Real-time license plate recognition with 'openalpr' using a video file as input. Please check out my "Building and Testing 'openalpr' on Jetson TX2" post for more information: https://jkjung-avt.github.io/openalpr-on-tx2/

ALPRS0.2.py

import numpy as np
import cv2
from openalpr import Alpr


RTSP_SOURCE  = 'rtsp://face:Face12345@10.15.19.201:554/live.sdp'
WINDOW_NAME  = 'openalpr'
FRAME_SKIP   = 15


def open_cam_rtsp(uri, width=1280, height=720, latency=2000):
    gst_str = ('rtspsrc location={} latency={} ! '
               'rtph264depay ! h264parse ! omxh264dec ! nvvidconv ! '
               'video/x-raw, width=(int){}, height=(int){}, format=(string)BGRx ! '
               'videoconvert ! appsink').format(uri, latency, width, height)
    return cv2.VideoCapture(gst_str, cv2.CAP_GSTREAMER)


def main():
    alpr = Alpr('tw', 'tx2.conf', '/usr/local/share/openalpr/runtime_data')
    if not alpr.is_loaded():
        print('Error loading OpenALPR')
        sys.exit(1)
    alpr.set_top_n(3)
    #alpr.set_default_region('new')

    cap = open_cam_rtsp(RTSP_SOURCE)
    if not cap.isOpened():
        alpr.unload()
        sys.exit('Failed to open video file!')
    cv2.namedWindow(WINDOW_NAME, cv2.WINDOW_AUTOSIZE)
    cv2.setWindowTitle(WINDOW_NAME, 'OpenALPR video test')

    _frame_number = 0
    while True:
        ret_val, frame = cap.read()
        if not ret_val:
            print('VidepCapture.read() failed. Exiting...')
            break

        _frame_number += 1
        if _frame_number % FRAME_SKIP != 0:
            continue
        cv2.imshow(WINDOW_NAME, frame)

        results = alpr.recognize_ndarray(frame)
        for i, plate in enumerate(results['results']):
            best_candidate = plate['candidates'][0]
            print('Plate #{}: {:7s} ({:.2f}%)'.format(i, best_candidate['plate'].upper(), best_candidate['confidence']))

        if cv2.waitKey(1) == 27:
            break

    cv2.destroyAllWindows()
    cap.release()
    alpr.unload()


if __name__ == "__main__":
    main()