Ho to find the interception

Question

Navaneeth Tejasvi Mysore Nagendra 2022-6-23

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1746480-ho-to-find-the-interception

评论： Star Strider 2022-6-23

I have a fitted Guassian plot to which I have plotted yline. Now I am interested to extrac two x- interception points through which my line is passing. I am not able to find any easy way to do it. so any help is appreciable.

code:

clc;close all;clear;

resultsdir = 'results';

Row = dir('cross_section_*.mat');

%Coefficients (with 95% confidence bounds):

a1 = 394.5 ;

b1 = 985.1 ;

c1 = 114.8 ;

a2 = 511.4 ;

b2 = 878.5 ;

c2 = 231.2 ;

a3 = -529.8 ;

b3 = 989.8 ;

c3 = 133.6 ;

xData = zeros(1,1640);

yData = zeros(1,1640);

color = ['r','g','b']

for X = 1:9

Filename = Row(X).name;

dest = fullfile(resultsdir, Filename);

Filedata(X) = load(Filename);

figure()

plot(Filedata(X).x)

[xData, yData] = prepareCurveData( [], Filedata(X).x);

ft = fittype( 'gauss3' );

opts = fitoptions( 'Method', 'NonlinearLeastSquares' );

opts.Display = 'Off';

opts.Lower = [-Inf -Inf 0 -Inf -Inf 0 -Inf -Inf 0];

opts.StartPoint = [446.913 842 37.5821195501848 401.619376603545 761 47.8742720232778 393.885950193204 926 55.7197242033307];

[fitresult, gof] = fit( xData, yData, ft, opts );

figure()

h = plot( fitresult,'k', xData, yData);

set(h,'LineWidth', 2)

title(sprintf('Name:%s , R-Square = %0.4f',Filename,gof.rsquare))

legend( h, 'Experiment', 'fit ', 'Location', 'NorthEast', 'Interpreter', 'none' );

% Label axes

ylabel('Intensity values')

xlabel( 'Along X of the CMOS', 'Interpreter', 'none' );

grid on

f = fitresult.a1*exp(-((xData-fitresult.b1)/fitresult.c1).^2) + fitresult.a2*exp(-((xData-fitresult.b2)/fitresult.c2).^2) + fitresult.a3*exp(-((xData-fitresult.b3)/fitresult.c3).^2);

Max(X) = max(f)

exp_perc(X) = Max(X)/exp(2);

yline(exp_perc(X))

% Max(X) = max(fitresult.val)

% f = a1*exp(-((Filedata(X)-b1)/c1).^2) + a2*exp(-((Filedata(X)-b2)/c2).^2) + a3*exp(-((Filedata(X)-b3)/c3).^2);

end

plot: