Distance between lanes from video or Frame as Pictures

Hello,

I would like to measure the distance between two lines from an video file or the single frames from this video file. (video is from an moving car, left lane and right lane)

I played around with the lane dedection and warning Example from Matlab. This example recognizes my lane marking very well. I have problems to get the width between the detected lines. I dont care if the width is given in pixels or already in world units, either way i can work with them.

I "just" need help on how i get the distance between the to lines. Similar to this example, but i would be satisfied with just an output i dont need the fancy graphics ;-) https://www.youtube.com/watch?v=SFqAAseL_1g

Maybe someone can help me.

Greetings Gabriel

English is not my native language, I'm sorry for any mistakes regarding grammer or spelling, i promise i will get better!