GrabCallback

GrabCallback.py

from itala import itala
import threading
import time

INDENT = "\t"

# Grab images in a polling loop (until the "done" flag is False). Then call the callback function
# provided by the user. The "done" flag is passed by reference. Don't forget to catch exceptions,
# otherwise the thread will terminate. This function is meant to be ran in a dedicated thread.
def acquisition_loop(callback, device, done):
    while not done[0]:
        try:
            image = device.get_next_image(1000)
            callback(image)
        except Exception as e:
            error_msg = str(e)
            if "timeout" in error_msg.lower():
                print(INDENT + "Timeout occurred!")
            else:
                print(INDENT + "\r" + error_msg)
                break

# The actual user callback, called when an image is available.
def grab_callback(image):
    # Simulate some image processing and then dispose the image
    time.sleep(0.01)  # 10 milliseconds
    print(INDENT + "Image with ID:" + str(image.frame_id) + " processed.")
    image.dispose()

def main():
    print("***** GrabCallback example started. *****")
    print()

    system = itala.create_system()
    devices_info = system.enumerate_devices(700)
    
    if len(devices_info) == 0:
        print("No devices found. Example canceled.")
        exit(1)
    if devices_info[0].access_status != itala.DeviceAccessStatus_AvailableReadWrite:
        print("Target device is unaccessible in RW mode. Example canceled.")
        exit(1)
    
    device = system.create_device(devices_info[0])
    print("First device initialized.")
    
    device.start_acquisition()
    print("Acquisition started.")
    print()

    # Flag passed to the thread to stop grabbing images
    # Using a list to allow mutation in the thread (mutable container)
    done = [False]

    # Start the acquisition thread
    grabber = threading.Thread(target=acquisition_loop, args=(grab_callback, device, done))
    grabber.start()

    # Wait for user input to set the "done" flag to True and stop the acquisition
    print("Press Enter to stop acquisition..")
    print()
    input()
    done[0] = True
    grabber.join()

    device.stop_acquisition()
    print()
    print("Acquisition stopped.")
    print()
    
    device.dispose()
    print("Device instance disposed.")
    
    system.dispose()
    print("System instance disposed.")

if __name__ == "__main__":
    try:
        main()
    except Exception as e:
        print(str(e))