Parallel Usage of Multiple Cameras

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Parallel Usage of Multiple Cameras

This topic explains how to use two cameras independently by running commands in separate execution nodes.

Please read the topics Opening a Camera and Grabbing 3D Data first.

Code Examples

Multi Threaded

Note: The code of the two threads only differs in the first two lines which specify a different execution node "thread1" or "thread2" and different camera serial number "1234" or "2345" to operate on.

hmtoggle_plus1C++

Thread 1 (opens and uses camera "1234"):

std::string executionSlot = "thread1"; // Use a separate execution slot name for all commands carried out by this thread
std::string cameraSerial = "1234"; //replace "1234" with your camera's serial number
 
// Call the Open command to open the cameras
NxLibCommand open(cmdOpen, executionSlot); // Make sure to execute all commands in the execution slot for this thread, so they don't collide with thread 2
open.parameters()[itmCameras] = cameraSerial;
open.execute();
 
for (int imageIndex = 0; imageIndex < 10; imageIndex++) {
   // Execute the Capture and ComputeDisparityMap command only on our own camera
   NxLibCommand capture(cmdCapture, executionSlot);
   capture.parameters()[itmCameras] = cameraSerial;
   capture.execute();
   NxLibCommand computeDisparityMap(cmdComputeDisparityMap, executionSlot);
   computeDisparityMap.parameters()[itmCameras] = cameraSerial;
   computeDisparityMap.execute();
}

Thread 2 (opens and uses camera "2345"):

std::string executionSlot = "thread2"; // Use a separate execution slot name for all commands carried out by this thread
std::string cameraSerial = "2345"; //replace "2345" with your camera's serial number
 
// Call the Open command to open the cameras
NxLibCommand open(cmdOpen, executionSlot); // Make sure to execute all commands in the execution slot for this thread, so they don't collide with thread 1
open.parameters()[itmCameras] = cameraSerial;
open.execute();
 
for (int imageIndex = 0; imageIndex < 10; imageIndex++) {
   // Execute the Capture and ComputeDisparityMap command only on our own camera
   NxLibCommand capture(cmdCapture, executionSlot);
   capture.parameters()[itmCameras] = cameraSerial;
   capture.execute();
   NxLibCommand computeDisparityMap(cmdComputeDisparityMap, executionSlot);
   computeDisparityMap.parameters()[itmCameras] = cameraSerial;
   computeDisparityMap.execute();
}
hmtoggle_plus1Halcon/HDevelop

Open frame grabbers with the parallel_execution flag. All NxLib commands (as well as grab_data operations) will then automatically be executed in a different command slot than the commands for other handles.

 

Procedure 1 (opens and uses camera "1234")

open_framegrabber ('Ensenso-NxLib', 0, 0, 0, 0, 0, 0, 'default', 0, 'Raw', 'parallel_execution=1', 'false', 'Stereo', '1234', 0, 0, CameraHandle)
 
set_framegrabber_param (CameraHandle, 'grab_data_items', 'Images/PointMap')
grab_data (Image, Region, Contours, CameraHandle, Data)

Procedure 2 (opens and uses camera "2345")

open_framegrabber ('Ensenso-NxLib', 0, 0, 0, 0, 0, 0, 'default', 0, 'Raw', 'parallel_execution=1', 'false', 'Stereo', '2345', 0, 0, CameraHandle)
 
set_framegrabber_param (CameraHandle, 'grab_data_items', 'Images/PointMap')
grab_data (Image, Region, Contours, CameraHandle, Data)