This modules isolates pixels within a given HSV range (hue, saturation, and value of color pixels), does some cleanups, and extracts object contrours. It sends information about object centers over serial. This module usually works best with the camera sensor set to manual exposure, gain, color balance, etc so that HSV color values are reliable. See the cript.cfg file in this module's directory for an example of how to set the camera settigs each time this module is loaded.
This code was loosely inspired by: https://raw.githubusercontent.com/kylehounslow/opencv-tuts/master/object-tracking-tut/objectTrackingTut.cpp written by Kyle Hounslow, 2013.
This module sends serial messages of the form
T2D x y
where x and y are the standardized coordinates of the center of each detected and good object (good objects have a pixel area within the range specified by
Trying it out
The default parameter settings (which are set in script.cfg explained below) attempt to detect light blue objects. Present a light blue object to the JeVois camera and see whether it is detected. When detected and good enough according to
You should adjust parameters hrange, srange, and vrange to isolate the range of Hue, Saturation, and Value (respectively) that correspond to the objects you want to detect. Note that there is a params.cfg file in this module's directory that provides a range tuned to a lighgt blue object, as shown in the demo screenshot.
Tuning the parameters is best done interactively by connecting to your JeVois camera while it is looking at some object of the desired color. Once you have achieved a tuning, you may want to set the hrange, srange, and vrange parameters in your script.cfg file for this module on the microSD card (see below).
Typically, you would start by narrowing down on the hue, then the value, and finally the saturation. Make sure you also move your camera around and show it typical background clutter so check for false positives (detections of things which you are not interested, which can happen if your ranges are too wide).
JeVois allows you to store parameter settings and commands in a file named script.cfg stored in the directory of a module. The file script.cfg may contain any sequence of commands as you would type them interactively in the JeVois command-line interface. For the ObjectTracker module, a default script is provided that sets the camera to manual color, gain, and exposure mode (for more reliable color values), and to setup communication with a pan/tilt head as described in Tutorial on how to write Arduino code that interacts with JeVois.
The script.cfg file for ObjectTracker is stored on your microSD at JEVOIS:/modules/JeVois/ObjectTracker/script.cfg and is shown in Tutorial on how to write Arduino code that interacts with JeVois as an example.