VisionSensor PV / PV2

Table of Contents

• Trigger Modes
  • Hardware trigger
• Controlling the integrated LED and exposure signal output

The VisionSensor PV / PV2 is a compact programmable Linux camera based on a single-core ARM Cortex-A9 SoC (armhf architecture). Unlike the VisionCam, it does not provide a "Real Time Communication Controller" (RTCC). Sensor trigger and the integrated LED are controlled by this libraray, while the digital I/Os are controlled by the VisionBox Interface Library.

Take a look at the Sensors page for information about available sensors for each platform.

Trigger Modes

The function FG_set_trigger_mode() is used to configure one of the trigger modes:

• Free-run
• Software triggered
• Hardware triggered

Example:

// Enable hardware trigger
FG_set_trigger_mode(FG_TRIGGER_MODE_HARDWARE);

Hardware trigger

The VisionSensor PV / PV2 uses a fixed connection from digital input IN0 to the sensor in hardware triggered mode. Therefore, no additional initialization code is necessary. The rising edge will be used.

Note

• The default settings after initialization is software trigger mode.
• The debounce setting for the digital inputs will also be applied for the trigger signal in hardware triggered mode. See VIB::DigitalInput::ConfigureDebounceTime() for adjustment of the debouncing time.

Controlling the integrated LED and exposure signal output

The operating mode of the integrated LED unit and the exposure output signal can be controlled by software or by a physical mode switch:

• If the integrated LED is enabled, the LED turns on during the integration period of the sensor. The image brightness can only be changed by adjusting the integration time with FG_set_shutter_time().
• The exposure signal of the sensor can be mirrored to a digital OUT wire. This allows synchronization of an external lighting unit. The output signal can be selected with the special feature StrobeOutput.

The position of the physical switch is used for mode selection unless it's overwritten by software. For software mode control, use the special feature StrobeMode. The value for this parameter is equal to the switch position for modes 0...2:

Strobe modes

Switch position	Software control (StrobeMode)	Integrated LED	Digital output OUT<i>
0	0	Enabled	Controlled by VIB::DigitalOutput
1	1	Off	Sensor exposure signal
2	2	Off	Controlled by VIB::DigitalOutput
-	3	Enabled	Sensor exposure signal
-	-1	Controlled by switch

Note

The mode switch is not present on most devices and is therefore only controlled by software.

Special features for strobe

Property name	Description	Library
StrobeMode	Sets the operating mode for the integrated LED and the exposure signal for replacing the physical mode switch. -1...3: strobe mode (default: 2 if no switch is present) Note This feature requires PRU firmware ≥ 1.1.0.0.	≥ 1.2.0.0
StrobeOutput	Selects the digital output line for the external exposure signal. 0...<i>: index of digital output signal OUT<i> (default: 0) Note This feature requires PRU firmware ≥ 1.3.0.0.	≥ 1.2.3.0

Example:

// Enable the integrated LED and exposure signal on digital output:
FG_set_special_option("StrobeMode", 3);
 
// Select output OUT1 for the exposure signal:
FG_set_special_option("StrobeOutput", 1);

Note

The maximum LED strobe time gets automatically limited to a duty cycle of 25% for protection of the hardware. For example: when using a frame rate of 60 fps, the LED strobe time will be dynamically limited to 4.17 ms if the exposure time setting is longer. The external strobe signal on digital outputs will not be limited.