Opencv-图像ROI与ROI操作

知识点

图像ROI与ROI操作
图像ROI解释:
图像的ROI(region of interest)是指图像中感兴趣区域、在OpenCV中图像设置图像ROI区域，实现只对ROI区域操作。

1. 矩形ROI区域提取

2. 矩形ROI区域copy

3. 不规则ROI区域

• ROI区域mask生成
• 像素位 and操作
• 提取到ROI区域
• 加背景or操作
• add 背景与ROI区域

python代码

import cv2 as cv
import numpy as np

src = cv.imread("C:/Users/qqxd/Desktop/opencvcode/images/test.png")
cv.namedWindow("input", cv.WINDOW_AUTOSIZE)
cv.imshow("input", src)
h, w = src.shape[:2]
print(h,w)

roi = src[20:230,130:300,:]
cv.imshow("roi", roi)
# copy ROI
image = np.copy(roi)
# modify ROI
#通过切片操作对图像的通道进行处理
#b通道为0
roi[:, :,0 ]  = 0
#g通道为0
# roi[:, :,1 ] = 0

# r通道为0
# roi[:, :,2] = 0
cv.imshow("result", src)


src2 = cv.imread("C:/Users/qqxd/Desktop/opencvcode/images/greenback.png");
cv.imshow("src2", src2)
hsv = cv.cvtColor(src2, cv.COLOR_BGR2HSV)
mask = cv.inRange(hsv, (35, 43, 46), (99, 255, 255))
mask = cv.bitwise_not(mask)
person = cv.bitwise_and(src2, src2,mask=mask)
cv.imshow("person",person)
result = np.zeros(src2.shape, src2.dtype)
result[:,:,0] = 255
mask = cv.bitwise_not(mask)
cv.imshow("mask",mask)
dst = cv.bitwise_or(person, result,mask = mask)
dst = cv.add(dst, person)
cv.imshow("dst",dst)
#从而完成换底操作
cv.waitKey(0)
cv.destroyAllWindows()

c++代码

#include
#include

using namespace cv;
using namespace std;

int main(int argc, char** argv) {
     
	Mat src = imread("C:/Users/qqxd/Desktop/opencvcode/images/test.png");
	namedWindow("input", WINDOW_AUTOSIZE);
	imshow("input", src);
	int h = src.rows;
	int w = src.cols;

	// 获取ROI
	Rect rect(130, 20, 300-130, 230-20);
	Mat roi = src(rect);
	imshow("roi", roi);

	Mat image = roi.clone();
	// modify ROI
	roi.setTo(Scalar(255, 0, 0));
	//imshow("result", src);

	// modify copy roi
	//image.setTo(Scalar(0, 0, 255));
	imshow("result", src);
	//imshow("copy roi", image);

	// example with ROI - generate mask
	Mat src2 = imread("C:/Users/qqxd/Desktop/opencvcode/images/greenback.png");
	imshow("src2", src2);
	Mat hsv, mask;
	cvtColor(src2, hsv, COLOR_BGR2HSV);
	inRange(hsv, Scalar(35, 43, 46), Scalar(99, 255, 255), mask);
	imshow("mask", mask);

	// extract person ROI
	Mat person;
	bitwise_not(mask, mask);
	bitwise_and(src2, src2, person, mask);
	imshow("person", person);

	// generate background
	Mat result = Mat::zeros(src2.size(), src2.type());
	result.setTo(Scalar(255, 0, 0));

	// combine background + person
	Mat dst;
	bitwise_not(mask, mask);
	bitwise_or(person, result, dst, mask);
	add(dst, person, dst);

	imshow("dst", dst);
	waitKey(0);
	return 0;
}

运行结果如下：