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Questions tagged [downsampling]

231 questions
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How to downsample a 2 dimensions array using python?

I'm trying to rebuild a project using python, one step of it needs me downsample a two dimensions array into a smaller one. Array like: [[1.0, 2.0, 1.0, 3.0, ..., 2.0] [2.0, 4.0, 6.0, 8.0, ..., 3.0] ... [3.0, 1.0, 6.0, 2.0, ..., 9.0]] (Just for…
P. Scotty
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Apply InfluxDB 1.x continuous query against multiple tables/columns?

For a monitoring project I have created a setup that uses InfluxDB 1.8. Because of compability reasons, using InfluxDB 2.x is not possible. In order to save disk space, I am trying to downsample data the older it gets, a.k.a, "thin it out." In…
PietiePoo
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Downsample tensor

I need to downsample a tensor by a factor 2, it is a 1-D tensor: I don't know how can I do it
jordi
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Image Downscaling

I need a bit of a clarification on this Process. I am trying to downsize from 6000 * 4000 pixel to 960 * 960 for website space purpose using MagickImageMagic. Would doing the same from 2000 * 2000 to 960 * 960 make any impact on the quality of the…
user3557716
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InfluxDB: keep min/max values while downsampling

I am pretty new to InfluxDB. I have an application that collects data with 20kHz, which is written to the database. At some point I need to query/show this data. Currently I achieve this with: from(bucket: "test-bucket") |> range(start: 0; stop:…
laa
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Timescaledb bi-interpolate without downsampling

There're two time series a(t TIMESTAMP,v REAL) and b(t TIMESTAMP,v REAL). How can I do math on two of them (e.g. a*b) WITHOUT downsampling (time bucket)? The way I imagine is: t = merge a.t b.t va = interpolate a against t vb = interpolate b against…
ZisIsNotZis
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Downsampling of timeseries results in artificial flattening of the power spectral density. Should I first apply low pass filter?

Edit: I have tried to incoroporate @dankal444 script. Even though it does indeed remove the high frequencies as shown in the second figure, I still get a flatter spectrum at high frequencies in the downsampled timeseries. I have been trying to…
Jokerp
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Influxdb2 : How to downsample data in a different measurement in same bucket?

I would like to create aggregation measurement into same bucket with monthly data. At the moment I have a task with this query: import "strings" option task = {name: "MTU Monthly", every: 1d} from(bucket: "my_bucket") |> range(start:…
Michal Špondr
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Downsample time series whenever abs(difference) since the previous sample exceeds threshold

I have a timeseries of intraday tick-by-tick stock prices that change gradually over time. Whenever there is a small change (e.g. the price increases by $0.01), a new row of data is created. This leads to a very large data series which is slow to…
Jase
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Reducing channel count when recording in NAudio

I'm recording in NAudio with a PS3Eye camera, using CLEye drivers. The camera has a 4 microphone array, and presents 4 channels of audio to the system. By default, all of the channels are being recorded by NAudio. I'm recording to PCM wave, and…
Elliot Woods
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Eliminate hairlines from a vector graphics by converting to oversampled bitmap and then downscaling - How with ImageMagick?

I used Apple Numbers (a Spreadsheet app with styling options) to create a UX flowchart of various user interfaces of an app. Apple Numbers has a PDF export option. The problem is that even though some border lines in the table have been set to…
porg
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Multiclass Sampling Strategy

Scenario : Currently I am working on multiclass classification problem. I have 2 million historical dataset of having 180 classes and need to create model which will predict the classes accurately. I have created model using HybridGradientboosting…
Makarand Rayate
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How to convert two ECG measurments to HR with frequency 20 hz

I have data from two ECG sensors taken at a frequency of 50hz. I want to convert this to an HR signal with a frequency of 20hz. I have tried a solution with heartpy, but I can't get good values for HR at low frequency. Does anybody have an example…
Marcusnh
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How to downsample/aggregate R rasters with custom function to produce multiple output rasters?

I have a rather complex function that I'm using to compute aggregates of raster-cells (downsampling). In this function I'm distuingishing between multiple cases, where the case determines which summary function is used. As a simplified example…
Honeybear
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Downsample time series to N equally spaced points

Let's say I have a list of of timestamps and associated indices of some event. I have M timestamps which are not evenly spaced. I would like to downsample this list to N < M in such a way that my timestamps will be more or less equally spaced, i.e I…
chess
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