Pixel Manipulations

[PyPK]

Does anyone know of a simple implementation for detecting straight line
.So something like if we have a 2D arary of pixel elements representing
a particular Image. How can we identify lines in this Image.
for example:

ary =
[[1,1,1,1,1],
 [1,1,0,0,0],
 [1,0,1,0,0],
 [1,0,0,1,0],
 [1,0,0,0,1]]
So if 'ary' represents pxl of an image which has a horizontal line(row
0),a vertical line(col 0) and a diagonal line(diagonal of ary). then
basically I want identify any horizontal or vertical or diagonal line
anywhere in the pxl array and return true if its composed of only lines
else false...

Thanks.