how can i select ROI dynamically for lane detection?

I want to remove background as more as possible and try for keeping only the lane.But I can not do the code,please help me to do the code for me.This image is a sample image.Other images are relatively close to this.

[Bish Erbas]

You can try this:

https://www.mathworks.com/help/images/color-based-segmentation-using-k-means-clustering.html

[ashraf]

Undefined function or variable ' imsegkmeans'.

Showing me this.How I can resolve it??

[Image Analyst]

It's in the R2018b release of the Image Processing Toolbox. You must not be using that.

Go here to find lane detection algorithms: http://www.visionbib.com/bibliography/contentsactive.html#Active%20Vision,%20Camera%20Calibration,%20Mobile%20Robots,%20Navigation,%20Road%20Following