Regex to extract and parse an array like string in string

I have to create a script parse a path and replace variables with existing array attribute. I have an multi-deminsional array like below:

$param = array(
        'titles'=>array(
            '[group1]'=>array(
                array('name'=>'picture','title'=>'personel_image','target_folder'=>'tmp/contacts/{name=picture}[value]'),
                array('name'=>'full_name','title'=>'Full Name'),
                array('name'=>'melli_code','title'=>'id code','format'=>'number'),
                )
        )
)

As you can see there is an attribute call target_folder that user write as following format,'tmp/contacts/{format=number}[title]/{name=picture}[title]'.

I need a solution to parse a bold part of above path as an array like below.

$search_for = array(
        '0'=>array(
            '[array_column]'=>'format',
            '[array_column_keyword']=>'number',
            '[array_column_value']=>'title',
        ),
        '1'=>array(
            '[array_column]'=>'name',
            '[array_column_keyword']=>'picture',
            '[array_column_value']=>'title',
        )
)

What is the best way to resolve the above problem?