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我有屏幕记录的代码，并且每一帧我都有一组我想在每一帧上显示的边界框。我可以使用matplotlib或其他方式执行此操作，但我mss的工作速度为 30fps，我需要能够快速显示边界框。

我在文档中注意到这个例子，但我尝试运行它并且无法让它显示任何东西。而且我什至不确定这是否适用于我的示例。

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一帧上，例如，

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

我可以以某种方式更改像素以显示它吗？我想我也可以通过它来做到这一点opencv，因为这是最终显示屏幕的内容。

编辑：参考关于边界框的评论，它们是x1, y1, width, height，并且在调整大小的(224,224)图像中

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1 回答 1

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有一些缺失的细节：

  • 边界框的格式是什么：[x1, y1, x2, y2]或[x1, y1, width, height]其他？
  • 边界框的值是在调整后的 ( 224, 224) 范围内还是在原始范围内？

无论如何，您可以使用下面的函数来绘制矩形（您需要根据格式选择）：

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)

假设您定义了bboxes，您可以调用该函数：

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

经过一些更改，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

输出将是这样的：

在此处输入图像描述

于 2019-01-21T19:57:47.550 回答