IO and Projector Control

The IOControl module is an optional on-board module of the rc_visard and requires a separate IOControl license to be purchased. This license is included in every rc_visard purchased after 01.07.2020.

The IOControl module allows reading the status of the general purpose digital inputs and controlling the digital general purpose outputs (GPIOs) of the rc_visard. The outputs can be set to LOW or HIGH, or configured to be HIGH for the exposure time of every image or every second image.

The purpose of the IOControl module is the control of an external light source or a projector, which is connected to one of the rc_visard’s GPIOs to be synchronized by the image acquisition trigger. In case a pattern projector is used to improve stereo matching, the intensity images also show the projected pattern, which might be a disadvantage for image processing tasks that are based on the intensity image (e.g. edge detection). For this reason, the IOControl module allows setting GPIO outputs to HIGH for the exposure time of every second image, so that intensity images without the projected pattern are also available.

Note

For more details on the rc_visard’s GPIOs please refer to Wiring.

Parameters

The IOControl module is called rc_iocontrol in the REST-API and is represented in the Web GUI under Configuration ‣ IOControl. The user can change the parameters via the Web GUI, the REST-API interface, or via GigE Vision using the DigitalIOControl parameters LineSelector and LineSource (Category: DigitalIOControl).

Parameter overview

This module offers the following run-time parameters:

Table 54 The rc_iocontrol module’s run-time parameters
Name Type Min Max Default Description
out1_mode string - - Low Out1 mode: [Low, High, ExposureActive, ExposureAlternateActive]
out2_mode string - - Low Out2 mode: [Low, High, ExposureActive, ExposureAlternateActive]

Description of run-time parameters

out1_mode and out2_mode (Out1 and Out2)

The output modes for GPIO Out 1 and Out 2 can be set individually:

Low sets the ouput permanently to LOW. This is the factory default.

High sets the output permanently to HIGH.

ExposureActive sets the output to HIGH for the exposure time of every image.

ExposureAlternateActive sets the output to HIGH for the exposure time of every second image.

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/nodes/rc_iocontrol/parameters/parameters?<out1_mode|out2_mode>=<value>

PUT http://<host>/api/v1/nodes/rc_iocontrol/parameters?<out1_mode|out2_mode>=<value>

Note

The parameters can only be changed if the IOControl license is available on the rc_visard. Otherwise, the parameters will stay at their factory defaults, i.e. out1_mode = Low and out2_mode = Low.

Fig. 56 shows which images are used for stereo matching and transmission via GigE Vision in ExposureActive mode with a user-defined frame rate of 8 Hz.

_images/fps_exposure.png

Fig. 56 Example of using the ExposureActive mode for GPIO Out 1 with a user-defined frame rate of 8 Hz. The internal image acquisition is always 25 Hz. GPIO Out 1 is HIGH for the exposure time of every image. A disparity image is computed for camera images that are sent out via GigE Vision according to the user-defined frame rate.

The mode ExposureAlternateActive is meant to be used when an external random dot projector is connected to the rc_visard’s GPIO Out 1. When setting Out 1 to ExposureAlternateActive, the stereo matching module only uses images with GPIO Out 1 being HIGH, i.e. projector is on. The maximum frame rate that is used for stereo matching is therefore half of the frame rate configured by the user (see FPS). All modules which make use of the intensity image, like TagDetect and ItemPick, use the intensity images with GPIO Out 1 being LOW, i.e. projector is off. Fig. 57 shows an example.

_images/fps_alternate.png

Fig. 57 Example of using the ExposureAlternateActive mode for GPIO Out 1 with a user-defined frame rate of 8 Hz. The internal image acquisition is always 25 Hz. GPIO Out 1 is HIGH for the exposure time of every second image. A disparity image is computed for images where Out 1 is HIGH and that are sent out via GigE Vision according to the user-defined frame rate. In ExposureAlternateActive mode, intensity images are always transmitted pairwise: one with GPIO Out 1 HIGH, for which a disparity image might be available, and one with GPIO Out 1 LOW.

Note

In ExposureAlternateActive mode, an intensity image with GPIO Out 1 being HIGH (i.e. with projection) is always 40 ms away from an intensity image with Out 1 being LOW (i.e. without projection), regardless of the user-defined frame rate. This needs to be considered when synchronizing disparity images and camera images without projection in this special mode.

The functionality can also be controlled by the DigitalIOControl parameters of the GenICam interface (Category: DigitalIOControl).

Services

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 IOControl module offers the following services.

get_io_values

Retrieves the current state of the rc_visard’s general purpose inputs and outputs (GPIOs).

Details

This service can be called as follows.

API version 2
API version 1 (deprecated)
PUT http://<host>/api/v2/pipelines/0/nodes/rc_iocontrol/services/get_io_values

PUT http://<host>/api/v1/nodes/rc_iocontrol/services/get_io_values
Request
Response
This service has no arguments.

The returned timestamp is the time of measurement.

input_mask and output_mask are bit masks defining which bits are used for input and output values, respectively.

values holds the values of the bits corresponding to input and output as given by the input_mask and output_mask.

return_code holds possible warnings or error codes and messages. Possible return_code values are shown below.

Code Description
0 Success
-2 Internal error
-9 License for IOControl is not available

The definition for the response with corresponding datatypes is:

{
  "name": "get_io_values",
  "response": {
    "input_mask": "uint32",
    "output_mask": "uint32",
    "return_code": {
      "message": "string",
      "value": "int16"
    },
    "timestamp": {
      "nsec": "int32",
      "sec": "int32"
    },
    "values": "uint32"
  }
}

reset_defaults

Restores and applies the default values for this module’s parameters (“factory reset”).

Details

This service can be called as follows.

API version 2
API version 1 (deprecated)
PUT http://<host>/api/v2/pipelines/0/nodes/rc_iocontrol/services/reset_defaults

PUT http://<host>/api/v1/nodes/rc_iocontrol/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"
    }
  }
}