CADMatch¶

Introduction¶

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

Warning

This module is not available in camera pipelines of type blaze.

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.

Warning

This module is pipeline specific. Changes to its settings or parameters only affect the respective camera pipeline and have no influence on other pipelines running on the rc_cube.

However, the object templates, grasp points and pose priors are stored globally. Setting, changing or deleting an object template, its grasps or pose priors affects all camera pipelines.

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 RoiDB).
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 option to use user-defined object pose priors.
Storing of up to 50 templates.
The definition of up to 100 grasp points for each template via an interactive visualization in the Web GUI.
Collision checking between the gripper and the load carrier, other detected objects and/or the point cloud.
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.
Selection of a sorting strategy to sort the detected objects and returned grasps.
3D visualization of the detection results with grasp points and gripper animations in the Web GUI.

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. 24

Fig. 24 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 100 grasp points per template.

When a grasp is defined on a symmetric object, all grasps symmetric to the defined one will automatically be considered in the CADMatch module’s detect_object service call. Symmetric grasps for a given grasp point can be retrieved using the get_symmetric_grasps service call and visualized in the Web GUI.

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 in the Web GUI in any pipeline under Modules ‣ CADMatch by clicking on + Add a new Template in the Templates, Grasps and Pose Priors section, or in Database ‣ Templates in the CADMatch Templates, Grasps and Pose Priors section. 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:

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.
Adding grasps interactively: Grasp points can be added interactively by first clicking on the Add Grasp button in the upper right 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 of pose priors¶

The CADMatch module offers the possibility to define prior poses of the objects to be detected. If a pose prior is given, the object detection will use this pose prior and only refine the given pose. This speeds up the detection significantly. A pose prior represents the approximate position and orientation of the object to be detected. The pose can be defined in the camera or the external coordinate frame, if a hand-eye calibration is available.

Each pose prior consists of an id which must be unique within all pose priors for an object template, the template_id representing the template the pose prior applies to, the pose and the pose_frame of the prior. Pose priors can be set via the REST-API interface, or by using the interactive visualization in the Web GUI. The Web GUI allows to interactively position the object in the current point cloud. This can be done in the “Pose Priors” tab during editing a template.

Pose priors should be used in applications where the approximate object poses are known beforehand. The rc_cube can store up to 50 pose priors per 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 can be used to sort the reachable grasps by setting the corresponding sorting strategy.

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, optionally, 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.

Setting the sorting strategies¶

The objects and grasps returned by the detect_object service call are sorted according to a sorting strategy which can be chosen by the user. The following sorting strategies are available and can be set in the Web GUI or using the set_sorting_strategies service call:

gravity: highest matches and grasp points along the gravity direction are returned first,
match_score: matches with the highest match score and grasp points on objects with the highest match score are returned first,
preferred_orientation: matches and grasp points with minimal rotation difference between their orientation and the preferred orientation of the TCP are returned first,
direction: matches and grasp points with the shortest distance along a defined direction vector in a given pose_frame are returned first.

If no sorting strategy is set or default sorting is chosen in the Web GUI, sorting is done based on a combination of match_score and the minimal distance from the camera along the z axis of 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. CADMatch also supports partial object templates, which contain only a specific part of the object that can be detected well, e.g., in case of occlusions. Furthermore, templates can require a pose prior for the detection which is then only refined using the image data.

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. If pose priors are given, only the pose refinement step is performed based, which decreases runtime significantly.

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 IDs of the pose priors which approximately match the poses of the objects to be detected. In case a template is used that requires a pose prior, one or more pose prior IDs have to be provided.
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.
Data acquisition mode: The user can choose if a new image dataset is acquired for the detection (default), or if the detection should be performed on the previously used image dataset. This saves data acquisition time, e.g. in case several detections with different templates have to be run on the same image.

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, sorted according to the selected sorting strategy (see Setting the sorting strategies). 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 is returned in addition to the list of detected objects. The grasps are sorted according to the selected sorting strategy (see Setting the sorting strategies). The grasp poses are given in the desired coordinate frame. There are references between the detected objects and the grasps via their uuids.

For objects with a discrete symmetry (e.g. prismatic objects), all collision-free symmetries of each grasp point which are reachable according to the given preferred TCP orientation are returned, ordered by the given sorting strategy.

For objects with a continuous symmetry (e.g. cylindrical objects), all grasps symmetric to each grasp point on an object are checked for reachability and collisions, and only the best one according to the given sorting strategy is returned.

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. To avoid this, the warmup_template service can be used to load a template so that it is ready when the first detection is triggered.

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 Camera module (rc_camera);
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 object detection inside a load carrier, the module estimates the gravity vector as described in Estimation of gravity vector.

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:

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).
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 GripperDB 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 the run-time parameter check_collisions_with_point_cloud is true, also collisions between the gripper and a watertight version of the point cloud are checked. If this feature is used with suctions grippers, it should be ensured that the TCP is defined to be outside the gripper geometry, or that the grasp points are defined above the object surface. Otherwise every grasp will result in a collision between the gripper and the point cloud.

If collision checking is enabled, only grasps which are collision free will be returned. However, the result image on top of the CADMatch page 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 in the Web GUI in the desired pipeline under Modules ‣ CADMatch. 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 31 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
`check_collisions_with_point_cloud`	bool	false	true	false	Whether to check for collisions between gripper and point cloud
`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	0.05	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
`max_matches`	int32	1	30	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. 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.
API version 2

API version 1 (deprecated)
PUT http://<host>/api/v2/pipelines/<0,1,2,3>/nodes/rc_cadmatch/parameters?max_matches=<value>
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.
API version 2

API version 1 (deprecated)
PUT http://<host>/api/v2/pipelines/<0,1,2,3>/nodes/rc_cadmatch/parameters?min_score=<value>
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.
API version 2

API version 1 (deprecated)
PUT http://<host>/api/v2/pipelines/<0,1,2,3>/nodes/rc_cadmatch/parameters?edge_sensitivity=<value>
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.
API version 2

API version 1 (deprecated)
PUT http://<host>/api/v2/pipelines/<0,1,2,3>/nodes/rc_cadmatch/parameters?edge_max_distance=<value>
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.
API version 2

API version 1 (deprecated)
PUT http://<host>/api/v2/pipelines/<0,1,2,3>/nodes/rc_cadmatch/parameters?grasp_filter_orientation_threshold=<value>
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.
API version 2

API version 1 (deprecated)
PUT http://<host>/api/v2/pipelines/<0,1,2,3>/nodes/rc_cadmatch/parameters?check_collisions_with_matches=<value>
PUT http://<host>/api/v1/nodes/rc_cadmatch/parameters?check_collisions_with_matches=<value>

`check_collisions_with_point_cloud` (Check Collisions with Point Cloud)¶

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 a watertight version of the point cloud, and only grasp points at which the gripper would not collide with this point cloud will be returned.

Via the REST-API, this parameter can be set as follows.
API version 2

API version 1 (deprecated)
PUT http://<host>/api/v2/pipelines/<0,1,2,3>/nodes/rc_cadmatch/parameters?check_collisions_with_point_cloud=<value>
PUT http://<host>/api/v1/nodes/rc_cadmatch/parameters?check_collisions_with_point_cloud=<value>

Status values¶

The rc_cadmatch module reports the following status values:

Table 32 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
`last_request_timestamp`	The timestamp of the last detection request
`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
`processing_time`	Processing time of the last detection (including load carrier detection) in seconds
`state`	The current state of the rc_cadmatch node

The reported state can take one of the following values.

Table 33 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.

The CADMatch modules offer the following services.

`detect_object`¶

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

Details

This service can be called as follows.

PUT http://<host>/api/v2/pipelines/<0,1,2,3>/nodes/rc_cadmatch/services/detect_object

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

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.

pose_prior_ids: IDs of the pose priors for the items to be detected. In case the chosen template requires a pose prior for the detection, this argument must be provided.

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.

data_acquisition_mode: if set to CAPTURE_NEW (default), a new image dataset will be used for the detection. If set to USE_LAST the previous dataset will be used for the detection.

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"
      }
    },
    "data_acquisition_mode": "string",
    "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",
    "pose_prior_ids": [
      "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"
  }
}

grasps: list of grasps on the detected objects, ordered according to the chosen sorting strategy. The match_uuid gives the reference to the detected object in matches this grasp belongs to. The list of returned grasps will be trimmed to the 100 best grasps if more reachable grasps are found.

load_carriers: list of detected load carriers.

matches: list of detected objects matching the template. The matches are ordered according to the chosen sorting strategy. 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.

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_ledge": {
          "x": "float64",
          "y": "float64"
        },
        "rim_step_height": "float64",
        "rim_thickness": {
          "x": "float64",
          "y": "float64"
        },
        "type": "string"
      }
    ],
    "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"
    }
  }
}

`set_preferred_orientation`¶

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

Details
This service can be called as follows.
API version 2

API version 1 (deprecated)
PUT http://<host>/api/v2/pipelines/<0,1,2,3>/nodes/rc_cadmatch/services/set_preferred_orientation
PUT http://<host>/api/v1/nodes/rc_cadmatch/services/set_preferred_orientation
Request

Response
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, optionally, sorting the grasps returned by the detect_object service (see Setting the preferred orientation of the TCP).

Details
This service can be called as follows.
API version 2

API version 1 (deprecated)
PUT http://<host>/api/v2/pipelines/<0,1,2,3>/nodes/rc_cadmatch/services/get_preferred_orientation
PUT http://<host>/api/v1/nodes/rc_cadmatch/services/get_preferred_orientation
Request

Response

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_sorting_strategies`¶

Persistently stores the sorting strategy for sorting the grasps and matches returned by the detect_object service (see Detection of objects).

Details
This service can be called as follows.
API version 2

API version 1 (deprecated)
PUT http://<host>/api/v2/pipelines/<0,1,2,3>/nodes/rc_cadmatch/services/set_sorting_strategies
PUT http://<host>/api/v1/nodes/rc_cadmatch/services/set_sorting_strategies
Request

Response
Only one strategy may have a weight greater than 0. If all weight values are set to 0, the module will use the default sorting strategy.

If the weight for direction is set, the vector must contain the direction vector and pose_frame must be either camera or external.

The definition for the request arguments with corresponding datatypes is:
{
  "args": {
    "direction": {
      "pose_frame": "string",
      "vector": {
        "x": "float64",
        "y": "float64",
        "z": "float64"
      },
      "weight": "float64"
    },
    "gravity": {
      "weight": "float64"
    },
    "match_score": {
      "weight": "float64"
    },
    "preferred_orientation": {
      "weight": "float64"
    }
  }
}
The definition for the response with corresponding datatypes is:
{
  "name": "set_sorting_strategies",
  "response": {
    "return_code": {
      "message": "string",
      "value": "int16"
    }
  }
}

`get_sorting_strategies`¶

Returns the sorting strategy for sorting the grasps and matches returned by the detect_object service (see Detection of objects).

Details

This service can be called as follows.

PUT http://<host>/api/v2/pipelines/<0,1,2,3>/nodes/rc_cadmatch/services/get_sorting_strategies

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

This service has no arguments.

All weight values are 0 when the module uses the default sorting strategy.

The definition for the response with corresponding datatypes is:

{
  "name": "get_sorting_strategies",
  "response": {
    "direction": {
      "pose_frame": "string",
      "vector": {
        "x": "float64",
        "y": "float64",
        "z": "float64"
      },
      "weight": "float64"
    },
    "gravity": {
      "weight": "float64"
    },
    "match_score": {
      "weight": "float64"
    },
    "preferred_orientation": {
      "weight": "float64"
    },
    "return_code": {
      "message": "string",
      "value": "int16"
    }
  }
}

`warmup_template`¶

Loads a template so that it is ready when the first detection with this template is triggered. Without using this service, the first detection with a new template takes longer than the following ones, because the template is then loaded at the first detection.

Details
This service can be called as follows.
API version 2

API version 1 (deprecated)
PUT http://<host>/api/v2/pipelines/<0,1,2,3>/nodes/rc_cadmatch/services/warmup_template
PUT http://<host>/api/v1/nodes/rc_cadmatch/services/warmup_template
Request

Response
The definition for the request arguments with corresponding datatypes is:
{
  "args": {
    "template_id": "string"
  }
}
The template_id is the ID of the template to be loaded into the CADMatch module.
The definition for the response with corresponding datatypes is:
{
  "name": "warmup_template",
  "response": {
    "return_code": {
      "message": "string",
      "value": "int16"
    }
  }
}

`start`¶

Starts the module. If the command is accepted, the module moves to state RUNNING.

Details
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.
API version 2

API version 1 (deprecated)
PUT http://<host>/api/v2/pipelines/<0,1,2,3>/nodes/rc_cadmatch/services/start
PUT http://<host>/api/v1/nodes/rc_cadmatch/services/start
Request

Response

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.

Details
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.
API version 2

API version 1 (deprecated)
PUT http://<host>/api/v2/pipelines/<0,1,2,3>/nodes/rc_cadmatch/services/stop
PUT http://<host>/api/v1/nodes/rc_cadmatch/services/stop
Request

Response

This service has no arguments.
The definition for the response with corresponding datatypes is:
{
  "name": "stop",
  "response": {
    "accepted": "bool",
    "current_state": "string"
  }
}

`reset_defaults`¶

Resets all parameters of the module to its default values, as listed in above table. The reset does not apply to templates, preferred orientation and sorting strategies.

Details
This service can be called as follows.
API version 2

API version 1 (deprecated)
PUT http://<host>/api/v2/pipelines/<0,1,2,3>/nodes/rc_cadmatch/services/reset_defaults
PUT http://<host>/api/v1/nodes/rc_cadmatch/services/reset_defaults
Request

Response

This service has no arguments.
The definition for the response with corresponding datatypes is:
{
  "name": "reset_defaults",
  "response": {
    "return_code": {
      "message": "string",
      "value": "int16"
    }
  }
}

`set_region_of_interest` (deprecated)¶

Persistently stores a 3D region of interest on the rc_cube.

Details
This service can be called as follows.
API version 2

API version 1 (deprecated)

This service is not available in API version 2. Use set_region_of_interest in rc_roi_db instead.
PUT http://<host>/api/v1/nodes/rc_cadmatch/services/set_region_of_interest

`get_regions_of_interest` (deprecated)¶

Returns the configured 3D regions of interest with the requested region_of_interest_ids.

Details
This service can be called as follows.
API version 2

API version 1 (deprecated)

This service is not available in API version 2. Use get_regions_of_interest in rc_roi_db instead.
PUT http://<host>/api/v1/nodes/rc_cadmatch/services/get_regions_of_interest

`delete_regions_of_interest` (deprecated)¶

Deletes the configured 3D regions of interest with the requested region_of_interest_ids.

Details
This service can be called as follows.
API version 2

API version 1 (deprecated)

This service is not available in API version 2. Use delete_regions_of_interest in rc_roi_db instead.
PUT http://<host>/api/v1/nodes/rc_cadmatch/services/delete_regions_of_interest

Internal services¶

The following services for configuring grasps and pose priors can change in future without notice. Setting, retrieving and deleting grasps and pose priors is recommended to be done via the Web GUI.

Warning

Configuring grasps and pose priors is global for all templates on the rc_cube and affects all camera pipelines.

`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.

Details

This service can be called as follows.

PUT http://<host>/api/v2/pipelines/<0,1,2,3>/nodes/rc_cadmatch/services/set_grasp

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

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

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"
    }
  }
}

`set_all_grasps`¶

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

Details

This service can be called as follows.

PUT http://<host>/api/v2/pipelines/<0,1,2,3>/nodes/rc_cadmatch/services/set_all_grasps

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

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

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"
    }
  }
}

`get_grasps`¶

Returns all configured grasps which have the requested grasp_ids and belong to the requested template_ids.

Details

This service can be called as follows.

PUT http://<host>/api/v2/pipelines/<0,1,2,3>/nodes/rc_cadmatch/services/get_grasps

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

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.

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.

Details
This service can be called as follows.
API version 2

API version 1 (deprecated)
PUT http://<host>/api/v2/pipelines/<0,1,2,3>/nodes/rc_cadmatch/services/delete_grasps
PUT http://<host>/api/v1/nodes/rc_cadmatch/services/delete_grasps
Request

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

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.

Details

This service can be called as follows.

PUT http://<host>/api/v2/pipelines/<0,1,2,3>/nodes/rc_cadmatch/services/get_symmetric_grasps

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 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.

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

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"
    }
  }
}

`set_pose_prior`¶

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

Details

This service can be called as follows.

PUT http://<host>/api/v2/pipelines/<0,1,2,3>/nodes/rc_cadmatch/services/set_pose_prior

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

Details for the definition of the pose_prior type are given in Setting of pose priors.

The definition for the request arguments with corresponding datatypes is:

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

The definition for the response with corresponding datatypes is:

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

`set_all_pose_priors`¶

Replaces the list of pose priors for the given object template on the rc_cube.

Details

This service can be called as follows.

PUT http://<host>/api/v2/pipelines/<0,1,2,3>/nodes/rc_cadmatch/services/set_all_pose_priors

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

Details for the definition of the pose_prior type are given in Setting of pose priors.

The definition for the request arguments with corresponding datatypes is:

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

The definition for the response with corresponding datatypes is:

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

`get_pose_priors`¶

Returns all configured pose priors which have the requested pose_prior_ids and belong to the requested template_ids.

Details

This service can be called as follows.

PUT http://<host>/api/v2/pipelines/<0,1,2,3>/nodes/rc_cadmatch/services/get_pose_priors

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

If no pose_prior_ids are provided, all pose priors belonging to the requested template_ids are returned. If no template_ids are provided, all pose priors with the requested pose_prior_ids are returned. If neither IDs are provided, all configured pose priors are returned.

The definition for the request arguments with corresponding datatypes is:

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

The definition for the response with corresponding datatypes is:

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

`delete_pose_priors`¶

Deletes all pose priors with the requested pose_prior_ids that belong to the requested template_ids.

Details
This service can be called as follows.
API version 2

API version 1 (deprecated)
PUT http://<host>/api/v2/pipelines/<0,1,2,3>/nodes/rc_cadmatch/services/delete_pose_priors
PUT http://<host>/api/v1/nodes/rc_cadmatch/services/delete_pose_priors
Request

Response
If no pose_prior_ids are provided, all pose priors belonging to the requested template_ids are deleted. The template_ids list must not be empty.

The definition for the request arguments with corresponding datatypes is:
{
  "args": {
    "pose_prior_ids": [
      "string"
    ],
    "template_ids": [
      "string"
    ]
  }
}
The definition for the response with corresponding datatypes is:
{
  "name": "delete_pose_priors",
  "response": {
    "return_code": {
      "message": "string",
      "value": "int16"
    }
  }
}

Return codes¶

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 34 Return codes of the CADMatch services¶
Code	Description
0	Success
-1	An invalid argument was provided.
-2	An internal error occurred.
-3	An internal timeout occurred.
-4	Data acquisition took longer than allowed.
-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.
-11	Sensor not connected, not supported or not ready.
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.
106	The list of returned grasps has been trimmed to the 100 best grasps.
110	Hints for setting up the application, e.g. reducing the distance from the camera, setting a region of interest.
151	The object template has a continuous symmetry.
152	The objects are outside the given region of interest, outside the load carrier or outside the image.
153	No edges could be detected in the camera image. Check the Edge Sensitivity.
999	Additional hints for application development

Template API¶

For template upload, download, listing and removal, special REST-API endpoints are provided. Templates can also be uploaded, downloaded and removed via the Web GUI. The templates include the grasp points and pose priors, if grasp points or pose priors have been configured. Up to 50 templates can be stored persistently on the rc_cube.

GET /templates/rc_cadmatch¶

Get list of all rc_cadmatch templates.

Template request

GET /api/v2/templates/rc_cadmatch 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 /templates/rc_cadmatch/{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/v2/templates/rc_cadmatch/<id> HTTP/1.1

Template response

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

{
  "id": "string"
}

Response Headers:
Parameters:	id (string) – id of the template (required)
	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 /templates/rc_cadmatch/{id}¶

Create or update a rc_cadmatch template.

Template request

PUT /api/v2/templates/rc_cadmatch/<id> HTTP/1.1
Accept: multipart/form-data application/json

Template response

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

{
  "id": "string"
}

Form Parameters:
Parameters:	id (string) – id of the template (required)
	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 /templates/rc_cadmatch/{id}¶

Remove a rc_cadmatch template.

Template request

DELETE /api/v2/templates/rc_cadmatch/<id> HTTP/1.1
Accept: application/json

Request Headers:
Parameters:	id (string) – id of the template (required)
	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

CADMatch¶

Introduction¶

Setting of grasp points¶

Setting grasp points in the Web GUI¶

Setting grasp points via the REST-API¶

Setting of pose priors¶

Setting the preferred orientation of the TCP¶

Setting the sorting strategies¶

Detection of objects¶

Interaction with other modules¶

Stereo camera and Stereo matching¶

Estimation of gravity vector¶

IO and Projector Control¶

Hand-eye calibration¶

CollisionCheck¶

Parameters¶

Parameter overview¶

Description of run-time parameters¶

max_matches (Maximum Matches)¶

min_score (Minimum Score)¶

edge_sensitivity (Edge Sensitivity)¶

edge_max_distance (Maximum Edge Distance)¶

grasp_filter_orientation_threshold (Grasp Orientation Threshold)¶

check_collisions_with_matches (Check Collisions with Matches)¶

check_collisions_with_point_cloud (Check Collisions with Point Cloud)¶

Status values¶

Services¶

detect_object¶

set_preferred_orientation¶

get_preferred_orientation¶

set_sorting_strategies¶

get_sorting_strategies¶

warmup_template¶

start¶

stop¶

reset_defaults¶

set_region_of_interest (deprecated)¶

get_regions_of_interest (deprecated)¶

delete_regions_of_interest (deprecated)¶

Internal services¶

set_grasp¶

set_all_grasps¶

get_grasps¶

delete_grasps¶

get_symmetric_grasps¶

set_pose_prior¶

set_all_pose_priors¶

get_pose_priors¶

delete_pose_priors¶

Return codes¶

Template API¶

`max_matches` (Maximum Matches)¶

`min_score` (Minimum Score)¶

`edge_sensitivity` (Edge Sensitivity)¶

`edge_max_distance` (Maximum Edge Distance)¶

`grasp_filter_orientation_threshold` (Grasp Orientation Threshold)¶

`check_collisions_with_matches` (Check Collisions with Matches)¶

`check_collisions_with_point_cloud` (Check Collisions with Point Cloud)¶

`detect_object`¶

`set_preferred_orientation`¶

`get_preferred_orientation`¶

`set_sorting_strategies`¶

`get_sorting_strategies`¶

`warmup_template`¶

`start`¶

`stop`¶

`reset_defaults`¶

`set_region_of_interest` (deprecated)¶

`get_regions_of_interest` (deprecated)¶

`delete_regions_of_interest` (deprecated)¶

`set_grasp`¶

`set_all_grasps`¶

`get_grasps`¶

`delete_grasps`¶

`get_symmetric_grasps`¶

`set_pose_prior`¶

`set_all_pose_priors`¶

`get_pose_priors`¶

`delete_pose_priors`¶