Python は Opencv ライブラリを使用してカメラを呼び出します

Python は Opencv ライブラリを使用してカメラを呼び出します

1. Opencv ライブラリを参照する

import cv2

ヒント: コマンドラインから直接 opencv ライブラリをインストールします: pip install opencv -python

2. カメラの電源を入れます

camera = cv2.VideoCapture(1,cv2.CAP_DSHOW)

ヒント: 1 は外部カメラを開くことを意味し、0 はコンピュータの内蔵カメラ (外部カメラを使用します) を意味します。それに応じて複数の外部カメラを 0、1、2... と列挙できます。

3. カメラパラメータを設定する

カメラの解像度を 1920*1080 に設定する例:

width = 1920
heigth = 1080
camera.set(cv2.CAP_PROP_FRAME_WIDTH,width)
camera.set(cv2.CAP_PROP_FRAME_HEIGHT,heigth)

カメラ パラメーターを取得する例は次のとおりです (特定のパラメーターを渡します)。

heigth = camera.get(cv2.CAP_PROP_FRAME_WIDTH,width)

カメラのパラメータは次のとおりです。

CAP_PROP_POS_MSEC       =0, //!< Current position of the video file in milliseconds.
CAP_PROP_POS_FRAMES     =1, //!< 0-based index of the frame to be decoded/captured next.
CAP_PROP_POS_AVI_RATIO  =2, //!< Relative position of the video file: 0=start of the film, 1=end of the film.
CAP_PROP_FRAME_WIDTH    =3, //!< Width of the frames in the video stream.
CAP_PROP_FRAME_HEIGHT   =4, //!< Height of the frames in the video stream.
CAP_PROP_FPS            =5, //!< Frame rate.
CAP_PROP_FOURCC         =6, //!< 4-character code of codec. see VideoWriter::fourcc .
CAP_PROP_FRAME_COUNT    =7, //!< Number of frames in the video file.
CAP_PROP_FORMAT         =8, //!< Format of the %Mat objects (see Mat::type()) returned by VideoCapture::retrieve().
					   //!< Set value -1 to fetch undecoded RAW video streams (as Mat 8UC1).
CAP_PROP_MODE           =9, //!< Backend-specific value indicating the current capture mode.
CAP_PROP_BRIGHTNESS    =10, //!< Brightness of the image (only for those cameras that support).
CAP_PROP_CONTRAST      =11, //!< Contrast of the image (only for cameras).
CAP_PROP_SATURATION    =12, //!< Saturation of the image (only for cameras).
CAP_PROP_HUE           =13, //!< Hue of the image (only for cameras).
CAP_PROP_GAIN          =14, //!< Gain of the image (only for those cameras that support).
CAP_PROP_EXPOSURE      =15, //!< Exposure (only for those cameras that support).
CAP_PROP_CONVERT_RGB   =16, //!< Boolean flags indicating whether images should be converted to RGB. <br/>
					   //!< *GStreamer note*: The flag is ignored in case if custom pipeline is used. It's user responsibility to interpret pipeline output.
CAP_PROP_WHITE_BALANCE_BLUE_U =17, //!< Currently unsupported.
CAP_PROP_RECTIFICATION =18, //!< Rectification flag for stereo cameras (note: only supported by DC1394 v 2.x backend currently).
CAP_PROP_MONOCHROME    =19,
CAP_PROP_SHARPNESS     =20,
CAP_PROP_AUTO_EXPOSURE =21, //!< DC1394: exposure control done by camera, user can adjust reference level using this feature.
CAP_PROP_GAMMA         =22,
CAP_PROP_TEMPERATURE   =23,
CAP_PROP_TRIGGER       =24,
CAP_PROP_TRIGGER_DELAY =25,
CAP_PROP_WHITE_BALANCE_RED_V =26,
CAP_PROP_ZOOM          =27,
CAP_PROP_FOCUS         =28,
CAP_PROP_GUID          =29,
CAP_PROP_ISO_SPEED     =30,
CAP_PROP_BACKLIGHT     =32,
CAP_PROP_PAN           =33,
CAP_PROP_TILT          =34,
CAP_PROP_ROLL          =35,
CAP_PROP_IRIS          =36,
CAP_PROP_SETTINGS      =37, //!< Pop up video/camera filter dialog (note: only supported by DSHOW backend currently. The property value is ignored)
CAP_PROP_BUFFERSIZE    =38,
CAP_PROP_AUTOFOCUS     =39,
CAP_PROP_SAR_NUM       =40, //!< Sample aspect ratio: num/den (num)
CAP_PROP_SAR_DEN       =41, //!< Sample aspect ratio: num/den (den)
CAP_PROP_BACKEND       =42, //!< Current backend (enum VideoCaptureAPIs). Read-only property
CAP_PROP_CHANNEL       =43, //!< Video input or Channel Number (only for those cameras that support)
CAP_PROP_AUTO_WB       =44, //!< enable/ disable auto white-balance
CAP_PROP_WB_TEMPERATURE=45, //!< white-balance color temperature
CAP_PROP_CODEC_PIXEL_FORMAT =46,    //!< (read-only) codec's pixel format. 4-character code - see VideoWriter::fourcc . Subset of [AV_PIX_FMT_*](https://github.com/FFmpeg/FFmpeg/blob/master/libavcodec/raw.c) or -1 if unknown
CAP_PROP_BITRATE       =47, //!< (read-only) Video bitrate in kbits/s
CAP_PROP_ORIENTATION_META=48, //!< (read-only) Frame rotation defined by stream meta (applicable for FFmpeg back-end only)
CAP_PROP_ORIENTATION_AUTO=49, //!< if true - rotates output frames of CvCapture considering video file's metadata  (applicable for FFmpeg back-end only) (https://github.com/opencv/opencv/issues/15499)
CAP_PROP_HW_ACCELERATION=50, //!< (**open-only**) Hardware acceleration type (see #VideoAccelerationType). Setting supported only via `params` parameter in cv::VideoCapture constructor / .open() method. Default value is backend-specific.
CAP_PROP_HW_DEVICE      =51, //!< (**open-only**) Hardware device index (select GPU if multiple available). Device enumeration is acceleration type specific.
CAP_PROP_HW_ACCELERATION_USE_OPENCL=52, //!< (**open-only**) If non-zero, create new OpenCL context and bind it to current thread. The OpenCL context created with Video Acceleration context attached it (if not attached yet) for optimized GPU data copy between HW accelerated decoder and cv::UMat.
CAP_PROP_OPEN_TIMEOUT_MSEC=53, //!< (**open-only**) timeout in milliseconds for opening a video capture (applicable for FFmpeg back-end only)
CAP_PROP_READ_TIMEOUT_MSEC=54, //!< (**open-only**) timeout in milliseconds for reading from a video capture (applicable for FFmpeg back-end only)
CAP_PROP_STREAM_OPEN_TIME_USEC =55, //<! (read-only) time in microseconds since Jan 1 1970 when stream was opened. Applicable for FFmpeg backend only. Useful for RTSP and other live streams
CAP_PROP_VIDEO_TOTAL_CHANNELS = 56, //!< (read-only) Number of video channels
CAP_PROP_VIDEO_STREAM = 57, //!< (**open-only**) Specify video stream, 0-based index. Use -1 to disable video stream from file or IP cameras. Default value is 0.
CAP_PROP_AUDIO_STREAM = 58, //!< (**open-only**) Specify stream in multi-language media files, -1 - disable audio processing or microphone. Default value is -1.
CAP_PROP_AUDIO_POS = 59, //!< (read-only) Audio position is measured in samples. Accurate audio sample timestamp of previous grabbed fragment. See CAP_PROP_AUDIO_SAMPLES_PER_SECOND and CAP_PROP_AUDIO_SHIFT_NSEC.
CAP_PROP_AUDIO_SHIFT_NSEC = 60, //!< (read only) Contains the time difference between the start of the audio stream and the video stream in nanoseconds. Positive value means that audio is started after the first video frame. Negative value means that audio is started before the first video frame.
CAP_PROP_AUDIO_DATA_DEPTH = 61, //!< (open, read) Alternative definition to bits-per-sample, but with clear handling of 32F / 32S
CAP_PROP_AUDIO_SAMPLES_PER_SECOND = 62, //!< (open, read) determined from file/codec input. If not specified, then selected audio sample rate is 44100
CAP_PROP_AUDIO_BASE_INDEX = 63, //!< (read-only) Index of the first audio channel for .retrieve() calls. That audio channel number continues enumeration after video channels.
CAP_PROP_AUDIO_TOTAL_CHANNELS = 64, //!< (read-only) Number of audio channels in the selected audio stream (mono, stereo, etc)
CAP_PROP_AUDIO_TOTAL_STREAMS = 65, //!< (read-only) Number of audio streams.
CAP_PROP_AUDIO_SYNCHRONIZE = 66, //!< (open, read) Enables audio synchronization.
CAP_PROP_LRF_HAS_KEY_FRAME = 67, //!< FFmpeg back-end only - Indicates whether the Last Raw Frame (LRF), output from VideoCapture::read() when VideoCapture is initialized with VideoCapture::open(CAP_FFMPEG, {CAP_PROP_FORMAT, -1}) or VideoCapture::set(CAP_PROP_FORMAT,-1) is called before the first call to VideoCapture::read(), contains encoded data for a key frame.
CAP_PROP_CODEC_EXTRADATA_INDEX = 68, //!< Positive index indicates that returning extra data is supported by the video back end.  This can be retrieved as cap.retrieve(data, <returned index>).  E.g. When reading from a h264 encoded RTSP stream, the FFmpeg backend could return the SPS and/or PPS if available (if sent in reply to a DESCRIBE request), from calls to cap.retrieve(data, <returned index>).
CAP_PROP_FRAME_TYPE = 69, //!< (read-only) FFmpeg back-end only - Frame type ascii code (73 = 'I', 80 = 'P', 66 = 'B' or 63 = '?' if unknown) of the most recently read frame.

ヒント: どのパラメータを調整できるかは、カメラがサポートしているパラメータ調整によって異なります。パラメータ値を出力することで、opencv ライブラリを通じてパラメータを直接調整できるかどうかを判断できます。戻り値は -1 で、通常、このパラメータ設定が有効であることを意味しますカメラの特定のパラメータは、通常の状況では調整すべきではありません。

例

for i in range(15):
    print("No.={} parameter={}".format(i,camera.get(i)))

4. カメラの電源を入れてパラメータを設定した後、写真を撮ったり、画面を録画したりできます。

投稿者はカメラ機能をデモンストレーションするためだけにデモを書きましたが、いきなりスプレーするのは好きではありません。

コンソール入力 1 は、押されると自動的にフレームをキャプチャし、画像を生成します (生成された写真はプログラムと同じディレクトリにあります)。

コンソールに 3 つのウィンドウを入力して現在のカメラ画面を表示し、ESC を押してウィンドウ表示を終了します。

# -*- coding: utf-8 -*-
"""
Created on Fri Jul 29 19:41:05 2022

@author: user
"""
import cv2
import numpy as np
import threading
import time
from multiprocessing import Process, Queue
import os, time, random

class Camera(threading.Thread):
    __slots__ = ['camera','Flag','count','width','heigth','frame']
    def __init__(self):
        threading.Thread.__init__(self)
        self.camera = cv2.VideoCapture(0,cv2.CAP_DSHOW)
        self.Flag = 0
        self.count = 1
        self.width = 1920
        self.heigth = 1080
        self.name = ''
        self.path = ''
        self.camera.set(cv2.CAP_PROP_FRAME_WIDTH,self.width)
        self.camera.set(cv2.CAP_PROP_FRAME_HEIGHT,self.heigth)
        #for i in range(46):
            #print("No.={} parameter={}".format(i,self.camera.get(i)))
    def run(self):
        while True:
            ret, self.frame =  self.camera.read() # 摄像头读取,ret为是否成功打开摄像头,true,false。 frame为视频的每一帧图像
            self.frame = cv2.flip(self.frame, 1) # 摄像头是和人对立的，将图像左右调换回来正常显示。
            if self.Flag == 1:
                print("拍照")
                if self.name == ''and self.path == '':
                    cv2.imwrite(str(self.count) + '.jpg', self.frame) #将画面写入到文件中生成一张图片
                elif self.name != '':
                    cv2.imwrite(self.name+ '.jpg', self.frame)
                self.count+=1
                self.Flag = 0
            if self.Flag == 2:
                print("退出")
                self.camera.release()#释放内存空间
                cv2.destroyAllWindows()#删除窗口
                break
            
    def take_photo(self):
        self.Flag = 1
    def exit_program(self):
        self.Flag = 2
    def set_name(self,str):
        self.name = str
    def set_path(self,str):
        self.path = str

def show_window(cap):
        while True:
            cv2.namedWindow("window", 1)# 1代表外置摄像头
            cv2.resizeWindow("window", cap.width,cap.heigth )  #指定显示窗口大小
            cv2.imshow('window', cap.frame)
            c = cv2.waitKey(50) #按ESC退出画面
            if c == 27:
                cv2.destroyAllWindows()
                break

if __name__ == '__main__':
    cap = Camera()
    cap.start()
    while True:
        i = int(input("input:"))
        if i == 1:
            cap.take_photo()
        if i == 2:
            cap.exit_program()
        if i == 3:
            recv_data_thread = threading.Thread(target=show_window,args=(cap,))
            recv_data_thread.start()
        time.sleep(1)