How would I extract the "wave-like" signals in this attached image.

I need to extract the "wave-like" signals present in this image. How would I go about doing it.

My first attempt was to just sum and averaging column-wise, this gave me the signal but it had distortions.

%=========CODE
close all
%I=imread('c:\dev\arcDensityImage1.bmp');
I=imread('c:\dev\RotVideoArcDensityImage.bmp');
%I=cdata;
I1s=sum(I,1)/190;
plot(I1s-I1s(2),'r')
I2=I(1:100,:);
I2s=sum(I2,1)/100;
hold on
plot(I2s,'b')
I3s=sum(I(100:190,:))/90;
plot(I3s,'g');