MATLAB: Exponential decay extrap to y=0

expexponential

Hi peeps,

I am trying to fit an exponential decay curve to my data;

x = [0;10;20;30;40;50;60]; %time in minutes

y = [12.5; 7.8;5.1;3.2;2;1.2;0.7];

I am reasonably new to matlab and I am unsure about how to fit an exponential curve to the plot that reaches y=0

Any assistance would be greatly appreciated.

Many thanks,

Jamie

Best Answer

Hello,

You could try this

clear 
close all
x0 = linspace(0,100,100);
x = [0;10;20;30;40;50;60]; %time in minutes
y = [12.5; 7.8;5.1;3.2;2;1.2;0.7];
f = fittype('exp(-a*x+b)');
[fit1,gof,fitinfo] = fit(x,y,f,'StartPoint',[1 0]); % ,'StartPoint',1
figure
plot(x0,fit1(x0),'r',x,y,'o')

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% Demo to find fitted curve.
% By Image Analyst
clc;    % Clear the command window.
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format compact;
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	% grayImage = grayImage(:, :, 2); % Take green channel.
end
%--------------------------------------------------------------------------------------------------------
%    SEGMENTATION OF IMAGE
% Get a binary image
binaryImage = imbinarize(grayImage);
subplot(3, 1, 1);
imshow(binaryImage, []);
impixelinfo;
title('Binary Image', 'FontSize', fontSize, 'Interpreter', 'None');
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drawnow;
%--------------------------------------------------------------------------------------------------------
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subplot(3, 1, 2);
imshow(binaryImage)
grid on;
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Try this:

clc;    % Clear the command window.
close all;  % Close all figures (except those of imtool.)
clear;  % Erase all existing variables. Or clearvars if you want.
workspace;  % Make sure the workspace panel is showing.
format long g;
format compact;
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[rows, columns, numberOfColorBands] = size(rgbImage);
% Display the original color image.
subplot(2, 2, 1);
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title('Original Color Image', 'FontSize', fontSize, 'Interpreter', 'None');
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Best Answer

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MATLAB: Fit a polynimial function on a image curve

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