how to fit an exponential curve to my signal in a plot?

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2NOR_Kh
2NOR_Kh 2022 年 7 月 31 日
コメント済み: Star Strider 2022 年 8 月 1 日
I have a signal and I should fit an exponential curve to it. This curve should be made based on the max imum peaks in the signal. To make it more clear I attached a photo of what I am looking for.
I appreciate any help
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2NOR_Kh
2NOR_Kh 2022 年 8 月 1 日
編集済み: 2NOR_Kh 2022 年 8 月 1 日
it's a line of ultrasound in the liver. Based on the physics of ultrasound, the sound will attenuate as a function of time or depth. This attenuation is an exponential term, a decay exponential term. The simplest way to estimate attenuation is to find an exponential curve that will fit the peaks of the signal. I know there is a bunch of fit distribution functions in MATLAB but I couldn't find anything which will fit a curve based on the peaks in the diagram.
I upploaded my signal.

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回答 (1 件)

Star Strider
Star Strider 2022 年 7 月 31 日
It would help to have the signal. There appears to be high-frequency noise, so the first step would be to calculate the one-sided fft, amd then using that information, design a lowpass or bandpass filter to filter it out, using the 'ImpulseResponse','iir' name-value pair for best results. The envelope function would then be helpful in defining the exponential characteristic.
I doubt that without some pre-processing it would be possible to define an exponential envelope for those data.
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Star Strider
Star Strider 2022 年 8 月 1 日
I am not certain what your data are, so I cannot suggest any other approaches. The one file that was supplied was significantly different from the plot image in the original post. I have no idea how — or if — they are related.
If you have not already searched the literature, the best option would be to do a PubMed search to see how others have approached this problem. Ultrasound has been available for about a half century, so there is likely literature on the problem you are working with that could make the analysis easier.

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