get image after press submit button in angularjs

Question

I have following bootstrap html

<div class="modal fade" id="myModal" tabindex="-1" role="dialog" aria-labelledby="myModalLabel">
    <div class="modal-dialog" role="document">
        <div class="modal-content">
            <div class="modal-header">
                <button type="button" class="close" data-dismiss="modal" aria-label="Close"><span aria-hidden="true">&times;</span></button>
                <h4 class="modal-title" id="myModalLabel">Modal title</h4>
            </div>
            <form ng-submit="setFile()" enctype="multipart/form-data">
                <div class="modal-body">
                    <input type="file" accept="image/*">
                </div>
                <div class="modal-footer">
                    <button type="button" class="btn btn-default" data-dismiss="modal">Close</button>
                    <button type="submit" class="btn btn-primary">Save changes</button>
                </div>
            </form>
        </div>
    </div>
</div>

And following function in controller

$scope.setFile = function () { 
    console.log($scope.image); // this console logs undefined
}

The above code somehow does not get image from input type file. How can I get that image and the I want to preview it when user clicks submit button?

UPDATE

I want to get file on form submit not on input change.