OpenCV 图片和视频基本操作

这个主要是查 $API$，不涉及原理，如果用到新的功能，则更新此博客。

import cv2

img = cv2.imread('1.jpg')
shape = img.shape     # 返回图片的高度、宽度、深度组成的 tuple，高度和宽度指的是像素点个数
size = img.size       # 获取图像的像素数目，返回高*宽*通道数(三通道的话顺序为 BGR)
dataType = img.dtype  # 图像的数据类型
res = cv2.resize(img, (0, 0), fx=0.5, fy=0.5, interpolation=cv2.INTER_NEAREST)  # 图片缩放到原来的二分之一，注意这里参数顺序为(w, h)

cv2.namedWindow('input_image', cv2.WINDOW_AUTOSIZE)  # 窗口大小不可调整
cv2.imshow('input_image', res)
cv2.waitKey()  # 窗口默认一直处于弹出窗状态, 可以加持续时间参数。
cv2.destroyAllWindows()  # 按任意键盘关闭窗口

图片生成视频

import cv2
import numpy as np
import pixels

fps = 25
size = (900, 485)
escapeTime = 0
pointSize = 2
thickness = 2

def ReadImg(file_name):
    img = cv2.imread(file_name)
    img = cv2.resize(img, size, interpolation=cv2.INTER_NEAREST)
    return img

def AddTimeToImage(img, time):
    m, second = divmod(int(time), 60)
    hour, minute = divmod(m, 60)
    h_m_s = "{0}:{1}:{2}".format(str(hour).zfill(2), str(minute).zfill(2), str(second).zfill(2))
    cv2.putText(img,                       # 图像
                h_m_s,                     # 文字内容
                (740, 450),                # 坐标
                cv2.FONT_HERSHEY_SIMPLEX,  # 字体
                1,                         # 大小
                (0, 0, 0),                 # 颜色
                1,                         # 字体厚度
                cv2.LINE_AA)

blankImg = cv2.cvtColor(np.zeros((485, 900), dtype=np.uint8) + 255, cv2.COLOR_GRAY2BGR)
videoWriter = cv2.VideoWriter("video.avi", cv2.VideoWriter_fourcc('M','J','P','G'), fps, size)

for i in range(1,3):
    img = ReadImg(("%s" + ".jpg") % str(i))
    for j in range(50):
        escapeTime += 0.04
        frame = img.copy()
        AddTimeToImage(frame, escapeTime)
        videoWriter.write(frame)

count = 0
for item in pixels.datas:
    point = item[1::-1]
    pointColor= item[2:]
    cv2.circle(blankImg, point, pointSize, pointColor, thickness)
    count += 1
    if count == 50:
        count = 0
        escapeTime += 0.04
        frame = blankImg.copy()
        AddTimeToImage(frame, escapeTime)
        videoWriter.write(frame)

OpenCV 读取 gif 文件：

gif = cv2.VideoCapture('3.gif')
gif.read()

while True:
    ret, frame = gif.read()
    if ret:
        frame = cv2.resize(frame, size)
        for i in range(2):
            videoWriter.write(frame)
    else:
        break

OpenCV 调用电脑摄像头录制视频：

def RecordVideo(duration=10):
    fps = 25
    size = (640, 480)
    frameCount = duration * fps

    cap = cv2.VideoCapture(0)  # 打开摄像头
    videoWriter = cv2.VideoWriter("video.avi", cv2.VideoWriter_fourcc('M', 'J', 'P', 'G'), fps, size)

    success, frame = cap.read()
    while success and frameCount > 0:
        videoWriter.write(frame)
        success, frame = cap.read()
        frameCount -= 1

    cap.release()