使用 OpenCV 和 Python-2.7 进行屏幕截图
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Screen Capture with OpenCV and Python-2.7
提问by Renan V. Novas
I'm using Python 2.7and OpenCV 2.4.9.
我正在使用Python 2.7和OpenCV 2.4.9。
I need to capture the current frame that is being shown to the user and load it as an cv::Matobject in Python.
我需要捕获向用户显示的当前帧，并将其加载为Python 中的cv:: Mat对象。
Do you guys know a fast way to do it recursively?
你们知道递归的快速方法吗？
I need something like what's done in the example below, that captures Matframes from a webcam recursively:
我需要类似于下面示例中所做的事情，它以递归方式从网络摄像头捕获Mat帧：
import cv2
cap = cv2.VideoCapture(0)
while(cap.isOpened()):
ret, frame = cap.read()
cv2.imshow('WindowName', frame)
if cv2.waitKey(25) & 0xFF == ord('q'):
cap.release()
cv2.destroyAllWindows()
break
In the example it's used the VideoCapture classto work with the captured image from the webcam.
在示例中，它使用VideoCapture 类来处理从网络摄像头捕获的图像。
With VideoCapture.read() a new frame is always being readed and stored into a Matobject.
使用 VideoCapture.read() 总是会读取新帧并将其存储到Mat对象中。
Could I load a "printscreens stream"into a VideoCapture object? Could I create a streaming of my computer's screen with OpenCV in Python, without having to save and delete lots of .bmpfiles per second?
我可以将“printscreens 流”加载到 VideoCapture 对象中吗？我可以在 Python 中使用 OpenCV 创建计算机屏幕的流媒体，而不必每秒保存和删除大量.bmp文件吗？
I need this frames to be Matobjects or NumPy arrays, so I can perform some Computer Vision routines with this frames in real time.
我需要这些帧是Mat对象或NumPy 数组，因此我可以实时使用这些帧执行一些计算机视觉例程。
采纳答案by Renan V. Novas
That's a solution code I've written using @Raoul tips.
这是我使用@Raoul 提示编写的解决方案代码。
I used PIL ImageGrab module to grab the printscreen frames.
我使用 PIL ImageGrab 模块来抓取打印屏幕帧。
import numpy as np
from PIL import ImageGrab
import cv2
while(True):
printscreen_pil = ImageGrab.grab()
printscreen_numpy = np.array(printscreen_pil.getdata(),dtype='uint8')\
.reshape((printscreen_pil.size[1],printscreen_pil.size[0],3))
cv2.imshow('window',printscreen_numpy)
if cv2.waitKey(25) & 0xFF == ord('q'):
cv2.destroyAllWindows()
break
回答by Neabfi
I had frame rate problems with other solutions, msssolve them.
我在使用其他解决方案时遇到了帧速率问题，请mss解决它们。
import numpy as np
import cv2
from mss import mss
from PIL import Image
mon = {'top': 160, 'left': 160, 'width': 200, 'height': 200}
sct = mss()
while 1:
sct.get_pixels(mon)
img = Image.frombytes('RGB', (sct.width, sct.height), sct.image)
cv2.imshow('test', np.array(img))
if cv2.waitKey(25) & 0xFF == ord('q'):
cv2.destroyAllWindows()
break
回答by Phani Rithvij
This is the updated answer for the answer by @Neabfi
这是@Neabfi 的答案的更新答案
import time
import cv2
import numpy as np
from mss import mss
mon = {'top': 160, 'left': 160, 'width': 200, 'height': 200}
with mss() as sct:
# mon = sct.monitors[0]
while True:
last_time = time.time()
img = sct.grab(mon)
print('fps: {0}'.format(1 / (time.time()-last_time)))
cv2.imw('test', np.array(img))
if cv2.waitKey(25) & 0xFF == ord('q'):
cv2.destroyAllWindows()
break
And to save to a mp4 video
并保存到 mp4 视频
import time
import cv2
import numpy as np
from mss import mss
def record(name):
with mss() as sct:
# mon = {'top': 160, 'left': 160, 'width': 200, 'height': 200}
mon = sct.monitors[0]
name = name + '.mp4'
fourcc = cv2.VideoWriter_fourcc(*'mp4v')
desired_fps = 30.0
out = cv2.VideoWriter(name, fourcc, desired_fps,
(mon['width'], mon['height']))
last_time = 0
while True:
img = sct.grab(mon)
# cv2.imshow('test', np.array(img))
if time.time() - last_time > 1./desired_fps:
last_time = time.time()
destRGB = cv2.cvtColor(np.array(img), cv2.COLOR_BGRA2BGR)
out.write(destRGB)
if cv2.waitKey(25) & 0xFF == ord('q'):
cv2.destroyAllWindows()
break
record("Video")
