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Introduction, usage

With opencv_apps, you can run a lot of functionalities OpenCV provides in the simplest manner in ROS, i.e., running a launch file that corresponds to the functionality.

• You can have a look at all launch files provided here (be sure to choose the correct branch. As of Sept. 2016 indigo branch is used for ROS Indigo, Jade, and Kinetic distros).

• Some of the features covered by opencv_apps are explained in this wiki.

Edge Detection Nodes

edge_detection

Apply edge detecion algorithm to input and output ROS sensor_msgs/Image topics.

Subscribed Topics

image (sensor_msgs/Image)

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

Published Topics

image (sensor_msgs/Image)

• Ouptut edge image.

Parameters

~use_camera_info (bool, default: true)

• Indicates that the camera_info topic should be subscribed to to get the default input_frame_id. Otherwise the frame from the image message will be used.

~debug_view (bool, default: false)

• Specify whether the node displays a window to show edge image

~edge_type (int, default: 0)

• Specify edge dtection methods. 0: Sobel Derivatives, 1: Lapalace Operator, 2, Canny Edge Detector.

~canny_threshold1 (int, default: 100)

• Specify second canny threashold value.

~canny_threshold2 (int, default: 200)

• Specity first canny threashold value.

~apertureSize (int, default: 3)

• Aperture size for the Sobel() operator.

~apply_blur_pre (bool, default: True)

• Flag, applygin Blur() to input image

~postBlurSize (int, default: 13)

• Aperture size for the Blur() to input image()

~postBlurSigma (int, default: 3.2)

• Sigma for the GaussianBlur() to input image.

~apply_blur_post (bool, default: False)

• Flag, applying GaussinaBlur() to output(edge) image

~L2gradient (bool, default: False)

• Flag, L2Gradient

~queue_size (int, default: 3)

• Specigy queue_size of input image subscribers

hough_lines

Apply Hough Transform to the input ROS sensor_msgs/Image and outputs detected lines as ROS opencv_apps/LineArrayStamped messages. See HoughLines_Demo.cpp for more info.

Subscribed Topics

image (sensor_msgs/Image)

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

Published Topics

image (sensor_msgs/Image)

• A copy of input image which indicates detected lines

lines (opencv_apps/LineArrayStamped)

• Array of detected lines in image coordiinates.

Parameters

~use_camera_info (bool, default: true)

• Indicates that the camera_info topic should be subscribed to to get the default input_frame_id. Otherwise the frame from the image message will be used.

~debug_view (bool, default: false)

• Specify whether the node displays a window to show edge image

~hough_type (int, default: 0)

• Apecify Hough transform type, 0 for Standard Hough Detection and 1 for Probabilistic Hough Detection

~threshould (int, default: 150)

• Threshould value for hough line detection

~rho (double, default: 1.0)

• The resolution of the parameter r in pixels.

~theta (double, default: 1.0)

• The resolution of the parameter theta in radians.

~minLineLength (double, default: 30)

• The minimum number of points that can form a line.

~maxLineGrap (double, default: 10)

• The maximum gap between two points to be considered in the same line.

~queue_size (int, default: 3)

• Specigy queue_size of input image subscribers

hough_circles

Apply Hough Circle Transform to the input ROS sensor_msgs/Image and outputs detected lines as ROS opencv_apps/CircleArrayStamped messages. See HoughCircle_Demo.cpp for more info.

Subscribed Topics

image (sensor_msgs/Image)

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

Published Topics

image (sensor_msgs/Image)

• A copy of input image which indicates detected circles

circles (opencv_apps/CircleArrayStamped)

• Array of detected circles in image coordiinates.

Parameters

~use_camera_info (bool, default: true)

• Indicates that the camera_info topic should be subscribed to to get the default input_frame_id. Otherwise the frame from the image message will be used.

~debug_view (bool, default: false)

• Specify whether the node displays a window to show edge image

~canny_threshold (int, default: 200)

• Upper threshold for the internal Canny edge detector.

~accumulator_threshold (int, default: 50)

• Threshold for center detection.

~gaussian_blur_size (int, default: 9)

• The size of gaussian blur (should be odd number)

~gaussian_sigma_x (double, default: 2)

• sigma x of gaussian kernel

~gaussian_sigma_y (double, default: 2)

• sigma y of gaussian kernel

~dp (int, default: 2)

• The inverse ratio of resolution

~min_circle_radius (int, default: 0)

• the minimum size of the circle. If unknown, put zero as default.

~max_circle_radius (int, default: 0)

• the maximum size of the circle. If unknown, put zero as default.

~queue_size (int, default: 3)

• Specigy queue_size of input image subscribers

Structual Analysis Nodes

find_contours

Find Contours to the input ROS sensor_msgs/Image and to find contours and outpus as ROS opencv_apps/ContoursArrayStamped messages. See findContours_Demo.cpp for more info.

Subscribed Topics

image (sensor_msgs/Image)

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

Published Topics

image (sensor_msgs/Image)

• A copy of input image which indicates detected contours

contours (opencv_apps/ContourArrayStamped)

• Detected contours. Each contour is stored as a vector of point

Parameters

~use_camera_info (bool, default: true)

• Indicates that the camera_info topic should be subscribed to to get the default input_frame_id. Otherwise the frame from the image message will be used.

~debug_view (bool, default: false)

• Specify whether the node displays a window to show edge image

~canny_low_threshold (int, default: 10)

• Lower threshold for the internal Canny edge detector.

~queue_size (int, default: 3)

• Specigy queue_size of input image subscribers

convex_hull

Apply Convex Hull to the input ROS sensor_msgs/Image and to find contours and outpus as ROS opencv_apps/ContoursArrayStamped messages. See hull_demo.cpp for more info

Subscribed Topics

image (sensor_msgs/Image)

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

Published Topics

image (sensor_msgs/Image)

• A copy of input image which indicates detected convex hulls

hulls (opencv_apps/ContourArrayStamped)

• Detected convex hulls of contours. Each contour is stored as a vector of point

Parameters

~use_camera_info (bool, default: true)

• Indicates that the camera_info topic should be subscribed to to get the default input_frame_id. Otherwise the frame from the image message will be used.

~debug_view (bool, default: false)

• Specify whether the node displays a window to show edge image

~threshold (int, default: 100)

• Treshold for the detecting edges.

~queue_size (int, default: 3)

• Specigy queue_size of input image subscribers

general_contours

Creating Bounding rotated boxes and ellipses for contours to the input ROS sensor_msgs/Image and outpus as ROS opencv_apps/RotatedRectArrayStamped messages. See generalContours_demo2.cpp for more info.

Subscribed Topics

image (sensor_msgs/Image)

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

Published Topics

image (sensor_msgs/Image)

• A copy of input image which indicates detected contours as bobxes or ellipses

rectangles (opencv_apps/RotatedRectArrayStamped)

• Bounding rotated boxes of contours.

ellipses (opencv_apps/RotatedRectArrayStamped)

• Bounding rotated ellipses of contours.

Parameters

~use_camera_info (bool, default: true)

• Indicates that the camera_info topic should be subscribed to to get the default input_frame_id. Otherwise the frame from the image message will be used.

~debug_view (bool, default: false)

• Specify whether the node displays a window to show edge image

~threshold (int, default: 100)

• Treshold for the detecting edges.

~queue_size (int, default: 3)

• Specigy queue_size of input image subscribers

contour_moments

Calculating Image Moment of the input ROS sensor_msgs/Image and outpus as ROS opencv_apps/MomentArrayStamped messages. See moments_demo.cpp for more info.

Subscribed Topics

image (sensor_msgs/Image)

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

Published Topics

image (sensor_msgs/Image)

• A copy of input image which indicates detected contours

moment (opencv_apps/MomentArrayStamped)

• Image moments of contours.

Parameters

~use_camera_info (bool, default: true)

• Indicates that the camera_info topic should be subscribed to to get the default input_frame_id. Otherwise the frame from the image message will be used.

~debug_view (bool, default: false)

• Specify whether the node displays a window to show edge image

~canny_low_threshold (int, default: 100)

• Canny Edge low Threshold

~queue_size (int, default: 3)

• Specigy queue_size of input image subscribers

People/Face Detection Nodes

face_detection

Detect faces in ROS sensor_msgs/Image using Cascade Classifier and outputs detected faces as ROS opencv_apps/FaceArrayStamped message. See objectDetection.cpp for more info.

Subscribed Topics

image (sensor_msgs/Image)

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

Published Topics

image (sensor_msgs/Image)

• A copy of input image which indicates detected faces position as a circle

faces (opencv_apps/FaceArrayStamped)

• Array of detected face location in image coordiinates.

face_image (sensor_msgs/Image)

• A cropped image of detected faces

~queue_size (invalid message type for MsgLink(msg/type))

• Specigy queue_size of input image subscribers

Parameters

~use_camera_info (bool, default: true)

• Indicates that the camera_info topic should be subscribed to to get the default input_frame_id. Otherwise the frame from the image message will be used.

~debug_view (bool, default: true)

• Specify whether the node displays a window to show edge image

~face_cascade_name (string, default: "/usr/share/opencv/haarcascades/haarcascade_frontalface_alt.xml")

• Face dtection cascade Filename

~eyes_cascade_name (string, default: "/usr/share/opencv/haarcascades/haarcascade_eye_tree_eyeglasses.xml")

• Eye dtection cascade Filename

~queue_size (int, default: 3)

• Specigy queue_size of input image subscribers

face_recognition

Recognize faces in ROS sensor_msgs/Image using Face Recognition and outputs detected faces with labels as ROS opencv_apps/FaceArrayStamped message. See Tutorials for more info.

Subscribed Topics

image (sensor_msgs/Image)

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

faces (opencv_apps/FaceArrayStamped)

• Array of detected face location in image coordiinates.

Published Topics

~output (opencv_apps/FaceArrayStamped)

• A copy of input image which indicates detected faces position as a circle

~debug_image (sensor_msgs/Image)

• A copy of input image which indicates detected faces' positions, labels and confidences

Parameters

~approximate_sync (bool, default: false)

• Approximately synchronize messages of input image and face array

~queue_size (int, default: 100)

• Size of queue for subscribing topics

~model_method (string, default: "eigen")

• Method for face recognition (Either "eigen", "fisher" or "LBPH")

~use_saved_data (bool, default: true)

• Load and train data from path specified by ~data_dir

~save_train_data (bool, default: true)

• Save train data to path specified by ~data_dir for retraining

~data_dir (string, default: "~/.ros/opencv_apps/face_data")

• Path to directory for saving train data

~face_model_width (int, default: 190)

• Width of training face image

~face_model_height (int, default: 90)

• Height of training face image

~face_padding (double, default: 0.1)

• Padding ratio for each face

~model_num_components (int, default: 0)

• Number of components for face recognizer model (0 is treated as unlimited)

~model_threshold (double, default: 8000.0)

• Threshold for face recognizer model

~lbph_radius (int, default: 1)

• Radius parameter (available only for LBPH model)

~lbph_neighbors (int, default: 8)

• Neighbors parameter (available only for LBPH model)

~lbph_grid_x (int, default: 8)

• grid_x parameter (available only for LBPH model)

~lbph_grid_y (int, default: 8)

• grid_y parameter (available only for LBPH model)

~queue_size (int, default: 100)

• Specigy queue_size of input image subscribers

people_detect

Detecting people using Histogram of Oriented Gradients(HOG)]. This node outputs <<MsgLink(opencv_apps::RectArrayStamped)>> message. See [[https://github.com/Itseez/opencv/blob/2.4/samples/cpp/peopledetect.cpp for more info

Subscribed Topics

image (sensor_msgs/Image)

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

Published Topics

image (sensor_msgs/Image)

• A copy of input image which indicates detected people position as a box

found (opencv_apps/RectArrayStamped)

• Array of detected people location in image coordiinates.

Parameters

~use_camera_info (bool, default: true)

• Indicates that the camera_info topic should be subscribed to to get the default input_frame_id. Otherwise the frame from the image message will be used.

~debug_view (bool, default: false)

• Specify whether the node displays a window to show edge image

~hit_threshold (double, default: 0)

• Threshold for the distance between features and SVM classifying plane

~win_stride (int, default: 8)

• Window stride. It must be a multiple of block stride.

~padding (int, default: 32)

• Mock parameter to keep the CPU interface compatibility. It must be (0,0).

~scale0 (double, default: 1.05)

• Coefficient of the detection window increase.

~group_threshold (int, default: 2)

• Coefficient to regulate the similarity threshold. When detected, some objects can be covered by many rectangles. 0 means not to perform grouping.

~queue_size (int, default: 3)

• Specigy queue_size of input image subscribers

Motion Analysis Nodes

goodfeature_track

Determines strong corners on input ROS sensor_msgs/Image using goodFeatureToTrack and outputs detected corners as ROS opencv_apps/Point2DArrayStamped message. See goodFeaturesToTrack_Demo.cpp for more info.

Subscribed Topics

image (sensor_msgs/Image)

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

Published Topics

image (sensor_msgs/Image)

• A copy of input image which indicates detected corners

corners (opencv_apps/Point2DArrayStamped)

• Array of detected corner location in image coordiinates.

Parameters

~use_camera_info (bool, default: true)

• Indicates that the camera_info topic should be subscribed to to get the default input_frame_id. Otherwise the frame from the image message will be used.

~debug_view (bool, default: false)

• Specify whether the node displays a window to show edge image

~max_corners (int, default: 23)

• Maximum number of corners to return. If there are more corners than are found, the strongest of them is returned.

~queue_size (int, default: 3)

• Specigy queue_size of input image subscribers

camshift

Find an object center, size and orientation of a input ROS sensor_msgs/Image using CamShift algorithm and outputs detected object as ROS invalid message type for MsgLink(msg/type) message. See camshiftdemo.cpp for more info.

Subscribed Topics

image (sensor_msgs/Image)

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

Published Topics

image (sensor_msgs/Image)

• A copy of input image which indicates detected object as a ellipse

back_project (sensor_msgs/Image)

• Back projection of the object histogram.

track_box (opencv_apps/RotatedRectStamped)

• Detected objects

Parameters

~use_camera_info (bool, default: true)

• Indicates that the camera_info topic should be subscribed to to get the default input_frame_id. Otherwise the frame from the image message will be used.

~debug_view (bool, default: false)

• Specify whether the node displays a window to show edge image

~histogram (array, default: [])

• Histogram of tracked color object

~vmin (int, default: 10)

• Min threshould of lightness.

~vmax (int, default: 256)

• Max threshould of lightness.

~smin (int, default: 30)

• Min value of saturation.

~queue_size (int, default: 3)

• Specigy queue_size of input image subscribers

fback_flow

Calculate dense opetical flow using Gunnar Farneback Algorithm. This node outputs invalid message type for MsgLink(msg/type) message. See fback.cpp for more info.

Subscribed Topics

image (sensor_msgs/Image)

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

Published Topics

image (sensor_msgs/Image)

• A copy of input image with computed optical flows.

flows (opencv_apps/FlowArrayStamped)

• Computed optical flows.

Parameters

~use_camera_info (bool, default: true)

• Indicates that the camera_info topic should be subscribed to to get the default input_frame_id. Otherwise the frame from the image message will be used.

~debug_view (bool, default: false)

• Specify whether the node displays a window to show edge image

~queue_size (int, default: 3)

• Specigy queue_size of input image subscribers

lk_flow

Calculates an optical flow for a sparse feature set using the iterative Lucas-Kanade method with pyramids and outputs invalid message type for MsgLink(msg/type) message. See lkdemo.cpp for more info

Subscribed Topics

image (sensor_msgs/Image)

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

Published Topics

image (sensor_msgs/Image)

• A copy of input image with computed optical flows.

flows (opencv_apps/FlowArrayStamped)

• Computed optical flows.

Services

initialize_points (invalid message type for SrvLink(srv/type))

• Auto-initialize tracking.

delete_points (invalid message type for SrvLink(srv/type))

• Delete all the points.

toggle_night_mode (invalid message type for SrvLink(srv/type))

• switch the night mode on/off.

Parameters

~use_camera_info (bool, default: true)

• Indicates that the camera_info topic should be subscribed to to get the default input_frame_id. Otherwise the frame from the image message will be used.

~debug_view (bool, default: false)

• Specify whether the node displays a window to show edge image

~quality_level (double, default: 0.01)

• Parameter characterizing the minimal acceptance quality of image corners.

~min_distance (int, default: 10)

• Minimum possible Euclidean distance between the returned corners.

~block_size (int, default: 3)

• Size of an average block for computing a derivative covariation matrix over each pixel neighborhood.

~harris_k (double, default: 0.04)

• Free parameter of the Harris detector

~queue_size (int, default: 3)

• Specigy queue_size of input image subscribers

phase_corr

The node detects the translational shift in the frequency domain based on the Fourier shift theorem. See phase_corr.cpp for more info.

Subscribed Topics

image (sensor_msgs/Image)

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

Published Topics

image (sensor_msgs/Image)

• A copy of input image with computed translational shift

shift (opencv_apps/Point2DStamped)

• Computed translational shift

Parameters

~use_camera_info (bool, default: true)

• Indicates that the camera_info topic should be subscribed to to get the default input_frame_id. Otherwise the frame from the image message will be used.

~debug_view (bool, default: false)

• Specify whether the node displays a window to show edge image

~queue_size (int, default: 3)

• Specigy queue_size of input image subscribers

simple_flow

Calculate dense opetical flow using Simple Flow algorithm. This node outputs invalid message type for MsgLink(msg/type) message. See simpleflow_demo.cpp for more info.

Subscribed Topics

image (sensor_msgs/Image)

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

flows (opencv_apps/FlowArrayStamped)

• Computed optical flows.

Published Topics

image (sensor_msgs/Image)

• A copy of input image with computed optical flows.

Parameters

~use_camera_info (bool, default: true)

• Indicates that the camera_info topic should be subscribed to to get the default input_frame_id. Otherwise the frame from the image message will be used.

~debug_view (bool, default: false)

• Specify whether the node displays a window to show edge image

~scale (int, default: 4)

• Specify the scale factor to calculate optical flow.

~queue_size (int, default: 3)

• Specigy queue_size of input image subscribers

Object Segmentaion Nodes

segment_objects

This node apply Gaussian Mixture-based Background/Foreground Segmentation algorithm to input ROS sensor_msgs/Image and outputs segemted region as opencv_apps/ContourArrayStamped and area as std_msgs/Float64.

Subscribed Topics

image (sensor_msgs/Image)

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

Published Topics

image (sensor_msgs/Image)

• A copy of input image which indicates segmented region

contours (opencv_apps/ContoruArrayStamped)

• Contours of segmented region.

area (std_msgs/Float64)

• Number of pixes in segmented area

Services

update_bg_model (invalid message type for SrvLink(srv/type))

• Update Background Mdoel

Parameters

~use_camera_info (bool, default: true)

• Indicates that the camera_info topic should be subscribed to to get the default input_frame_id. Otherwise the frame from the image message will be used.

~debug_view (bool, default: false)

• Specify whether the node displays a window to show edge image

~queue_size (int, default: 3)

• Specigy queue_size of input image subscribers

watershed_segmentation

This node apply the watershed segmentation algorithm to input ROS sensor_msgs/Image and outputs segemted region as opencv_apps/ContourArrayStamped

Subscribed Topics

image (sensor_msgs/Image)

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

contours (opencv_apps/ContourArrayStamped)

• segmented contours.

Published Topics

image (sensor_msgs/Image)

• A copy of input image which indicates segmented region.

Parameters

~use_camera_info (bool, default: true)

• Indicates that the camera_info topic should be subscribed to to get the default input_frame_id. Otherwise the frame from the image message will be used.

~debug_view (bool, default: false)

• Specify whether the node displays a window to show edge image

~queue_size (int, default: 3)

• Specigy queue_size of input image subscribers

Histgrams Mathcing

New features since version 2.0.3

equalize_histogram

This node apply https://docs.opencv.org/2.4/modules/imgproc/doc/histograms.html#equalizehist and https://docs.opencv.org/3.4.7/d6/db6/classcv_1_1CLAHE.html to input ROS sensor_msgs/Image and normalizes the brightness and increases the contrast of the image.

Subscribed Topics

image (sensor_msgs/Image)

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

contours (opencv_apps/ContourArrayStamped)

• segmented contours.

Published Topics

image (sensor_msgs/Image)

• A normalized grayscale image copy of the input image.

Parameters

~use_camera_info (bool, default: true)

• Indicates that the camera_info topic should be subscribed to to get the default input_frame_id. Otherwise the frame from the image message will be used.

~debug_view (bool, default: false)

• Specify whether the node displays a window to show edge image

~queue_size (bool, default: true)

• Set true to use (OpenCL)https://opencv.org/opencl/ support.

~histogram_equalization_type (int, default: 0)

• Specify histogram equalization algorithm (0: Uses equalizeHist() Method, 1: CLAHE (Contrast Limited Adaptive Histogram Equalization) Method.)

~clahe_clip_limit (float, default: 20)

• Clip Limit for CLAHE filter

~queue_size (float) (, default: 32)

• X Tile Size for CLAHE filter

~queue_size (float, default: 32)

• Y Tile Size for CLAHE filter

Image Filter Nodes

New feature as of version 1.11.15

rgb_color_filter

This node filters the image by RGB color and generates a mask image.

Subscribed Topics

image (sensor_msgs/Image)

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

Published Topics

image (sensor_msgs/Image)

• Mask image filterd by RGB color.

Parameters

~use_camera_info (bool, default: true)

• Indicates that the camera_info topic should be subscribed to to get the default input_frame_id. Otherwise the frame from the image message will be used.

~debug_view (bool, default: false)

• Specify whether the node displays a window to show mask image

~r_limit_max (int, default: 250)

• Maximum value of Red

~r_limit_min (int, default: 50)

• Minimum value of Red

~g_limit_max (int, default: 200)

• Maximum value of Green

~g_limit_min (int, default: 100)

• Minimum value of Green

~b_limit_max (int, default: 150)

• Maximum value of Blue

~b_limit_min (int, default: 20)

• Minimum value of Blue

~queue_size (int, default: 3)

• Specigy queue_size of input image subscribers

hls_color_filter

This node filters the image by HSL color and generates a mask image.

Subscribed Topics

image (sensor_msgs/Image)

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

Published Topics

image (sensor_msgs/Image)

• Mask image filterd by HSL color.

Parameters

~use_camera_info (bool, default: true)

• Indicates that the camera_info topic should be subscribed to to get the default input_frame_id. Otherwise the frame from the image message will be used.

~debug_view (bool, default: false)

• Specify whether the node displays a window to show mask image

~h_limit_max (int, default: 250)

• Maximum value of Hue

~h_limit_min (int, default: 0)

• Minimum value of Hue

~s_limit_max (int, default: 255)

• Maximum value of Saturation

~s_limit_min (int, default: 150)

• Minimum value of Saturation

~l_limit_max (int, default: 255)

• Maximum value of Luminance

~l_limit_min (int, default: 50)

• Minimum value of Luminance

~queue_size (int, default: 3)

• Specigy queue_size of input image subscribers

hsv_color_filter

This node filters the image by HSL color and generates a mask image.

Subscribed Topics

image (sensor_msgs/Image)

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

Published Topics

image (sensor_msgs/Image)

• Mask image filterd by HSV color.

Parameters

~use_camera_info (bool, default: true)

• Indicates that the camera_info topic should be subscribed to to get the default input_frame_id. Otherwise the frame from the image message will be used.

~debug_view (bool, default: false)

• Specify whether the node displays a window to show mask image

~h_limit_max (int, default: 250)

• Maximum value of Hue

~h_limit_min (int, default: 0)

• Minimum value of Hue

~s_limit_max (int, default: 255)

• Maximum value of Saturation

~s_limit_min (int, default: 150)

• Minimum value of Saturation

~v_limit_max (int, default: 255)

• Maximum value of Value

~v_limit_min (int, default: 50)

• Minimum value of Value

~queue_size (int, default: 3)

• Specigy queue_size of input image subscribers

lab_color_filter

This node filters the image by Lab color and generates a mask image. Note that L, a, and b have been converted so that their value ranges are in the range 0~255. (New feature since version 2.0.3)

Subscribed Topics

image (sensor_msgs/Image)

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

Published Topics

image (sensor_msgs/Image)

• Mask image filterd by Lab color space.

Parameters

~use_camera_info (bool, default: true)

• Indicates that the camera_info topic should be subscribed to to get the default input_frame_id. Otherwise the frame from the image message will be used.

~debug_view (bool, default: false)

• Specify whether the node displays a window to show mask image

~l_limit_max (int, default: 255)

• Maximum value of L.

~l_limit_min (int, default: 0)

• Minimum value of L.

~a_limit_max (int, default: 255)

• Maximum value of a.

~a_limit_min (int, default: 0)

• Minimum value of a.

~b_limit_max (int, default: 255)

• Maximum value of b.

~b_limit_min (int, default: 0)

• Minimum value of b.

~queue_size (int, default: 3)

• Specigy queue_size of input image subscribers

morphology

This node apply morphology transformation (New feature since version 2.0.3). Please also check test/test-blob-extraction.test example, which apply erode->dilite->contour extraction to get blob of black-white images.

Subscribed Topics

image (sensor_msgs/Image)

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

Published Topics

image (sensor_msgs/Image)

• Mask image filterd by HSV color.

Parameters

~use_camera_info (bool, default: true)

• Indicates that the camera_info topic should be subscribed to to get the default input_frame_id. Otherwise the frame from the image message will be used.

~debug_view (bool, default: false)

• Specify whether the node displays a window to show mask image

~morph_operator (int, default: 0)

• "Morphology Operation Methods 0: Opening, 1: Closing, 2: Gradient, 3: Top Hat, 4: Black Hat

~morph_element (int, default: 0)

• Type of the kernel 0: Rect, 1: Cross, 2: Ellipse

~s_limit_max (int, default: 21)

• Size of kernel(min:0, max 21)

~queue_size (int, default: 3)

• Specigy queue_size of input image subscribers

smoothing

This node apply smoothing filter (New feature since version 2.0.3). Please also check test/test-smoothing.test example, which applies homogeneous blur, gaussian blur, median blur, and bilateral blur to get blur images.

Subscribed Topics

image (sensor_msgs/Image)

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

Published Topics

image (sensor_msgs/Image)

• Blurred image.

Parameters

~use_camera_info (bool, default: true)

• Indicates that the camera_info topic should be subscribed to to get the default input_frame_id. Otherwise the frame from the image message will be used.

~debug_view (bool, default: false)

• Specify whether the node displays a window to show mask image

~filter_type (int, default: 1)

• "Smoothing Methods 0: Homogeneous blur, 1: Gaussian blur, 2: Median blur, 3: Bilateral Filter

~kernel_size (int, default: 7)

• Size of the kernel (only one because we use a square window). Must be odd.

~queue_size (int, default: 3)

• Specigy queue_size of input image subscribers

Simple Image Processing Nodes

adding_images

This node merges two images into one.

Subscribed Topics

image1 (sensor_msgs/Image)

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

image2 (sensor_msgs/Image)

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

Published Topics

image (sensor_msgs/Image)

• Merged image.

Parameters

~use_camera_info (bool, default: false)

• Indicates that the camera_info topic should be subscribed to to get the default input_frame_id. Otherwise the frame from the image message will be used.

~alpha (float, default: 0.5)

• Specify the blending weight of the image1.

~beta (float, default: 0.5)

• Specify the blending weight of the image2 (When auto_beta is true, this value is automatically set as (1 - alpha)).

~auto_beta (bool, default: true)

• Automatically adjust beta value to keep (alpha + beta = 1).

~gamma (float, default: 0)

• Add extra brightness to the result (0~255).