Including interpolation row by row in a matrix using a for loop

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Rahim Yousefi
Rahim Yousefi 2021-6-24
回答： dpb 2021-6-24
I have a Raman spectral data which contains 140 rows and 1317 columns.
The wavenumbers are in the range of 102-4050 with the resolution of 3.
I want to perform an interpolation to make the data set similar to a calibration data set which the
wavenumbers are in the range of 300-3425.
I have used interp1 as follow:
X = Ramandata
Wave_no_X = linspace(102,4050,1317);
Wave_no_intrest = linspace(300,3425,1000);
Interpolated = interp1(Wave_no_X, X, Wave_no_intrest);
However this would not work because X should only be a column vector X(1,:).
Therefore I tried a loop to pass all the rows of X through interp1. But the codeis not working. Could any one help?
[n,m] = size(X)
Interpolated = []
for i = 1: n
Interpolated(i) = interp1(Wave_no_X, (X(i,:)), Wave_no_intrest);
end

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采纳的回答

dpb
dpb 2021-6-24
What error? Looks like should be ok but didn't have data to try and didn't make up any...but should be able to use the vectorized form here
Wave_no_X = linspace(102,4050,1317);
Wave_no_intrest = linspace(300,3425,1000);
Interpolated = interp1(Wave_no_X, Ramandata.', Wave_no_intrest);
would give the interpolated array
A sample just random data of the same idea --
>> interp1(1:10,rand(10,3),3:9)
ans =
0.6845 0.3365 0.9711
0.7025 0.6972 0.7023
0.9285 0.4717 0.9040
0.1740 0.3085 0.3593
0.9693 0.1514 0.0041
0.7826 0.2067 0.9643
0.4238 0.1314 0.2428
>>
NB: the interpolated xq values must be within the range of the x values; interp1 will not extrapolate automatically.

更多回答（1 个）

Cris LaPierre
Cris LaPierre 2021-6-24
You will likely find this example helpful. Just make your X values a column vector. You should transpose your Y values so each row corresponds to X. You can transpose the result back if you prefer to have the columns represent frequency.
X = linspace(102,4050,1317)';
Xq = linspace(300,3425,1000);
Interpolated = interp1(X, Ramandata', Wave_no_intrest)';
Note that this is untested, since you did not share your data.

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