How to detect two different colors using `cv2.inRange` in Python-OpenCV?

Question

How can I define \"lower\" and \"upper\" range of two different color, such as red and blue (because red and blue are not next to each other in the HSV color)

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Answer 1

As you get two masks of colors, then use cv2.bitwise_or to get the final mask.

import cv2

## Read
img = cv2.imread("sunflower.jpg")

## convert to hsv
hsv = cv2.cvtColor(img, cv2.COLOR_BGR2HSV)

## mask of green (36,0,0) ~ (70, 255,255)
mask1 = cv2.inRange(hsv, (36, 0, 0), (70, 255,255))

## mask o yellow (15,0,0) ~ (36, 255, 255)
mask2 = cv2.inRange(hsv, (15,0,0), (36, 255, 255))

## final mask and masked
mask = cv2.bitwise_or(mask1, mask2)
target = cv2.bitwise_and(img,img, mask=mask)

cv2.imwrite("target.png", target)

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Source:

Find green and yellow(the range is not that accurate):

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BTW, to get more accurate range, here is a refer map in my related answer:

How to define a threshold value to detect only green colour objects in an image :Opencv