Questions tagged [spectral]
145 questions
0
votes
1 answer
Matlab - Spectral Method (Matrix Syntax)
I'm reading Trefethen's Spectral Methods in Matlab.
When creating the differentiation matrices,
column= [ anything ]
D=toeplitz(column,column([1 N:-1:2]))
Can someone please explain what exactly is happening inside the [ ... ] in the line above.
I…
Jamaica-Jan
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- 9
0
votes
1 answer
Graph for high dimensional data in Mahout
I am interested in running the spectral clustering algorithm in Mahout on high dimensional data. My question is how does one take a list of high dimensional data vectors and create a nearest neighbor graph? Is this done in Mahout or are there…
clakhani
- 1
0
votes
3 answers
Fit sinusoidal models
I have tried to fit following sinusoidal model by the following model, which means that deterministic model + white noise:
function [x]=generate(N,m,A3)
f1=100;
f2=200;
T=1/f1;
for t=0:N*T/m:N*T
WN(t)=rand(1,t)*2-1;
…
user466534
0
votes
2 answers
generate white noise in matlab interval [-1 1]
I would like to create or generate white noise in the range of [-1 1], but I don't know exactly how to do it. My programming language of choice is matlab. As far as I know there exists a function named randn and also a function named wgn (white…
user466534
-1
votes
1 answer
Flat-field correction on hyperspectral data
I am working on hyperspectral data set using the spectral python library. I started using python for the first time on Monday, so everything is taking me a long time.
My data is in envi format, and i believe I have successfully read it in and…
russj
- 25
- 1
- 6
-1
votes
1 answer
What does the locality linear coding function do?
I got this code for spectral clustering.
https://github.com/BirdYin/scllc/blob/master/scllc.py
This is a landmark-based spectral clustering code.
What does the locality_linear_coding function do in this code?
class Scllc:
def…
-1
votes
1 answer
Reading Hyperion Satellite E-01 dataset (.L1R file) in python
I am trying to find a way to read hyperion e-01 satellite data (hyperspectral data) which has .L1R file extension , in python. Kindly suggest any library to read this data in python.
KHIZER
- 21
- 4
-1
votes
1 answer
Measure two max value in Excel graph
In the context, I have a star spectral graph and there are two spectral line. The coordonate of graph are : x = Angstrom and y = relative intensity.
For example, on 6562 Angstrom there is a relative intensity of 2.12 and on 6520 Angstrom 2.19.
I…
Alpha Aurigae
- 11
- 3
-1
votes
1 answer
How do I add each frame back together after spectral subtraction (MATLAB)?
I'm following this guide in order to perform spectral subtraction and so far I have the following code but I can't work out how to successfully concatenate each overlapping frame back together at the end. Thanks for your help.
function [ cleanFile ]…
Matt Pashby
- 33
- 1
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- 8
-2
votes
1 answer
How to make a reflectance by wavelength plot in R?
I would like to make a graph like this. I saw that it is possible using the pavo R package, but I do not have the values of wavelength or reflectance, I did not understand very well how I get it. What I have is an image (from UAV) and I can get…
Igor Cobelo
- 419
- 3
- 12