smoothing a curve efficiently

Hi , I need to make my curve smooth and I use all of the method simoltaneouly but my data need to be more smooth. how can I make this happen ?

very thanks in advance

Answer 1

[DGM]

Since you haven't said what you actually attempted and haven't given any sample data or even revealed the domain and range of the plot image, I can only offer a simple example.

% make up some function with a similar appearance
x = linspace(0,10,100);
y = -0.01*(x-6).^2 + 0.05*abs(sin(4*x));

% smooth the thing with an averaging filter
ys = smooth(y,20);

% smooth the thing with a spline fit (uses CFT)
fm = fit(x',y','smoothingspline','smoothingparam',0.9);

plot(x,y,'k:'); hold on; grid on
plot(x,ys,'r')
plot(x,fm(x),'b')
legend('original','average','spline','location','southeast')

You'd obviously have to tailor the parameters to whatever data you're actually using.

[raha ahmadi]

Dear DGM;

I really appericiate your help and time. It works

I wish the best for you

Answer 2

[Das Siddharth]

Did you try the smooth (MAF) function from the MATLAB ? Try that with smoothing a specific coloumn or row and see what gives you the best result. Hope it helps.

[raha ahmadi]

Yes I did. As I said I used all of the methodes but I need more smoothness Thank you

[Das Siddharth]

Can you give a sample of your data so that I can try ?

[raha ahmadi]

Dear Siddharth

Thank you for your attention. This is a small part of my data. I need a realy smooth gradient but as you see although the graph seems smooth but the gradient has sharp changes

Best wishes

clc
clear 
close all

T=[304.998454103946;304.997649607535;305.004722282365;305.01001273423;...
    305.013520963129;305.015246969062;305.015190752029;305.013352312031;...
    305.01902116925;305.022835253892;305.024794565955];
x=[3848.22104674965;3849.36319865994;3850.50535057022;3851.64750248051;...
    3852.78965439079;3853.93180630108;3855.07395821137;3856.21611012166;...
    3857.35826203194;3858.50041394223;3859.64256585251];


 T1=smooth(T,'moving');
 T2=smooth(T1,'lowess');
 T3=smooth(T2,'loess');
 T4=smooth(T3,'sgolay');
 T5=smooth(T4,'rlowess');
 T6=smooth(T5,'rloess');
 plot(x,T,'k:');
 hold on
 plot(x,T6,'k')
 legend('original','to be smooth')
 ylabel('T')
 dTdy=gradient(T);
 figure
 plot(x,dTdy,'k:')
 hold on
 dT6dy=gradient(T6);
 ylabel('dTdx')
 plot(x,dT6dy,'k')
 legend('original', 'to be smooth')