Finding several local maximum values in a given range and corresponding indices

28 次查看（过去 30 天）

FW 2019-9-27

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/482390-finding-several-local-maximum-values-in-a-given-range-and-corresponding-indices

回答： Image Analyst 2019-9-28

If we have a dataset "y" which consists of a sum of 5 gaussian peaks as function of time t, there will be 5 local maximum values in the whole y values. Basically, I would like to obtain the y axis maximum values and their corresponding t axis values. For example peak 1, has a maximum value 5 and it corresponds to t value of 19.

One can individually find the maximum values by giving a range say

[a ,i]=max(y(1:20));% locating maxima in a given range of the first peak

value_1= t(i); % Corresponding value of time for index i1.

One can repeat this 5 times by specifying the ranges for all peaks. Is there a better way to achieve the same result as an output in a single vector, and the corresponding time for those maxima in another vector . Thanks.

2 个评论
显示无隐藏无

madhan ravi 2019-9-27

在 MATLAB Online 中打开

If you mean all the indices of the max value:

Indices = find(y==max(y(:))

FW 2019-9-27

I have edited the question to clarify it. Basically, I would like to obtain the y axis maximum values and their corresponding t axis values. For example peak 1, has a maximum value 5 and it corresponds to t value of 19. I want to have all the 5 values of maximum and their corresponding time values?

请先登录，再进行评论。

请先登录，再回答此问题。

采纳的回答

Star Strider 2019-9-27

1
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/482390-finding-several-local-maximum-values-in-a-given-range-and-corresponding-indices#answer_393777

Use the Signal Processing Toolbox findpeaks function, or the islocalmax (R2017b and later) function.

8 个评论
显示 6更早的评论隐藏 6更早的评论

MW 2019-9-28

That sounds good, will try that. I hope Matlab includes peak area determination just like OriginPro where one can pan the area of interest and determine its area.

Star Strider 2019-9-28

Thank you.

‘I hope Matlab includes peak area determination just like OriginPro where one can pan the area of interest and determine its area.’

I doubt that’s an option, or if it is, I’ve not heard of it.

Fitting Gaussians is not difficult. See: Area under each peak for an illustration, including findpeaks calls. You can probably use that code with a few tweaks to use your own data. (I will help as necesary, since it’s my code. That code uses trapz, however it would probably not be very difficult to tweak it to use integral to calculate the areas, once the parameters of the Gaussians are known.)

请先登录，再进行评论。