Angular controller without single responsability

I'm new in cordova / angularJS and I wonder how much responsibility a controller can have. This particular one validates users entry data, display messaging, takes pictures calling the camera API, serialize them and finally calls a service to upload them to the cloud. I want to refactor functionality and move it to a separate service for example but not sure which functions should be moved.

  .controller('pictureOfTheVehicleCtrl', function ($scope, $cordovaCamera, $rootScope, $ionicPopup, Upload, $ionicLoading, $timeout) {

    $scope.upload = function () {
      // Validate user input
      var message = undefined;
      if ($scope.registrationNumber === undefined)
        message = 'Please, provide a valid registration number.';
      else if ($scope.damage === undefined)
        message = "Please, provide a valid picture of the damage. ";
      else if ($scope.vehicle === undefined)
        message = "Please, provide a valid vehicle picture. ";

      if (message) {
        $ionicLoading.show({ template: message });
        $timeout(function () {
          $ionicLoading.hide();
        }, 2000);
        return null;
      }

      // Upload damage picture
      var file = dataURItoBlob($scope.damage);
      $ionicLoading.show({ template: 'Uploading picture of the damage...' });
      Upload.uploadImage($rootScope.userName, $rootScope.userPass, $scope.registrationNumber, 'damage', file)
        .then(function (response) { // success
        }, function (response) {  // error
          showAlert('Error', 'Error uploading picture of the damage: ' + response)
          return null;
        }).then(function () {
          $ionicLoading.hide();
        });

      // Upload vehicle picture
      file = dataURItoBlob($scope.vehicle);
      $ionicLoading.show({ template: 'Uploading vehicle picture...' });
      Upload.uploadImage($rootScope.userName, $rootScope.userPass, $scope.registrationNumber, 'licenseplate', file)
        .then(function (response) { // success
          if (response == 0) {
            showAlert('Upload', 'Pictures successfully uploaded!')
            wipeData();
          }
          else {
            showAlert('Error', 'Error uploading picture of the vehicle: ' + response)
          }
        }, function (response) {  // error
          showAlert('Error', 'Error uploading picture of the vehicle: ' + response)
          return null;
        }).finally(function () {
          $timeout(function () {
            $ionicLoading.hide();
          }, 2000);
        });
    }

    function showAlert(title, message) {
      $ionicPopup.alert({
        title: title,
        template: message
      });
    }

    function wipeData() {
      // Wipe temp data
      $rootScope.damage = undefined;
      $rootScope.vehicle = undefined;
      $rootScope.registrationNumber = undefined;
    }

    function dataURItoBlob(dataURI) {
      // convert base64/URLEncoded data component to raw binary data held in a string
      var byteString;
      if (dataURI.split(',')[0].indexOf('base64') >= 0)
        byteString = atob(dataURI.split(',')[1]);
      else
        byteString = unescape(dataURI.split(',')[1]);

      // separate out the mime component
      var mimeString = dataURI.split(',')[0].split(':')[1].split(';')[0];

      // write the bytes of the string to a typed array
      var ia = new Uint8Array(byteString.length);
      for (var i = 0; i < byteString.length; i++) {
        ia[i] = byteString.charCodeAt(i);
      }

      return new Blob([ia], { type: mimeString });
    }  

    $scope.takePicture = function () {
      var options = {
        quality: 75,
        destinationType: Camera.DestinationType.DATA_URL,
        sourceType: Camera.PictureSourceType.CAMERA,
        allowEdit: false,
        targetWidth: 1024,
        targetHeight: 567,
        encodingType: Camera.EncodingType.JPEG,
        popoverOptions: CameraPopoverOptions,
        saveToPhotoAlbum: false
      };

      $cordovaCamera.getPicture(options).then(function (imageURI) {
        $rootScope.vehicle = "data:image/jpeg;base64," + imageURI;
      }, function (err) {
        $ionicPopup.alert({
          title: 'Camera',
          template: 'Something went wrong: ' + err
        });
      });
    }
  })