SingleCaptureMasterSlave.cpp

The SingleCaptureMasterSlave program is based on the SingleCapture.cpp example. This sample program will (for mvBlueCOUGAR devices) show, how to set up a set of devices in a master/slave mode. One camera's digital output will be fed into a user selectable digital input of all cameras. All cameras will be set up to run in "external triggered" mode then and the sample application will toggle the selected digital output with a user selectable frequency. This will result in all devices being triggered synchronously when a pulse is generated on the master devices digital output

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 SingleCaptureMasterSlave.cpp can be found under:

%INSTALLDIR%\apps\SingleCaptureMasterSlave\

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.

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. 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).

The sample needs at least two valid devices to run properly and checks this with getValidDevices() from the included exampleHelper.h.

The application will allow the user to specify the master and some slave devices. The selected master devices digital output must be connected appropriately to the selected digital inputs of all. An example for the electrical setup can be seen in the following picture:

Figure 1: Electrical setup.

You could extend the sample and trigger this configuration externally. The electrical setup would be like this:

Figure 2: Electrical setup external trigger. OUT0 = ExposureActive

All the device specific init code is wrapped in the DeviceData struct.

The user can select the digital output of the master and the digital inputs of all devices (via function setupTriggerInput()).

The application will start a capture thread for each device and within the thread the capture queue of each device is pre-filled with some requests (using a DeviceData array with both devices). Once the acquisition threads are running another thread will be started, that will periodically generate trigger signals by flipping the state of the selected digital output with a user defined frequency.

Note

The sample shows when and how you have to release the imageRequest buffer (unlock) in this type of application.

Source code

//
// @description: Example applications for Impact Acquire
// @copyright: Copyright (C) 2010 - 2024 Balluff GmbH
// @authors: APIs and drivers development team at Balluff GmbH
// @initial date: 2010-05-11
//
// 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 <cstdio>
#include <iostream>
#include <memory>
#include <mutex>
#include <thread>
#include <apps/Common/exampleHelper.h>
#include <mvIMPACT_CPP/mvIMPACT_acquire.h>
#ifdef _WIN32
#   include <mvDisplay/Include/mvIMPACT_acquire_display.h>
using namespace mvIMPACT::acquire::display;
#   define USE_DISPLAY
#endif // #ifdef _WIN32
 
using namespace std;
using namespace mvIMPACT::acquire;
 
static mutex s_mutex;
 
//-----------------------------------------------------------------------------
class ThreadData
//-----------------------------------------------------------------------------
{
    volatile bool boTerminateThread_;
    unique_ptr<thread> pThread_;
public:
    explicit ThreadData() : boTerminateThread_( false ), pThread_() {}
    virtual ~ThreadData() {}
    bool terminated( void ) const
    {
        return boTerminateThread_;
    }
    template<class _Fn, class _Arg>
    void startThread( _Fn&& _Fx, _Arg&& _Ax )
    {
        pThread_ = unique_ptr<thread>( new thread( _Fx, _Ax ) );
    }
    void terminateThread( void )
    {
        boTerminateThread_ = true;
        if( pThread_ )
        {
            pThread_->join();
        }
    }
};
 
//-----------------------------------------------------------------------------
class DeviceData : public ThreadData
//-----------------------------------------------------------------------------
{
    Device* pDev_;
    bool isMaster_;
    unique_ptr<FunctionInterface> pFI_;
    unique_ptr<IOSubSystem> pIOSS_;
    unique_ptr<Statistics> pSS_;
#ifdef USE_DISPLAY
    unique_ptr<ImageDisplayWindow> pDisplayWindow_;
#endif // #ifdef USE_DISPLAY
    int lastRequestNr_;
public:
    explicit DeviceData( Device* p ) : ThreadData(), pDev_( p ), isMaster_( false ), pFI_(), pIOSS_(), pSS_(),
#ifdef USE_DISPLAY
        pDisplayWindow_(),
#endif // #ifdef USE_DISPLAY
        lastRequestNr_( INVALID_ID ) {}
    ~DeviceData()
    {
        if( pFI_->isRequestNrValid( lastRequestNr_ ) )
        {
            pFI_->imageRequestUnlock( lastRequestNr_ );
            lastRequestNr_ = INVALID_ID;
        }
    }
    void init( const bool isMaster )
    {
        pDev_->open();
        isMaster_ = isMaster;
        pFI_ = unique_ptr<FunctionInterface>( new FunctionInterface( pDev_ ) );
        pSS_ = unique_ptr<Statistics>( new Statistics( pDev_ ) );
        pIOSS_ = unique_ptr<IOSubSystemCommon>( new IOSubSystemCommon( pDev_ ) );
        {
            lock_guard<mutex> lockedScope( s_mutex );
            cout << "Please note that there will be just one refresh for the display window, so if it is\n"
                 << "hidden under another window the result will not be visible.\n";
        }
#ifdef USE_DISPLAY
        pDisplayWindow_ = unique_ptr<ImageDisplayWindow>( new ImageDisplayWindow( string( isMaster ? "Master " : "Slave " ) + pDev_->serial.read() ) );
#endif // #ifdef USE_DISPLAY
    }
    Device* device( void ) const
    {
        return pDev_;
    }
    FunctionInterface* functionInterface( void ) const
    {
        return pFI_.get();
    }
    bool isMaster( void ) const
    {
        return isMaster_;
    }
    IOSubSystem* IOSS( void ) const
    {
        return pIOSS_.get();
    }
    Statistics* statistics( void ) const
    {
        return pSS_.get();
    }
#ifdef USE_DISPLAY
    ImageDisplayWindow* pDisp( void )
    {
        return pDisplayWindow_.get();
    }
#endif // USE_DISPLAY
};
 
//-----------------------------------------------------------------------------
class TriggerSignal : public ThreadData
//-----------------------------------------------------------------------------
{
    DigitalOutput* pTriggerOutput_;
    unsigned int frequency_Hz_;
public:
    explicit TriggerSignal( DigitalOutput* pTriggerOutput, unsigned int frequency_Hz ) : ThreadData(), pTriggerOutput_( pTriggerOutput ), frequency_Hz_( frequency_Hz ) {}
    DigitalOutput* triggerOutput( void ) const
    {
        return pTriggerOutput_;
    }
    unsigned int frequency_Hz( void ) const
    {
        return frequency_Hz_;
    }
};
 
//-----------------------------------------------------------------------------
void liveThread( DeviceData* pThreadParameter )
//-----------------------------------------------------------------------------
{
#ifdef USE_DISPLAY
    ImageDisplay& display = pThreadParameter->pDisp()->GetImageDisplay();
#endif // #ifdef USE_DISPLAY
    // establish access to the statistic properties
    Statistics* pSS = pThreadParameter->statistics();
    // create an interface to the device found
    FunctionInterface* pFI = pThreadParameter->functionInterface();
 
    // 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 = DMR_NO_ERROR;
    while( ( result = static_cast<TDMR_ERROR>( pFI->imageRequestSingle() ) ) == DMR_NO_ERROR ) {};
    if( result != DEV_NO_FREE_REQUEST_AVAILABLE )
    {
        lock_guard<mutex> lockedScope( s_mutex );
        cout << "'FunctionInterface.imageRequestSingle' returned with an unexpected result: " << result
             << "(" << ImpactAcquireException::getErrorCodeAsString( result ) << ")" << endl;
    }
 
    manuallyStartAcquisitionIfNeeded( pThreadParameter->device(), *pFI );
    // run thread loop
    const unsigned int timeout_ms = {200};
    // 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 = {INVALID_ID};
    unsigned int cnt = {0};
    while( !pThreadParameter->terminated() )
    {
        // wait for results from the default capture queue
        const int requestNr = pFI->imageRequestWaitFor( timeout_ms );
        if( pFI->isRequestNrValid( requestNr ) )
        {
            const Request* pRequest = pFI->getRequest( requestNr );
            if( pRequest->isOK() )
            {
                ++cnt;
                // here we can display some statistical information every 100th image
                if( cnt % 100 == 0 )
                {
                    lock_guard<mutex> lockedScope( s_mutex );
                    cout << "Info from " << pThreadParameter->device()->serial.read() << "(" << ( pThreadParameter->isMaster() ? "Master" : "Slave" ) << ")"
                         << ": " << pSS->framesPerSecond.name() << ": " << pSS->framesPerSecond.readS()
                         << ", " << pSS->errorCount.name() << ": " << pSS->errorCount.readS()
                         << ", " << pRequest->infoFrameNr
                         << ", " << pRequest->infoFrameID
                         << ", " << pSS->frameCount << endl;
                }
#ifdef USE_DISPLAY
                display.SetImage( pRequest );
                display.Update();
#endif // #ifdef USE_DISPLAY
            }
            else
            {
                lock_guard<mutex> lockedScope( s_mutex );
                cout << "Error: " << pRequest->requestResult.readS() << endl;
            }
            if( pFI->isRequestNrValid( lastRequestNr ) )
            {
                // this image has been displayed thus the buffer is no longer needed...
                pFI->imageRequestUnlock( lastRequestNr );
            }
            lastRequestNr = requestNr;
            // send a new image request into the capture queue
            pFI->imageRequestSingle();
        }
        else
        {
            //lock_guard<mutex> lockedScope( s_mutex );
            // 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.
            // cout << "imageRequestWaitFor failed (" << requestNr << ", " << ImpactAcquireException::getErrorCodeAsString( requestNr ) << ")"
            //   << ", timeout value too small?" << endl;
        }
    }
 
    {
        lock_guard<mutex> lockedScope( s_mutex );
        cout << "Overall good frames captured from device " << pThreadParameter->device()->serial.read() << ": " << cnt << endl;
    }
    manuallyStopAcquisitionIfNeeded( pThreadParameter->device(), *pFI );
 
#ifdef USE_DISPLAY
    // stop the display from showing freed memory
    display.RemoveImage();
#endif // #ifdef 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( pFI->isRequestNrValid( lastRequestNr ) )
    {
        pFI->imageRequestUnlock( lastRequestNr );
    }
    // clear all queues
    pFI->imageRequestReset( 0, 0 );
}
 
//-----------------------------------------------------------------------------
void triggerThread( TriggerSignal* pSignal )
//-----------------------------------------------------------------------------
{
    unsigned int cnt = {0};
    const unsigned int sleepPeriod_ms = 1000 / ( pSignal->frequency_Hz() * 2 );
    while( !pSignal->terminated() )
    {
        // generate a trigger signal
        this_thread::sleep_for( chrono::milliseconds( sleepPeriod_ms ) );
        pSignal->triggerOutput()->flip();
        this_thread::sleep_for( chrono::milliseconds( sleepPeriod_ms ) );
        pSignal->triggerOutput()->flip();
        ++cnt;
        if( cnt % 100 == 0 )
        {
            lock_guard<mutex> lockedScope( s_mutex );
            cout << "Trigger signals generated: " << cnt << endl;
        }
    }
    lock_guard<mutex> lockedScope( s_mutex );
    cout << "Overall trigger signals generated: " << cnt << endl;
}
 
//-----------------------------------------------------------------------------
unsigned int getNumberFromUser( void )
//-----------------------------------------------------------------------------
{
    unsigned int nr = {0};
    std::cin >> nr;
    // remove the '\n' from the stream
    std::cin.get();
    return nr;
}
 
//-----------------------------------------------------------------------------
bool isDeviceSupportedBySample( const Device* const pDev )
//-----------------------------------------------------------------------------
{
    return match( pDev->product.read(), string( "mvBlueCOUGAR-X*" ), '*' ) == 0;
}
 
//-----------------------------------------------------------------------------
void setupTriggerInput( DeviceData* pDevData )
//-----------------------------------------------------------------------------
{
    cout << "Select the digital INPUT of device(" << pDevData->device()->serial.read() << ")(as a string) that shall serve as a trigger input:" << endl;
    CameraSettingsBlueCOUGAR cs( pDevData->device() );
    DisplayPropertyDictionary<mvIMPACT::acquire::PropertyI>( cs.triggerSource );
    modifyPropertyValue( cs.triggerSource );
    cs.triggerMode.write( ctmOnRisingEdge );
    // infinite trigger timeout
    cs.imageRequestTimeout_ms.write( 0 );
}
 
//-----------------------------------------------------------------------------
int main( void )
//-----------------------------------------------------------------------------
{
    cout << "This sample is meant for mvBlueCOUGAR-X devices only. Other devices might be installed" << endl
         << "but won't be recognized by the application." << endl
         << endl;
 
    DeviceManager devMgr;
    std::vector<mvIMPACT::acquire::Device*> validDevices;
    if( getValidDevices( devMgr, validDevices, isDeviceSupportedBySample ) < 2 )
    {
        cout << "This sample needs at least 2 valid devices(one master and one slave). " << validDevices.size() << " device(s) has/have been detected." << endl
             << "Unable to continue! Press [ENTER] to end the application" << endl;
        cin.get();
        return 1;
    }
 
    cout << "Please select the MASTER device(the one that will create the trigger for all devices).\n\n";
    Device* pMaster = getDeviceFromUserInput( devMgr, isDeviceSupportedBySample, true );
    if( pMaster == nullptr )
    {
        cout << "Master device has not been properly selected. Unable to continue!\n"
             << "Press [ENTER] to end the application\n";
        cin.get();
        return 1;
    }
 
    set<Device*> setOfSlaves;
    do
    {
        cout << "\nPlease select a SLAVE device(this one will be triggered by the master).\n\n";
        Device* p = getDeviceFromUserInput( devMgr, isDeviceSupportedBySample, true );
        if( p == pMaster )
        {
            cout << "Master and slave must be different. Skipped!" << endl;
        }
        else if( p != nullptr )
        {
            if( setOfSlaves.find( p ) == setOfSlaves.end() )
            {
                setOfSlaves.insert( p );
            }
            else
            {
                cout << "ALL slaves must be different. This one has already been selected. Skipped!" << endl;
            }
        }
        cout << "\nAdd another slave device('y')? ";
    }
    while( getchar() == 'y' );
 
    cout << endl;
    vector<DeviceData*> devices;
    devices.push_back( new DeviceData( pMaster ) );
    for( auto* const pSlave : setOfSlaves )
    {
        devices.push_back( new DeviceData( pSlave ) );
    }
    const vector<DeviceData*>::size_type DEV_COUNT = devices.size();
    DigitalOutput* pTriggerOutput = nullptr;
    try
    {
        for( vector<DeviceData*>::size_type i = 0; i < DEV_COUNT; i++ )
        {
            cout << "Initialising device " << devices[i]->device()->serial.read() << "..." << endl;
            const bool isMaster = i == 0;
            devices[i]->init( isMaster );
            cout << endl
                 << "Setup the " << ( isMaster ? "MASTER" : "SLAVE" ) << " device:" << endl
                 << "===========================" << endl
                 << endl;
            if( isMaster )
            {
                const unsigned int digoutCount = devices[i]->IOSS()->getOutputCount();
                for( unsigned int digOut = 0; digOut < digoutCount; digOut++ )
                {
                    cout << "  [" << digOut << "]: " << devices[i]->IOSS()->output( digOut )->getDescription() << endl;
                }
                cout << endl
                     << "Select the digital OUTPUT of the MASTER device(" << devices[i]->device()->serial.read() << ") where the trigger pulse shall be generated on: ";
                pTriggerOutput = devices[i]->IOSS()->output( getNumberFromUser() );
                cout << endl;
            }
            setupTriggerInput( devices[i] );
        }
    }
    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 devices(error code: " << e.getErrorCodeAsString() << ")." << endl
             << "Press [ENTER] to end the application" << endl;
        cin.get();
        return 1;
    }
 
    try
    {
        // get trigger frequency from user
        unsigned int triggerFrequency_Hz = {0};
        bool boRun = {true};
        while( boRun )
        {
            cout << "Please enter the approx. desired trigger frequency in Hz: ";
            triggerFrequency_Hz = getNumberFromUser();
            if( ( triggerFrequency_Hz >= 1 ) && ( triggerFrequency_Hz <= 100 ) )
            {
                boRun = false;
                continue;
            }
            cout << "Invalid Selection. This sample will accept values from 1 - 100." << endl;
        }
        TriggerSignal triggerSignal( pTriggerOutput, triggerFrequency_Hz );
 
        // start live threads
        for( auto* pDevData : devices )
        {
            pDevData->startThread( liveThread, pDevData );
        }
 
        // now all capture threads will start running...
        // before starting the trigger thread wait a little bit to allow the camera threads to set up completely
        this_thread::sleep_for( chrono::milliseconds( 1000 ) );
        triggerSignal.startThread( triggerThread, &triggerSignal );
 
        {
            lock_guard<mutex> lockedScope( s_mutex );
            cout << "Press [ENTER] to end the acquisition" << endl;
        }
        if( getchar() == EOF )
        {
            printf( "Calling '_getch()' did return EOF...\n" );
        }
 
        // stop all threads again
        {
            lock_guard<mutex> lockedScope( s_mutex );
            cout << "Terminating threads..." << endl;
        }
 
        for( auto* pDevData : devices )
        {
            pDevData->terminateThread();
        }
        triggerSignal.terminateThread();
    }
    catch( const ImpactAcquireException& e )
    {
        cout << "An error occurred(error code: " << e.getErrorCodeAsString() << ")." << endl;
        cout << "Press [ENTER] to end the application" << endl;
        cin.get();
        return 1;
    }
    cout << "Press [ENTER] to end the application" << endl;
    cin.get();
    return 0;
}