Capturing Image Data

To capture an image an instance of the class mv.impact.acquire.FunctionInterface must be created. This class can be constructed by passing a reference to the mv.impact.acquire.Device object obtained from the mv.impact.acquire.DeviceManager to the class constructor.

The function interface class provides access to most of the devices executable functions, while most of the settings (e.g. the exposure time or the trigger mode) are implemented as properties (see e.g. mv.impact.acquire.Property for details).

Getting the first image might e.g. look like that:

static void Main(string[] args)
{
  if (mv.impact.acquire.DeviceManager.deviceCount == 0)
  {
    Console.WriteLine("No device found! Unable to continue! Press any key to end the program.");
    Console.Read();
    Environment.Exit(1);
  }
 
  Device pDev = mv.impact.acquire.DeviceManager.getDevice(0); // get the first device found
  Console.WriteLine("Initialising device {0}. This might take some time...", pDev.serial.read());
  try
  {
    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 " + pDev.serial +
        "(error code: " + e.Message + "). Press any key to end the application...");
    Console.ReadLine();
    Environment.Exit(1);
  }
 
  mv.impact.acquire.FunctionInterface fi = new FunctionInterface(pDev);
 
  // send a request to the default request queue of the device and wait for the result.
  fi.imageRequestSingle();
  // Start the acquisition manually if this was requested(this is to prepare the framework for data capture and tell the device to start streaming data)
  if (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}({1})", result, ImpactAcquireException.getErrorCodeAsString(result));
    }
  }
  // wait for results from the default capture queue
  int requestNr = fi.imageRequestWaitFor(-1);
 
  // check if the image has been captured without any problems
  if (!fi.isRequestNrValid(requestNr))
  {
    // 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}), timeout value too small? Press any key to end the application...", requestNr, ImpactAcquireException.getErrorCodeAsString(requestNr));
    Console.ReadLine();
    Environment.Exit(1);
  }
 
  mv.impact.acquire.Request pRequest = fi.getRequest(requestNr);
  if (!pRequest->isOK())
  {
    Console.WriteLine("Error: {0}", pRequest.requestResult.readS());
    Environment.Exit(1);
  }
 
  // everything went well. Do whatever you like with the result
  int width = pRequest->imageWidth.read();
  // unlock the buffer to let the framework know that you no longer need this buffer
  fi.imageRequestUnlock(requestNr);
}

This sample contains everything the user needs to do to capture one image including all initialization work and error handling for every source of error one can think of.

Several example applications will provide an even better understanding of the interface.