自学教程：python利用opencv实现颜色检测

import cv2img = cv2.imread('l3.png')gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)hsv = cv2.cvtColor(img, cv2.COLOR_BGR2HSV)def mouse_click(event, x, y, flags, para): if event == cv2.EVENT_LBUTTONDOWN: # 左边鼠标点击  print('PIX:', x, y)  print("BGR:", img[y, x])  print("GRAY:", gray[y, x])  print("HSV:", hsv[y, x])if __name__ == '__main__': cv2.namedWindow("img") cv2.setMouseCallback("img", mouse_click) while True:  cv2.imshow('img', img)  if cv2.waitKey() == ord('q'):   break cv2.destroyAllWindows()

import numpy as npimport cv2font = cv2.FONT_HERSHEY_SIMPLEXlower_red = np.array([0, 127, 128]) # 红色阈值下界higher_red = np.array([10, 255, 255]) # 红色阈值上界lower_yellow = np.array([15, 230, 230]) # 黄色阈值下界higher_yellow = np.array([35, 255, 255]) # 黄色阈值上界lower_blue = np.array([85,240,140])higher_blue = np.array([100,255,165])frame=cv2.imread("l3.png")img_hsv = cv2.cvtColor(frame, cv2.COLOR_BGR2HSV)mask_red = cv2.inRange(img_hsv, lower_red, higher_red) # 可以认为是过滤出红色部分，获得红色的掩膜mask_yellow = cv2.inRange(img_hsv, lower_yellow, higher_yellow) # 获得绿色部分掩膜mask_yellow = cv2.medianBlur(mask_yellow, 7) # 中值滤波mask_red = cv2.medianBlur(mask_red, 7) # 中值滤波mask_blue = cv2.inRange(img_hsv, lower_blue, higher_blue) # 获得绿色部分掩膜mask_blue = cv2.medianBlur(mask_blue, 7) # 中值滤波#mask = cv2.bitwise_or(mask_green, mask_red) # 三部分掩膜进行按位或运算print(mask_red)cnts1, hierarchy1 = cv2.findContours(mask_red, cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_NONE) # 轮廓检测 #红色cnts2, hierarchy2 = cv2.findContours(mask_blue, cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_NONE) # 轮廓检测 #红色cnts3, hierarchy3 = cv2.findContours(mask_yellow, cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_NONE)for cnt in cnts1: (x, y, w, h) = cv2.boundingRect(cnt) # 该函数返回矩阵四个点 cv2.rectangle(frame, (x, y), (x + w, y + h), (0, 0, 255), 2) # 将检测到的颜色框起来 cv2.putText(frame, 'red', (x, y - 5), font, 0.7, (0, 0, 255), 2)for cnt in cnts2: (x, y, w, h) = cv2.boundingRect(cnt) # 该函数返回矩阵四个点 cv2.rectangle(frame, (x, y), (x + w, y + h), (0, 0, 255), 2) # 将检测到的颜色框起来 cv2.putText(frame, 'blue', (x, y - 5), font, 0.7, (0, 0, 255), 2)for cnt in cnts3: (x, y, w, h) = cv2.boundingRect(cnt) # 该函数返回矩阵四个点 cv2.rectangle(frame, (x, y), (x + w, y + h), (0, 255, 0), 2) # 将检测到的颜色框起来 cv2.putText(frame, 'yellow', (x, y - 5), font, 0.7, (0, 255, 0), 2)cv2.imshow('frame', frame)cv2.waitKey(0)cv2.destroyAllWindows()