Image processing (#1742)

* Add image_processing

* add to demo

source/_components/image_processing.markdown

@@ -0,0 +1,36 @@
+---
+layout: page
+title: "Image Processing"
+description: "Instructions how to setup image processing with Home Assistant."
+date: 2017-01-09 00:00
+sidebar: true
+comments: false
+sharing: true
+footer: true
+ha_release: 0.36
+---
+
+Image processing enables Home Assistant to process image from cameras.
+As source is only supported camera entities.
+
+For interval controll, use `scan_interval` in platform.
+
+## {% linkable_title Alpr %}
+
+Alpr entities attribute have a vehicle counter `vehicles` and all found plates as `plates`.
+
+This event is trigger after openalpr found a new licence plate.
+```yaml
+# Example configuration.yaml automation entry
+automation:
+- alias: Open garage door
+  trigger:
+    platform: event
+    event_type: openalpr.found
+    event_data:
+      entity_id: openalpr.camera_garage_1
+      plate: BE2183423
+...
+```
+
+follow event data while be present: `entity_id`, `plate`, `confidence`