Frequency extraction for pixel , for different number of frames (Hyperspectral data) in spectroscopy

I have to find absorbtion profile of sample gas in spectroscopy experiment. I have recieved multiple images at 40 frames/sec and total number is 400 frames which is actually a hyperspectral data. Now I have to extract frequency information from a specific pixel for multiple frames so that to know the pixel intensity response for different frequencies. How can I get Amp vs Freq plot? whenevr I plot FFT I get Amp vs number of frames instead. Current plot is attached.

Any one can help!

[YOGITAA YOGITAA]

hey, did you find the solution?

Answer 1

[Tarunbir Gambhir]

For plotting the FFT of the signal with a correct frequency axis, you need to incorporate the sampling rate into the frequency domain while plotting the graph. I suggest you refer the example for plotting 'Single-Sided Amplitude Spectrum of X(t)' here.