/darknet_ros/found_object uses custom msg with Header for improving synchronization

[martinspedro]

YOLOObjectDetector publishes a custom message named ObjectCount, instead of std_msgs::Int8 under the darknet_ros/found_object topic. The former allows for the synchronization with darknet_ros/bounding_boxes on a single callback function using ROS message filters.

ObjectCount message prototype:
Header header
int8 count

[martinspedro]

Hi @Shame-fight ,

darknet_ros/found_object topic initially published a boolean variable: 1 if any object was found and 0 if no object was found.
Pull Request (PR) #35 changed the boolean variable to be an integer, returning the number of objects founded. This number counts all objects, independently of their class.

This PR creates wraps the std_msgs::Int8 with a Header on a custom ROS msg, allowing an easier synchronization between the darknet_ros/found_object topic with the darknet_ros/bounding_boxes, which contain the class information of the detected objects.

Individual count of objects per class is not implemented on darknet_ros and not sure if it is on the roadmap, but @mbjelonic will answer that way better than me.

I believe you have two options:

• Fork this repo and make the changes you are proposing;
• Implement the count per class on your listener node.