Source Code for Module pyvision.beta.videotasks

  1  ''' 
  2  Created on Jan 13, 2012 
  3   
  4  @author: bolme 
  5  ''' 
  6  import pyvision as pv 
  7  from pyvision.face.CascadeDetector import CascadeDetector 
  8  import vtm 
  9  import numpy as np 
 10   
 11 -class ChangeDetectionVT(vtm.VideoTask): 
 12       
 13 -    def __init__(self,frame_id): 
 14          ''' 
 15          This is a change detection task that computes the difference between the current and previous frames. 
 16          ''' 
 17          # request the current and previous frames. 
 18          vtm.VideoTask.__init__(self, frame_id, args=[("FRAME",frame_id),("FRAME",frame_id-1)]) 
 19           
 20 -    def execute(self, curr, prev): 
 21          ''' 
 22          Perform change detection between two frames. 
 23          ''' 
 24          # Get the frames as matrices 
 25          curr = curr.asMatrix2D() 
 26          prev = prev.asMatrix2D() 
 27           
 28          # Compute changes 
 29          diff = np.abs(curr - prev) 
 30          mask = diff > 20.0 
 31           
 32          # Create a new mask data item. 
 33          return [("CHANGE_MASK",self.getFrameId(),mask)] 
 34       
 35       
 36 -class ChangeDetectionAnnotationVT(vtm.VideoTask): 
 37       
 38 -    def __init__(self,frame_id): 
 39          ''' 
 40          Register for the current and previous frames. 
 41          ''' 
 42          vtm.VideoTask.__init__(self, frame_id, args=[("FRAME",frame_id),("CHANGE_MASK",frame_id)]) 
 43           
 44 -    def execute(self, frame, mask): 
 45          ''' 
 46          Perform change detection between two frames. 
 47          ''' 
 48          # Annotate the frame with the mask. 
 49          frame.annotateMask(mask,color='red') 
 50           
 51          # Return an empty list because no new items were created. 
 52          return [] 
 53       
 54 -class FaceDetectorVT(vtm.VideoTask): 
 55      ''' 
 56      This tasks illustrates one way to initialize data in the first frame by  
 57      changing the number of required arguments required by additional frames. 
 58      ''' 
 59 -    def __init__(self,frame_id): 
 60          if frame_id == 0: 
 61              # The first frame only requires the frame 
 62              vtm.VideoTask.__init__(self,frame_id,args=[("FRAME",frame_id)]) 
 63          else: 
 64              # Each additional frame requires an initialized detector. 
 65              # The underscore in _FACE_DETECTOR indicates this is not shared 
 66              # data. 
 67              vtm.VideoTask.__init__(self,frame_id,args=[("FRAME",frame_id),("_FACE_DETECTOR",frame_id-1)]) 
 68       
 69 -    def execute(self,frame,detector=None): 
 70          if detector == None: 
 71              print "Initializing Face Detector." 
 72              detector = CascadeDetector(min_size=(128,128)) 
 73           
 74          faces = detector(frame) 
 75          for rect in faces: 
 76              frame.annotateRect(rect) 
 77           
 78          return [('FACES',self.getFrameId(),faces),("_FACE_DETECTOR",self.getFrameId(),detector)] 
 79   
 80   
 81 -def runChangeDetectionExample(): 
 82      video = pv.Video(pv.BUGS_VIDEO) 
 83       
 84      vtm = vtm.VideoTaskManager(buffer_size=2,debug_level=2) 
 85      vtm.addTaskFactory(ChangeDetectionVT) 
 86      vtm.addTaskFactory(ChangeDetectionAnnotationVT) 
 87       
 88      for frame in video: 
 89          vtm.addFrame(frame) 
 90   
 91 -def runFaceDetectionExample(): 
 92      video = pv.Webcam() 
 93       
 94      vtm = vtm.VideoTaskManager(buffer_size=2,debug_level=3) 
 95      vtm.addTaskFactory(FaceDetectorVT) 
 96       
 97      for frame in video: 
 98          vtm.addFrame(frame) 
 99   
100  if __name__ == '__main__': 
101      #runChangeDetectionExample() 
102      runFaceDetectionExample() 
103