memory leak found while run in php_cli mode

[lilien1010]

function checkQrCode($filename,$mid){ 
        if(false==file_exists($filename)){
            return false;
        } 
        $QRimage    = new ZBarCodeImage($filename);

        $QRscanner  = new ZBarCodeScanner();

        try{ 
            $barcode = $QRscanner->scan($QRimage); 
        }catch(Exception $e){
            $barcode    =   false; 
            zLog(HT_ERROR,' e = '.$e->getMessage(),__FUNCTION__,__LINE__); 
        }

        $QRimage->clear();
        $QRscanner  =   null;
        $QRimage    =   null;
        unset($QRscanner);
        unset($QRimage);

        if (!empty($barcode)) {
              //handle barcode          
        } 
        return false; 
    }

while I call the function in a loop to check amount of files, the memory keep increasing.
,is there any wrong with my code?

[lanbiaowan]

hehe