diff --git a/README.md b/README.md
index a3119af..f98faf0 100644
--- a/README.md
+++ b/README.md
@@ -17,5 +17,5 @@ Parameters
 * `scan_time` (float) - The time in seconds between scans to report to the consumer of the LaserScan message.  This is set directly in the published message.  Defaults to 0.033 seconds.
 * `range_min` (float) - The minimum distance in meters a projected point should be.  Points closer than this are discarded.  Defaults to 0.45 meters.
 * `range_max` (float) - The maximum distance in meters a projected point should be.  Points further than this are discarded.  Defaults to 10.0 meters.
-* `scan_height` (int) - The row from the depth image to use for the laser projection.  Defaults to 1.
+* `scan_height` (int) - The number of rows from the depth image to use for the laser projection. Center of the projections is the vertical center of the image.  Defaults to 1.
 * `output_frame` (string) - The frame id to publish in the LaserScan message.  Defaults to "camera_depth_frame".