python OpenCV学习笔记

pip install imutils

import cv2
import imutils

'''
imutils.rotate
第一个参数是翻转的图像，第二个参数的翻转角度
函数还提供翻转中心的设置，但默认就是中心翻转。
'''
vc = cv2.VideoCapture(0)

if vc.isOpened():
  flag, frame = vc.read()
  img = imutils.rotate(frame, 180)  # 图像翻转 
  cv2.imshow("frame", img)
else:
  flag = False

while flag:
  flag, frame = vc.read()
  if frame is None:
    break
  if flag is True:
    img = imutils.rotate(frame, 180)  # 图像翻转
    cv2.imshow("frame", img)
    if cv2.waitKey(10) == 27:
      break
vc.release()
cv2.destroyAllWindows()

from imutils import contours
import cv2
'''
contours.sort_contours
可选排序方式："left-to-right", "right-to-left", "top-to-bottom", "bottom-to-top"
返回值为轮廓和外接矩形

contours.label_contour
contours包内自带的画轮廓的函数，可以直接用，然后可以在图片上标出轮廓序号
也可以直接使用cv2.drawContours直接画轮廓
'''
img = cv2.imread(r"D:\opencv-workspace\Opencv\test17--VScode\shapes.png")
draw_img = img.copy()
img_rect = img.copy()
gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)
img = cv2.Canny(gray, 10, 20)  # Canny边缘检测
cnts, hierarchy = cv2.findContours(img, cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_NONE)  # 获得轮廓
(cnts, boundingBoxes) = contours.sort_contours(cnts, "top-to-bottom")  # 对轮廓进行排序处理
for (i, c) in enumerate(cnts):
  sortedImage = contours.label_contour(draw_img, c, i, color=(240, 0, 159))
# img_out = cv2.drawContours(draw_img, cnts, -1, (240, 0, 159), 2)
# 根据boundingBoxes画外接矩形
for (x, y, w, h) in boundingBoxes:
  img_rect = cv2.rectangle(img_rect, (x, y), (x+w, y+h), (240, 0, 159), 2)
cv2.imshow("top-to-bottom", sortedImage)
cv2.imshow("rect", img_rect)
cv2.waitKey(0)
cv2.destroyAllWindows()

from imutils import contours
import cv2
'''
contours.sort_contours
可选排序方式："left-to-right", "right-to-left", "top-to-bottom", "bottom-to-top"
返回值为轮廓和外接矩形

contours.label_contour
contours包内自带的画轮廓的函数，可以直接用，然后可以在图片上标出轮廓序号
也可以直接使用cv2.drawContours直接画轮廓
'''
img = cv2.imread(r"D:\opencv-workspace\Opencv\test17--VScode\shapes.png")
draw_img = img.copy()
img_rect = img.copy()
gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)
img = cv2.Canny(gray, 10, 20)  # Canny边缘检测
cnts, hierarchy = cv2.findContours(img, cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_NONE)  # 获得轮廓
(cnts, boundingBoxes) = contours.sort_contours(cnts, "top-to-bottom")  # 对轮廓进行排序处理
for (i, c) in enumerate(cnts):
  sortedImage = contours.label_contour(draw_img, c, i, color=(240, 0, 159))
# img_out = cv2.drawContours(draw_img, cnts, -1, (240, 0, 159), 2)
# 根据boundingBoxes画外接矩形
for (x, y, w, h) in boundingBoxes:
  img_rect = cv2.rectangle(img_rect, (x, y), (x+w, y+h), (240, 0, 159), 2)
cv2.imshow("top-to-bottom", sortedImage)
cv2.imshow("rect", img_rect)
cv2.waitKey(0)
cv2.destroyAllWindows()

'''使用下面这个函数进行转换，第一个参数填写要转换的图片，第二个参数填写cv2.COLOR_BGR2HSV'''
cv2.cvtColor

import cv2
import numpy as np
'''
cv2.inRange
函数很简单，参数有三个
第一个参数：hsv指的是原图
第二个参数：lower_red指的是图像中低于这个lower_red的值，图像值变为0
第三个参数：upper_red指的是图像中高于这个upper_red的值，图像值变为0
而在lower_red～upper_red之间的值变成255
'''
# 阈值
lower_green = np.array([50, 255, 255])
upper_green = np.array([70, 255, 255])
img = cv2.imread(r"D:\opencv-workspace\Opencv\test16--VScode\photo.jpg")
img_hsv = cv2.cvtColor(img, cv2.COLOR_BGR2HSV)
mask_green = cv2.inRange(img_hsv, lower_green, upper_green)
cv2.imshow("img_or", mask_green)
# 使用下面这个函数能显示原来的颜色。
res_green = cv2.bitwise_and(img, img, mask=mask_green)
cv2.imshow("img", res_green)
cv2.waitKey(0)
cv2.destroyAllWindows()

import cv2

color = np.uint8([[[193, 189, 147]]])  # 参数填写BGR的值
hsv = cv2.cvtColor(color, cv2.COLOR_BGR2HSV)
print(hsv)  # 打印出来的数值就是对应的HSV值

[[[ 93 61 193]]]

import cv2
import numpy as np


def function(x):
  lowH = cv2.getTrackbarPos("lowH", "img_666")
  lowS = cv2.getTrackbarPos("lowS", "img_666")
  lowV = cv2.getTrackbarPos("lowV", "img_666")
  HighH = cv2.getTrackbarPos("HighH", "img_666")
  HighS = cv2.getTrackbarPos("HighS", "img_666")
  HighV = cv2.getTrackbarPos("HighV", "img_666")
  # print(lowH, lowS, lowV, HighH, HighS, HighV)
  lower = np.uint8([lowH, lowS, lowV])
  upper = np.uint8([HighH, HighS, HighV])
  mask = cv2.inRange(img_hsv, lower, upper)
  res = cv2.bitwise_and(img, img, mask=mask)
  cv2.imshow("img", res)


img = cv2.imread(r"D:\opencv-workspace\Opencv\test16--VScode\test.jpg")
img_hsv = cv2.cvtColor(img, cv2.COLOR_BGR2HSV)
cv2.namedWindow("img_666")
cv2.createTrackbar("lowH", "img_666", 0, 179, function)
cv2.createTrackbar("lowS", "img_666", 0, 255, function)
cv2.createTrackbar("lowV", "img_666", 0, 255, function)
cv2.createTrackbar("HighH", "img_666", 0, 179, function)
cv2.createTrackbar("HighS", "img_666", 0, 255, function)
cv2.createTrackbar("HighV", "img_666", 0, 255, function)
cv2.imshow("img", img)
cv2.waitKey(0)
cv2.destroyAllWindows()