CADMatch

Introduction

The CADMatch module is an optional module of the rc_cube and requires a separate CADMatch license to be purchased.

This module provides an out-of-the-box perception solution for 3D object detection and grasping. CADMatch targets the detection of 3D objects based on a CAD template for picking with a general gripper. The objects can be located in a bin or placed arbitrarily in the field of view of the camera.

For the CADMatch module to work, special object templates are required for each type of object to be detected. Please get in touch with the Roboception support (Contact) to order a template for your CAD file.

The CADMatch module offers:

• A dedicated page on the rc_cube Web GUI for easy setup, configuration, testing, and application tuning.
• A REST-API interface and a KUKA Ethernet KRL Interface.
• The definition of regions of interest to select relevant volumes in the scene (see Region of interest).
• A load carrier detection functionality for bin-picking applications (see LoadCarrier), to provide grasps for objects inside a bin only.
• The definition of compartments inside a load carrier to provide grasps for specific volumes of the bin only.
• The definition of grasp points for each template via an interactive visualization in the Web GUI
• Support for static and robot-mounted cameras and. optional integration with the Hand-eye calibration module, to provide grasps in the user-configured external reference frame.
• Sorting of grasps according to reachability so that the best ones are returned first.

Setting of grasp points

The CADMatch module detects 3D objects in a scene based on a CAD template and returns the poses of the object origins. To use CADMatch directly in a robot application, grasp points can be defined for each template. A grasp point represents the desired position and orientation of the robot’s TCP (Tool Center Point) to grasp an object as shown in Fig. 22

Fig. 22 Definition of grasp points with respect to the robot’s TCP

Each grasp consists of an id which must be unique within all grasps for an object template, the template_id representing the template the grasp should be attached to, and the pose in the coordinate frame of the object template. Grasp points can be set via the REST-API interface, or by using the interactive visualization in the Web GUI. The rc_cube can store up to 50 grasp points per template.

Setting grasp points in the Web GUI

The rc_cube Web GUI provides an intuitive and interactive way of defining grasp points for object templates. In a first step, the object template has to be uploaded to the rc_cube. This can be done on the CADMatch page in the Modules tab of the Web GUI by clicking on add new Template in the Templates and Grasps section of the CADMatch page. Once the template upload is complete, a dialog with a 3D visualization of the object for adding or editing grasp points is shown. The same dialog appears when editing an existing template.

This dialog provides two ways for setting grasp points:

1. Adding grasps manually: By clicking on the + symbol, a new grasp is placed in the object origin. The grasp can be given a unique name which corresponds to its ID. The desired pose of the grasp can be entered in the fields for Position and Roll/Pitch/Yaw which are given in the coordinate frame of the object template represented by the long x, y and z axes in the visualization. The grasp point can be placed freely with respect to the object template - inside, outside or on the surface. The grasp point and its orientation are visualized in 3D for verification.
2. Adding grasps interactively: Grasp points can be added interactively by first clicking on the Add Grasp button in the upper left corner of the visualization and then clicking on the desired point on the object template visualization. The grasp is attached to the object surface. The grasp orientation is a right-handed coordinate system and is chosen such that its z axis is normal to the surface pointing inside the object at the grasp position. The position and orientation in the object coordinate frame is displayed on the right. The position and orientation of the grasp can also be changed interactively. In case Snap to surface is enabled in the visualization (default), the grasp can be moved along the object surface by clicking on the Translate button in the visualization and then clicking on the grasp point and dragging it to the desired position. The orientation of the grasp around the surface normal can also be changed by choosing Rotate and then rotating the grasp with the cursor. In case Snap to surface is disabled, the grasp can be translated and rotated freely in all three dimensions.

If the object template has symmetries, the grasps which are symmetric to the defined grasps can be displayed by clicking on Show symmetric grasps.

Setting grasp points via the REST-API

Grasp points can be set via the REST-API interface using the set_grasp or set_all_grasps service calls (see Services). In the CADMatch module a grasp consists of the template_id of the template the grasp should be attached to, an id uniquely identifying the grasp point and the pose with position in meters and orientation as quaternion in the coordinate frame of the object template.

Setting the preferred orientation of the TCP

The CADMatch module determines the reachability of grasp points based on the preferred orientation of the gripper or TCP. The preferred orientation can be set via the set_preferred_orientation service call or on the CADMatch page in the Web GUI. The resulting direction of the TCP’s z axis is used to reject grasps which cannot be reached by the gripper.

Furthermore, the preferred orientation is used to sort the reachable grasps. Grasps sorting is performed based on a combination of

• the matching score of the object the grasp is located on, and
• the distance from the camera along the z axis of the preferred orientation of the TCP.

The preferred orientation can be set in the camera coordinate frame or in the external coordinate frame, in case a hand-eye calibration is available. If the preferred orientation is specified in the external coordinate frame and the sensor is robot mounted, the current robot pose has to be given to each object detection call, so that the preferred orientation can be used for filtering and sorting the grasps on the detected objects. If no preferred orientation is set, the orientation of the left camera is used as the preferred orientation of the TCP.

Detection of objects

The CADMatch module requires an object template for object detection. This template contains information about the 3D shape of the object and prominent edges that can be visible in the camera images.

The object detection is a two-stage process consisting of a prior estimation step and a pose refinement step. First, a pose prior is computed based on the appearance of the object in the camera images. Second, the pose is refined by using the 3D point cloud and edges in the camera image. For this to work, the objects to detect must be visible in both left and right camera images.

For triggering the object detection, in general, the following information must be provided to the CADMatch module:

• The template ID of the object to be detected in the scene.
• The coordinate frame in which the poses of the detected objects and the grasp points shall be returned (ref. Hand-eye calibration).

Optionally, further information can be given to the CADMatch module:

• The ID of the load carrier which contains the items to be detected.
• A compartment inside the load carrier where to detect objects (see Load carrier compartments).
• The ID of the 3D region of interest where to search for the load carriers if a load carrier is set. Otherwise, the ID of the 3D region of interest where to search for the objects.
• The current robot pose in case the camera is mounted on the robot and the chosen coordinate frame for the poses is external, or the preferred orientation is given in the external frame, or the chosen region of interest is defined in the external frame.
• Collision detection information: The ID of the gripper to enable collision checking and optionally a pre-grasp offset to define a pre-grasp position. Details on collision checking are given below in CollisionCheck.

On the Web GUI the detection can be tested in the Try Out section of the CADMatch module’s page.

The detected objects are returned in a list of matches. Each detected object includes a uuid (Universally Unique Identifier) and the timestamp of the oldest image that was used to detect it. The pose of a detected object corresponds to the pose of the origin of the object template used for detection. Furthermore, the matching score is given to indicate the quality of the detection.

If the chosen template also has grasp points attached (see Setting of grasp points), a list of grasps for all objects sorted by their reachability (see Setting the preferred orientation of the TCP) is returned in addition to the list of detected objects. The grasp poses are given in the desired coordinate frame. There are references between the detected objects and the grasps via their uuids.

Note

The first detection call with a new object template takes longer than the following detection calls, because the object template has to be loaded into the CADMatch module first.

Interaction with other modules

Internally, the CADMatch module depends on, and interacts with other on-board modules as listed below.

Note

All changes and configuration updates to these modules will affect the performance of the CADMatch modules.

Stereo camera and Stereo matching

The CADMatch module makes internally use of the following data:

• Rectified images from the Stereo camera module (rc_stereocamera);
• Disparity, error, and confidence images from the Stereo matching module (rc_stereomatching).

The quality parameter of the stereo matching module must be set to Medium or higher (see Parameters). We recommend Full or High quality for using CADMatch.

All processed images are guaranteed to be captured after the module trigger time.

Estimation of gravity vector

For each load carrier detection or object detection inside a load carrier, the module estimates the gravity vector by subscribing to the rc_visard’s IMU data stream.

Note

The gravity vector is estimated from linear acceleration readings from the on-board IMU. For this reason, the CADMatch module requires the rc_visard to remain still while the gravity vector is being estimated.

IO and Projector Control

In case the rc_cube is used in conjunction with an external random dot projector and the IO and Projector Control module (rc_iocontrol), it is recommended to connect the projector to GPIO Out 1 and set the stereo-camera module’s acquisition mode to SingleFrameOut1 (see Stereo matching parameters), so that on each image acquisition trigger an image with and without projector pattern is acquired.

Alternatively, the output mode for the GPIO output in use should be set to ExposureAlternateActive (see Description of run-time parameters).

In either case, the Auto Exposure Mode exp_auto_mode should be set to AdaptiveOut1 to optimize the exposure of both images (see Stereo camera parameters).

Hand-eye calibration

In case the camera has been calibrated to a robot, the CADMatch module can automatically provide poses in the robot coordinate frame. For the CADMatch node’s Services, the frame of the output poses can be controlled with the pose_frame argument.

Two different pose_frame values can be chosen:

1. Camera frame (camera). All poses provided by the modules are in the camera frame, and no prior knowledge about the pose of the camera in the environment is required. This means that the configured regions of interest and load carriers move with the camera. It is the user’s responsibility to update the configured poses if the camera frame moves (e.g. with a robot-mounted camera).
2. External frame (external). All poses provided by the modules are in the external frame, configured by the user during the hand-eye calibration process. The module relies on the on-board Hand-eye calibration module to retrieve the sensor mounting (static or robot mounted) and the hand-eye transformation. If the mounting is static, no further information is needed. If the sensor is robot-mounted, the robot_pose is required to transform poses to and from the external frame.

Note

If no hand-eye calibration is available, all pose_frame values should be set to camera.

All pose_frame values that are not camera or external are rejected.

CollisionCheck

Collision checking can be easily enabled for grasp computation of the CADMatch module by passing a collision_detection argument to the detect_object service call. It contains the ID of the used gripper and optionally a pre-grasp offset. The gripper has to be defined in the CollisionCheck module (see Setting a gripper) and details about collision checking are given in Collision checking within other modules. If the selected CADMatch template contains a collision geometry and the run-time parameter check_collisions_with_matches is true, also collisions between the gripper and all other detected objects (not limited to max_matches) will be checked. The object on which the grasp point to be checked is located, is excluded from the collision check.

If collision checking is enabled, only grasps which are collision free will be returned. However, the result image on top of the CADMatch tab of the Web GUI also shows colliding grasp points in red. The objects which are considered in the collision check are also visualized with their edges in red.

The CollisionCheck module’s run-time parameters affect the collision detection as described in CollisionCheck Parameters.

Parameters

The CADMatch module is called rc_cadmatch in the REST-API and is represented by the CADMatch page in the Modules tab of the Web GUI. The user can explore and configure the rc_cadmatch module’s run-time parameters, e.g. for development and testing, using the Web GUI or the REST-API interface.

Parameter overview

This module offers the following run-time parameters:

Table 25 The rc_cadmatch module’s run-time parameters

Name	Type	Min	Max	Default	Description
check_collisions_with_matches	bool	false	true	true	Whether to check for collisions between gripper and detected matches
edge_max_distance	float64	0.5	5.0	2.0	Maximum allowed distance in pixels between the template edges and the detected edges in the image
edge_sensitivity	float64	0.0	1.0	0.5	Sensitivity of the edge detector
grasp_filter_-orientation_threshold	float64	0.0	180.0	45.0	Maximum allowed orientation change between grasp and preferred orientation in degrees
load_carrier_crop_distance	float64	0.0	0.05	0.005	Safety margin in meters by which the load carrier inner dimensions are reduced to define the region of interest for detection
load_carrier_model_tolerance	float64	0.003	0.025	0.008	Indicates how much the estimated load carrier dimensions are allowed to differ from the load carrier model dimensions in meters
max_matches	int32	1	20	10	Maximum number of matches
min_score	float64	0.05	1.0	0.3	Minimum score for matches

Description of run-time parameters

Each run-time parameter is represented by a row on the Web GUI’s CADMatch page in the Modules tab. The name in the Web GUI is given in brackets behind the parameter name and the parameters are listed in the order they appear in the Web GUI:

max_matches (Maximum Matches)

is the maximum number of objects to detect.

Via the REST-API, this parameter can be set as follows.

PUT http://<host>/api/v1/nodes/rc_cadmatch/parameters?max_matches=<value>

min_score (Minimum Score)

is the minimum detection score after refinement. The higher this value, the better 2D edges and 3D point cloud must match the given template.

Via the REST-API, this parameter can be set as follows.

PUT http://<host>/api/v1/nodes/rc_cadmatch/parameters?min_score=<value>

edge_sensitivity (Edge Sensitivity)

is the sensitivity of the edge detector. The higher the value of this parameter, the more edges will be used for pose refinement.

Via the REST-API, this parameter can be set as follows.

PUT http://<host>/api/v1/nodes/rc_cadmatch/parameters?edge_sensitivity=<value>

edge_max_distance (Maximum Edge Distance)

is the maximum allowed distance in pixels between the template edges and the detected edges in the image during the refinement step.

Via the REST-API, this parameter can be set as follows.

PUT http://<host>/api/v1/nodes/rc_cadmatch/parameters?edge_max_distance=<value>

grasp_filter_orientation_threshold (Grasp Orientation Threshold)

is the maximum deviation of the TCP’s z axis at the grasp point from the z axis of the TCP’s preferred orientation in degrees. Only grasp points which are within this threshold are returned.

Via the REST-API, this parameter can be set as follows.

PUT http://<host>/api/v1/nodes/rc_cadmatch/parameters?grasp_filter_orientation_threshold=<value>

check_collisions_with_matches (Check Collisions with Matches)

If this parameter is set to true, and collision checking is enabled by passing a gripper to the detect_object service call, all grasp points will be checked for collisions between the gripper and all other detected objects (not limited to max_matches), and only grasp points at which the gripper would not collide with any other detected object will be returned.

Via the REST-API, this parameter can be set as follows.

PUT http://<host>/api/v1/nodes/rc_cadmatch/parameters?check_collisions_with_matches=<value>

load_carrier_model_tolerance

see Parameters of the load carrier functionality.

Via the REST-API, this parameter can be set as follows.

PUT http://<host>/api/v1/nodes/rc_cadmatch/parameters?load_carrier_model_tolerance=<value>

load_carrier_crop_distance

see Parameters of the load carrier functionality.

Via the REST-API, this parameter can be set as follows.

PUT http://<host>/api/v1/nodes/rc_cadmatch/parameters?load_carrier_crop_distance=<value>

Status values

The rc_cadmatch module reports the following status values:

Table 26 The rc_cadmatch module’s status values

Name	Description
data_acquisition_time	Time in seconds required by the last active service to acquire images
last_timestamp_processed	The timestamp of the last processed dataset
load_carrier_detection_time	Processing time of the last load carrier detection in seconds
object_detection_time	Processing time of the last last object detection in seconds
state	The current state of the rc_cadmatch node

The reported state can take one of the following values.

Table 27 Possible states of the CADMatch module

State name	Description
IDLE	The module is idle.
RUNNING	The module is running and ready for load carrier detection and object detection.
FATAL	A fatal error has occurred.

Services

The user can explore and call the rc_cadmatch module’s services, e.g. for development and testing, using the REST-API interface or the rc_cube Web GUI.

Each service response contains a return_code, which consists of a value plus an optional message. A successful service returns with a return_code value of 0. Negative return_code values indicate that the service failed. Positive return_code values indicate that the service succeeded with additional information. The smaller value is selected in case a service has multiple return_code values, but all messages are appended in the return_code message.

The following table contains a list of common codes:

Table 28 Return codes of the CADMatch services

Code	Description
0	Success
-1	An invalid argument was provided
-2	An internal error occurred
-3	An internal time-out occurred
-4	Data acquisition took longer than the maximum allowed time of 5.0 seconds
-8	Not applicable, stereo quality must be at least Medium
-9	No valid license for the module
-10	New element could not be added as the maximum storage capacity of load carriers or regions of interest has been exceeded
10	The maximum storage capacity of load carriers or regions of interest has been reached
11	Existing data was overwritten
100	The requested load carrier was not detected in the scene
101	None of the detected grasps is reachable
102	The detected load carrier is empty
103	All detected grasps are in collision
151	The object template has a continuous symmetry
999	Additional hints for application development

The CADMatch modules offer the following services.

start

Starts the module. If the command is accepted, the module moves to state RUNNING. The current_state value in the service response may differ from RUNNING if the state transition is still in process when the service returns.

This service can be called as follows.

PUT http://<host>/api/v1/nodes/rc_cadmatch/services/start

This service has no arguments.

The definition for the response with corresponding datatypes is:

{
  "name": "start",
  "response": {
    "accepted": "bool",
    "current_state": "string"
  }
}

stop

Stops the module. If the command is accepted, the module moves to state IDLE. The current_state value in the service response may differ from IDLE if the state transition is still in process when the service returns.

This service can be called as follows.

PUT http://<host>/api/v1/nodes/rc_cadmatch/services/stop

This service has no arguments.

The definition for the response with corresponding datatypes is:

{
  "name": "stop",
  "response": {
    "accepted": "bool",
    "current_state": "string"
  }
}

set_region_of_interest

see set_region_of_interest.

This service can be called as follows.

PUT http://<host>/api/v1/nodes/rc_cadmatch/services/set_region_of_interest

get_regions_of_interest

see get_regions_of_interest.

This service can be called as follows.

PUT http://<host>/api/v1/nodes/rc_cadmatch/services/get_regions_of_interest

delete_regions_of_interest

see delete_regions_of_interest.

This service can be called as follows.

PUT http://<host>/api/v1/nodes/rc_cadmatch/services/delete_regions_of_interest

set_load_carrier

see set_load_carrier.

This service can be called as follows.

PUT http://<host>/api/v1/nodes/rc_cadmatch/services/set_load_carrier

get_load_carriers

see get_load_carriers.

This service can be called as follows.

PUT http://<host>/api/v1/nodes/rc_cadmatch/services/get_load_carriers

delete_load_carriers

see delete_load_carriers.

This service can be called as follows.

PUT http://<host>/api/v1/nodes/rc_cadmatch/services/delete_load_carriers

detect_load_carriers

see detect_load_carriers.

This service can be called as follows.

PUT http://<host>/api/v1/nodes/rc_cadmatch/services/detect_load_carriers

detect_filling_level

see detect_filling_level.

This service can be called as follows.

PUT http://<host>/api/v1/nodes/rc_cadmatch/services/detect_filling_level

set_preferred_orientation

Persistently stores the preferred orientation of the gripper to compute the reachability of the grasps, which is used for filtering and sorting the grasps returned by the detect_object service (see Setting the preferred orientation of the TCP).

This service can be called as follows.

PUT http://<host>/api/v1/nodes/rc_cadmatch/services/set_preferred_orientation

The definition for the request arguments with corresponding datatypes is:

{
  "args": {
    "orientation": {
      "w": "float64",
      "x": "float64",
      "y": "float64",
      "z": "float64"
    },
    "pose_frame": "string"
  }
}

The definition for the response with corresponding datatypes is:

{
  "name": "set_preferred_orientation",
  "response": {
    "return_code": {
      "message": "string",
      "value": "int16"
    }
  }
}

get_preferred_orientation

Returns the preferred orientation of the gripper to compute the reachability of the grasps, which is used for filtering and sorting the grasps returned by the detect_object service (see Setting the preferred orientation of the TCP).

This service can be called as follows.

PUT http://<host>/api/v1/nodes/rc_cadmatch/services/get_preferred_orientation

This service has no arguments.

The definition for the response with corresponding datatypes is:

{
  "name": "get_preferred_orientation",
  "response": {
    "orientation": {
      "w": "float64",
      "x": "float64",
      "y": "float64",
      "z": "float64"
    },
    "pose_frame": "string",
    "return_code": {
      "message": "string",
      "value": "int16"
    }
  }
}

set_grasp

Persistently stores a grasp for the given object template on the rc_cube. All configured grasps are persistent over firmware updates and rollbacks.

This service can be called as follows.

PUT http://<host>/api/v1/nodes/rc_cadmatch/services/set_grasp

The definition for the request arguments with corresponding datatypes is:

{
  "args": {
    "grasp": {
      "id": "string",
      "pose": {
        "orientation": {
          "w": "float64",
          "x": "float64",
          "y": "float64",
          "z": "float64"
        },
        "position": {
          "x": "float64",
          "y": "float64",
          "z": "float64"
        }
      },
      "template_id": "string"
    }
  }
}

The definition for the response with corresponding datatypes is:

{
  "name": "set_grasp",
  "response": {
    "return_code": {
      "message": "string",
      "value": "int16"
    }
  }
}

Details for the definition of the grasp type are given in Setting of grasp points.

set_all_grasps

Replaces the list of grasps for the given object template on the rc_cube.

This service can be called as follows.

PUT http://<host>/api/v1/nodes/rc_cadmatch/services/set_all_grasps

The definition for the request arguments with corresponding datatypes is:

{
  "args": {
    "grasps": [
      {
        "id": "string",
        "pose": {
          "orientation": {
            "w": "float64",
            "x": "float64",
            "y": "float64",
            "z": "float64"
          },
          "position": {
            "x": "float64",
            "y": "float64",
            "z": "float64"
          }
        },
        "template_id": "string"
      }
    ],
    "template_id": "string"
  }
}

The definition for the response with corresponding datatypes is:

{
  "name": "set_all_grasps",
  "response": {
    "return_code": {
      "message": "string",
      "value": "int16"
    }
  }
}

Details for the definition of the grasp type are given in Setting of grasp points.

get_grasps

Returns all configured grasps which have the requested grasp_ids and belong to the requested template_ids. If no grasp_ids are provided, all grasps belonging to the requested template_ids are returned. If no template_ids are provided, all grasps with the requested grasp_ids are returned. If neither IDs are provided, all configured grasps are returned.

This service can be called as follows.

PUT http://<host>/api/v1/nodes/rc_cadmatch/services/get_grasps

The definition for the request arguments with corresponding datatypes is:

{
  "args": {
    "grasp_ids": [
      "string"
    ],
    "template_ids": [
      "string"
    ]
  }
}

The definition for the response with corresponding datatypes is:

{
  "name": "get_grasps",
  "response": {
    "grasps": [
      {
        "id": "string",
        "pose": {
          "orientation": {
            "w": "float64",
            "x": "float64",
            "y": "float64",
            "z": "float64"
          },
          "position": {
            "x": "float64",
            "y": "float64",
            "z": "float64"
          }
        },
        "template_id": "string"
      }
    ],
    "return_code": {
      "message": "string",
      "value": "int16"
    }
  }
}

delete_grasps

Deletes all grasps with the requested grasp_ids that belong to the requested template_ids. If no grasp_ids are provided, all grasps belonging to the requested template_ids are deleted. The template_ids list must not be empty.

This service can be called as follows.

PUT http://<host>/api/v1/nodes/rc_cadmatch/services/delete_grasps

The definition for the request arguments with corresponding datatypes is:

{
  "args": {
    "grasp_ids": [
      "string"
    ],
    "template_ids": [
      "string"
    ]
  }
}

The definition for the response with corresponding datatypes is:

{
  "name": "delete_grasps",
  "response": {
    "return_code": {
      "message": "string",
      "value": "int16"
    }
  }
}

get_symmetric_grasps

Returns all grasps that are symmetric to the given grasp. The first grasp in the returned list is the one that was passed with the service call. If the object template does not have an exact symmetry, only the grasp passed with the service call will be returned. If the object template has a continuous symmetry (e.g. a cylindrical object), only 12 equally spaced sample grasps will be returned.

This service can be called as follows.

PUT http://<host>/api/v1/nodes/rc_cadmatch/services/get_symmetric_grasps

The definition for the request arguments with corresponding datatypes is:

{
  "args": {
    "grasp": {
      "id": "string",
      "pose": {
        "orientation": {
          "w": "float64",
          "x": "float64",
          "y": "float64",
          "z": "float64"
        },
        "position": {
          "x": "float64",
          "y": "float64",
          "z": "float64"
        }
      },
      "template_id": "string"
    }
  }
}

The definition for the response with corresponding datatypes is:

{
  "name": "get_symmetric_grasps",
  "response": {
    "grasps": [
      {
        "id": "string",
        "pose": {
          "orientation": {
            "w": "float64",
            "x": "float64",
            "y": "float64",
            "z": "float64"
          },
          "position": {
            "x": "float64",
            "y": "float64",
            "z": "float64"
          }
        },
        "template_id": "string"
      }
    ],
    "return_code": {
      "message": "string",
      "value": "int16"
    }
  }
}

Details for the definition of the grasp type are given in Setting of grasp points.

detect_object

Triggers the detection of objects as described in Detection of objects based on an object template.

This service can be called as follows.

PUT http://<host>/api/v1/nodes/rc_cadmatch/services/detect_object

Request:

The definition for the request arguments with corresponding datatypes is:

{
  "args": {
    "collision_detection": {
      "gripper_id": "string",
      "pre_grasp_offset": {
        "x": "float64",
        "y": "float64",
        "z": "float64"
      }
    },
    "load_carrier_compartment": {
      "box": {
        "x": "float64",
        "y": "float64",
        "z": "float64"
      },
      "pose": {
        "orientation": {
          "w": "float64",
          "x": "float64",
          "y": "float64",
          "z": "float64"
        },
        "position": {
          "x": "float64",
          "y": "float64",
          "z": "float64"
        }
      }
    },
    "load_carrier_id": "string",
    "pose_frame": "string",
    "region_of_interest_id": "string",
    "robot_pose": {
      "orientation": {
        "w": "float64",
        "x": "float64",
        "y": "float64",
        "z": "float64"
      },
      "position": {
        "x": "float64",
        "y": "float64",
        "z": "float64"
      }
    },
    "template_id": "string"
  }
}

Required arguments:

pose_frame: see Hand-eye calibration.

template_id: the ID of the template to be detected.

Potentially required arguments:

robot_pose: see Hand-eye calibration.

Optional arguments:

load_carrier_id: ID of the load carrier which contains the items to be detected.

load_carrier_compartment: compartment inside the load carrier where to detect items (see Load carrier compartments).

region_of_interest_id: if load_carrier_id is set, ID of the 3D region of interest where to search for the load carriers. Otherwise, ID of the 3D region of interest where to search for the objects.

collision_detection: see Collision checking within other modules.

Response:

The definition for the response with corresponding datatypes is:

{
  "name": "detect_object",
  "response": {
    "grasps": [
      {
        "id": "string",
        "match_uuid": "string",
        "pose": {
          "orientation": {
            "w": "float64",
            "x": "float64",
            "y": "float64",
            "z": "float64"
          },
          "position": {
            "x": "float64",
            "y": "float64",
            "z": "float64"
          }
        },
        "pose_frame": "string",
        "timestamp": {
          "nsec": "int32",
          "sec": "int32"
        },
        "uuid": "string"
      }
    ],
    "load_carriers": [
      {
        "id": "string",
        "inner_dimensions": {
          "x": "float64",
          "y": "float64",
          "z": "float64"
        },
        "outer_dimensions": {
          "x": "float64",
          "y": "float64",
          "z": "float64"
        },
        "overfilled": "bool",
        "pose": {
          "orientation": {
            "w": "float64",
            "x": "float64",
            "y": "float64",
            "z": "float64"
          },
          "position": {
            "x": "float64",
            "y": "float64",
            "z": "float64"
          }
        },
        "pose_frame": "string",
        "rim_thickness": {
          "x": "float64",
          "y": "float64"
        }
      }
    ],
    "matches": [
      {
        "grasp_uuids": [
          "string"
        ],
        "pose": {
          "orientation": {
            "w": "float64",
            "x": "float64",
            "y": "float64",
            "z": "float64"
          },
          "position": {
            "x": "float64",
            "y": "float64",
            "z": "float64"
          }
        },
        "pose_frame": "string",
        "score": "float32",
        "template_id": "string",
        "timestamp": {
          "nsec": "int32",
          "sec": "int32"
        },
        "uuid": "string"
      }
    ],
    "return_code": {
      "message": "string",
      "value": "int16"
    },
    "timestamp": {
      "nsec": "int32",
      "sec": "int32"
    }
  }
}

grasps: list of grasps on the detected objects. The grasps are ordered by their reachability starting with the grasp that can be reached most easily by the robot. The match_uuid gives the reference to the detected object in matches this grasp belongs to.

load_carriers: list of detected load carriers.

matches: list of detected objects matching the template. The score indicates how well the object matches the template. The grasp_uuids refer to the grasps in grasps which are reachable on this object.

timestamp: timestamp of the image set the detection ran on.

return_code: holds possible warnings or error codes and messages.

save_parameters

This service saves the currently set parameters persistently. Thereby, the same parameters will still apply after a reboot of the rc_cube. The node parameters are not persistent over firmware updates and rollbacks.

This service can be called as follows.

PUT http://<host>/api/v1/nodes/rc_cadmatch/services/save_parameters

This service has no arguments.

The definition for the response with corresponding datatypes is:

{
  "name": "save_parameters",
  "response": {
    "return_code": {
      "message": "string",
      "value": "int16"
    }
  }
}

reset_defaults

This service resets all parameters of the module to its default values, as listed in above table. The reset does not apply to regions of interest and load carriers.

This service can be called as follows.

PUT http://<host>/api/v1/nodes/rc_cadmatch/services/reset_defaults

This service has no arguments.

The definition for the response with corresponding datatypes is:

{
  "name": "reset_defaults",
  "response": {
    "return_code": {
      "message": "string",
      "value": "int16"
    }
  }
}

Template Upload

For template upload, download and listing, special REST-API endpoints are provided. Up to 30 templates can be stored persistently on the rc_cube.

GET /nodes/rc_cadmatch/templates

Get list of all rc_cadmatch templates.

Template request

GET /api/v1/nodes/rc_cadmatch/templates HTTP/1.1

Template response

HTTP/1.1 200 OK
Content-Type: application/json

[
  {
    "id": "string"
  }
]

Response Headers:  

• Content-Type – application/json

Status Codes:

• 200 OK – successful operation (returns array of Template)
• 404 Not Found – node not found

Referenced Data Models:  

• Template

GET /nodes/rc_cadmatch/templates/{id}

Get a rc_cadmatch template. If the requested content-type is application/octet-stream, the template is returned as file.

Template request

GET /api/v1/nodes/rc_cadmatch/templates/<id> HTTP/1.1

Template response

HTTP/1.1 200 OK
Content-Type: application/json

{
  "id": "string"
}

Parameters:

• id (string) – id of the template (required)

Response Headers:  

• Content-Type – application/json application/octet-stream

Status Codes:

• 200 OK – successful operation (returns Template)
• 404 Not Found – node or template not found

Referenced Data Models:  

• Template

PUT /nodes/rc_cadmatch/templates/{id}

Create or update a rc_cadmatch template.

Template request

PUT /api/v1/nodes/rc_cadmatch/templates/<id> HTTP/1.1
Accept: multipart/form-data application/json

Template response

HTTP/1.1 200 OK
Content-Type: application/json

{
  "id": "string"
}

Parameters:

• id (string) – id of the template (required)

Form Parameters:  

• file – template file (required)

Request Headers:  

• Accept – multipart/form-data application/json

Response Headers:  

• Content-Type – application/json

Status Codes:

• 200 OK – successful operation (returns Template)
• 400 Bad Request – Template is not valid or max number of templates reached
• 403 Forbidden – forbidden, e.g. because there is no valid license for this module.
• 404 Not Found – node or template not found
• 413 Request Entity Too Large – Template too large

Referenced Data Models:  

• Template

DELETE /nodes/rc_cadmatch/templates/{id}

Remove a rc_cadmatch template.

Template request

DELETE /api/v1/nodes/rc_cadmatch/templates/<id> HTTP/1.1
Accept: application/json

Parameters:

• id (string) – id of the template (required)

Request Headers:  

• Accept – application/json

Response Headers:  

• Content-Type – application/json

Status Codes:

• 200 OK – successful operation
• 403 Forbidden – forbidden, e.g. because there is no valid license for this module.
• 404 Not Found – node or template not found