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Usage

Selecting Blob Colors

rosrun cmvision colorgui image:=<image topic>

The above command will bring up an interface that provides a means for graphically selecting desired colors for blobs. colorgui displays values for RGB and YUV which can be used in a colors file.

Colors File Format

Blob parameters are specified to cmvision using two components:

• Blob colors in RGB color space, specified as follows:

(r, g, b) merge expected_num name

• Blob threshold parameters in YUV color space, specified as follows:

(min_y:max_y, min_u:max_u, min_v:max_v)

Example colors.txt for detecting a Research Robot Red RWI B21r

[colors]
(159,  62, 71) 0.000000 7 ResearchRobotRed

[thresholds]
(56:99, 108:117, 173:193)

Multiple blob colors can be specified in the same file by adding lines under colors and thresholds.

Detecting Blobs

rosparam set /cmvision/color_file /path/to/colors.txt
rosrun cmvision cmvision image:=<image topic>

Nodes

colorgui

Simple node for selecting blob colors.

Subscribed Topics

image (sensor_msgs/Image)

• The image topic. Should be remapped to the name of the real image topic.

cmvision

Node for detecting blobs.

Subscribed Topics

image (sensor_msgs/Image)

• The image topic. Should be remapped to the name of the real image appropriately.

Published Topics

blobs (cmvision/Blobs)

• A list of detected blobs.

Parameters

/cmvision/color_file (string, default: "")

• Specifies a path to the colors file.

/cmvision/mean_shift_on (bool, default: false)

• If true, smooth the image using the mean shift algorithm before doing blob detection.

/cmvision/debug_on (bool, default: false)

• Enables or disables debug output.

/cmvision/spatial_radius_pix (int, default: 0)

• If using mean shift, sets mean shift's spacial radius parameter.

/cmvision/color_radius_pix (int)

• If using mean shift, sets mean shift's color radius parameter.

(, default: 0)