Just make a regular expression to process each line two characters at a time, and then translate. 
my %translate = (
    '0 0' => -1,
    '0 1' => -1,
    '0 2' => -1,
    '1 0' => -1,
    '1 1' => 0,
    '1 2' => 1,
    '2 0' => -1,
    '2 1' => 1,
    '2 2' => 2,
);

while (<$fh>) {
    s/(\d \d)/$translate{$1}/g;
    print "New line: $_";
}

[download]
And just for kicks, here is more obfuscated, but purely mathematical solution for the translation 
while (<DATA>) {
    s{(\d)\s+(\d)}{log(($1 * $2) || (1/2)) / log(2)}eg;
    print "New line: $_";
}

__DATA__
1 1 1 1 0 0 0 0 0 0 0 0
1 1 1 2 0 1 0 1 0 1 0 1
1 1 2 2 0 2 0 2 0 2 0 2
1 2 1 1 1 0 1 0 1 0 1 0
1 2 1 2 1 1 1 1 1 1 1 1
1 2 2 2 1 2 1 2 1 2 1 2
2 2 1 1 2 0 2 0 2 0 2 0
2 2 1 2 2 1 2 1 2 1 2 1
2 2 2 2 2 2 2 2 2 2 2 2

[download]
Outputs 
New line: 0 0 -1 -1 -1 -1
New line: 0 1 -1 -1 -1 -1
New line: 0 2 -1 -1 -1 -1
New line: 1 0 -1 -1 -1 -1
New line: 1 1 0 0 0 0
New line: 1 2 1 1 1 1
New line: 2 0 -1 -1 -1 -1
New line: 2 1 1 1 1 1
New line: 2 2 2 2 2 2

[download]
- Miller

In reply to Re: Reading lines going by 2 characters at a time by wind
in thread Reading lines going by 2 characters at a time by Renyulb28

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