Sensing the data changes and plotting

2 次查看（过去 30 天）

uzzi 2022-10-27

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1837568-sensing-the-data-changes-and-plotting

评论： uzzi 2022-11-1

I have a table "a" which has multiple rows and 2 columns; t for time and q for data. I attached here.

I want to plots the period only where the sudden change of value happens (from start to end of the changes) such as I showed in figure where the value jumped from nearly -4 to -43.65.

After that I'd like to generate a table of the data of the plot. There will be many periods where such kind of data changes occurs so I want to plot everytime with that data changes.

load = 'newdata3.csv';

data = readtable(load);

data = sortrows(data,'Var1','ascend');

timetable(data.Var1, data.Var2);

plot(data.Var1,data.Var2)

findchangepts(data.Var2,'MaxNumChanges',20)

Here, I tried and it is not showing at the correct changes points. There are 12 changes points and it is only showing 5 of them. I don't know how to fix this.

回答（1 个）

Image Analyst 2022-10-27

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1837568-sensing-the-data-changes-and-plotting#answer_1085733

在 MATLAB Online 中打开

Do you have the Image Processing Toolbox? If so, it's easy.

v = a.V;
mask = v > 200
props = regionprops(mask, 'PixelIdxList');
numRegions = numel(props);
coords = vertcat(props.PixelIdxList);
startingRows = coords(:, 2);

or something similar. It would have been easier if you had read the posting guidelines and remembered to attach your data.

To learn other fundamental concepts, invest 2 hours of your time here:

MATLAB Academy - Free 2 hour training

See my Image Processing Tutorial in my File Exchange:

Image Analyst's File Exchange

If you have any more questions, then attach your data and code to read it in with the paperclip icon after you read this:

TUTORIAL: How to ask a question (on Answers) and get a fast answer

12 个评论
显示 10更早的评论隐藏 10更早的评论

Image Analyst 2022-11-1

Yes. But I don't know what you want.

If you have any more questions, then attach your data and code to read it in with the paperclip icon after you read this:

TUTORIAL: How to ask a question (on Answers) and get a fast answer

uzzi 2022-11-1

I think you didn't understand my question. That's the question I'm asking from the start. I can plot in conventional way. According to the plot, you can see that there are 6 places where big data changes happen.

What I want is I want the MATLAB to sense the data automatically and generate a graph where a big data changes is sensed.

In this case, I want the MATLAB to automatically generated 6 figures where big data changes occurs.

I hope this explanation is clear to you.

请先登录，再进行评论。

请先登录，再回答此问题。