Added the description of the two services to set and get the filter parameters.

Added the instructions to build the node.
Added a link to the iri_color_calibration tool.

README.md

@@ -39,6 +39,15 @@ parameters. The information provided for each blob is:
     
     **size** (float): Size of the blob in pixels.
 
+## services
+
+This node provides the following service clients:
+
+ * ** ~/set_filter (iri_blob_detector/set_hsv_filter.srv): A service to change on-line the color parameters used by the node to filter the input images. 
+All parameters are updated when this service is called. 
+
+ * ** ~/get_filter (iri_blob_detector/get_hsv_filter.srv): A service to get the current color parameters used by the node to filter the input images.
+
 ## parameters
 
 This node has the following parameters. These parameters can be modified with the dynamic reconfigure tool.
@@ -69,18 +78,32 @@ This node has the following dependencies:
 
  * boost
 
+All these dependencies should be already available with a standard ROS installation.
+
 # How to use it
 
+Download the node inside a catkin workspace:
+
+ git clone https://gitlab.iri.upc.edu/seat_adc/iri_blob_detector.git
+
+Build the node:
+
+ roscd
+
+ cd ..
+
+ catkin_make --only-pkg-with-deps iri_blob_detector
+
 This node provides two launch files:
 
- * **blob_detector.launch**: this file load the default parameters from ./config/default_params.yaml and launches the blob detector 
+ * **blob_detector.launch**: this file loads the default parameters from ./config/default_params.yaml and launches the blob detector 
 node together with the usb_cam ROS node. This launch file will use the first USB camera compatible found in the system. If a 
 specific camera is desired, fill in the vendor, product and serial parameters for the desired camera.
 
- * **blob_detector_sim.launch**: this file load the default parameters from ./config/default_params.yaml and launches the blob detector
+ * **blob_detector_sim.launch**: this file loads the default parameters from ./config/default_params.yaml and launches the blob detector
 node, but expects the model car simulator to be already running.
 
-You can use the iri_color_calibration ROS node to easily generate new yaml configuration files for this node.
+You can use the [iri_color_calibration](https://gitlab.iri.upc.edu/seat_adc/iri_color_calibration "IRI color calibration tool") ROS node to easily generate new yaml configuration files for this node.
 
 Once the node is running, use the dynamic reconfigure ROS tool to change online the blob detector parameters: