未定义的属性：通过PHP上传Image的路径时的stdClass

I am uploading the description, the number and the image path through the PHP database.

When trying to call the image from the controller, an error is displayed which states: Undefined property: stdClass::$imgPath .... on line 9. On the other hand, the text elements are uploaded successfully.

Please find the PHP code below:

<?php
    $prov = json_decode(file_get_contents("php://input"));
    require_once("connection.php");
    $connection = connectToMySQL();

    // Check if image file is a actual image or fake image
        $proverbDescription = $prov->proverbDescription;
        $proverbNumber = $prov->proverbNumber;  
        $imgPath = $prov->imgPath;


        $query = "INSERT INTO tbl_proverb (proverbDescription, proverbNumber, imgPath) VALUES ('$proverbDescription', '$proverbNumber', '$imgPath')";
        echo($proverbDescription);
        echo($proverbNumber);
        echo($imgPath);
        if (move_uploaded_file($_FILES['imgPath']['tmp_name'], $target_file))  //for uploading file
        {
            echo("File uploaded to: " . $target_dir);
        }

        $result = mysqli_query($connection, $query)
             or die("Error in query: ". mysqli_error($connection));
        if(mysqli_affected_rows($connection) > 0){
                $success = true;
        }else{
                $success = false;
        }   
?>

The AngularJS Controller:

app.controller('proverbCtrl', function($scope, $http, $location) {

$scope.addProverb = function(prov) {
    $http.post('php/addProverbs.php', prov).success(function(prov) {
        console.log(prov);
     // $location.path("/home");
    });
};
});

And my HTML form:

<form id="demo" class="collapse" ng-submit="addProverb(prov)" enctype="multipart/form-data" method="POST">
    <label>Image:</label>
        <input type="file" ng-model="prov.imgPath" name="imgPath" id="imgPath" accept="image/*"> 
    <label>Proverb Description:</label>
        <input type="text" ng-model="prov.proverbDescription" ><br><br>
    <label>Proverb Number:</label>                          
        <input type="text" ng-model="prov.proverbNumber"><br><br>
    <input type="submit" name="submit"><br>
    <a href="#/proverbs">See your post</a>
</form>

If all you need is to get the file name to PHP try something like this:

HTML:

 <input type="file" onchange="angular.element(this).scope().fileName(this)" 
ng-model="prov.imgPath" name="imgPath" id="imgPath" accept="image/*">

Controller:

$scope.fileName= function(element) {
     $scope.$apply(function(scope) {
        scope.prov.imgPath = element.name;
     });
};