How can I find the value of vector for the local maximum and the nearest local minima (befor and after maximum value)?

Question

Ashraf Afana 2013-6-8

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/78454-how-can-i-find-the-value-of-vector-for-the-local-maximum-and-the-nearest-local-minima-befor-and-af

Hi,

I have a vector array (e.g. 2 12 4 6 9 4 2 5 10 19 7 5 3 7 4) and I need to define the part of the vector with local maximum value and the neighbouring minima, located to the left and right of the maximum). In the above example it should be [2 5 10 19 7 5 3].how can I code that in matlab? any help please..

Thanks,

0 个评论
显示 -2更早的评论隐藏 -2更早的评论

请先登录，再进行评论。

请先登录，再回答此问题。

Answer 1

Image Analyst 2013-6-8

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/78454-how-can-i-find-the-value-of-vector-for-the-local-maximum-and-the-nearest-local-minima-befor-and-af#answer_88178

Why does the 12 at element 2 not qualify as a local max? Do you have the Image Processing Toolbox, try imregionalmax(). If you have the Signal Processing Toolbox, try findpeaks on the signal and the inverted signal.

3 个评论
显示 1更早的评论隐藏 1更早的评论

Image Analyst 2013-6-8

编辑：Image Analyst 2013-6-8

在 MATLAB Online 中打开

Try this:

m = [2 12 4 6 9 4 2 5 10 19 7 5 3 7 4]
regMax = imregionalmax(m)
regMin = imregionalmin(m)
% Find the 3rd peak
index3 = find(regMax, 3, 'first')
index3 = index3(end)
% Find out the mins on either side of that.
% Find the min locations
minLocations = find(regMin)-index3
% Find where the first one goes positive (right side)
rightIndex = minLocations(find(minLocations>0, 1, 'first'))+index3
% Get the left side:
leftIndex = minLocations(find(minLocations<=0, 1, 'last'))+index3
% Get the stretch from left min to right min on either side of the 19.
stretch = m(leftIndex:rightIndex)