Find the central line (midpoint) of a sinusoidal wave

I used another program (tracker) to track the oscillation of a laser. I generated a plot of position with respect to time with the data used from the program.

Attached is an image of the data with a curve fit generated in matlab.

Is there a way to generate a horizontal line on this same plot in order to show the centerline of the oscillation?

For example, The biggest peak ranges fromo 45 to 75 cm. Its midpoint would be 57.5cm. A horizontal line at 57.5 would indicate the centerline of this oscillation.

Answer 1

[Matt J]

yline(mean(y))

Answer 2

[Angelo Yeo]

Please consider the following example.

clear;

%% creating an oscillating signal with bias
fs = 10000;
t = 0: 1/fs: 1- 1/fs;

x1 = sin(2*pi*10*t);
x2 = exp(-1*t);

my_bias = exp(0.1 * t);
x = x1.*x2 + my_bias;
figure
plot(t, x);

%%
[pks_p, locs_p] = findpeaks(x); % find peaks 
[pks_n, locs_n] = findpeaks(-x);

hold on;
plot(t(locs_p), pks_p, 'r*');
plot(t(locs_n), -1 * pks_n, 'b*');

%% creating a center line

yline(mean([pks_p, -1 * pks_n]))