camshift

Tracks a colored object with the CamShift algorithm (cv::CamShift()), by the back projection of the hue histogram of the region given by the mouse or the x, y, width and height parameters.

opencv_apps	1.11 and later (ROS 1), 3.0.0 and later (ROS 2)
ROS	noetic, ROS One, jazzy, kilted, lyrical and later
OpenCV	any version of the distributions
Group	Tracking, the nodes of which publish `~/output` (RectArrayStamped), `~/track_box` (RotatedRectStamped) of camshift

Usage

# ROS 2
ros2 launch opencv_apps camshift.launch.xml image:=/camera/image_raw debug_view:=false
# ROS 1
roslaunch opencv_apps camshift.launch image:=/camera/image_raw debug_view:=false

Try it with the demo video

Download the input video of the demo above, publish it as image with image_publisher, and run the node on it, in the terminals:

wget https://ros-perception.github.io/opencv_apps/media/clips/tos_canal.mp4
# terminal 1: publish the video as image in a loop
ros2 run image_publisher image_publisher_node tos_canal.mp4 --ros-args -p publish_rate:=10.0 -r image_raw:=image
# terminal 2: run the node with the parameters of the demo
ros2 launch opencv_apps camshift.launch.xml image:=image height:=220 node_name:=camshift_roi width:=160 x:=300 y:=160
# terminal 3: view the result
ros2 run rqt_image_view rqt_image_view /camshift_roi/image

The ROI is the man, as the other tracking nodes; camshift tracks the hue histogram of the ROI, and the ellipse also takes the areas of the same hue; back_project and image are shown.

In ROS 1:

# terminal 1
rosrun image_publisher image_publisher tos_canal.mp4 _publish_rate:=10 __name:=camera
# terminal 2
roslaunch opencv_apps camshift.launch image:=camera/image_raw height:=220 node_name:=camshift_roi width:=160 x:=300 y:=160

See Credits of the demo videos for the license of the video.

Subscribed topics

Topic	Type
`image`	`sensor_msgs/msg/Image`

Published topics

Topic	Type
`~/back_project`	`sensor_msgs/msg/Image`
`~/confidence`	`std_msgs/msg/Float64`
`~/image`	`sensor_msgs/msg/Image`
`~/track_box`	opencv_apps/msg/RotatedRectStamped

Parameters

See also the common parameters.

Name	Type	Default (range)	Changed at run time	Description
`height`	int	0 (0 - 4096)	yes	Height of the rectangle to track, 0 for none (setting it to 0 stops tracking)
`histogram`	double[]	[]	no, restart the node	Histogram of tracked color object
`queue_size`	int	3	no, restart the node	Specigy queue_size of input image subscribers
`smin`	int	30 (1 - 256)	yes	Smin
`vmax`	int	256 (1 - 256)	yes	Vmax
`vmin`	int	10 (1 - 256)	yes	Vmin
`width`	int	0 (0 - 4096)	yes	Width of the rectangle to track, 0 for none (setting it to 0 stops tracking)
`x`	int	0 (0 - 4096)	yes	Center x of the rectangle to track
`y`	int	0 (0 - 4096)	yes	Center y of the rectangle to track

Source

src/nodelet/camshift_nodelet.cpp, launch/camshift.launch.xml