How shall i read the data which is in [form]?

Array
(
    [i_id] => 0
    [f_tok] => _p9kmWKZaplimWSZeJlymVKZQplEmUwH7AfkE~xB5BsXLZtBnZ8HmQefnw!!
    [form] => [{"name":"Incident.Threads","value":"asd","required":true},{"name":"Incident.Product","value":188,"required":false},{"name":"Incident.Category","value":142,"required":false},{"name":"Contact.Name.First","value":"asd","required":true}]
)

This is received through the $_POST. Using Print_r I have printed this data out of $_POST.

How can I get data which is in "[form] => [{.....}]"??