$image = <<IMAGE;
0000000000000000000000
0000000001111100000000
0000000001111100000000
0000000001111100000000
0000000001111100000000
0000011111111111110000
0000011111111111110000
0000011111111111110000
0000011111111111110000
0000000001111100000000
0000000001111100000000
0000000001111100000000
0000000001111100000000
0000000000000000000000
IMAGE

$result =
    transpose(
        trim( vertical_squish( transpose(
            trim( vertical_squish( $image ) ) ) ) ) );

$result eq <<EXPECT or die "Failed.\n$result\n";
010
111
010
EXPECT

sub trim {
    local $_ = shift;

    s/\A(?:^0+[\r\n]+)+//m;
    s/(?:^0+[\r\n]+)+\z//m;

    return $_;
}

sub vertical_squish {
    local $_ = shift;

    s/(^[^\r\n]+[\r\n]+)\1+/$1/gm;

    return $_;
}

use Algorithm::Loops 'MapCarU';
sub transpose {
    local $_ = shift;

    return
        join( "",
              &MapCarU(
                  sub { join( "", @_ ) . "\n" },
                  map( [ split // ],
                       split( /[\r\n]+/ ) ) ) );
}