imshow ROI的大小与ROI.shape不同

Question

晚上！

我的问题如下：

1。roi的形状仅应为200,200。这里显示313313，我不确定为什么。

2。当我将frame的{​​{1}}切换为imshow（）的参数时，结果也不是roi的正确大小。我得到的是以下输出：

roi

此文件的输出为：

from imutils.video import VideoStream import argparse import cv2 import numpy as np import imutils import time ap = argparse.ArgumentParser(description="Pass the .mp4 file and optional buffer size as arguments.") ap.add_argument("-video", type=str, help="Path to the video file") . ap.add_argument("-buffer", type=int, default=64, help="Optional max buffer size") args = vars(ap.parse_args()) video = cv2.VideoCapture(args["video"]) time.sleep(2.0) offsetx = 38 offsety = 5 while (video.isOpened()): ret, frame = video.read() frame = imutils.resize(frame, width=1280) (screenheight, screenwidth) = frame.shape[:2] mid_y = screenheight/2 mid_x = screenwidth /2 roi_x = (mid_x + offsetx) - 100 roi_y = (mid_y + offsety) - 100 roi = frame[int(roi_y):int(roi_x),int(roi_y)+200:int(roi_x)+200] cv2.rectangle(frame,(int(roi_x),int(roi_y)),(int(roi_x)+200,int(roi_y)+200),(0,255,0),3) print(int(roi_x),int(roi_y),int(roi_x)+200,int(roi_y)+200) print(roi.shape) cv2.imshow('frame',roi) if cv2.waitKey(1) & 0xFF == ord('q'): break video.release() cv2.destroyAllWindows()

Answer 1

您的投资回报率规范不正确。应该是[y1：y2，x1：x2]而不是[y1：x1，y2：x2]

我在这里测试静态图像：

import cv2

img = cv2.imread('lena.jpg')
height = img.shape[0]
width = img.shape[1]

mid_y = height/2
mid_x = width/2

offset_y = -50
offset_x = -25
y1 = int(mid_y + offset_y) 
x1 = int(mid_x + offset_x)
rows = 100
cols = 50
y2 = y1+rows
x2 = x1+cols
print(y1, y2, x1, x2)

roi = img[y1:y2, x1:x2]
cv2.rectangle(img, (x1,y1), (x2,y2), (0,255,0), 3)
print(roi.shape)

cv2.imshow("ROI", roi)
cv2.waitKey(0)
cv2.destroyAllWindows()

cv2.imwrite("lena_roi.jpg", roi)

    打印：

78 178 103 153
(100, 50, 3)

结果：