Python 使用Opencv实现cameo功能

雨点打透心脏的1/2处 2022-05-24 07:22 200阅读 0赞

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[文件temp.py][temp.py]，实现类WindowManager和CaptureManager

import cv2
    import numpy
    import time
    # 视频图像管理类
    class CaptureManager(object):
        # 类变量前加 _ 代表将变量设置保护变量，只有类对象和子类才能访问
        # 类变量前加 __ 代表将变量设置私有变量，只有类对象才能访问
        def __init__(self, capture, previewWindowManager = None, shouldMirrorPreview = False):
            self.previewWindowManager = previewWindowManager
            self.shouldMirrorPreview = shouldMirrorPreview
            self._capture = capture
            self._channel = 0
            self._enteredFrame = False
            self._frame = None
            self._imageFilename = None
            self._videoFilename = None
            self._videoEncoding = None
            self._videoWriter = None
            self._startTime = None
            self._framesElapsed = float(0)
            self._fpsEstimate = None
    
        # 设置只读属性
        @property
        def channel(self):
            return self._channel
    
        # 设置可写属性
        @channel.setter
        def channel(self, value):
            if self._channel != value:
                self._channel = value
                self._frame = None
    
        # 设置只读属性
        @property
        def frame(self):
            if self._enteredFrame and self._frame is None:
                _, self._frame = self._capture.retrieve()
            return self._frame
    
        # 设置只读属性
        @property
        def isWritingImage(self):
            # return self._imageFilename is not None 首先判断self._imageFilename是否为None，若是，返回False，否则返回True
            # if self._imageFilename:
            #     return True
            # else:
            #     return False
            return self._imageFilename is not None
    
        # 设置只读属性
        @property
        def isWritingVideo(self):
            return self._videoFilename is not None
        # 启动摄像头录制功能
        def enterFrame(self):
            """Capture the next frame, if any"""
            assert not self._enteredFrame, 'previous enterFrame() had no mathcing exitFrame'
            if self._capture is not None:
                self._enteredFrame = self._capture.grab()
    
        # 程序里最复杂的就是这方法了，担负了视频显示、视频视频录制、截屏保存的功能。
        def exitFrame (self):
            """Draw to the window. Write to files. Release the frame"""
            if self.frame is None:
                self._enteredFrame = False
                return
            # 计算fps
            if self._framesElapsed == 0:
                self._startTime = time.time()
            else:
                timeElapsed = time.time() - self._startTime
                self._fpsEstimate = self._framesElapsed / timeElapsed
    
            self._framesElapsed += 1
            # 显示图像
            if self.previewWindowManager is not None:
                if self.shouldMirrorPreview:
                    # 向左/右方向翻转阵列，翻转图像
                    mirroredFrame = numpy.fliplr(self._frame).copy()
                    self.previewWindowManager.show(mirroredFrame)
                else:
                    self.previewWindowManager.show(self._frame)
    
            # 图片文件生成
            if self.isWritingImage:
                cv2.imwrite(self._imageFilename, self._frame)
                self._imageFilename = None
    
            # 录像生成
            self._writeVideoFrame()
    
            self._frame = None
            self._enteredFrame = False
    
        # 设置图片文件名
        def writeImage(self, filename):
            """Wirte the next exited frame to an image file."""
            self._imageFilename = filename
    
        # 开始录制
        def startWritingVideo(self, filename, encodeing = cv2.VideoWriter_fourcc('I', '4', '2', '0')):
            """Start wirting exited frames to a video file."""
            self._videoFilename = filename
            self._videoEncoding = encodeing
        # 停止录制
        def stopWritingVideo(self):
            """Stop writing eited frames to a video file."""
            self._videoFilename = None
            self._videoEncodding = None
            self._videoWriter = None
    
        # 录制视频
        def _writeVideoFrame(self):
            if not self.isWritingVideo:
                return
            if self._videoWriter is None:
                fps = self._capture.get(cv2.CAP_PROP_FPS)
                if fps == 0.0:
                    if self._framesElapsed < 20:
                        return
                    else:
                        fps = self._fpsEstimate
                size = (int(self._capture.get(cv2.CAP_PROP_FRAME_WIDTH)), int(self._capture.get(cv2.CAP_PROP_FRAME_HEIGHT)))
                self._videoWriter = cv2.VideoWriter(self._videoFilename, self._videoEncoding, fps, size)
            self._videoWriter.write(self._frame)
    
    # 创建界面管理类
    class WindowManager(object):
        def __init__(self, windowName, keypressCallback = None):
            self.keypressCallback = keypressCallback
            self._windowName = windowName
            self._isWindowCreated = False
        # 设置只读属性
        @property
        def isWindowCreated(self):
            return self._isWindowCreated
        # 创建窗口
        def createWindow(self):
            cv2.namedWindow(self._windowName)
            self._isWindowCreated = True
        # 显示窗口
        def show(self, frame):
            cv2.imshow(self._windowName, frame)
            cv2.waitKey(1)
        # 注销窗口
        def destroyWindow(self):
            cv2.destroyWindow(self._windowName)
            self._isWindowCreated = False
        # 执行键盘操作的回调函数
        def processEvents(self):
            keycode = cv2.waitKey(1)
            if self.keypressCallback is not None and keycode != 255:
                #Discard any non-ASCII info encoded by GTK.
                keycode &= 0xFF
                self.keypressCallback(keycode)

程序运行文件

import cv2
    from temp import WindowManager, CaptureManager
    
    class Cameo(object):
        def __init__(self):
            # 创建一个窗口，并将键盘的回调函数传入
            self._windowManager = WindowManager('Cameo', self.onKeypress)
            # 告诉程序数据来自摄像头， 还有镜面效果
            self._captureManager = CaptureManager(capture=cv2.VideoCapture(0), previewWindowManager=self._windowManager, shouldMirrorPreview=True)
    
        def run(self):
            """Run the main loop."""
            self._windowManager.createWindow()
            while self._windowManager.isWindowCreated:
                # 这里的enterFrame就是告诉程序从摄像头中取数据
                self._captureManager.enterFrame()
                # 下面的这个frame是原始帧数据，这里没有做任何修改，后面的教程会对这个帧数据进行修改
                frame = self._captureManager._frame
                # exitFrame看起来是像是退出的意思，其实主要功能都是在这里方法里实现的，截屏、录像都是在这里
                self._captureManager.exitFrame()
                # 回调函数
                self._windowManager.processEvents()
        # 定义键盘的回调函数，用于self._windowManager.processEvents()的调用
        def onKeypress(self, keycode):
            '''
            快捷键设置：
            当按下“空格”键的时候，会进行抓屏。
            当按下‘tab’键的时候，就开始或者停止录像。
            当然相应的目录也会生成图片或者视频文件
            '''
            if keycode == 32:#space
                # 截屏保存的文件名字
                self._captureManager.writeImage('changeOnePixel.png')
            elif keycode == 9:#tab
                if not self._captureManager.isWritingVideo:
                    # 告诉程序，录像保存的文件名字
                    self._captureManager.startWritingVideo('record.avi')
                else:
                    self._captureManager.stopWritingVideo()
            elif keycode == 27: #escape
                self._windowManager.destroyWindow()
    
    if __name__=="__main__":
        Cameo().run()

参考资料：OpenCV 3计算机视觉 Python语言实现第二版

[temp.py]: http://xn--temp-p85f980j.py