彩票走势图

Dynamsoft Barcode Reader SDK一款多功能的条码读取控件，只需要几行代码就可以将条码读取功能嵌入到Web或桌面应用程序。这可以节省数月的开发时间和成本。能支持多种图像文件格式以及从摄像机或扫描仪获取的DIB格式。使用Dynamsoft Barcode Reader SDK，你可以创建强大且实用的条形码扫描仪软件，以满足你的业务需求。

点击下载Dynamsoft Barcode Reader最新版

 如果要使用Python和Qt构建跨平台的GUI应用程序，则可以使用PyQt或PySide。它们都是Python的Qt绑定。主要区别在于许可证：PyQt5是根据GPL还是商业PySide2发布，而根据则发布LGPL。由于正式建议使用PySide2，因此我将使用PySid2和Dynamsoft Python条形码SDK在Raspberry Pi上创建GUI条形码读取器应用程序。

要求

• OpenCV Python

python3 -m pip install opencv-python

• Dynamsoft Python条形码SDK

python3 -m pip install dbr

• PySide2

sudo apt-get install python3-pyside2.qt3dcore python3-pyside2.qt3dinput python3-pyside2.qt3dlogic python3-pyside2.qt3drender python3-pyside2.qtcharts python3-pyside2.qtconcurrent python3-pyside2.qtcore python3-pyside2.qtgui python3-pyside2.qthelp python3-pyside2.qtlocation python3-pyside2.qtmultimedia python3-pyside2.qtmultimediawidgets python3-pyside2.qtnetwork python3-pyside2.qtopengl python3-pyside2.qtpositioning python3-pyside2.qtprintsupport python3-pyside2.qtqml python3-pyside2.qtquick python3-pyside2.qtquickwidgets python3-pyside2.qtscript python3-pyside2.qtscripttools python3-pyside2.qtsensors python3-pyside2.qtsql python3-pyside2.qtsvg python3-pyside2.qttest python3-pyside2.qttexttospeech python3-pyside2.qtuitools python3-pyside2.qtwebchannel python3-pyside2.qtwebsockets python3-pyside2.qtwidgets python3-pyside2.qtx11extras python3-pyside2.qtxml python3-pyside2.qtxmlpatterns python3-pyside2uic

让我们开始使用UI小部件：

• 用于加载图像文件的按钮：

self.btn = QPushButton("Load an image")
self.btn.clicked.connect(self.pickFile)

def pickFile(self):
    filename = QFileDialog.getOpenFileName(self, 'Open file',
                                            self._path, "Barcode images (*)")
    if filename is None or filename[0] == '':
        self.showMessageBox("No file selected")
        return

• 用于打开实时摄像机流的按钮：

btnCamera = QPushButton("Open camera")
btnCamera.clicked.connect(self.openCamera)

self.timer = QTimer()
self.timer.timeout.connect(self.nextFrameUpdate)

def openCamera(self):

    if not self._cap.isOpened(): 
        self.showMessageBox("Failed to open camera.")
        return

    self.timer.start(1000./24)

• 用于停止摄像机流的按钮：

btnCamera = QPushButton("Stop camera")
btnCamera.clicked.connect(self.stopCamera)

def stopCamera(self):
    self.timer.stop()

• 用于显示摄像机框架的标签和用于显示条形码解码结果的文本区域：

self.label = QLabel()
self.label.setFixedSize(self.WINDOW_WIDTH - 30, self.WINDOW_HEIGHT - 160)

self.results = QTextEdit()

def showResults(self, frame, results):
    frame = cv2.cvtColor(frame, cv2.COLOR_BGR2RGB)
    image = QImage(frame, frame.shape[1], frame.shape[0], frame.strides[0], QImage.Format_RGB888)
    pixmap = QPixmap.fromImage(image)
    pixmap = self.resizeImage(pixmap)
    self.label.setPixmap(pixmap)
    self.results.setText(results)

frame = cv2.imread(filename)

self._cap = cv2.VideoCapture(0)
self._cap.set(cv2.CAP_PROP_FRAME_WIDTH, 640)
self._cap.set(cv2.CAP_PROP_FRAME_HEIGHT, 480)
ret, frame = self._cap.read()

我们立即想到的最简单的方法是，一旦获得帧，便调用解码方法：

def nextFrameSlot(self):
      ret, frame = self._cap.read()

      if not ret:
          self.showMessageBox('Failed to get camera frame!')
          return

      frame, results = self._manager.decode_frame(frame)
      self.showResults(frame, results)

class WorkerSignals(QObject):
    result = Signal(object)

class BarcodeManager(QThread):
    def __init__(self, license):
        super(BarcodeManager, self).__init__()
        self.signals = WorkerSignals()

        self._reader = BarcodeReader()
        self._reader.init_license(license)
        settings = self._reader.get_runtime_settings()
        settings.max_algorithm_thread_count = 1
        self._reader.update_runtime_settings(settings)
        self.frameQueue = Queue(1)

    def register_callback(self, fn):
        self.signals.result.connect(fn)

    def run(self):
        while True:
            try:
                frame = self.frameQueue.get(False, 10)

                if type(frame) is str:
                    break
            except:
                time.sleep(0.01)
                continue

            try:
                results = self._reader.decode_buffer(frame)
                self.signals.result.emit(results)

            except BarcodeReaderError as error:
                print(error)

from multiprocessing import Process, Queue
import time
import numpy as np


def process_barcode_frame(license, frameQueue, resultQueue):
    # Create Dynamsoft Barcode Reader
    reader = BarcodeReader()
    # Apply for a trial license: //www.dynamsoft.com/customer/license/trialLicense
    reader.init_license(license)
    settings = reader.get_runtime_settings()
    settings.max_algorithm_thread_count = 1
    reader.update_runtime_settings(settings)

    while True:
        results = None

        try:
            frame = frameQueue.get(False, 10)
            if type(frame) is str:
                break
        except:
            time.sleep(0.01)
            continue

        try:
            frameHeight, frameWidth, channel = frame.shape[:3]
            results = reader.decode_buffer_manually(np.array(frame).tobytes(), frameWidth, frameHeight, frame.strides[0], EnumImagePixelFormat.IPF_RGB_888)
        except BarcodeReaderError as error:
            print(error)

        try:
            resultQueue.put(results, False, 10)
        except:
            pass

def create_decoding_process(license):
        size = 1
        frameQueue = Queue(size)
        resultQueue = Queue(size)
        barcodeScanning = Process(target=process_barcode_frame, args=(license, frameQueue, resultQueue))
        barcodeScanning.start()
        return frameQueue, resultQueue, barcodeScanning

到目前为止，该应用程序已完成。另一件事是申请免费试用许可证并将其保存到本地磁盘。

将USB网络摄像头连接到Raspberry Pi，然后运行该应用程序：

python3 app.py license.txt