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使用python mss在屏幕记录顶部绘制边界框

python-mss opencv python

0

conv3d · 技术社区 · 6 年前

我有屏幕记录的代码,每一帧我都有一组边界框要显示在每一帧上。我可以用 matplotlib 或者别的,但我 mss 正在以30帧的速度工作,我需要能够快速显示边界框。

我在医生那里注意到的 this example 但我试着运行它,却无法让它显示任何内容。我甚至不确定这是否适用于我的例子。

import cv2
import time
import numpy as np
from mss import mss

with mss() as sct:
        # Part of the screen to capture
        monitor = {"top": 79, "left": 265, "width": 905, "height": 586}

        while "Screen capturing":
            last_time = time.time()

            # Get raw pixels from the screen, save it to a Numpy array
            screen = np.array(sct.grab(monitor))

            # print("fps: {}".format(1 / (time.time() - last_time)))

            print('loop took {} seconds'.format(time.time()-last_time))
            last_time = time.time()
            screen = cv2.cvtColor(screen, cv2.COLOR_BGR2RGB)
            screen = cv2.resize(screen, (224,224)).astype(np.float32)/255

            # Display the picture
            cv2.imshow("OpenCV/Numpy normal", screen)

            # Press "q" to quit
            if cv2.waitKey(25) & 0xFF == ord("q"):
                cv2.destroyAllWindows()
                break

现在假设我有一组边界框要显示在每个帧上,例如,

bboxes = [np.array([12, 16, 29, 25]), np.array([5,  5, 38, 35])]

我能以某种方式改变像素来显示这个吗?我想我可以通过 opencv 因为这就是最终显示屏幕的原因。

编辑:参考关于边界框的注释,它们是 x1, y1, width, height ,并在调整大小后 (224,224) 形象

1 回复 | 直到 6 年前

1

Berriel 6 年前

缺少一些详细信息:

边界框的格式是什么: [x1, y1, x2, y2] 或 [x1, y1, width, height] 或者别的什么?
边界框中的值是否已调整大小( 224, 224 )还是原始范围?

无论如何,您可以使用下面的函数绘制矩形(您需要根据格式进行选择):

def draw_bboxes(img, bboxes, color=(0, 0, 255), thickness=1):
    for bbox in bboxes:
        # if [x1, y1, x2, y2]
        cv2.rectangle(img, tuple(bbox[:2]), tuple(bbox[-2:]), color, thickness)
        # if [x1, y1, width, height]
        cv2.rectangle(img, tuple(bbox[:2]), tuple(bbox[:2]+bbox[-2:]), color, thickness)

假设你定义了你的 bboxes ,可以调用函数:

如果要在原始帧上绘制:

# [...]
screen = np.array(sct.grab(monitor))
draw_bboxes(screen, bboxes)
# [...]

如果要在调整大小的框架上绘制:

# [...]
screen = cv2.resize(screen, (224,224)).astype(np.float32)/255
draw_bboxes(screen, bboxes)
# [...]

如果进行了一些更改,完整代码将如下所示:

import cv2
import time
import numpy as np
from mss import mss

def draw_bboxes(img, bboxes, color=(0, 0, 255), thickness=1):
    for bbox in bboxes:
        cv2.rectangle(img, tuple(bbox[:2]), tuple(bbox[:2]+bbox[-2:]), color, thickness)

# bounding boxes
bboxes = [np.array([12, 16, 29, 25]), np.array([5,  5, 38, 35])]

with mss() as sct:
    # part of the screen to capture
    monitor = {"top": 79, "left": 265, "width": 905, "height": 586}
    while "Screen capturing":
        # get screen
        last_time = time.time()
        screen = np.asarray(sct.grab(monitor))
        print('loop took {} seconds'.format(time.time()-last_time))

        # convert from BGRA --> BGR
        screen = cv2.cvtColor(screen, cv2.COLOR_BGRA2BGR)
        # resize and draw bboxes
        screen = cv2.resize(screen, (224,224))
        draw_bboxes(screen, bboxes)

        # display
        cv2.imshow("OpenCV/Numpy normal", screen)

        # Press "q" to quit
        if cv2.waitKey(25) & 0xFF == ord("q"):
            cv2.destroyAllWindows()
            break

输出如下: