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.
The IOControl module is called
rc_iocontrol in the REST-API and is represented by the
IOControl page in the Configuration tab of the
The user can change the parameters via the Web GUI, the
REST-API interface, or via GigE Vision
using the DigitalIOControl parameters
This module offers the following run-time parameters:
||string||-||-||Low||Out1 mode: [Low, High, ExposureActive, ExposureAlternateActive]|
||string||-||-||Low||Out2 mode: [Low, High, ExposureActive, ExposureAlternateActive]|
Description of run-time parameters¶
out2_mode (Out1 and Out2)¶
The output modes for GPIO Out 1 and Out 2 can be set individually:
Lowsets the ouput permanently to LOW. This is the factory default.
Highsets the output permanently to HIGH.
ExposureActivesets the output to HIGH for the exposure time of every image.
ExposureAlternateActivesets the output to HIGH for the exposure time of every second image.
Via the REST-API, this parameter can be set as follows.PUT http://<host>/api/v1/nodes/rc_iocontrol/parameters?<out1_mode|out2_mode>=<value>
The parameters can only be changed if the IOControl license is available on
the rc_cube. Otherwise, the parameters will stay at their factory
Fig. 38 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.
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
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
use the intensity images with GPIO Out 1 being LOW, i.e. projector is off.
Fig. 39 shows an example.
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).
Each service response contains a
which consists of a
value plus an optional
A successful service returns with a
return_code value of
return_code values indicate that the service failed.
return_code values indicate that the service succeeded with additional information.
The IOControl module offers the following services.
Retrieves the current state of the rc_visard’s general purpose inputs and outputs (GPIOs).
This service can be called as follows.PUT http://<host>/api/v1/nodes/rc_iocontrol/services/get_io_values
Restores and applies the default values for this module’s parameters (“factory reset”).
This service can be called as follows.PUT http://<host>/api/v1/nodes/rc_iocontrol/services/reset_defaults
This service is deprecated and has no effect, parameters are always auto-saved.