data (Datetime, temperature) that I need to downsample before ploting with bokeh (to keep smooth user interface) Because there are irregular physical phenomens I want to see, I can't just resample the data or take…
Louc
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R: Downsample JPEG while preserving resolution?

I know that there is the jpeg package for R that can deal with JPEG images. In my workflow, there is a step where I would like to downsample images while retaining their original pixel resolution. For example, the following is a 640x480 JPEG I…
hpy
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