File not Passing on ng-file-select in Angular JS

Question

I am trying to pass a file from html view to angular controller, for this I am using ng-file-select in the view. My view code looks like:

<div ng-controller="fileController">
<input type="file" ng-model="fibQuestion.fibContentLanguage.colUploadPaperUrl" name="PaperDocUrl" ng-file-select="onPaperFileSelect($files)" onclick="this.value = null" id="forPracticalTestPaper" />
<div>
<input type="button" id="save" class="btn btn-success" value="Save" ng-click="PaperFileProcessing()" />
</div>
</div>

But here, ng-file-select="onPaperFileSelect($files)" cannot passing the file to the controllers. The controller code is :

app.controller('fileController',function($scope) {
       $scope.message = "From Controller";
       $scope.onPaperFileSelect = function ($files) {
 if ($scope.verifiedFileType($files[0].name, 'paper')) {
             $scope.saveFileLoacation = '~/UploadedFiles/PracticalTestPaperFiles/';
            $scope.yesDisable = false;
             $scope.uploadedPaper = $files;
            $('#upload-paper-file-info').text($files[0].name);
             $scope.showPaperDeleteButton = true;
         }     };
         $scope.verifiedFileType = function (fileName, fileType) {
 var extension = (fileName.substring(fileName.lastIndexOf('.'), fileName.length)).toLowerCase();
 if (extension == ".pdf") {return true;}
 else {alert("file extension not valid for " + fileType + ". available extensions are pdf.");
            angular.element("input[type='file']").val(null);
 return false;
        }     };
             $scope.PaperFileProcessing = function () {
           $scope.upload = [];
         $scope.yesDisable = true;
 var fileBank = $scope.uploadedPaper;
         console.log(fileBank);
 var status = false;
 var i = fileBank.length;
        console.log(i);
         };
     });

When , I press the save button, that calls the function PaperFileProcessing(), but then, var fileBank = $scope.uploadedPaper; is showing undefined.