ContinuousCaptureAllDevices.cs

The ContinuousCaptureAllDevices program is based on the ContinuousCapture example. It will try to open every device detected in the system and will display a live image with using the current settings stored for the individual device. Each live image will be displayed in a separate window.

Note

Please note that when there are a lot of devices connected to the system, the system might start to react slowly because of the massive amount of data it has to cope with. In that case the ContinuousCapture sample can be used to acquire live images from a particular device.

Program location

The source file ContinuousCaptureAllDevices.cs can be found under:

%INSTALLDIR%\apps\CSharp\ContinuousCaptureAllDevices\

Note

If you have installed the package without example applications, this file will not be available. On Windows® the sample application can be installed or removed from the target system at any time by simply restarting the installation package.

ContinuousCaptureAllDevices example:

1. Opens a Balluff device.
2. Snaps images from every detected device continuously (without display using Linux).

Console Output

[0]: BF000306 (mvBlueFOX-202C, Family: mvBlueFOX, interface layout: DeviceSpecific)

Please enter the number in front of the listed device followed by [ENTER] to open it: 0
Using device number 0.
Press [ENTER] to end the application
Initialising the device. This might take some time...
Info from BF000306: FramesPerSecond: 28.655660, ErrorCount: 0, CaptureTime_s: 0.104195
Info from BF000306: FramesPerSecond: 28.655636, ErrorCount: 0, CaptureTime_s: 0.104017
Info from BF000306: FramesPerSecond: 28.655659, ErrorCount: 0, CaptureTime_s: 0.104153
Info from BF000306: FramesPerSecond: 28.655636, ErrorCount: 0, CaptureTime_s: 0.104072
Info from BF000306: FramesPerSecond: 28.655660, ErrorCount: 0, CaptureTime_s: 0.104234

How it works

The continuous acquisition is similar to the single capture. The only major difference is, that this sample starts a separate thread that continuously requests images from the device.

However, the general stuff (selection of a device etc.) are similar to the SingleCapture source example. The major difference is that the user is not prompted to select a device as this application will use every recognized device anyway. Thus the main function looks slightly different while the actual acquisition thread remains unchanged (apart from some sync. Work that needs to be done for writing to the standard output).

Note

The thread related functions are written with the Windows® API. Users working on other platforms therefore will have to replace these system calls by the corresponding functions calls appropriate on their platforms.

static void Main(string[] args)
{
  mv.impact.acquire.LibraryPath.init(); // this will add the folders containing unmanaged libraries to the PATH variable.
  if (DeviceManager.deviceCount < 1)
  {
    Console.WriteLine("Unable to continue! Press any key to end the program.");
    Console.Read();
    Environment.Exit(1);
  }
 
  string productFilter = "";
 
  // scan command line
  if (args.Length == 1)
  {
    for (int i = 0; i < args.Length; i++)
    {
      string param = args[i], key, value;
      int keyEnd = param.IndexOf('=');
      if ((!param.Contains("=")) || (keyEnd == param.Length))
      {
        Console.WriteLine("Invalid command-line parameter: '{0}' (ignored).", param);
      }
      else
      {
        key = param.Substring(0, keyEnd);
        value = param.Substring(keyEnd + 1);
        if ((key == "product") || (key == "p"))
        {
          productFilter = value;
        }
        else
        {
          Console.WriteLine("Invalid command-line parameter: '{0}' (ignored).", param);
        }
      }
    }
  }
  else
  {
    Console.WriteLine("No command-line parameters specified. Available parameters:");
    Console.WriteLine("  'product' or 'p' to specify a certain product type. All other products will be ignored then");
    Console.WriteLine("      a '*' serves as a wildcard.");
    Console.WriteLine();
    Console.WriteLine("USAGE EXAMPLE:");
    Console.WriteLine("  ContinuousCaptureAllDevices p=mvBlue* ");
    Console.WriteLine();
  }
 
  // store all device infos in a vector
  // and start the execution of a 'live' thread for each device.
  List<ThreadParameters> threadParams = new List<ThreadParameters>();
  for (int i = 0; i < DeviceManager.deviceCount; i++)
  {
    if (DeviceManager.deviceList[i].product.read().Contains(productFilter))
    {
      // initialise display window
      // IMPORTANT: It's NOT save to create multiple display windows in multiple threads!!!
      // Therefore this must be done before starting the threads
      string windowtitle = String.Concat("mvIMPACT_acquire sample, Device " + DeviceManager.deviceList[i].serial.read());
      // store thread parameter for this device in the vector
      threadParams.Add(new ThreadParameters(DeviceManager.deviceList[i], windowtitle));
      Console.WriteLine("{0} ({1})", DeviceManager.deviceList[i].family.read(), DeviceManager.deviceList[i].serial.read());
    }
  }
 
  if (threadParams.Count == 0)
  {
    Console.WriteLine("No device found that matches the product filter '{0}'! Unable to continue!", productFilter);
    Environment.Exit(1);
  }
 
  // start live threads
  foreach (ThreadParameters p in threadParams)
  {
    p.thread = new Thread(ContinuousCaptureAllDevices.liveThread);
    p.thread.Start(p);
  }
 
  // now all threads will start running...
  Console.WriteLine("Press [ENTER] to start the acquisition( the initialisation of the devices might take some time )");
  Console.ReadKey();
 
  // stop all threads again
  Console.WriteLine("Terminating live threads...");
 
  // wait until each live thread has terminated.
  foreach (ThreadParameters p in threadParams)
  {
    p.terminated = true;
    p.thread.Join();
  }
}

Then after the device has been initialized successfully image requests will constantly be sent to the drivers request queue and the application waits for the results:

// Send all requests to the capture queue. There can be more than 1 queue for some devices, but for this sample
// we will work with the default capture queue. If a device supports more than one capture or result
// queue, this will be stated in the manual. If nothing is mentioned about it, the device supports one
// queue only. This loop will send all requests currently available to the driver. To modify the number of requests
// use the property mv.impactacquire.SystemSettings.requestCount at runtime (note that some devices will
// only allow to modify this parameter while NOT streaming data!) or the property
// mv.impactacquire.Device.defaultRequestCount BEFORE opening the device.
TDMR_ERROR result = TDMR_ERROR.DMR_NO_ERROR;
while ((result = (TDMR_ERROR)fi.imageRequestSingle()) == TDMR_ERROR.DMR_NO_ERROR) { };
if (result != TDMR_ERROR.DEV_NO_FREE_REQUEST_AVAILABLE)
{
  Console.WriteLine("'FunctionInterface.imageRequestSingle' returned with an unexpected result: {0}", result);
  Console.WriteLine("({0})", ImpactAcquireException.getErrorCodeAsString(result));
}
// Start the acquisition manually if this was requested(this is to prepare the driver for data capture and tell the device to start streaming data)
if (pThreadParameter.pDev.acquisitionStartStopBehaviour.read() == TAcquisitionStartStopBehaviour.assbUser)
{
  if ((result = (TDMR_ERROR)(fi.acquisitionStart())) != TDMR_ERROR.DMR_NO_ERROR)
  {
    Console.WriteLine("'FunctionInterface.acquisitionStart' returned with an unexpected result: {0}", result);
    Console.WriteLine("({0})", ImpactAcquireException.getErrorCodeAsString(result));
  }
}
 
// run thread loop
Request pRequest = null;
int timeout_ms = 500;
int requestNr = -1;
// we always have to keep at least 2 images as the display module might want to repaint the image, thus we
// can't free it unless we have a assigned the display to a new buffer.
int lastRequestNr = -1;
while (!pThreadParameter.terminated)
{
  // wait for results from the default capture queue
  requestNr = fi.imageRequestWaitFor(timeout_ms);
  if (fi.isRequestNrValid(requestNr))
  {
    pRequest = fi.getRequest(requestNr);
    if (pRequest.isOK)
    {
      ++cnt;
      // here we can display some statistical information every 100th image
      if (cnt % 100 == 0)
      {
        Console.WriteLine("Info from {0}: {1}: {2}, {3}: {4}, {5}: {6}", pThreadParameter.pDev.serial.read(),
        statistics.framesPerSecond.name, statistics.framesPerSecond.readS(),
        statistics.errorCount.name, statistics.errorCount.readS(),
        statistics.captureTime_s.name, statistics.captureTime_s.readS());
      }
    }
    else
    {
      Console.WriteLine("Error: {0}", pRequest.requestResult.readS());
    }
    if (fi.isRequestNrValid(lastRequestNr))
    {
      // this image has been displayed thus the buffer is no longer needed...
      fi.imageRequestUnlock(lastRequestNr);
    }
    lastRequestNr = requestNr;
    // send a new image request into the capture queue
    fi.imageRequestSingle();
  }
  else
  {
    // If the error code is -2119(DEV_WAIT_FOR_REQUEST_FAILED), the documentation will provide 
    // additional information under TDMR_ERROR in the interface reference (
    Console.WriteLine("imageRequestWaitFor failed ({0}, {1}, device {2})", requestNr, ImpactAcquireException.getErrorCodeAsString(requestNr), pThreadParameter.pDev.serial.read());
    Console.WriteLine(", timeout value too small?");
  }
}

With the request number returned by mv.impact.acquire.FunctionInterface.imageRequestWaitFor you can gain access the image buffer:

pRequest = fi.getRequest(requestNr);

The image attached to the request can then be processed and/or displayed if the request does not report an error.

When the image is no longer needed you have to unlock the image buffer as otherwise the driver will refuse to use it again. This makes sure, that no image, that is still used by the user will be overwritten by the device:

fi.imageRequestUnlock(lastRequestNr);

Source code

using System;
using System.Collections.Generic;
using System.Threading;
using mv.impact.acquire;
#if USE_DISPLAY
using mv.impact.acquire.display;
#endif // #if USE_DISPLAY
using mv.impact.acquire.examples.helper;
 
 
// Unlike the respective C++ example, no special measures have been taken to ensure
// "synchronised" console output by multiple threads. This is not necessary, since the
// Console.WriteLine() method of the .NET Framework guarantees thread-safety by itself.
 
namespace ContinuousCaptureAllDevices
{
    class ContinuousCaptureAllDevices
    {
        public class ThreadParameters
        {
            public Device pDev;
            public Thread thread;
#if USE_DISPLAY
            public ImageDisplayWindow window;
#endif // #if USE_DISPLAY
            public bool terminated = false;
 
            public ThreadParameters(Device Dev, string windowtitle)
            {
                pDev = Dev;
#if USE_DISPLAY
                window = new ImageDisplayWindow(windowtitle);
#endif // #if USE_DISPLAY
            }
 
            public void terminateThread()
            {
                terminated = true;
            }
        }
 
        public static void liveThread(Object pData)
        {
            ThreadParameters pThreadParameter = (ThreadParameters)pData;
            Device pDev = pThreadParameter.pDev;
            uint cnt = 0;
            Console.WriteLine("Trying to open {0}", pDev.serial.read());
            try
            {
                // if this device offers the 'GenICam' interface switch it on, as this will
                // allow are better control over GenICam compliant devices
                FeatureAccess.conditionalSetProperty(pDev.interfaceLayout, TDeviceInterfaceLayout.dilGenICam);
                // if this device offers a user defined acquisition start/stop behaviour
                // enable it as this allows finer control about the streaming behaviour
                FeatureAccess.conditionalSetProperty(pDev.acquisitionStartStopBehaviour, TAcquisitionStartStopBehaviour.assbUser);
                pDev.open();
            }
            catch (ImpactAcquireException e)
            {
                // this e.g. might happen if the same device is already opened in another process...
                Console.WriteLine("An error occurred while opening the device {0}", pDev.serial.read());
                Console.WriteLine("(error code: {0} ({1})). Terminating thread.", e.errorCode, e.errorCodeAsString);
                Console.WriteLine("Press [ENTER] to end the application...");
                return;
            }
 
            Console.WriteLine("Opened {0}", pDev.serial.read());
#if USE_DISPLAY
            ImageDisplay display = pThreadParameter.window.imageDisplay;
#endif // #if USE_DISPLAY
            // establish access to the statistic properties
            Statistics statistics = new Statistics(pDev);
            // create an interface to the device found
            FunctionInterface fi = new FunctionInterface(pDev);
 
            // Send all requests to the capture queue. There can be more than 1 queue for some devices, but for this sample
            // we will work with the default capture queue. If a device supports more than one capture or result
            // queue, this will be stated in the manual. If nothing is mentioned about it, the device supports one
            // queue only. This loop will send all requests currently available to the driver. To modify the number of requests
            // use the property mvIMPACT::acquire::SystemSettings::requestCount at runtime (note that some devices will
            // only allow to modify this parameter while NOT streaming data!) or the property
            // mvIMPACT::acquire::Device::defaultRequestCount BEFORE opening the device.
            TDMR_ERROR result = TDMR_ERROR.DMR_NO_ERROR;
            while ((result = (TDMR_ERROR)fi.imageRequestSingle()) == TDMR_ERROR.DMR_NO_ERROR) { };
            if (result != TDMR_ERROR.DEV_NO_FREE_REQUEST_AVAILABLE)
            {
                Console.WriteLine("'FunctionInterface.imageRequestSingle' returned with an unexpected result: {0}", result);
                Console.WriteLine("({0})", ImpactAcquireException.getErrorCodeAsString(result));
            }
 
            DeviceAccess.manuallyStartAcquisitionIfNeeded(pDev, fi);
            // run thread loop
            Request pRequest = null;
            int timeout_ms = 500;
            int requestNr = -1;
            // we always have to keep at least 2 images as the display module might want to repaint the image, thus we
            // can't free it unless we have a assigned the display to a new buffer.
            int lastRequestNr = -1;
            while (!pThreadParameter.terminated)
            {
                // wait for results from the default capture queue
                requestNr = fi.imageRequestWaitFor(timeout_ms);
                if (fi.isRequestNrValid(requestNr))
                {
                    pRequest = fi.getRequest(requestNr);
                    if (pRequest.isOK)
                    {
                        ++cnt;
                        // here we can display some statistical information every 100th image
                        if (cnt % 100 == 0)
                        {
                            Console.WriteLine("Info from {0}: {1}: {2}, {3}: {4}, {5}: {6}", pDev.serial.read(),
                            statistics.framesPerSecond.name, statistics.framesPerSecond.readS(),
                            statistics.errorCount.name, statistics.errorCount.readS(),
                            statistics.captureTime_s.name, statistics.captureTime_s.readS());
                        }
#if USE_DISPLAY
#   if CLR_AT_LEAST_3_DOT_5
                        // Extension methods are not supported by CLR versions smaller than 3.5 and this next function
                        // is therefore not available then.
                        display.SetImage(pRequest);
#   else
                        // If extension methods are not available, the following function can be used instead. It is
                        // not as convenient and will only work for some pixel formats. For more complex pixel formats
                        // use other overloads of this method
                        display.SetImage(pRequest.imageData.read(), pRequest.imageWidth.read(), pRequest.imageHeight.read(), pRequest.imageBytesPerPixel.read() * 8, pRequest.imageLinePitch.read());
#   endif
                        display.Update();
#endif // #if USE_DISPLAY
                    }
                    else
                    {
                        Console.WriteLine("Error: {0}", pRequest.requestResult.readS());
                    }
                    if (fi.isRequestNrValid(lastRequestNr))
                    {
                        // this image has been displayed thus the buffer is no longer needed...
                        fi.imageRequestUnlock(lastRequestNr);
                    }
                    lastRequestNr = requestNr;
                    // send a new image request into the capture queue
                    fi.imageRequestSingle();
                }
                //else
                //{
                // Please note that slow systems or interface technologies in combination with high resolution sensors
                // might need more time to transmit an image than the timeout value which has been passed to imageRequestWaitFor().
                // If this is the case simply wait multiple times OR increase the timeout(not recommended as usually not necessary
                // and potentially makes the capture thread less responsive) and rebuild this application.
                // Once the device is configured for triggered image acquisition and the timeout elapsed before
                // the device has been triggered this might happen as well.
                // The return code would be -2119(DEV_WAIT_FOR_REQUEST_FAILED) in that case, the documentation will provide
                // additional information under TDMR_ERROR in the interface reference.
                // If waiting with an infinite timeout(-1) it will be necessary to call 'imageRequestReset' from another thread
                // to force 'imageRequestWaitFor' to return when no data is coming from the device/can be captured.
                // Console.WriteLine("imageRequestWaitFor failed ({0}, {1}), timeout value too small?", requestNr, ImpactAcquireException.getErrorCodeAsString(requestNr));
                //}
            }
            DeviceAccess.manuallyStopAcquisitionIfNeeded(pDev, fi);
 
#if USE_DISPLAY
            // stop the display from showing freed memory
            display.RemoveImage();
#endif // #if USE_DISPLAY
            // In this sample all the next lines are redundant as the device driver will be
            // closed now, but in a real world application a thread like this might be started
            // several times an then it becomes crucial to clean up correctly.
 
            // free the last potentially locked request
            if (fi.isRequestNrValid(requestNr))
            {
                fi.imageRequestUnlock(requestNr);
            }
            // clear all queues
            fi.imageRequestReset(0, 0);
        }
 
        static void Main(string[] args)
        {
            mv.impact.acquire.LibraryPath.init(); // this will add the folders containing unmanaged libraries to the PATH variable.
            if (DeviceManager.deviceCount < 1)
            {
                Console.WriteLine("Unable to continue! Press any key to end the program.");
                Console.Read();
                Environment.Exit(1);
            }
 
            string productFilter = "";
 
            // scan command line
            if (args.Length >= 1)
            {
                for (int i = 0; i < args.Length; i++)
                {
                    string param = args[i];
                    int keyEnd = param.IndexOf('=');
                    if ((!param.Contains("=")) || (keyEnd == param.Length))
                    {
                        Console.WriteLine("Invalid command-line parameter: '{0}' (ignored).", param);
                    }
                    else
                    {
                        string key = param.Substring(0, keyEnd);
                        string value = param.Substring(keyEnd + 1);
                        if ((key == "product") || (key == "p"))
                        {
                            productFilter = value;
                        }
                        else
                        {
                            Console.WriteLine("Invalid command-line parameter: '{0}' (ignored).", param);
                        }
                    }
                }
            }
            else
            {
                Console.WriteLine("No command-line parameters specified. Available parameters:");
                Console.WriteLine("  'product' or 'p' to specify a certain product type. All other products will be ignored then");
                Console.WriteLine("      a '*' serves as a wildcard.");
                Console.WriteLine();
                Console.WriteLine("USAGE EXAMPLE:");
                Console.WriteLine("  ContinuousCaptureAllDevices p=mvBlue*");
                Console.WriteLine();
            }
 
            // store all device infos in a vector
            // and start the execution of a 'live' thread for each device.
            List<ThreadParameters> threadParams = new List<ThreadParameters>();
            for (int i = 0; i < DeviceManager.deviceCount; i++)
            {
                if (DeviceManager.deviceList[i].product.read().Contains(productFilter))
                {
                    // initialise display window
                    // IMPORTANT: It's NOT safe to create multiple display windows in multiple threads!!!
                    // Therefore this must be done before starting the threads
                    string windowtitle = String.Concat("mvIMPACT_acquire sample, Device " + DeviceManager.deviceList[i].serial.read());
                    // store thread parameter for this device in the vector
                    threadParams.Add(new ThreadParameters(DeviceManager.deviceList[i], windowtitle));
                    Console.WriteLine("{0} ({1})", DeviceManager.deviceList[i].family.read(), DeviceManager.deviceList[i].serial.read());
                }
            }
 
            if (threadParams.Count == 0)
            {
                Console.WriteLine("No device found that matches the product filter '{0}'! Unable to continue!", productFilter);
                Environment.Exit(1);
            }
 
            // start live threads
            foreach (ThreadParameters p in threadParams)
            {
                p.thread = new Thread(ContinuousCaptureAllDevices.liveThread);
                p.thread.Start(p);
            }
 
            // now all threads will start running...
            Console.WriteLine("Press [ENTER] to start the acquisition( the initialisation of the devices might take some time )");
            Console.ReadKey();
 
            // stop all threads again
            Console.WriteLine("Terminating live threads...");
 
            // wait until each live thread has terminated.
            foreach (ThreadParameters p in threadParams)
            {
                p.terminated = true;
                p.thread.Join();
            }
        }
    }
}