# Straight line detection

Nigel Rowe see at signature.invalid
Sat Oct 15 07:31:24 CEST 2005

```Tim Roberts wrote:

> "PyPK" <superprad at gmail.com> wrote:
>>
>>Does anyone know of a simple implementation of a straight line
>>detection algorithm something like hough or anything simpler.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.
>
> If all you want is horizontal, vertical, or 45 degree diagonal, it's
> pretty easy to do that just be checking all of the possibilities.
>
> But what if your array is:
>
>  [[1,1,1,1,1],
>   [1,1,1,1,1],
>   [1,1,1,1,1],
>   [1,1,1,1,1],
>   [1,1,1,1,1]]
>
> Would you say there were 12 lines there?

Actually I'd say 24.

5 vertical,
5 horizontal,
7 diagonal downward to the right (lengths 2,3,4,5,4,3,2)
7 diagonal downward to the left (lengths 2,3,4,5,4,3,2)

--
Nigel Rowe
A pox upon the spammers that make me write my address like..
rho (snail) swiftdsl (stop) com (stop) au

```

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