diff --git a/.gitignore b/.gitignore
index 0fd5f5c..52ef876 100644
--- a/.gitignore
+++ b/.gitignore
@@ -2,3 +2,4 @@
 __pycache__
 tests-dev/
 bk/
+build
\ No newline at end of file
diff --git a/=3.21.0 b/=3.21.0
new file mode 100644
index 0000000..928e227
--- /dev/null
+++ b/=3.21.0
@@ -0,0 +1 @@
+Requirement already satisfied: protobuf in /usr/local/lib/python3.13/dist-packages (6.33.0)
diff --git a/vilib/vilib.py b/vilib/vilib.py
index 5144f10..6008f22 100644
--- a/vilib/vilib.py
+++ b/vilib/vilib.py
@@ -247,9 +247,24 @@ def camera():
 
         picam2 = Vilib.picam2
 
-        preview_config = picam2.preview_configuration
+        # Ensure we have a fresh configuration
+        try:
+            preview_config = picam2.preview_configuration
+            if preview_config is None:
+                # Create new configuration if needed
+                config = picam2.create_preview_configuration()
+                picam2.configure(config)
+                preview_config = picam2.preview_configuration
+        except Exception as e:
+            print(f"Error getting preview configuration: {e}")
+            # Try to create a new configuration
+            config = picam2.create_preview_configuration()
+            picam2.configure(config)
+            preview_config = picam2.preview_configuration
+        
         # preview_config.size = (800, 600)
-        preview_config.size = Vilib.camera_size
+        if preview_config is not None:
+            preview_config.size = Vilib.camera_size
         preview_config.format = 'RGB888'  # 'XRGB8888', 'XBGR8888', 'RGB888', 'BGR888', 'YUV420'
         preview_config.transform = libcamera.Transform(
                                         hflip=Vilib.camera_hflip,
@@ -378,7 +393,30 @@ def camera_start(vflip=False, hflip=False, size=None):
     def camera_close():
         if Vilib.camera_thread != None:
             Vilib.camera_run = False
-            time.sleep(0.1)
+            time.sleep(0.2)
+            # Wait for camera thread to finish
+            if Vilib.camera_thread.is_alive():
+                Vilib.camera_thread.join(timeout=3.0)
+            
+            # Properly close and reinitialize Picamera2
+            try:
+                if Vilib.picam2 is not None:
+                    Vilib.picam2.close()
+                    time.sleep(0.2)
+                    
+                # Recreate Picamera2 object completely fresh
+                Vilib.picam2 = Picamera2()
+                
+            except Exception as e:
+                print(f"Warning during camera cleanup: {e}")
+                # Force recreation of Picamera2 object
+                try:
+                    Vilib.picam2 = Picamera2()
+                except Exception as e2:
+                    print(f"Failed to reinitialize camera: {e2}")
+            
+            # Reset thread reference
+            Vilib.camera_thread = None
 
     @staticmethod
     def display(local=True, web=True):
diff --git a/vilib/vilib_debug.py b/vilib/vilib_debug.py
new file mode 100644
index 0000000..f209b82
--- /dev/null
+++ b/vilib/vilib_debug.py
@@ -0,0 +1,846 @@
+#!/usr/bin/env python3
+
+# whther print welcome message
+import os
+import logging
+
+from .version import __version__
+if 'VILIB_WELCOME' not in os.environ or os.environ['VILIB_WELCOME'] not in [
+        'False', '0'
+]:
+    from pkg_resources import require
+    picamera2_version = require('picamera2')[0].version
+    print(f'vilib {__version__} launching ...')
+    print(f'picamera2 {picamera2_version}')
+
+# set libcamera2 log level
+os.environ['LIBCAMERA_LOG_LEVELS'] = '*:ERROR'
+from picamera2 import Picamera2
+import libcamera
+
+import cv2
+import numpy as np
+from PIL import Image, ImageDraw, ImageFont
+
+from flask import Flask, render_template, Response
+
+import time
+import datetime
+import threading
+from multiprocessing import Process, Manager
+
+from .utils import *
+
+# user and user home directory
+# =================================================================
+user = os.popen("echo ${SUDO_USER:-$(who -m | awk '{ print $1 }')}").readline().strip()
+user_home = os.popen(f'getent passwd {user} | cut -d: -f 6').readline().strip()
+# print(f"user: {user}")
+# print(f"user_home: {user_home}")
+
+# Default path for pictures and videos
+DEFAULLT_PICTURES_PATH = '%s/Pictures/vilib/'%user_home
+DEFAULLT_VIDEOS_PATH = '%s/Videos/vilib/'%user_home
+
+# utils
+# =================================================================
+def findContours(img):
+    _tuple = cv2.findContours(img, cv2.RETR_EXTERNAL,cv2.CHAIN_APPROX_SIMPLE)      
+    # compatible with opencv3.x and openc4.x
+    if len(_tuple) == 3:
+        _, contours, hierarchy = _tuple
+    else:
+        contours, hierarchy = _tuple
+    return contours, hierarchy
+
+# flask
+# =================================================================
+os.environ['FLASK_DEBUG'] = 'development'
+app = Flask(__name__)
+
+log = logging.getLogger('werkzeug')
+log.setLevel(logging.ERROR)
+
+@app.route('/')
+def index():
+    """Video streaming home page."""
+    return render_template('index.html')
+
+def get_frame():
+    return cv2.imencode('.jpg', Vilib.flask_img)[1].tobytes()
+
+def get_qrcode_pictrue():
+    return cv2.imencode('.jpg', Vilib.flask_img)[1].tobytes()
+
+def get_png_frame():
+    return cv2.imencode('.png', Vilib.flask_img)[1].tobytes()
+
+def get_qrcode():
+    while Vilib.qrcode_img_encode is None:
+         time.sleep(0.2)
+
+    return Vilib.qrcode_img_encode
+
+def gen():
+    """Video streaming generator function."""
+    while True:  
+        # start_time = time.time()
+        frame = get_frame()
+        yield (b'--frame\r\n'
+               b'Content-Type: image/jpeg\r\n\r\n' + frame + b'\r\n')
+        time.sleep(0.03)
+        # end_time = time.time() - start_time
+        # print('flask fps:%s'%int(1/end_time))
+
+@app.route('/mjpg') ## video
+def video_feed():
+    # from camera import Camera
+    """Video streaming route. Put this in the src attribute of an img tag."""
+    if Vilib.web_display_flag:
+        response = Response(gen(),
+                        mimetype='multipart/x-mixed-replace; boundary=frame') 
+        response.headers.add("Access-Control-Allow-Origin", "*")
+        return response
+    else:
+        tip = '''
+    Please enable web display first:
+        Vilib.display(web=True)
+'''
+        html = f"<html><style>p{{white-space: pre-wrap;}}</style><body><p>{tip}</p></body></html>"
+        return Response(html, mimetype='text/html')
+
+@app.route('/mjpg.jpg')  # jpg
+def video_feed_jpg():
+    # from camera import Camera
+    """Video streaming route. Put this in the src attribute of an img tag."""
+    response = Response(get_frame(), mimetype="image/jpeg")
+    response.headers.add("Access-Control-Allow-Origin", "*")
+    return response
+
+@app.route('/mjpg.png')  # png
+def video_feed_png():
+    # from camera import Camera
+    """Video streaming route. Put this in the src attribute of an img tag."""
+    response = Response(get_png_frame(), mimetype="image/png")
+    response.headers.add("Access-Control-Allow-Origin", "*")
+    return response
+
+@app.route("/qrcode")
+def qrcode_feed():
+    qrcode_html = '''
+<!DOCTYPE html>
+<html>
+<head>
+    <title>QRcode</title>
+    <script>
+        function refreshQRCode() {
+            var imgElement = document.getElementById('qrcode-img');
+            imgElement.src = '/qrcode.png?' + new Date().getTime();  // Add timestamp to avoid caching
+        }
+        var refreshInterval = 500;  // 2s
+
+        window.onload = function() {
+            refreshQRCode(); 
+            setInterval(refreshQRCode, refreshInterval);
+        };
+    </script>
+</head>
+<body>
+    <img id="qrcode-img" src="/qrcode.png" alt="QR Code" />
+</body>
+</html>
+'''
+    return Response(qrcode_html, mimetype='text/html')
+
+
+@app.route("/qrcode.png")
+def qrcode_feed_png():
+    """Video streaming route. Put this in the src attribute of an img tag."""
+    if Vilib.web_qrcode_flag:
+        # response = Response(get_qrcode(),
+        #                 mimetype='multipart/x-mixed-replace; boundary=frame')
+        response = Response(get_qrcode(), mimetype="image/png")
+        response.headers.add("Access-Control-Allow-Origin", "*")
+        return response
+    else:
+        tip = '''
+    Please enable web display first:
+        Vilib.display_qrcode(web=True)
+'''
+        html = f"<html><style>p{{white-space: pre-wrap;}}</style><body><p>{tip}</p></body></html>"
+        return Response(html, mimetype='text/html')
+
+def web_camera_start():
+    try:
+        Vilib.flask_start = True
+        app.run(host='0.0.0.0', port=9000, threaded=True, debug=False)
+    except Exception as e:
+        print(e)
+
+# Vilib
+# =================================================================
+class Vilib(object):
+
+    picam2 = Picamera2()
+
+    camera_size = (640, 480)
+    camera_width = 640
+    camera_height = 480
+    camera_vflip = False
+    camera_hflip = False
+    camera_run = False
+
+    flask_thread = None
+    camera_thread = None
+    flask_start = False
+
+    qrcode_display_thread = None
+    qrcode_making_completed = False
+    qrcode_img = Manager().list(range(1))
+    qrcode_img_encode = None
+    qrcode_win_name = 'qrcode'
+
+    img = Manager().list(range(1))
+    flask_img = Manager().list(range(1))
+
+    Windows_Name = "picamera"
+    imshow_flag = False
+    web_display_flag = False
+    imshow_qrcode_flag = False
+    web_qrcode_flag = False
+
+    draw_fps = False
+    fps_origin = (camera_width-105, 20)
+    fps_size = 0.6
+    fps_color = (255, 255, 255)
+
+    detect_obj_parameter = {}
+    color_detect_color = None
+    face_detect_sw = False
+    hands_detect_sw = False
+    pose_detect_sw = False
+    image_classify_sw = False
+    image_classification_model = None
+    image_classification_labels = None
+    objects_detect_sw = False
+    objects_detection_model = None
+    objects_detection_labels = None
+    qrcode_detect_sw = False
+    traffic_detect_sw = False
+        
+    @staticmethod
+    def get_instance():
+        return Vilib.picam2
+
+    @staticmethod
+    def set_controls(controls):
+        Vilib.picam2.set_controls(controls)
+
+    @staticmethod
+    def get_controls():
+        return Vilib.picam2.capture_metadata()
+
+    @staticmethod
+    def camera():
+        Vilib.camera_width = Vilib.camera_size[0]
+        Vilib.camera_height = Vilib.camera_size[1]
+
+        picam2 = Vilib.picam2
+
+        preview_config = picam2.preview_configuration
+        # preview_config.size = (800, 600)
+        preview_config.size = Vilib.camera_size
+        preview_config.format = 'RGB888'  # 'XRGB8888', 'XBGR8888', 'RGB888', 'BGR888', 'YUV420'
+        preview_config.transform = libcamera.Transform(
+                                        hflip=Vilib.camera_hflip,
+                                        vflip=Vilib.camera_vflip
+                                    )
+        preview_config.colour_space = libcamera.ColorSpace.Sycc()
+        preview_config.buffer_count = 4
+        preview_config.queue = True
+        # preview_config.raw = {'size': (2304, 1296)}
+        preview_config.controls = {'FrameRate': 60} # change picam2.capture_array() takes time
+
+        try:
+            picam2.start()
+        except Exception as e:
+            print(f"\033[38;5;1mError:\033[0m\n{e}")
+            print("\nPlease check whether the camera is connected well" +\
+                "You can use the \"libcamea-hello\" command to test the camera"
+                )
+            exit(1)
+        Vilib.camera_run = True
+        Vilib.fps_origin = (Vilib.camera_width-105, 20)
+        fps = 0
+        start_time = 0
+        framecount = 0
+        try:
+            start_time = time.time()
+            while True:
+                # ----------- extract image data ----------------
+                # st = time.time()
+                Vilib.img = picam2.capture_array()
+                # print(f'picam2.capture_array(): {time.time() - st:.6f}')
+                # st = time.time()
+
+                # ----------- image gains and effects ----------------
+
+                # ----------- image detection and recognition ----------------
+                Vilib.img = Vilib.color_detect_func(Vilib.img)
+                Vilib.img = Vilib.face_detect_func(Vilib.img)
+                Vilib.img = Vilib.traffic_detect_fuc(Vilib.img)
+                Vilib.img = Vilib.qrcode_detect_func(Vilib.img)
+
+                Vilib.img = Vilib.image_classify_fuc(Vilib.img)
+                Vilib.img = Vilib.object_detect_fuc(Vilib.img)
+                Vilib.img = Vilib.hands_detect_fuc(Vilib.img)
+                Vilib.img = Vilib.pose_detect_fuc(Vilib.img)
+
+                # ----------- calculate fps and draw fps ----------------
+                # calculate fps
+                framecount += 1
+                elapsed_time = float(time.time() - start_time)
+                if (elapsed_time > 1):
+                    fps = round(framecount/elapsed_time, 1)
+                    framecount = 0
+                    start_time = time.time()
+
+                # print(f"elapsed_time: {elapsed_time}, fps: {fps}")
+
+                # draw fps
+                if Vilib.draw_fps:
+                    cv2.putText(
+                            # img, # image
+                            Vilib.img,
+                            f"FPS: {fps}", # text
+                            Vilib.fps_origin, # origin
+                            cv2.FONT_HERSHEY_SIMPLEX, # font
+                            Vilib.fps_size, # font_scale
+                            Vilib.fps_color, # font_color
+                            1, # thickness
+                            cv2.LINE_AA, # line_type: LINE_8 (default), LINE_4, LINE_AA
+                        )
+
+                # ---- copy img for flask --- 
+                # st = time.time()
+                Vilib.flask_img = Vilib.img
+                # print(f'vilib.flask_img: {time.time() - st:.6f}')
+
+                # ----------- display on desktop ----------------
+                if Vilib.imshow_flag == True:
+                    try:
+                        try:
+                            prop = cv2.getWindowProperty(Vilib.Windows_Name, cv2.WND_PROP_VISIBLE)
+                            qrcode_prop = cv2.getWindowProperty(Vilib.qrcode_win_name, cv2.WND_PROP_VISIBLE)
+                            if prop < 1 or qrcode_prop < 1:
+                                break
+                        except:
+                            pass
+
+                        cv2.imshow(Vilib.Windows_Name, Vilib.img)
+
+                        if Vilib.imshow_qrcode_flag and Vilib.qrcode_making_completed:
+                                Vilib.qrcode_making_completed = False
+                                cv2.imshow(Vilib.qrcode_win_name, Vilib.qrcode_img)
+
+                        cv2.waitKey(1)
+
+                    except Exception as e:
+                        Vilib.imshow_flag = False
+                        print(f"imshow failed:\n  {e}")
+                        break
+
+                # ----------- exit ----------------
+                if Vilib.camera_run == False:
+                    break
+
+                # print(f'loop end: {time.time() - st:.6f}')
+                
+        except KeyboardInterrupt as e:
+            print(e)
+        finally:
+            picam2.close()
+            cv2.destroyAllWindows()
+
+    @staticmethod
+    def camera_start(vflip=False, hflip=False, size=None):
+        if size is not None:
+            Vilib.camera_size = size
+        Vilib.camera_hflip = hflip
+        Vilib.camera_vflip = vflip
+        Vilib.camera_thread = threading.Thread(target=Vilib.camera, name="vilib")
+        Vilib.camera_thread.daemon = False
+        Vilib.camera_thread.start()
+        while not Vilib.camera_run:
+            time.sleep(0.1)
+
+    @staticmethod
+    def camera_close():
+        if Vilib.camera_thread != None:
+            Vilib.camera_run = False
+            time.sleep(0.1)
+            # Wait for camera thread to finish
+            if Vilib.camera_thread.is_alive():
+                Vilib.camera_thread.join(timeout=2.0)
+            
+            # Properly close and reinitialize Picamera2
+            try:
+                if Vilib.picam2 is not None:
+                    Vilib.picam2.close()
+                    time.sleep(0.1)
+                    
+                # Recreate Picamera2 object completely fresh
+                Vilib.picam2 = Picamera2()
+                
+                # Create and configure a default preview configuration
+                preview_config = Vilib.picam2.create_preview_configuration()
+                Vilib.picam2.configure(preview_config)
+                
+            except Exception as e:
+                print(f"Warning during camera cleanup: {e}")
+                # Force recreation of Picamera2 object with basic setup
+                try:
+                    Vilib.picam2 = Picamera2()
+                    preview_config = Vilib.picam2.create_preview_configuration()
+                    Vilib.picam2.configure(preview_config)
+                except Exception as e2:
+                    print(f"Failed to reinitialize camera: {e2}")
+            
+            # Reset thread reference
+            Vilib.camera_thread = None
+    @staticmethod
+    def display(local=True, web=True):
+        # cheack camera thread is_alive
+        if Vilib.camera_thread != None and Vilib.camera_thread.is_alive():
+            # check gui
+            if local == True:
+                if 'DISPLAY' in os.environ.keys():
+                    Vilib.imshow_flag = True  
+                    print("Imgshow start ...")
+                else:
+                    Vilib.imshow_flag = False 
+                    print("Local display failed, because there is no gui.") 
+            # web video
+            if web == True:
+                Vilib.web_display_flag = True
+                print("\nWeb display on:")
+                wlan0, eth0 = getIP()
+                if wlan0 != None:
+                    print(f"      http://{wlan0}:9000/mjpg")
+                if eth0 != None:
+                    print(f"      http://{eth0}:9000/mjpg")
+                print() # new line
+
+                # ----------- flask_thread ----------------
+                if Vilib.flask_thread == None or Vilib.flask_thread.is_alive() == False:
+                    print('Starting web streaming ...')
+                    Vilib.flask_thread = threading.Thread(name='flask_thread',target=web_camera_start)
+                    Vilib.flask_thread.daemon = True
+                    Vilib.flask_thread.start()
+        else:
+            print('Error: Please execute < camera_start() > first.')
+
+    @staticmethod
+    def show_fps(color=None, fps_size=None, fps_origin=None):
+        if color is not None:
+            Vilib.fps_color = color
+        if fps_size is not None:
+            Vilib.fps_size = fps_size
+        if fps_origin is not None:
+            Vilib.fps_origin = fps_origin
+
+        Vilib.draw_fps = True
+
+    @staticmethod
+    def hide_fps():
+        Vilib.draw_fps = False
+
+    # take photo
+    # =================================================================
+    @staticmethod
+    def take_photo(photo_name, path=DEFAULLT_PICTURES_PATH):
+        # ----- check path -----
+        if not os.path.exists(path):
+            # print('Path does not exist. Creating path now ... ')
+            os.makedirs(name=path, mode=0o751, exist_ok=True)
+            time.sleep(0.01) 
+        # ----- save photo -----
+        status = False
+        for _ in range(5):
+            if  Vilib.img is not None:
+                status = cv2.imwrite(path + '/' + photo_name +'.jpg', Vilib.img)
+                break
+            else:
+                time.sleep(0.01)
+        else:
+            status = False
+
+        # if status:
+        #     print('The photo is saved as '+path+'/'+photo_name+'.jpg')
+        # else:
+        #     print('Photo save failed .. ')
+
+        return status
+
+
+    # record video
+    # =================================================================
+    rec_video_set = {}
+
+    rec_video_set["fourcc"] = cv2.VideoWriter_fourcc(*'XVID') 
+    #rec_video_set["fourcc"] = cv2.cv.CV_FOURCC("D", "I", "B", " ") 
+
+    rec_video_set["fps"] = 30.0
+    rec_video_set["framesize"] = (640, 480)
+    rec_video_set["isColor"] = True
+
+    rec_video_set["name"] = "default"
+    rec_video_set["path"] = DEFAULLT_VIDEOS_PATH
+
+    rec_video_set["start_flag"] = False
+    rec_video_set["stop_flag"] =  False
+
+    rec_thread = None
+
+    @staticmethod
+    def rec_video_work():
+        if not os.path.exists(Vilib.rec_video_set["path"]):
+            # print('Path does not exist. Creating path now ... ')
+            os.makedirs(name=Vilib.rec_video_set["path"],
+                        mode=0o751,
+                        exist_ok=True
+            )
+            time.sleep(0.01)
+        video_out = cv2.VideoWriter(Vilib.rec_video_set["path"]+'/'+Vilib.rec_video_set["name"]+'.avi',
+                                    Vilib.rec_video_set["fourcc"], Vilib.rec_video_set["fps"], 
+                                    Vilib.rec_video_set["framesize"], Vilib.rec_video_set["isColor"])
+    
+        while True:
+            if Vilib.rec_video_set["start_flag"] == True:
+                # video_out.write(Vilib.img_array[0])
+                video_out.write(Vilib.img)
+            if Vilib.rec_video_set["stop_flag"] == True:
+                video_out.release() # note need to release the video writer
+                Vilib.rec_video_set["start_flag"] == False
+                break
+
+    @staticmethod
+    def rec_video_run():
+        if Vilib.rec_thread != None:
+            Vilib.rec_video_stop()
+        Vilib.rec_video_set["stop_flag"] = False
+        Vilib.rec_thread = threading.Thread(name='rec_video', target=Vilib.rec_video_work)
+        Vilib.rec_thread.daemon = True
+        Vilib.rec_thread.start()
+
+    @staticmethod
+    def rec_video_start():
+        Vilib.rec_video_set["start_flag"] = True 
+        Vilib.rec_video_set["stop_flag"] = False
+
+    @staticmethod
+    def rec_video_pause():
+        Vilib.rec_video_set["start_flag"] = False
+
+    @staticmethod
+    def rec_video_stop():
+        Vilib.rec_video_set["start_flag"] == False
+        Vilib.rec_video_set["stop_flag"] = True
+        if Vilib.rec_thread != None:
+            Vilib.rec_thread.join(3)
+            Vilib.rec_thread = None
+
+   # color detection
+    # =================================================================
+    @staticmethod 
+    def color_detect(color="red"):
+        '''
+        :param color: could be red, green, blue, yellow , orange, purple
+        '''
+        Vilib.color_detect_color = color
+        from .color_detection import color_detect_work, color_obj_parameter
+        Vilib.color_detect_work = color_detect_work
+        Vilib.color_obj_parameter = color_obj_parameter
+        Vilib.detect_obj_parameter['color_x'] = Vilib.color_obj_parameter['x']
+        Vilib.detect_obj_parameter['color_y'] = Vilib.color_obj_parameter['y']
+        Vilib.detect_obj_parameter['color_w'] = Vilib.color_obj_parameter['w']
+        Vilib.detect_obj_parameter['color_h'] = Vilib.color_obj_parameter['h']
+        Vilib.detect_obj_parameter['color_n'] = Vilib.color_obj_parameter['n']
+
+    @staticmethod
+    def color_detect_func(img):
+        if Vilib.color_detect_color is not None \
+            and Vilib.color_detect_color != 'close' \
+            and hasattr(Vilib, "color_detect_work"):
+            img = Vilib.color_detect_work(img, Vilib.camera_width, Vilib.camera_height, Vilib.color_detect_color)
+            Vilib.detect_obj_parameter['color_x'] = Vilib.color_obj_parameter['x']
+            Vilib.detect_obj_parameter['color_y'] = Vilib.color_obj_parameter['y']
+            Vilib.detect_obj_parameter['color_w'] = Vilib.color_obj_parameter['w']
+            Vilib.detect_obj_parameter['color_h'] = Vilib.color_obj_parameter['h']
+            Vilib.detect_obj_parameter['color_n'] = Vilib.color_obj_parameter['n']
+        return img
+
+    @staticmethod
+    def close_color_detection():
+        Vilib.color_detect_color = None
+
+  # face detection
+    # =================================================================
+    @staticmethod   
+    def face_detect_switch(flag=False):
+        Vilib.face_detect_sw = flag
+        if Vilib.face_detect_sw:
+            from .face_detection import face_detect, set_face_detection_model, face_obj_parameter
+            Vilib.face_detect_work = face_detect
+            Vilib.set_face_detection_model = set_face_detection_model
+            Vilib.face_obj_parameter = face_obj_parameter
+            Vilib.detect_obj_parameter['human_x'] = Vilib.face_obj_parameter['x']
+            Vilib.detect_obj_parameter['human_y'] = Vilib.face_obj_parameter['y']
+            Vilib.detect_obj_parameter['human_w'] = Vilib.face_obj_parameter['w']
+            Vilib.detect_obj_parameter['human_h'] = Vilib.face_obj_parameter['h']
+            Vilib.detect_obj_parameter['human_n'] = Vilib.face_obj_parameter['n']
+
+    @staticmethod
+    def face_detect_func(img):
+        if Vilib.face_detect_sw and hasattr(Vilib, "face_detect_work"):
+            img = Vilib.face_detect_work(img, Vilib.camera_width, Vilib.camera_height)
+            Vilib.detect_obj_parameter['human_x'] = Vilib.face_obj_parameter['x']
+            Vilib.detect_obj_parameter['human_y'] = Vilib.face_obj_parameter['y']
+            Vilib.detect_obj_parameter['human_w'] = Vilib.face_obj_parameter['w']
+            Vilib.detect_obj_parameter['human_h'] = Vilib.face_obj_parameter['h']
+            Vilib.detect_obj_parameter['human_n'] = Vilib.face_obj_parameter['n']
+        return img
+
+   # traffic sign detection
+    # =================================================================
+    @staticmethod
+    def traffic_detect_switch(flag=False):
+        Vilib.traffic_detect_sw  = flag
+        if Vilib.traffic_detect_sw:
+            from .traffic_sign_detection import traffic_sign_detect, traffic_sign_obj_parameter
+            Vilib.traffic_detect_work = traffic_sign_detect
+            Vilib.traffic_sign_obj_parameter = traffic_sign_obj_parameter
+            Vilib.detect_obj_parameter['traffic_sign_x'] = Vilib.traffic_sign_obj_parameter['x']
+            Vilib.detect_obj_parameter['traffic_sign_y'] = Vilib.traffic_sign_obj_parameter['y']
+            Vilib.detect_obj_parameter['traffic_sign_w'] = Vilib.traffic_sign_obj_parameter['w']
+            Vilib.detect_obj_parameter['traffic_sign_h'] = Vilib.traffic_sign_obj_parameter['h']
+            Vilib.detect_obj_parameter['traffic_sign_t'] = Vilib.traffic_sign_obj_parameter['t']
+            Vilib.detect_obj_parameter['traffic_sign_acc'] = Vilib.traffic_sign_obj_parameter['acc']
+
+    @staticmethod
+    def traffic_detect_fuc(img):
+        if Vilib.traffic_detect_sw and hasattr(Vilib, "traffic_detect_work"):
+            img = Vilib.traffic_detect_work(img, border_rgb=(255, 0, 0))
+            Vilib.detect_obj_parameter['traffic_sign_x'] = Vilib.traffic_sign_obj_parameter['x']
+            Vilib.detect_obj_parameter['traffic_sign_y'] = Vilib.traffic_sign_obj_parameter['y']
+            Vilib.detect_obj_parameter['traffic_sign_w'] = Vilib.traffic_sign_obj_parameter['w']
+            Vilib.detect_obj_parameter['traffic_sign_h'] = Vilib.traffic_sign_obj_parameter['h']
+            Vilib.detect_obj_parameter['traffic_sign_t'] = Vilib.traffic_sign_obj_parameter['t']
+            Vilib.detect_obj_parameter['traffic_sign_acc'] = Vilib.traffic_sign_obj_parameter['acc']
+        return img
+
+    # qrcode recognition
+    # =================================================================
+    @staticmethod
+    def qrcode_detect_switch(flag=False):
+        Vilib.qrcode_detect_sw  = flag
+        if Vilib.qrcode_detect_sw:
+            from .qrcode_recognition import qrcode_recognize, qrcode_obj_parameter
+            Vilib.qrcode_recognize = qrcode_recognize
+            Vilib.qrcode_obj_parameter = qrcode_obj_parameter
+            Vilib.detect_obj_parameter['qr_x'] = Vilib.qrcode_obj_parameter['x']
+            Vilib.detect_obj_parameter['qr_y'] = Vilib.qrcode_obj_parameter['y']
+            Vilib.detect_obj_parameter['qr_w'] = Vilib.qrcode_obj_parameter['w']
+            Vilib.detect_obj_parameter['qr_h'] = Vilib.qrcode_obj_parameter['h']
+            Vilib.detect_obj_parameter['qr_data'] = Vilib.qrcode_obj_parameter['data']
+            Vilib.detect_obj_parameter['qr_list'] = Vilib.qrcode_obj_parameter['list']
+
+    @staticmethod
+    def qrcode_detect_func(img):
+        if Vilib.qrcode_detect_sw and hasattr(Vilib, "qrcode_recognize"):
+            img = Vilib.qrcode_recognize(img, border_rgb=(255, 0, 0))
+            Vilib.detect_obj_parameter['qr_x'] = Vilib.qrcode_obj_parameter['x']
+            Vilib.detect_obj_parameter['qr_y'] = Vilib.qrcode_obj_parameter['y']
+            Vilib.detect_obj_parameter['qr_w'] = Vilib.qrcode_obj_parameter['w']
+            Vilib.detect_obj_parameter['qr_h'] = Vilib.qrcode_obj_parameter['h']
+            Vilib.detect_obj_parameter['qr_data'] = Vilib.qrcode_obj_parameter['data']
+        return img
+
+    # qrcode making
+    # =================================================================
+    @staticmethod
+    def make_qrcode(data, 
+                    path=None,
+                    version=1,
+                    box_size=10,
+                    border=4,
+                    fill_color=(132,  112, 255),
+                    back_color=(255, 255, 255)
+                    ):
+        import qrcode # https://github.com/lincolnloop/python-qrcode
+
+        qr = qrcode.QRCode(
+            version=version,
+            error_correction=qrcode.constants.ERROR_CORRECT_L,
+            box_size=box_size,
+            border=border,
+        )
+        qr.add_data(data)
+        qr.make(fit=True)
+        qr_pil = qr.make_image(fill_color=fill_color,
+                            back_color=back_color)
+        if path != None:
+            qr_pil.save(path)
+
+        Vilib.qrcode_img = cv2.cvtColor(np.array(qr_pil), cv2.COLOR_RGB2BGR)
+        Vilib.qrcode_making_completed = True
+
+        if Vilib.web_qrcode_flag:
+            Vilib.qrcode_img_encode = cv2.imencode('.jpg', Vilib.qrcode_img)[1].tobytes()
+
+
+
+    @staticmethod
+    def display_qrcode_work():
+        while True:
+            if Vilib.imshow_flag:
+                time.sleep(0.1)
+                continue
+
+            # ----------- display qrcode on desktop ----------------
+            if Vilib.imshow_qrcode_flag and Vilib.qrcode_making_completed :
+                    Vilib.qrcode_making_completed = False
+                    try:
+                        if len(Vilib.qrcode_img) > 10:
+                            cv2.imshow(Vilib.qrcode_win_name, Vilib.qrcode_img)
+                            cv2.waitKey(1)
+                            if cv2.getWindowProperty(Vilib.qrcode_win_name, cv2.WND_PROP_VISIBLE) == 0:
+                                cv2.destroyWindow(Vilib.qrcode_win_name)
+                    except Exception as e:
+                        Vilib.imshow_qrcode_flag = False
+                        print(f"imshow qrcode failed:\n  {e}")
+                        break
+            time.sleep(0.1)
+
+    @staticmethod
+    def display_qrcode(local=True, web=True):
+        # check gui
+        if local == True:
+            if 'DISPLAY' in os.environ.keys():
+                Vilib.imshow_qrcode_flag = True  
+                print("Imgshow qrcode start ...")
+            else:
+                Vilib.imshow_qrcode_flag = False 
+                print("Local display failed, because there is no gui.") 
+        # web video
+        if web == True:
+            Vilib.web_qrcode_flag = True
+            print(f'QRcode display on:')
+            wlan0, eth0 = getIP()
+            if wlan0 != None:
+                print(f"      http://{wlan0}:9000/qrcode")
+            if eth0 != None:
+                print(f"      http://{eth0}:9000/qrcode")
+            print() # new line
+
+            # ----------- flask_thread ----------------
+            if Vilib.flask_thread == None or Vilib.flask_thread.is_alive() == False:
+                print('Starting web streaming ...')
+                Vilib.flask_thread = threading.Thread(name='flask_thread',target=web_camera_start)
+                Vilib.flask_thread.daemon = True
+                Vilib.flask_thread.start()
+
+        if Vilib.qrcode_display_thread == None or Vilib.qrcode_display_thread.is_alive() == False:
+            Vilib.qrcode_display_thread = threading.Thread(name='qrcode_display',target=Vilib.display_qrcode_work)
+            Vilib.qrcode_display_thread.daemon = True
+            Vilib.qrcode_display_thread.start()
+
+
+    # image classification
+    # =================================================================
+    @staticmethod
+    def image_classify_switch(flag=False):
+        from .image_classification import image_classification_obj_parameter
+        Vilib.image_classify_sw = flag
+        Vilib.image_classification_obj_parameter = image_classification_obj_parameter
+
+    @staticmethod
+    def image_classify_set_model(path):
+        if not os.path.exists(path):
+            raise ValueError('incorrect model path ')          
+        Vilib.image_classification_model = path
+
+    @staticmethod
+    def image_classify_set_labels(path):
+        if not os.path.exists(path):
+            raise ValueError('incorrect labels path ')  
+        Vilib.image_classification_labels = path
+
+    @staticmethod
+    def image_classify_fuc(img):
+        if Vilib.image_classify_sw == True:
+            # print('classify_image starting')
+            from .image_classification import classify_image
+            img = classify_image(image=img,
+                                model=Vilib.image_classification_model,
+                                labels=Vilib.image_classification_labels)   
+        return img
+
+    # objects detection
+    # =================================================================
+    @staticmethod
+    def object_detect_switch(flag=False):
+        Vilib.objects_detect_sw = flag
+        if Vilib.objects_detect_sw == True:
+            from .objects_detection import object_detection_list_parameter
+            Vilib.object_detection_list_parameter = object_detection_list_parameter
+
+    @staticmethod
+    def object_detect_set_model(path):
+        if not os.path.exists(path):
+            raise ValueError('incorrect model path ')    
+        Vilib.objects_detection_model = path
+
+    @staticmethod
+    def object_detect_set_labels(path):
+        if not os.path.exists(path):
+            raise ValueError('incorrect labels path ')    
+        Vilib.objects_detection_labels = path
+
+    @staticmethod
+    def object_detect_fuc(img):
+        if Vilib.objects_detect_sw == True:
+            # print('detect_objects starting')
+            from .objects_detection import detect_objects
+            img = detect_objects(image=img,
+                                model=Vilib.objects_detection_model,
+                                labels=Vilib.objects_detection_labels)   
+        return img
+
+    # hands detection
+    # =================================================================
+    @staticmethod
+    def hands_detect_switch(flag=False):
+        from .hands_detection import DetectHands
+        Vilib.detect_hands = DetectHands()
+        Vilib.hands_detect_sw = flag
+
+    @staticmethod
+    def hands_detect_fuc(img):
+        if Vilib.hands_detect_sw == True:
+            img, Vilib.detect_obj_parameter['hands_joints'] = Vilib.detect_hands.work(image=img)   
+        return img
+
+    # pose detection
+    # =================================================================
+    @staticmethod
+    def pose_detect_switch(flag=False):
+        from .pose_detection import DetectPose
+        Vilib.pose_detect = DetectPose()
+        Vilib.pose_detect_sw = flag
+
+    @staticmethod
+    def pose_detect_fuc(img):
+        if Vilib.pose_detect_sw == True and hasattr(Vilib, "pose_detect"):
+            img, Vilib.detect_obj_parameter['body_joints'] = Vilib.pose_detect.work(image=img)   
+        return img