ContinuousCapture.cpp

The ContinuousCapture program is a simple example for a continuous acquisition.

Note

On Linux this example can only be built when using CMake with C++11 compliant compiler (e.g. gcc 5.0 or greater).

Program location

The source file ContinuousCapture.cpp can be found under:

%INSTALLDIR%\apps\ContinuousCapture\

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.

ContinuousCapture example:

1. Opens a Balluff device.
2. Snaps images 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.) is similar to the SingleCapture.cpp source example.

First of all the user is prompted to select the device he wants to use for this sample:

DeviceManager devMgr;
Device* pDev = getDeviceFromUserInput( devMgr );

The function getDeviceFromUserInput() is included via

#include <apps/Common/exampleHelper.h>

Then after the device has been initialized successfully a continuous acquisition is started using the mvIMPACT::acquire::helper::RequestProvider class:

helper::RequestProvider requestProvider( pDev );
requestProvider.acquisitionStart( myThreadCallback, std::ref( threadParam ) );

The function myThreadCallback will be called for each mvIMPACT::acquire::Request object becoming ready. An application can define an arbitrary function with arbitrary parameters for this operation. The first parameter however always has to be std::shared_ptr<mvIMPACT::acquire::Request>.

In this example the thread callback looks like this:

//-----------------------------------------------------------------------------
void myThreadCallback( shared_ptr<Request> pRequest, ThreadParameter& threadParameter )
//-----------------------------------------------------------------------------
{
  ++threadParameter.requestsCaptured_;
  // display some statistical information every 100th image
  if( threadParameter.requestsCaptured_ % 100 == 0 )
  {
    const Statistics& s = threadParameter.statistics_;
    cout << "Info from " << threadParameter.pDev_->serial.read()
         << ": " << s.framesPerSecond.name() << ": " << s.framesPerSecond.readS()
         << ", " << s.errorCount.name() << ": " << s.errorCount.readS()
         << ", " << s.captureTime_s.name() << ": " << s.captureTime_s.readS() << endl;
  }
  if( pRequest->isOK() )
  {
#ifdef USE_DISPLAY
    threadParameter.displayWindow_.GetImageDisplay().SetImage( pRequest );
    threadParameter.displayWindow_.GetImageDisplay().Update();
#else
    cout << "Image captured: " << pRequest->imageOffsetX.read() << "x" << pRequest->imageOffsetY.read() << "@" << pRequest->imageWidth.read() << "x" << pRequest->imageHeight.read() << endl;
#endif // #ifdef USE_DISPLAY
  }
  else
  {
    cout << "Error: " << pRequest->requestResult.readS() << endl;
  }
}

Accessing the mvIMPACT::acquire::Request object can be done after it has been checked using the mvIMPACT::acquire::Request::isOK function. The image attached to the request can then be processed and/or displayed if the request does not report an error.

if( pRequest->isOK() )
{
  // all good! Access the data!
}
else
{
  cout << "Error: " << pRequest->requestResult.readS() << endl;
}

Source code

//
// @description: Example applications for Impact Acquire
// @copyright: Copyright (C) 2005 - 2020 Balluff GmbH
// @authors: APIs and drivers development team at Balluff GmbH
// @initial date: 2005-05-04
//
// Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"),
// to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense,
// and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice (including the next paragraph) shall be included in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,i
// WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
//
 
#include <apps/Common/exampleHelper.h>
#include <functional>
#include <iostream>
#include <mvIMPACT_CPP/mvIMPACT_acquire_helper.h>
#ifdef _WIN32
#   include <mvDisplay/Include/mvIMPACT_acquire_display.h>
using namespace mvIMPACT::acquire::display;
#   define USE_DISPLAY
#endif // #ifdef _WIN32
 
using namespace mvIMPACT::acquire;
using namespace std;
 
//=============================================================================
//================= Data type definitions =====================================
//=============================================================================
//-----------------------------------------------------------------------------
struct ThreadParameter
//-----------------------------------------------------------------------------
{
    Device* pDev_;
    unsigned int requestsCaptured_;
    Statistics statistics_;
#ifdef USE_DISPLAY
    ImageDisplayWindow displayWindow_;
#endif // #ifdef USE_DISPLAY
    explicit ThreadParameter( Device* pDev ) : pDev_( pDev ), requestsCaptured_( 0 ), statistics_( pDev )
#ifdef USE_DISPLAY
        // initialise display window
        // IMPORTANT: It's NOT safe to create multiple display windows in multiple threads!!!
        , displayWindow_( "mvIMPACT_acquire sample, Device " + pDev_->serial.read() )
#endif // #ifdef USE_DISPLAY
    {}
    ThreadParameter( const ThreadParameter& src ) = delete;
    ThreadParameter& operator=( const ThreadParameter& rhs ) = delete;
};
 
//=============================================================================
//================= implementation ============================================
//=============================================================================
//-----------------------------------------------------------------------------
void myThreadCallback( shared_ptr<Request> pRequest, ThreadParameter& threadParameter )
//-----------------------------------------------------------------------------
{
    ++threadParameter.requestsCaptured_;
    // display some statistical information every 100th image
    if( threadParameter.requestsCaptured_ % 100 == 0 )
    {
        const Statistics& s = threadParameter.statistics_;
        cout << "Info from " << threadParameter.pDev_->serial.read()
             << ": " << s.framesPerSecond.name() << ": " << s.framesPerSecond.readS()
             << ", " << s.errorCount.name() << ": " << s.errorCount.readS()
             << ", " << s.captureTime_s.name() << ": " << s.captureTime_s.readS() << endl;
    }
    if( pRequest->isOK() )
    {
#ifdef USE_DISPLAY
        threadParameter.displayWindow_.GetImageDisplay().SetImage( pRequest );
        threadParameter.displayWindow_.GetImageDisplay().Update();
#else
        cout << "Image captured: " << pRequest->imageOffsetX.read() << "x" << pRequest->imageOffsetY.read() << "@" << pRequest->imageWidth.read() << "x" << pRequest->imageHeight.read() << endl;
#endif // #ifdef USE_DISPLAY
    }
    else
    {
        cout << "Error: " << pRequest->requestResult.readS() << endl;
    }
}
 
//-----------------------------------------------------------------------------
int main( void )
//-----------------------------------------------------------------------------
{
    DeviceManager devMgr;
    Device* pDev = getDeviceFromUserInput( devMgr );
    if( pDev == nullptr )
    {
        cout << "Unable to continue! Press [ENTER] to end the application" << endl;
        cin.get();
        return 1;
    }
 
    cout << "Initialising the device. This might take some time..." << endl;
    try
    {
        pDev->open();
    }
    catch( const ImpactAcquireException& e )
    {
        // this e.g. might happen if the same device is already opened in another process...
        cout << "An error occurred while opening the device " << pDev->serial.read()
             << "(error code: " << e.getErrorCodeAsString() << ").";
        return 1;
    }
 
    cout << "Press [ENTER] to stop the acquisition thread" << endl;
    ThreadParameter threadParam( pDev );
    helper::RequestProvider requestProvider( pDev );
    requestProvider.acquisitionStart( myThreadCallback, std::ref( threadParam ) );
    cin.get();
    requestProvider.acquisitionStop();
    return 0;
}