Add examples: grab multiple image frames

samples/grabMultipleFrames.py

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+'''
+Use pypylon to grab multiple image frames with hardware triggers.
+Test camera: acA640-750um
+Version: pypylon == 4.1.0
+Maximum framerate: 1000fps
+'''
+from pypylon import pylon
+import traceback
+import numpy as np
+
+# your recording frames
+numFrames = 1000
+# Initialize camera instance and open the camera
+cam = pylon.InstantCamera(pylon.TlFactory.GetInstance().CreateFirstDevice())
+cam.Open()
+# Print the model name of the camera.
+print("Using camera device: ", cam.GetDeviceInfo().GetModelName())
+
+# class of image handler
+class ImageHandler(pylon.ImageEventHandler):
+    def __init__(self):
+        super().__init__()
+        self.count = 0
+        self.img_sum = []
+
+    def OnImagesSkipped(self, camera, countOfSkippedImages):
+        print(countOfSkippedImages, " images have been skipped.")
+
+    def OnImageGrabbed(self, camera, grabResult):
+        """ we get called on every image
+            !! this code is run in a pylon thread context
+            always wrap your code in the try .. except to capture
+            errors inside the grabbing as this can't be properly reported from 
+            the background thread to the foreground python code
+        """
+        try:
+            if grabResult.GrabSucceeded():
+                # check image contents
+                img = grabResult.Array
+                # Stack images to 3D array
+                self.img_sum.append(img)
+                self.count += 1
+                grabResult.Release()
+            else:
+                raise RuntimeError("Grab Failed")
+        except Exception as e:
+            traceback.print_exc() 
+
+# Control the parameter of the Basler camera
+# Get clean powerup state
+cam.UserSetSelector.Value = "Default"
+cam.UserSetLoad.Execute()
+# Set the io section
+cam.LineSelector.Value = "Line1"
+cam.LineMode.Value = "Input"
+# Setup the trigger/ acquisition controls
+cam.TriggerSelector.Value = "FrameStart"
+cam.TriggerSource.Value = "Line1"
+cam.TriggerMode.Value = "On"
+cam.TriggerActivation.Value = "RisingEdge"
+print("The resulting Trigger Activation is: " + str(cam.TriggerActivation.Value))
+
+# Instantiate callback handler of camera image
+handler = ImageHandler()
+# handler registration for camera
+cam.RegisterImageEventHandler(handler , pylon.RegistrationMode_ReplaceAll, pylon.Cleanup_None)
+# start capturing frames
+cam.StartGrabbingMax(numFrames + 1, pylon.GrabStrategy_LatestImages, pylon.GrabLoop_ProvidedByInstantCamera)
+# other hardware running time here...
+cam.StopGrabbing()
+cam.DeregisterImageEventHandler(handler)
+cam.TriggerMode.Value = "Off"
+cam.Close()
+print("Recorded frames in the camera is: ", str(handler.count)) 
+cameraImages = np.array(handler.img_sum).transpose(1,2,0)
+# check if captured camera frames are the same with the patterns
+assert cameraImages.shape[2] == numFrames