How to add foreach result to column grid?

I try to get the foreach result in a grid column (I have the result but I don't how to put it into the column for each category id).

My grid.php

public function _prepareCollection()
    {
    $subcategories = Mage::getModel('catalog/category')
    ->setStoreId(Mage::app()->getStore()->getId())
    ->getCollection()
    ->addAttributeToSelect('*')
    ->setOrder('parent_id', 'ASC');
    $categories = array();
foreach ($subcategories as $category){
    //do something with $category and put it in Route column
    if ($category['level'] > 1) {
    $categories[$category['entity_id']] = array('category_route' => $category['level'] == 2 ? $category['name'] : $categories[$category['parent_id']]['category_route'] ." -> ". $category['name']);
}
var_dump($categories[$category['entity_id']]);
}
        $collection = Mage::getModel('thorleif/commerciaux')->getCollection();
        $collection->addFieldToFilter('entity_id',array("nin"=>array(1,2))); 
        $this->setCollection($collection);
        return parent::_prepareCollection();
    }

    public function _prepareColumns()
    {
        $this->addColumn('entity_id',
            array(
                'header' => 'ID',
                'align' => 'left',
                'width' => '10%',
                'index' => 'entity_id'
            )
        );
        $this->addColumn('name',
            array(
                'header' => 'Category Name',
                'align' => 'left',
                'index' => 'name'
            )
        );
        $this->addColumn('route',
            array(
                'header' => 'Route',
                'align' => 'left',
                'index' => array($category['name'] .'>'. $category['name'])
            )
        );

The result of the var_dump it's like this

You can't directly show your custom collection in the required column. You need to use renderer class for this requirement. You need to create a renderer folder extends

Mage_Adminhtml_Block_Widget_Grid_Column_Renderer_Abstract class.

class Namespace_Module_Block_Product extends Mage_Adminhtml_Block_Widget_Grid_Column_Renderer_Abstract
{   

public function render(Varien_Object $row)
{
$productId =  $row->getData($this->getColumn()->getIndex());
$product = Mage::getModel('catalog/product')->load($productId);

$value = '<img src="">';
if($product->getImage()!= 'noselection')
{
     $value='<img src="' . $product->getImageUrl() . '" width="100" height="100" />';
}

return $value;
}
}

In the Grid column to need to call this class by using renderer parameter as shown below.

   $this->addColumn(
            'product_id',
            [
                'header' => __('Product Name'),
                'sortable' => true,
                'index' => 'product_id',
                'renderer'  => 'Namespace\Module\Block\Product'

            ]
        );

You can also pass the category ID, to this specific renderer class.