I know it's a bit late to answer here but maybe I may save some once's day.
I have been dealing with the same problem. A model will not populate once you update the value of input from jQuery. I tried using trigger events but no result.
Here is what I did that may save your day.
Declare a variable within your script tag in HTML.
Like:
<script>
var inputValue="";
// update that variable using your jQuery function with appropriate value, you want...
</script>
Once you did that by using below service of angular.
$window
Now below getData function called from the same controller scope will give you the value you want.
var myApp = angular.module('myApp', []);
app.controller('imageManagerCtrl',['$scope','$window',function($scope,$window) {
$scope.getData = function () {
console.log("Window value " + $window.inputValue);
}}]);