diff --git a/Modules/US/USModel/mitkUSVideoDevice.cpp b/Modules/US/USModel/mitkUSVideoDevice.cpp
index 225ce8d0c7..cf77b41cd4 100644
--- a/Modules/US/USModel/mitkUSVideoDevice.cpp
+++ b/Modules/US/USModel/mitkUSVideoDevice.cpp
@@ -1,190 +1,195 @@
 /*===================================================================
 
 The Medical Imaging Interaction Toolkit (MITK)
 
 Copyright (c) German Cancer Research Center,
 Division of Medical and Biological Informatics.
 All rights reserved.
 
 This software is distributed WITHOUT ANY WARRANTY; without
 even the implied warranty of MERCHANTABILITY or FITNESS FOR
 A PARTICULAR PURPOSE.
 
 See LICENSE.txt or http://www.mitk.org for details.
 
 ===================================================================*/
 
 #include "mitkUSVideoDevice.h"
 #include "mitkImageReadAccessor.h"
 
 mitk::USVideoDevice::USVideoDevice(int videoDeviceNumber, std::string manufacturer, std::string model) : mitk::USDevice(manufacturer, model)
 {
   Init();
   m_SourceIsFile = false;
   m_DeviceID = videoDeviceNumber;
   m_FilePath = "";
 }
 
 mitk::USVideoDevice::USVideoDevice(std::string videoFilePath, std::string manufacturer, std::string model) : mitk::USDevice(manufacturer, model)
 {
   Init();
   m_SourceIsFile = true;
   m_FilePath = videoFilePath;
 }
 
 mitk::USVideoDevice::USVideoDevice(int videoDeviceNumber, mitk::USImageMetadata::Pointer metadata) : mitk::USDevice(metadata)
 {
   Init();
   m_SourceIsFile = false;
   m_DeviceID = videoDeviceNumber;
   m_FilePath = "";
 }
 
 mitk::USVideoDevice::USVideoDevice(std::string videoFilePath, mitk::USImageMetadata::Pointer metadata) : mitk::USDevice(metadata)
 {
   Init();
   m_SourceIsFile = true;
   m_FilePath = videoFilePath;
 }
 
 mitk::USVideoDevice::~USVideoDevice()
 {
-  m_MultiThreader->TerminateThread(m_ThreadID);
+  if (m_ThreadID >= 0)
+  {
+    m_MultiThreader->TerminateThread(m_ThreadID);
+  }
 }
 
 void mitk::USVideoDevice::Init()
 {
+  m_ThreadID = -1; // initialize with invalid id
+
   m_Source = mitk::USImageVideoSource::New();
   //this->SetNumberOfInputs(1);
   this->SetNumberOfOutputs(1);
 
   // mitk::USImage::Pointer output = mitk::USImage::New();
   // output->Initialize();
   this->SetNthOutput(0, this->MakeOutput(0));
 
   this->m_MultiThreader = itk::MultiThreader::New();
   this->m_ImageMutex = itk::FastMutexLock::New();
   this->m_CameraActiveMutex= itk::FastMutexLock::New();
   m_IsActive = false;
 }
 
 std::string mitk::USVideoDevice::GetDeviceClass(){
   return "org.mitk.modules.us.USVideoDevice";
 }
 
 bool mitk::USVideoDevice::OnConnection()
 {
   if (m_SourceIsFile){
     m_Source->SetVideoFileInput(m_FilePath);
   } else {
      m_Source->SetCameraInput(m_DeviceID);
   }
   SetSourceCropArea();
   return true;
 }
 
 bool mitk::USVideoDevice::OnDisconnection()
 {
   if (m_IsActive) this->Deactivate();
   return true;
 }
 
 bool mitk::USVideoDevice::OnActivation()
 {
   // make sure that video device is ready before aquiring images
   if ( ! m_Source->GetIsReady() )
   {
     MITK_WARN("mitkUSDevice")("mitkUSVideoDevice") << "Could not activate us video device. Check if video grabber is configured correctly.";
     return false;
   }
 
   MITK_INFO << "Activated UsVideoDevice!";
   this->m_ThreadID = this->m_MultiThreader->SpawnThread(this->Acquire, this);
   return true;
 }
 
 void mitk::USVideoDevice::OnDeactivation()
 {
    // happens automatically when m_Active is set to false
 }
 
 void mitk::USVideoDevice::GenerateData()
 {
   m_ImageMutex->Lock();
 
   if ( m_Image.IsNull() || ! m_Image->IsInitialized() ) { m_ImageMutex->Unlock(); return; }
 
   mitk::USImage::Pointer result = this->GetOutput();
 
   if ( ! result->IsInitialized() )
   {
     result->Initialize(m_Image->GetPixelType(), m_Image->GetDimension(), m_Image->GetDimensions());
   }
 
   mitk::ImageReadAccessor inputReadAccessor(m_Image.GetPointer(), m_Image->GetSliceData(0,0,0));
   result->SetSlice(inputReadAccessor.GetData());
 
   m_ImageMutex->Unlock();
 
   // Set Metadata
   result->SetMetadata(this->m_Metadata);
   //Apply Transformation
   this->ApplyCalibration(result);
   // Set Output
   this->SetNthOutput(0, result);
 }
 
 void mitk::USVideoDevice::GrabImage()
 {
   mitk::USImage::Pointer image = m_Source->GetNextImage();
 
   this->m_ImageMutex->Lock();
   m_Image = image;
   this->m_ImageMutex->Unlock();
 
   //this->SetNthOutput(0, m_Image);
   //this->Modified();
 }
 
 void mitk::USVideoDevice::SetSourceCropArea()
 {
 if (this->m_Source.IsNotNull())
   {
     if((m_CropArea.cropBottom==0)&&
        (m_CropArea.cropTop==0)&&
        (m_CropArea.cropLeft==0)&&
        (m_CropArea.cropRight==0))
       {this->m_Source->RemoveRegionOfInterest();}
     else
       {
       int right = m_Source->GetImageWidth() - m_CropArea.cropRight;
       int bottom = m_Source->GetImageHeight() - m_CropArea.cropBottom;
       this->m_Source->SetRegionOfInterest(m_CropArea.cropLeft,
                                           m_CropArea.cropTop,
                                           right,
                                           bottom);
       }
   }
 else
   {MITK_WARN << "Cannot set crop are, source is not initialized!";}
 }
 
 void mitk::USVideoDevice::SetCropArea(mitk::USDevice::USImageCropArea newArea)
 {
 m_CropArea = newArea;
 MITK_INFO << "Set Crop Area L:" << m_CropArea.cropLeft << " R:" << m_CropArea.cropRight << " T:" << m_CropArea.cropTop << " B:" << m_CropArea.cropBottom;
 if (m_IsConnected) SetSourceCropArea();
 }
 
 ITK_THREAD_RETURN_TYPE mitk::USVideoDevice::Acquire(void* pInfoStruct)
 {
   /* extract this pointer from Thread Info structure */
   struct itk::MultiThreader::ThreadInfoStruct * pInfo = (struct itk::MultiThreader::ThreadInfoStruct*)pInfoStruct;
   mitk::USVideoDevice * device = (mitk::USVideoDevice *) pInfo->UserData;
   while (device->GetIsActive())
   {
     device->GrabImage();
   }
   return ITK_THREAD_RETURN_VALUE;
 }