【计算机视觉】OpenCV篇(4)

1.下载安装

（1）Pycharm：下载链接

（2）推荐使用Qt Designer来设计界面，如果你装的是Anaconda的话，就已经自带了designer.exe，我这里使用的是Pycharm的虚拟环境，通过以下的方式安装：

(venv) G:GitWorkspacePycharmProjectsPythonStudy>pip install pyqt5
Collecting pyqt5
  Downloading https://files.pythonhosted.org/packages/b2/87/219cd547c0deb902edd3fdbf1af01409f7f9d251344b9154d878203cf841/PyQt5-5.12.1-5.12.2-cp35.cp36.cp37.cp38-none-win_amd64.whl (47.4MB)
    100% |████████████████████████████████| 47.4MB 40kB/s
Collecting PyQt5_sip<4.20,>=4.19.14 (from pyqt5)
  Downloading https://files.pythonhosted.org/packages/ee/03/a11da2a5dd75b0ccd795ddbd944c18ce663ffb08d59a1e7f1ee5a597488c/PyQt5_sip-4.19.15-cp36-none-win_amd64.whl (51kB)
    100% |████████████████████████████████| 61kB 35kB/s
Installing collected packages: PyQt5-sip, pyqt5
Successfully installed PyQt5-sip-4.19.15 pyqt5-5.12.1

(venv) G:GitWorkspacePycharmProjectsPythonStudy>pip install pyqt5-tools
Collecting pyqt5-tools
  Downloading https://files.pythonhosted.org/packages/21/ff/7578d6d124926ff6cd1ef13c8c095063ad4c3811f4506788a915607aee81/pyqt5_tools-5.11.3.1.4-cp37-none-win32.whl (47.9MB)
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Collecting click (from pyqt5-tools)
  Downloading https://files.pythonhosted.org/packages/fa/37/45185cb5abbc30d7257104c434fe0b07e5a195a6847506c074527aa599ec/Click-7.0-py2.py3-none-any.whl (81kB)
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Collecting pyqt5==5.11.3 (from pyqt5-tools)
  Downloading https://files.pythonhosted.org/packages/26/78/c215008e70982944272b6c329a76cc11259e7378a3e23418fbe0bd48de96/PyQt5-5.11.3-5.11.2-cp35.cp36.cp37.cp38-none-win32.whl (39.4MB)
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Collecting python-dotenv (from pyqt5-tools)
  Downloading https://files.pythonhosted.org/packages/8c/14/501508b016e7b1ad0eb91bba581e66ad9bfc7c66fcacbb580eaf9bc38458/python_dotenv-0.10.1-py2.py3-none-any.whl
Requirement already satisfied: PyQt5_sip<4.20,>=4.19.11 in c:mzhu_working1023python-workspacestudyvenvlibsite-packages (from pyqt5==5.11.3->pyqt5-tools) (4.19.15)
Installing collected packages: click, pyqt5, python-dotenv, pyqt5-tools
  Found existing installation: PyQt5 5.12.1
    Uninstalling PyQt5-5.12.1:
      Successfully uninstalled PyQt5-5.12.1
Successfully installed click-7.0 pyqt5-5.11.3 pyqt5-tools-5.11.3.1.4 python-dotenv-0.10.1　　

2.环境配置

在Pycharm中，点击File->Settings->Tools->External Tools点击+添加以下工具：

(1)qtdesinger

(2)pyuic5，这个是把qt的UI文件转换成.py文件的工具

(3)pyrcc, 这个是将资源文件如图片等转成python代码能识别的文件，这个参数基本和pyuic5的是一样的

这样就基本完成PYQT5在Pycharm环境中的配置：

3.测试

（这里拿一个OpenCV的小练习来测试一下------）

打开qtdesinger，新建一个窗体：

界面的左侧是Qt的常用控件”Widget Box”，右侧有一个控件属性窗口”Property Editor”，其余暂时用不到。本例中我们只用到了”Push Button”控件和”Label”控件：最上面的三个Label控件用于显示图片，可以在属性窗口调整它的大小，我们统一调整到150×150：

另外，控件上显示的文字”text”属性和控件的名字”objectName”属性需要修改，便于显示和代码调用：

点击Designer工具栏的”Edit Signals/Slots”按钮，进入槽函数编辑界面，点击旁边的”Edit Widgets”可以恢复正常视图：

 

 然后点击按钮并拖动，当产生类似于电路中的接地符号时释放鼠标，在弹出的配置窗口中，可以看到左侧是按钮的常用事件，我们选择点击事件”clicked()”，然后添加一个名为”btnOpenCamera_Clicked()”的槽函数：

 重复上面的步骤，给五个按钮添加五个槽函数，最终结果如下：

到此，我们就完成了界面设计的所有工作，按下Ctrl+S保存当前窗口为.ui文件。.ui文件其实是按照XML格式标记的内容，可以用文本编辑器将.ui文件打开看看。

UI文件转py代码

因为我们是用Designer工具设计出的界面，并不是用Python代码敲出来的，所以要想真正运行，需要使用pyuic5将ui文件转成py文件。pyuic5.exe默认在%Scripts下，比如我的是在：G:GitWorkspacePycharmProjectsPythonStudyvenvScripts

打开cmd命令行，切换到ui文件的保存目录。Windows下有个小技巧，可以在目录的地址栏输入cmd，一步切换到当前目录. 然后执行这条指令：

pyuic5 -o mainForm.py pyqt_create_ui.ui　

 

执行正常的话，就会生成mainForm.py文件，里面应该包含一个名为”Ui_MainWindow”的类。

# -*- coding: utf-8 -*-

# Form implementation generated from reading ui file 'pyqt_create_ui.ui'
#
# Created by: PyQt5 UI code generator 5.11.3
#
# WARNING! All changes made in this file will be lost!

from PyQt5 import QtCore, QtGui, QtWidgets

class Ui_MainWindow(object):
    def setupUi(self, MainWindow):
        MainWindow.setObjectName("MainWindow")
        MainWindow.resize(859, 474)
        self.centralwidget = QtWidgets.QWidget(MainWindow)
        self.centralwidget.setObjectName("centralwidget")
        self.btnOpenCamera = QtWidgets.QPushButton(self.centralwidget)
        self.btnOpenCamera.setGeometry(QtCore.QRect(60, 370, 100, 30))
        self.btnOpenCamera.setObjectName("btnOpenCamera")
        self.btnCaptureImg = QtWidgets.QPushButton(self.centralwidget)
        self.btnCaptureImg.setGeometry(QtCore.QRect(220, 370, 100, 30))
        self.btnCaptureImg.setObjectName("btnCaptureImg")
        self.btnOpenImg = QtWidgets.QPushButton(self.centralwidget)
        self.btnOpenImg.setGeometry(QtCore.QRect(370, 370, 93, 28))
        self.btnOpenImg.setObjectName("btnOpenImg")
        self.btnGraying = QtWidgets.QPushButton(self.centralwidget)
        self.btnGraying.setGeometry(QtCore.QRect(520, 370, 100, 30))
        self.btnGraying.setObjectName("btnGraying")
        self.btnThresholdSegment = QtWidgets.QPushButton(self.centralwidget)
        self.btnThresholdSegment.setGeometry(QtCore.QRect(670, 370, 150, 30))
        self.btnThresholdSegment.setObjectName("btnThresholdSegment")
        self.labelCamera = QtWidgets.QLabel(self.centralwidget)
        self.labelCamera.setGeometry(QtCore.QRect(70, 100, 150, 150))
        self.labelCamera.setObjectName("labelCamera")
        self.labelCapture = QtWidgets.QLabel(self.centralwidget)
        self.labelCapture.setGeometry(QtCore.QRect(330, 100, 150, 150))
        self.labelCapture.setObjectName("labelCapture")
        self.labelResult = QtWidgets.QLabel(self.centralwidget)
        self.labelResult.setGeometry(QtCore.QRect(630, 100, 150, 150))
        self.labelResult.setObjectName("labelResult")
        MainWindow.setCentralWidget(self.centralwidget)
        self.menubar = QtWidgets.QMenuBar(MainWindow)
        self.menubar.setGeometry(QtCore.QRect(0, 0, 859, 26))
        self.menubar.setObjectName("menubar")
        MainWindow.setMenuBar(self.menubar)
        self.statusbar = QtWidgets.QStatusBar(MainWindow)
        self.statusbar.setObjectName("statusbar")
        MainWindow.setStatusBar(self.statusbar)

        self.retranslateUi(MainWindow)
        self.btnOpenCamera.clicked.connect(MainWindow.btnOpenCamera_Clicked)
        self.btnCaptureImg.clicked.connect(MainWindow.btnCaptureImg_Clicked)
        self.btnOpenImg.clicked.connect(MainWindow.btnOpenImg_Clicked)
        self.btnGraying.clicked.connect(MainWindow.btnGrayingImg_Clicked)
        self.btnThresholdSegment.clicked.connect(MainWindow.btnThresholdSegment_Clicked)
        QtCore.QMetaObject.connectSlotsByName(MainWindow)

    def retranslateUi(self, MainWindow):
        _translate = QtCore.QCoreApplication.translate
        MainWindow.setWindowTitle(_translate("MainWindow", "MainWindow"))
        self.btnOpenCamera.setText(_translate("MainWindow", "Open Camera"))
        self.btnCaptureImg.setText(_translate("MainWindow", "Capture Image"))
        self.btnOpenImg.setText(_translate("MainWindow", "Open Image"))
        self.btnGraying.setText(_translate("MainWindow", "Graying"))
        self.btnThresholdSegment.setText(_translate("MainWindow", "Threshold Segmentation"))
        self.labelCamera.setText(_translate("MainWindow", "Camera"))
        self.labelCapture.setText(_translate("MainWindow", "Captured Image"))
        self.labelResult.setText(_translate("MainWindow", "Result Image"))　

[注：mainForm.py文件是根据ui文件生成的，也就是说重新生成会覆盖掉。所以为了使界面与逻辑分离，我们需要新建一个逻辑文件。]

在同一工作目录下新建一个”mainEntry.py”的文件，存放逻辑代码。

import sys
import cv2

from PyQt5 import QtCore, QtGui, QtWidgets
from PyQt5.QtCore import *
from PyQt5.QtGui import *
from PyQt5.QtWidgets import QFileDialog, QMainWindow

from mainForm import Ui_MainWindow


class PyQtMainEntry(QMainWindow, Ui_MainWindow):
    def __init__(self):
        super().__init__()
        self.setupUi(self)

        self.camera = cv2.VideoCapture(1) # 0-调用笔记本内置摄像头,1-调用usb摄像头
        self.is_camera_opened = False  # 摄像头有没有打开标记

        # 定时器：30ms捕获一帧
        self._timer = QtCore.QTimer(self)
        self._timer.timeout.connect(self._queryFrame)
        self._timer.setInterval(30)

    def btnOpenCamera_Clicked(self):
        '''
        打开和关闭摄像头
        '''
        self.is_camera_opened = ~self.is_camera_opened
        if self.is_camera_opened:
            self.btnOpenCamera.setText("Close Camera")
            self._timer.start()
        else:
            self.btnOpenCamera.setText("Open Camera")
            self._timer.stop()

    def btnCaptureImg_Clicked(self):
        '''
        捕获图片
        '''
        # 摄像头未打开，不执行任何操作
        if not self.is_camera_opened:
            return

        self.captured = self.frame

        # 后面这几行代码几乎都一样，可以尝试封装成一个函数
        rows, cols, channels = self.captured.shape
        bytesPerLine = channels * cols
        # Qt显示图片时，需要先转换成QImgage类型
        QImg = QImage(self.captured.data, cols, rows,
                      bytesPerLine, QImage.Format_RGB888)
        self.labelCapture.setPixmap(QPixmap.fromImage(QImg).scaled(
            self.labelCapture.size(), Qt.KeepAspectRatio, Qt.SmoothTransformation))

    def btnOpenImg_Clicked(self):
        '''
        从本地读取图片
        '''
        # 打开文件选取对话框
        filename,  _ = QFileDialog.getOpenFileName(self, '打开图片')
        if filename:
            self.captured = cv2.imread(str(filename))
            # OpenCV图像以BGR通道存储，显示时需要从BGR转到RGB
            self.captured = cv2.cvtColor(self.captured, cv2.COLOR_BGR2RGB)

            rows, cols, channels = self.captured.shape
            bytesPerLine = channels * cols
            QImg = QImage(self.captured.data, cols, rows,
                          bytesPerLine, QImage.Format_RGB888)
            self.labelCapture.setPixmap(QPixmap.fromImage(QImg).scaled(
                self.labelCapture.size(), Qt.KeepAspectRatio, Qt.SmoothTransformation))

    def btnGrayingImg_Clicked(self):
        '''
        灰度化
        '''
        # 如果没有捕获图片，则不执行操作
        if not hasattr(self, "captured"):
            return

        self.cpatured = cv2.cvtColor(self.captured, cv2.COLOR_RGB2GRAY)

        rows, columns = self.cpatured.shape
        bytesPerLine = columns
        # 灰度图是单通道，所以需要用Format_Indexed8
        QImg = QImage(self.cpatured.data, columns, rows,
                      bytesPerLine, QImage.Format_Indexed8)
        self.labelResult.setPixmap(QPixmap.fromImage(QImg).scaled(
            self.labelResult.size(), Qt.KeepAspectRatio, Qt.SmoothTransformation))

    def btnThresholdSegment_Clicked(self):
        '''
        Otsu自动阈值分割
        '''
        if not hasattr(self, "captured"):
            return

        _, self.cpatured = cv2.threshold(
            self.cpatured, 0, 255, cv2.THRESH_BINARY + cv2.THRESH_OTSU)

        rows, columns = self.cpatured.shape
        bytesPerLine = columns
        # 阈值分割图也是单通道，也需要用Format_Indexed8
        QImg = QImage(self.cpatured.data, columns, rows,
                      bytesPerLine, QImage.Format_Indexed8)
        self.labelResult.setPixmap(QPixmap.fromImage(QImg).scaled(
            self.labelResult.size(), Qt.KeepAspectRatio, Qt.SmoothTransformation))

    @QtCore.pyqtSlot()
    def _queryFrame(self):
        '''
        循环捕获图片
        '''
        ret, self.frame = self.camera.read()

        img_rows, img_cols, channels = self.frame.shape
        bytesPerLine = channels * img_cols

        cv2.cvtColor(self.frame, cv2.COLOR_BGR2RGB, self.frame)
        QImg = QImage(self.frame.data, img_cols, img_rows,
                      bytesPerLine, QImage.Format_RGB888)
        self.labelCamera.setPixmap(QPixmap.fromImage(QImg).scaled(
            self.labelCamera.size(), Qt.KeepAspectRatio, Qt.SmoothTransformation))


if __name__ == "__main__":
    app = QtWidgets.QApplication(sys.argv)
    window = PyQtMainEntry()
    window.show()
    sys.exit(app.exec_())

运行结果：　

参考文章：

http://ex2tron.wang/opencv-python-using-pyqt5-create-gui/#%E6%8C%91%E6%88%98%E5%86%85%E5%AE%B9