ItemPick and BoxPick¶

Introduction¶

The ItemPick and BoxPick modules are optional on-board modules of the rc_cube and require separate ItemPick or BoxPick licenses to be purchased.

The modules provide out-of-the-box perception solutions for robotic pick-and-place applications. ItemPick targets the detection of flat surfaces of unknown objects for picking with a suction gripper. BoxPick detects rectangular surfaces and determines their position, orientation and size for grasping. The interface of both modules is very similar. Therefore both modules are described together in this chapter.

In addition, both modules offer:

A dedicated page on the rc_cube Web GUI for easy setup, configuration, testing, and application tuning.
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 items inside a bin only.
The definition of compartments inside a load carrier to provide grasps for specific volumes of the bin only.
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.
A quality value associated to each suggested grasp and related to the flatness of the grasping surface.
Sorting of grasps according to gravity and size so that items on top of a pile are grasped first.

Note

In this chapter, cluster and surface are used as synonyms and identify a set of points (or pixels) with defined geometrical properties.

Detection of items (BoxPick)¶

The BoxPick module supports the detection of multiple item_models of type RECTANGLE. Each item model is defined by its minimum and maximum size, with the minimum dimensions strictly smaller than the maximum dimensions. The dimensions should be given fairly accurately to avoid misdetections, while still considering a certain tolerance to account for possible production variations and measurement inaccuracies.

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

The ID of the load carrier which contains the items to be detected.
A compartment inside the load carrier where to detect items.
The ID of the region of interest where to search for the load carriers if a load carrier is set. Otherwise, the ID of the region of interest where to search for the items.
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 chosen region of interest is defined in the external frame.

The detected item poses are given relative to the centers of the rectangles, with the z axis pointing towards the camera. Each detected item includes a uuid (Universally Unique Identifier) and the timestamp of the oldest image that was used to detect it.

Computation of grasps¶

The ItemPick and BoxPick modules offer a service for computing grasps for suction grippers. The gripper is defined by its suction surface length and width.

The ItemPick module identifies flat surfaces in the scene and supports flexible and/or deformable items. The type of these item_models is called UNKNOWN since they don’t need to have a standard geometrical shape. Optionally, the user can also specify the minimum and maximum size of the item.

For BoxPick, the grasps are computed on the detected rectangular items (see Detection of items (BoxPick)).

Optionally, further information can be given to the modules in a grasp computation request:

The ID of the load carrier which contains the items to be grasped.
A compartment inside the load carrier where to compute grasps (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 compute grasps.
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.

A grasp provided by the ItemPick and BoxPick modules represents the recommended pose of the TCP (Tool Center Point) of the suction gripper. The grasp type is always set to SUCTION. The computed grasp pose is the center of the biggest ellipse that can be inscribed in each surface. The grasp orientation is a right-handed coordinate system and is defined such that its z axis is normal to the surface pointing inside the object at the grasp position and its x axis is directed along the maximum elongation of the ellipse.

Fig. 19 Illustration of suction grasp with coordinate system and ellipse representing the maximum suction surface.

Each grasp includes the dimensions of the maximum suction surface available, modelled as an ellipse of axes max_suction_surface_length and max_suction_surface_width. The user is enabled to filter grasps by specifying the minimum suction surface required by the suction device in use.

In the BoxPick module, the grasp position corresponds to the center of the detected rectangle and the dimensions of the maximum suction surface available matches the estimated rectangle dimensions. Detected rectangles with missing data or occlusions by other objects for more than 15% of their surface do not get an associated grasp.

Each grasp also includes a quality value, which gives an indication of the flatness of the grasping surface. The quality value varies between 0 and 1, where higher numbers correspond to a flatter reconstructed surface.

The grasp definition is complemented by a uuid (Universally Unique Identifier) and the timestamp of the oldest image that was used to compute the grasp.

Grasps sorting is performed based on a combination of

the distance from the camera along the gravity direction, and
the size of the item to grasp.

Grasp points on top of a pile and corresponding to larger items are grasped first.

Interaction with other modules¶

Internally, the ItemPick and BoxPick modules depend on, and interact with other on-board modules as listed below.

Note

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

Stereo camera and Stereo matching¶

The ItemPick and BoxPick modules make 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).

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

Estimation of gravity vector¶

For each load carrier detection and grasp computation, the modules estimate 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 ItemPick and BoxPick modules require 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 ItemPick and BoxPick modules can automatically provide poses in the robot coordinate frame. For the ItemPick and BoxPick nodes’ 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 ItemPick and BoxPick modules by passing the ID of the used gripper and optionally a pre-grasp offset to the compute_grasps service call. 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 collision checking is enabled, only grasps which are collision free will be returned. However, the visualization images on the ItemPick or BoxPick tab of the Web GUI also show colliding grasp points as black ellipses.

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

Parameters¶

The ItemPick and BoxPick modules are called rc_itempick and rc_boxpick in the REST-API and are represented by the ItemPick and BoxPick pages in the Modules tab of the Web GUI. The user can explore and configure the rc_itempick and rc_boxpick module’s run-time parameters, e.g. for development and testing, using the Web GUI or the REST-API interface.

Parameter overview¶

These modules offer the following run-time parameters:

Table 16 The `rc_itempick` and `rc_boxpick` modules application parameters¶
Name	Type	Min	Max	Default	Description
`max_grasps`	int32	1	20	5	Maximum number of provided grasps
`prefer_splits`	bool	false	true	false	Only for rc_boxpick. Indicates whether rectangles are split into smaller ones when possible

Table 17 The `rc_itempick` and `rc_boxpick` modules load carrier detection parameters¶
Name	Type	Min	Max	Default	Description
`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

Table 18 The `rc_itempick` and `rc_boxpick` modules surface clustering parameters¶
Name	Type	Min	Max	Default	Description
`cluster_max_dimension`	float64	0.05	0.8	0.3	Only for rc_itempick. Maximum allowed diameter for a cluster in meters. Clusters with a diameter larger than this value are not used for grasp computation.
`cluster_max_curvature`	float64	0.005	0.5	0.11	Maximum curvature allowed within one cluster. The smaller this value, the more clusters will be split apart.
`clustering_patch_size`	int32	3	10	4	Only for rc_itempick. Size in pixels of the square patches the depth map is subdivided into during the first clustering step
`clustering_max_surface_rmse`	float64	0.0005	0.01	0.004	Maximum root-mean-square error (RMSE) in meters of points belonging to a surface
`clustering_discontinuity_factor`	float64	0.5	5.0	1.0	Factor used to discriminate depth discontinuities within a patch. The smaller this value, the more clusters will be split apart.

Description of run-time parameters¶

Each run-time parameter is represented by a row on the Web GUI’s ItemPick or BoxPick 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_grasps` (Maximum Grasps)¶

sets the maximum number of provided grasps.

Via the REST-API, this parameter can be set as follows.
PUT http://<host>/api/v1/nodes/<rc_itempick|rc_boxpick>/parameters?max_grasps=<value>

`prefer_splits` (Only for BoxPick, Prefer Splits)¶

determines whether rectangles should be split into smaller ones if the smaller ones also match the given item models. This parameter should be set to for packed box layouts in which the given item models would also match a rectangle of the size of two adjoining boxes. If this parameter is set to false, the larger rectangles will be preferred in these cases.

Via the REST-API, this parameter can be set as follows.
PUT http://<host>/api/v1/nodes/rc_boxpick/parameters?prefer_splits=<value>

`cluster_max_dimension` (Only for ItemPick, Cluster Maximum Dimension)¶

is the maximum allowed diameter for a cluster in meters. Clusters with a diameter larger than this value are not used for grasp computation.

Via the REST-API, this parameter can be set as follows.
PUT http://<host>/api/v1/nodes/rc_itempick/parameters?cluster_max_dimension=<value>

`cluster_max_curvature` (Cluster Maximum Curvature)¶

is the maximum curvature allowed within one cluster. The smaller this value, the more clusters will be split apart.

Via the REST-API, this parameter can be set as follows.
PUT http://<host>/api/v1/nodes/<rc_itempick|rc_boxpick>/parameters?cluster_max_curvature=<value>

`clustering_patch_size` (Only for ItemPick, Patch Size)¶

is the size of the square patches the depth map is subdivided into during the first clustering step in pixels.

Via the REST-API, this parameter can be set as follows.
PUT http://<host>/api/v1/nodes/rc_itempick/parameters?clustering_patch_size=<value>

`clustering_discontinuity_factor` (Discontinuity Factor)¶

is the factor used to discriminate depth discontinuities within a patch. The smaller this value, the more clusters will be split apart.

Via the REST-API, this parameter can be set as follows.
PUT http://<host>/api/v1/nodes/<rc_itempick|rc_boxpick>/parameters?clustering_discontinuity_factor=<value>

`clustering_max_surface_rmse` (Maximum Surface RMSE)¶

is the maximum root-mean-square error (RMSE) in meters of points belonging to a surface.

Via the REST-API, this parameter can be set as follows.
PUT http://<host>/api/v1/nodes/<rc_itempick|rc_boxpick>/parameters?clustering_max_surface_rmse=<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_itempick|rc_boxpick>/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_itempick|rc_boxpick>/parameters?load_carrier_crop_distance=<value>

Status values¶

The rc_itempick and rc_boxpick modules report the following status values:

Table 19 The `rc_itempick` and `rc_boxpick` modules status values¶
Name	Description
`data_acquisition_time`	Time in seconds required by the last active service to acquire images. Standard values are between 0.5 s and 0.6 s with High depth image quality.
`grasp_computation_time`	Processing time of the last grasp computation in seconds
`last_timestamp_processed`	The timestamp of the last processed dataset
`load_carrier_detection_time`	Processing time of the last load carrier detection in seconds
`state`	The current state of the rc_itempick and rc_boxpick node

The reported state can take one of the following values.

Table 20 Possible states of the ItemPick and BoxPick modules¶
State name	Description
IDLE	The module is idle.
RUNNING	The module is running and ready for load carrier detection and grasp computation.
FATAL	A fatal error has occurred.

Services¶

The user can explore and call the rc_itempick and rc_boxpick 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 21 Return codes of the ItemPick and BoxPick services¶
Code	Description
0	Success
-1	An invalid argument was provided
-4	Data acquisition took longer than the maximum allowed time of 5.0 seconds
-10	New element could not be added as the maximum storage capacity of load carriers or regions of interest has been exceeded
-200	Fatal internal error
-301	More than one item model of type `UNKNOWN` provided to the `compute_grasps` service
-302	More than one load carrier provided to the `detect_load_carriers` or `detect_filling_level` services, but only one is supported
10	The maximum storage capacity of load carriers or regions of interest has been reached
11	An existent persistent model was overwritten by the call to `set_load_carrier` or `set_region_of_interest`
100	The requested load carriers were not detected in the scene
101	No valid surfaces or grasps were found in the scene
102	The detected load carrier is empty
103	All computed grasps are in collision with the load carrier
200	The module is in state `IDLE`
300	A valid `robot_pose` was provided as argument but it is not required
400	No `item_models` were provided to the `compute_grasps` service request

The ItemPick and BoxPick 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_itempick|rc_boxpick>/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_itempick|rc_boxpick>/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_itempick|rc_boxpick>/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_itempick|rc_boxpick>/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_itempick|rc_boxpick>/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_itempick|rc_boxpick>/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_itempick|rc_boxpick>/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_itempick|rc_boxpick>/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_itempick|rc_boxpick>/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_itempick|rc_boxpick>/services/detect_filling_level

`detect_items` (BoxPick only)¶

Triggers the detection of rectangles as described in Detection of items (BoxPick).

This service can be called as follows.

PUT http://<host>/api/v1/nodes/rc_boxpick/services/detect_items

Request:

The definition for the request arguments with corresponding datatypes is:

{
  "args": {
    "item_models": [
      {
        "rectangle": {
          "max_dimensions": {
            "x": "float64",
            "y": "float64"
          },
          "min_dimensions": {
            "x": "float64",
            "y": "float64"
          }
        },
        "type": "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",
    "region_of_interest_id": "string",
    "robot_pose": {
      "orientation": {
        "w": "float64",
        "x": "float64",
        "y": "float64",
        "z": "float64"
      },
      "position": {
        "x": "float64",
        "y": "float64",
        "z": "float64"
      }
    }
  }
}

Required arguments:

pose_frame: see Hand-eye calibration.

item_models: list of rectangles with minimum and maximum size, with the minimum dimensions strictly smaller than the maximum dimensions. The dimensions should be given fairly accurately to avoid misdetections, while still considering a certain tolerance to account for possible production variations and measurement inaccuracies.

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 items.

Response:

The definition for the response with corresponding datatypes is:

{
  "name": "detect_items",
  "response": {
    "items": [
      {
        "pose": {
          "orientation": {
            "w": "float64",
            "x": "float64",
            "y": "float64",
            "z": "float64"
          },
          "position": {
            "x": "float64",
            "y": "float64",
            "z": "float64"
          }
        },
        "pose_frame": "string",
        "rectangle": {
          "x": "float64",
          "y": "float64"
        },
        "timestamp": {
          "nsec": "int32",
          "sec": "int32"
        },
        "type": "string",
        "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"
        }
      }
    ],
    "return_code": {
      "message": "string",
      "value": "int16"
    },
    "timestamp": {
      "nsec": "int32",
      "sec": "int32"
    }
  }
}

load_carriers: list of detected load carriers.

items: list of detected rectangles.

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

return_code: holds possible warnings or error codes and messages.

`compute_grasps` (for ItemPick)¶

Triggers the computation of grasping poses for a suction device as described in Computation of grasps.

This service can be called as follows.

PUT http://<host>/api/v1/nodes/rc_itempick/services/compute_grasps

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"
      }
    },
    "item_models": [
      {
        "type": "string",
        "unknown": {
          "max_dimensions": {
            "x": "float64",
            "y": "float64",
            "z": "float64"
          },
          "min_dimensions": {
            "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"
      }
    },
    "suction_surface_length": "float64",
    "suction_surface_width": "float64"
  }
}

Required arguments:

pose_frame: see Hand-eye calibration.

suction_surface_length: length of the suction device grasping surface.

suction_surface_width: width of the suction device grasping surface.

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 grasped.

load_carrier_compartment: compartment inside the load carrier where to compute grasps (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 compute grasps.

item_models: list of unknown items with minimum and maximum dimensions, with the minimum dimensions strictly smaller than the maximum dimensions. Only one item_model of type UNKNOWN is currently supported.

collision_detection: see Collision checking within other modules.

Response:

The definition for the response with corresponding datatypes is:

{
  "name": "compute_grasps",
  "response": {
    "grasps": [
      {
        "item_uuid": "string",
        "max_suction_surface_length": "float64",
        "max_suction_surface_width": "float64",
        "pose": {
          "orientation": {
            "w": "float64",
            "x": "float64",
            "y": "float64",
            "z": "float64"
          },
          "position": {
            "x": "float64",
            "y": "float64",
            "z": "float64"
          }
        },
        "pose_frame": "string",
        "quality": "float64",
        "timestamp": {
          "nsec": "int32",
          "sec": "int32"
        },
        "type": "string",
        "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"
        }
      }
    ],
    "return_code": {
      "message": "string",
      "value": "int16"
    },
    "timestamp": {
      "nsec": "int32",
      "sec": "int32"
    }
  }
}

load_carriers: list of detected load carriers.

grasps: sorted list of suction grasps.

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

return_code: holds possible warnings or error codes and messages.

`compute_grasps` (for BoxPick)¶

Triggers the detection of rectangles and the computation of grasping poses for the detected rectangles as described in Computation of grasps.

This service can be called as follows.

PUT http://<host>/api/v1/nodes/rc_boxpick/services/compute_grasps

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"
      }
    },
    "item_models": [
      {
        "rectangle": {
          "max_dimensions": {
            "x": "float64",
            "y": "float64"
          },
          "min_dimensions": {
            "x": "float64",
            "y": "float64"
          }
        },
        "type": "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",
    "region_of_interest_id": "string",
    "robot_pose": {
      "orientation": {
        "w": "float64",
        "x": "float64",
        "y": "float64",
        "z": "float64"
      },
      "position": {
        "x": "float64",
        "y": "float64",
        "z": "float64"
      }
    },
    "suction_surface_length": "float64",
    "suction_surface_width": "float64"
  }
}

Required arguments:

pose_frame: see Hand-eye calibration.

item_models: list of rectangles with minimum and maximum size, with the minimum dimensions strictly smaller than the maximum dimensions. The dimensions should be given fairly accurately to avoid misdetections, while still considering a certain tolerance to account for possible production variations and measurement inaccuracies.

suction_surface_length: length of the suction device grasping surface.

suction_surface_width: width of the suction device grasping surface.

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 grasped.

load_carrier_compartment: compartment inside the load carrier where to compute grasps (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 compute grasps.

collision_detection: see Collision checking within other modules.

Response:

The definition for the response with corresponding datatypes is:

{
  "name": "compute_grasps",
  "response": {
    "grasps": [
      {
        "item_uuid": "string",
        "max_suction_surface_length": "float64",
        "max_suction_surface_width": "float64",
        "pose": {
          "orientation": {
            "w": "float64",
            "x": "float64",
            "y": "float64",
            "z": "float64"
          },
          "position": {
            "x": "float64",
            "y": "float64",
            "z": "float64"
          }
        },
        "pose_frame": "string",
        "quality": "float64",
        "timestamp": {
          "nsec": "int32",
          "sec": "int32"
        },
        "type": "string",
        "uuid": "string"
      }
    ],
    "items": [
      {
        "grasp_uuids": [
          "string"
        ],
        "pose": {
          "orientation": {
            "w": "float64",
            "x": "float64",
            "y": "float64",
            "z": "float64"
          },
          "position": {
            "x": "float64",
            "y": "float64",
            "z": "float64"
          }
        },
        "pose_frame": "string",
        "rectangle": {
          "x": "float64",
          "y": "float64"
        },
        "timestamp": {
          "nsec": "int32",
          "sec": "int32"
        },
        "type": "string",
        "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"
        }
      }
    ],
    "return_code": {
      "message": "string",
      "value": "int16"
    },
    "timestamp": {
      "nsec": "int32",
      "sec": "int32"
    }
  }
}

load_carriers: list of detected load carriers.

items: list of detected rectangles.

grasps: sorted list of suction grasps.

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_itempick|rc_boxpick>/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_itempick|rc_boxpick>/services/save_parameters
This service has no arguments.

The definition for the response with corresponding datatypes is:
{
  "name": "reset_defaults",
  "response": {
    "return_code": {
      "message": "string",
      "value": "int16"
    }
  }
}

ItemPick and BoxPick¶

Introduction¶

Detection of items (BoxPick)¶

Computation of grasps¶

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_grasps (Maximum Grasps)¶

prefer_splits (Only for BoxPick, Prefer Splits)¶

cluster_max_dimension (Only for ItemPick, Cluster Maximum Dimension)¶

cluster_max_curvature (Cluster Maximum Curvature)¶

clustering_patch_size (Only for ItemPick, Patch Size)¶

clustering_discontinuity_factor (Discontinuity Factor)¶

clustering_max_surface_rmse (Maximum Surface RMSE)¶

load_carrier_model_tolerance¶

load_carrier_crop_distance¶

Status values¶

Services¶

start¶

stop¶

set_region_of_interest¶

get_regions_of_interest¶

delete_regions_of_interest¶

set_load_carrier¶

get_load_carriers¶

delete_load_carriers¶

detect_load_carriers¶

detect_filling_level¶

detect_items (BoxPick only)¶

compute_grasps (for ItemPick)¶

compute_grasps (for BoxPick)¶

save_parameters¶

reset_defaults¶

`max_grasps` (Maximum Grasps)¶

`prefer_splits` (Only for BoxPick, Prefer Splits)¶

`cluster_max_dimension` (Only for ItemPick, Cluster Maximum Dimension)¶

`cluster_max_curvature` (Cluster Maximum Curvature)¶

`clustering_patch_size` (Only for ItemPick, Patch Size)¶

`clustering_discontinuity_factor` (Discontinuity Factor)¶

`clustering_max_surface_rmse` (Maximum Surface RMSE)¶

`load_carrier_model_tolerance`¶

`load_carrier_crop_distance`¶

`start`¶

`stop`¶

`set_region_of_interest`¶

`get_regions_of_interest`¶

`delete_regions_of_interest`¶

`set_load_carrier`¶

`get_load_carriers`¶

`delete_load_carriers`¶

`detect_load_carriers`¶

`detect_filling_level`¶

`detect_items` (BoxPick only)¶

`compute_grasps` (for ItemPick)¶

`compute_grasps` (for BoxPick)¶

`save_parameters`¶

`reset_defaults`¶