Alternating up and down in my script to find path through 'maze'

Scrip folder is attached! (.zip)

The point of this script is to find if a path exists of 1's between the bottom row and top row. A path consisting of straight lines only, no diagonals.

Concept of the script

The maze:

0 1 1 0 1 1 0 (path is made bold)

0 1 0 0 0 0 0

0 1 1 1 1 0 0

0 0 0 0 1 0 0

1 1 1 0 1 1 0

1 0 1 1 1 0 0

1 1 0 0 0 0 0

Initiating step:

Search the bottom row for values equal to 1, then change these into 2's.

Looping step:

Now scan the row above for values equal to 1, which are attached to values of 2. (Like a virus)

Now scan left and right of these new 2's for other 1's that are attached to these, and turn these into 2's aswell.

0 1 1 0 1 1 0

0 1 0 0 0 0 0

0 1 1 1 1 0 0

0 0 0 0 1 0 0

2 2 2 0 1 1 0

2 0 1 1 1 0 0

2 2 0 0 0 0 0

As can be seen above we now encounter a point where there's only 0s above and so the script should go down.

I am unable to find an efficient way for alternating up and down within my script, so that it keeps searching for new 1's connected to 2's.

I have been struggling with this specific problem for over 5 hours already and am getting really upset.

Any help is greatly aprecciated!

Answer 1

[Meg Noah]

Try this algorithm:

Goal:to assign a label to each connected track of 1's on a background of 0's.

Procedure: Scan image left to right and top to bottom.

Mask/Template:

- U
L C

for evaluating the C center pixel compared to the U up pixel and the L left pixel.

Algorithm:

let the initial label be k = 1

scan image left to right then top to bottom evaluating each pixel:

if f( C ) == 0

do nothing

else

if f(U)==1 & f(L) ==0

label( C) = label(U);

elseif f(U)==0 & f(L) ==1

label( C) = label(L)

elseif f(U) == 1 & f(L) ==1

label ( C) = label(L)

label(L) <-> label(U)

elseif f(U) == 0 and f(L) == 0

label( C) = k

k = k + 1 (increment label value)

end

end