Merge pull request #416 from kylejohnson/master

Added an FAQ for AlarmCheckMethod

docs/faq.rst

@@ -32,3 +32,29 @@ Snapshots and Zones images are stored in the `images` directory in your webroot.
 Ensure that the `images` directory is writable by the user which ZoneMinder is
 running as.  If the `images` directory is a symlink, ensure that your web server
 has access to that directory as well.
+
+How do the 3 AlarmCheckMethods interact?
+----------------------------------------
+
+In example, if I set the alarm % to 5-10% and the filtered and blob to 1-100%, what happens?
+
+1. If any of the min/max values is 0, the check that the value is applied to is skipped.
+2. If you have a min-alarmed area and you're below that, then it quits.
+3. If you have a max-alarmed area and you're above that, then it quits.
+4. If you're on filtered or blobs
+
+  1. and have a min filtered area that you're below then it quits
+  2. and have a max filtered area that you're above then it quits
+
+5. If you're on blobs
+
+  1. any blob smaller than the min blob area (if set) is discarded
+  2. any blob larger than the max blob area (if set) is discarded
+  3. If there are less remaining blobs than the minimum-blobs, then it quits.
+  4. If there are more remaining blobs than the maximum-blobs, then it quits.
+
+If AlarmedPixels is selected, you can only enter min/max pixel threshold and
+min/max alarmed area.  If FilteredPixels is selected, the Blob options are
+disabled.  The Blob check method allows you to specify all options.  Filtered
+adds more checks than alarmed, and blobs adds more checks than filtered.  The
+final 'score' is calculated using final check method.