Stack Overflow
Stack Overflow

Questions tagged [downsampling]

231 questions
1
vote
0 answers

Speeding up Reading and Decimating Large data files

I have some fairly simple code which read in some signal data, decimates it, and it appends each iteration to a cell. The data files are typically on the order of 20 - 100 GB in size, so I can't read the whole thing into memory. An exmaple of my…
user1147964
  • 143
  • 2
  • 11
1
vote
3 answers

Down-sampling specific period on dataframe using Pandas

I have a long time serie that starts in 1963 and ends in 2013. However, from 1963 til 2007 it has an hourly sampling period while after 2007's sampling rate changes to 5 minutes. Is it possible to resample data just after 2007 in a way that the…
vicemagui
  • 154
  • 13
1
vote
2 answers

How do I use win.disk.duration in Bosun or how do I downsample a counter type metric?

I'm using Bosun to gather information about the average response time of a hard disk (win.disk.duration), it produces a graph such as: I understand that this is showing the rate of change of the WMI reported value, AvgDiskSecPerRead. What I want to…
George Duckett
  • 31,770
  • 9
  • 95
  • 162
1
vote
2 answers

Resize MNIST Data on Tensorflow

I have been working on MNIST dataset to learn how to use Tensorflow and Python for my deep learning course. I could read the data internally/externally and also train it in softmax and cnn thanks to tensorflow tutorial at website. At the end, I…
Viper
  • 23
  • 1
  • 5
1
vote
1 answer

Downsampling text documents

I have two classes with 1000 documents in class one and 40000 documents in class two. The documents consist of texts. I want to use these texts in a neural network. But of course there is a unbalanced-dataset-problem. Each classifier would through…
pexmar
  • 331
  • 2
  • 12
1
vote
2 answers

downsampling a matrix in R

I have a matrix Q that is relatively high dimensional (100X500000), and I want to downsample it. By downsample, I will explain with an example. Let Q = 1 4 9 3 2 1 and downsample size= n. I want to draw n balls from a jar of sum(Q) = 20 balls, each…
lynnyi
  • 1,292
  • 1
  • 10
  • 14
1
vote
1 answer

libswresample: swr_convert() not producing enough samples

I'm trying to use ffmpeg/libswresample to resample streaming audio in my c++ application. Changing the sample width works well and the result sounds as one would expect; however, when changing the sample rate the result is somewhat crackly. I am…
Tsherr
  • 363
  • 5
  • 17
1
vote
1 answer

Rough Edges With Lanczos Resampling in Golang

I've been writing some basic methods to resize images in Golang. I've seen several posts about resizing images, but for the life of me I can't figure out what I'm missing... Essentially, my issue is that when resizing an image in Golang, my results…
Anish Goyal
  • 2,799
  • 12
  • 17
1
vote
1 answer

Python -Pandas Downsampling with first returns NaN

I am trying use pandas to resample vessel tracking data from seconds to minutes using how='first'. The dataframe is called hg1s. The unique ID is called MMSI. The datetime index is TX_DTTM. Here is a data sample: TX_DTTM MMSI …
user3512166
  • 121
  • 1
  • 7
1
vote
2 answers

GPS downsampling

My goal is to downsample my indata for every 100m and get the first and last line My problem is that I get a lot fewer lines than i should when I downsample and I don't know how to get the last line. Hope am clear enough for someone to understand To…
Cecilia Nilsson
  • 13
  • 3
1
vote
2 answers

Why does downsample appear as a gray image?

In the implementation of downsampling by a factor of 2 to the image, the downsampled image is gray. What should I do in order to add all of the color components to the downsampling implementation so that it will be a color image? I =…
Blu
  • 129
  • 1
  • 8
1
vote
1 answer

Speeding up double for loop for downsampling a numpy array

I am trying to find the most efficient way of downsampling an aribtrarily shaped 2d numpy array into a smaller (or potentially larger) square array - I want to take the max of each sub-array and put it into the new array. Here is my code: import…
vahndi
  • 1,055
  • 8
  • 16
1
vote
0 answers

Downsampling images using LayoutParams causes unsmoothness

I am trying to make an ImageView smaller as the user scrolls, using LayoutParams. The problem is, when the imageview size is decreased, it looks awful due to the default downsampling which occurs…
Shubham Kanodia
  • 6,036
  • 3
  • 32
  • 46
1
vote
0 answers

Python Fast Symmetrically Centered Image Downsampling Algorithm

I'm trying speed up a simple symmetrically centered image downsampling algorithm in Python. I've coded this up using a naive approach as a lower bound benchmark, however I'd like to get this to work significantly faster. For simplicity's sake, my…
Ian Daz
  • 143
  • 1
  • 11
1
vote
1 answer

How to achieve downsampling AA/filtering in OpenGL

I'm working on a game that uses pixelart and a camera that will not match the size of the pixel art one to one. To keep the pixels looking like pixels, I want to render the entire game at a higher resolution then downsample it to the actual window…
Layl Conway
  • 385
  • 9
  • 17
1 2 3
…
15 16