问题:在python中使用opencv改变图像中某个区域的颜色

我有一张图片,我想将所有白色像素更改为灰色,但仅限于图像的某个区域。示例图片,我只想更改红色矩形之外的图片,而不更改红色矩形内的图像:

我已经有了通用代码,这是其他人 Stackoverflow 问题的一部分,它改变了每个白色像素的颜色,而不仅仅是一个区域之外的像素。

image = cv.imread("meme 2.jpg")
hsv = cv.cvtColor(image, cv.COLOR_BGR2HSV)

# Define lower and uppper limits of what we call "white-ish"
sensitivity = 19
lower_white = np.array([0, 0, 255 - sensitivity])
upper_white = np.array([255, sensitivity, 255])

# Mask image to only select white
mask = cv.inRange(hsv, lower_white, upper_white)

# Change image to grey where we found brown
image[mask > 0] = (170, 170, 170)
cv.imwrite(file, image)

解答

这是在 Python/OpenCV 中执行此操作的一种方法。

• 读取输入

• 转换为 HSV 颜色空间

• 制作蒙版所需颜色的阈值

• 使用蒙版改变图像中所有对应像素的颜色

• 为不想改变的区域绘制一个新的矩形遮罩

• 反转要更改的区域的新蒙版

• 对原图应用新蒙版

• 将倒置的新蒙版应用于变色的图像

• 将两个结果相加,形成最终图像

• 保存结果

输入:

import cv2
import numpy as np

# Read image
image = cv2.imread('4animals.jpg')

# Convert to HSV
hsv = cv2.cvtColor(image, cv2.COLOR_BGR2HSV)

# Define lower and uppper limits of what we call "white-ish"
sensitivity = 19
lower_white = np.array([0, 0, 255 - sensitivity])
upper_white = np.array([255, sensitivity, 255])

# Create mask to only select white
mask = cv2.inRange(hsv, lower_white, upper_white)

# Change image to grey where we found white
image2 = image.copy()
image2[mask > 0] = (170, 170, 170)

# Create new rectangular mask that is white on black background
x,y,w,h = 33,100,430,550
mask2 = np.zeros_like(image)
cv2.rectangle(mask2, (x,y), (x+w,y+h), (255, 255, 255), -1)

# invert mask
mask2_inv = 255 - mask2

# apply mask to image
image_masked = cv2.bitwise_and(image, mask2)

# apply inverted mask to image2
image2_masked = cv2.bitwise_and(image2, mask2_inv)

# add together
result = cv2.add(image_masked, image2_masked)

# save results
cv2.imwrite('4animals_mask.jpg', mask)
cv2.imwrite('4animals_modified.png', image2)
cv2.imwrite('4animals_mask2.jpg', mask2)
cv2.imwrite('4animals_mask2_inv.jpg', mask2_inv)
cv2.imwrite('4animals_masked.jpg', image_masked)
cv2.imwrite('4animals_modified_masked.jpg', image2_masked)
cv2.imwrite('4animals_result.jpg', result)

cv2.imshow('mask', mask)
cv2.imshow('image2', image2)
cv2.imshow('mask2', mask2 )
cv2.imshow('mask2_inv', mask2_inv)
cv2.imshow('image_masked', image_masked)
cv2.imshow('image2_masked', image2_masked)
cv2.imshow('result', result)
cv2.waitKey(0)
cv2.destroyAllWindows()

彩色面膜:

矩形遮罩:

倒置矩形遮罩:

颜色改变的图像:

屏蔽输入:

蒙面颜色更改图像:

结果: