学习来自 如何使用 OpenCV Python 检测颜色

import cv2
import numpy as np


def red_hsv(img, save=False):
    lower_hsv1 = np.array([0, 175, 20])
    higher_hsv1 = np.array([10, 255, 255])

    lower_hsv2 = np.array([170, 175, 20])
    higer_hsv2 = np.array([10, 255, 255])

    mask1 = cv2.inRange(img, lower_hsv1, higher_hsv1)
    mask2 = cv2.inRange(img, lower_hsv2, higer_hsv2)

    if save:
        cv2.imwrite("red-mask-1.jpg", mask1)
        cv2.imwrite("red-mask-2.jpg", mask2)
        cv2.imwrite("red-mask.jpg", mask1+mask2)

    return mask1 + mask2


def green_hsv(img, save=False):
    lower_hsv1 = np.array([40, 150, 20])
    higher_hsv1 = np.array([70, 255, 255])

    mask1 = cv2.inRange(img, lower_hsv1, higher_hsv1)
    if save:
        cv2.imwrite("green-mask-1.jpg", mask1)

    return mask1


if __name__ == "__main__":
    bgr = cv2.imread("1.png")
    hsv = cv2.cvtColor(bgr, cv2.COLOR_BGR2HSV)
    cv2.imwrite("hsv.jpg", hsv)

    mask = red_hsv(hsv, save=True) + green_hsv(hsv, save=True)
    cv2.imwrite("mask.jpg", mask)

    result = cv2.bitwise_and(bgr, bgr, mask=mask)
    cv2.imshow("color detection", result)
    cv2.waitKey(0)
    cv2.destroyAllWindows()

转成 hsv 色域，来过滤掉相应的颜色

H 根据 x 轴取值，S 根据 y 轴取值，V 始终在 (20-255) 之间的范围内取值

bitwise_and，输出图像像素只有mask对应位置元素不为0的部分才输出，否则该位置像素的所有通道分量都设置为0

看看结果

输入图片

hsv

red-mask-1

red-mask-2

red-mask

green-mask-1

result