Find the distance beween two two lines from different images?

I want to find the distance between the line for same rows . So far i have trying to add the two images and distance is the number of black pixels between two white pixels from same row.

[Matt J]

first line.jpg and second line.jpg look almost identical.

[Sobit Singh]

Sir, The images were the earth coastline i think they should be nearly same

Answer 1

[Matt J]

Something like this, maybe

x=(1:size(firstline,2)).';

distance = double(secondline-firstline)*x;