在 opencv python 中更改图像的 hsv 值不起作用

Question

Im trying to set the Minimum and Maximum value of HSV of an Image in opencv python but after running the code all I can see is a blank rectangle box.

import cv2
import sys
import numpy as np

# Load in image
image = cv2.imread('power.jpg')


# Set minimum and max HSV values to display
lower = np.array([0, 209, 0])
upper = np.array([179, 255, 236])

# Create HSV Image and threshold into a range.
hsv = cv2.cvtColor(image, cv2.COLOR_BGR2HSV)
mask = cv2.inRange(hsv, lower, upper)
output = cv2.bitwise_and(image,image, mask= mask)


# Display output image
cv2.imshow('image',output)

Answer 1

I was able to solve it.

import numpy as np
import cv2

img = cv2.imread( "power.jpg" )

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

## mask of red (36,0,0) ~ (70, 255,255)
mask = cv2.inRange(hsv, (0, 209, 0), (179, 255,236))
bak = img.copy()

# Show only red
#bak[mask > 0] = (0, 0, 255)
imask = mask>0
green = np.zeros_like(img, np.uint8)
green[imask] = img[imask]

## save 
cv2.imwrite("image.png", green)