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法律研究如何使用 C++ 在 OpenCV 中检测最大的人脸?
我们将学习仅检测最大的人脸。此主题与上一个主题相同。唯一不同的是我们使用了一个额外的“矩形”结构和一个“for”循环来检测最大的人脸。
此函数的实际格式——
Mat faceROI = image_with_humanface(maxRect)
maxRect 有图像上最大人脸的区域和位置信息。上面一行在图像上最大人脸所在位置裁剪 maxRect 中存储的相同区域，并在“faceROI”矩阵中存储。
以下程序从静止图片中检测最大的人脸——
示例
#include<iostream>
#include<opencv2/highgui/highgui.hpp>
#include<opencv2/imgproc/imgproc.hpp>
//This header includes definition of 'rectangle()' function//
#include<opencv2/objdetect/objdetect.hpp>
//This header includes the definition of Cascade Classifier//
#include<string>
using namespace std;
using namespace cv;
int main(int argc, char** argv) {
Mat image_with_humanface;//Declaring a matrix to load image with human faces//
image_with_humanface = imread("person.jpg");//loading an image that contains human face in it//
namedWindow("Face Detection");//Declaring an window to show the result//
string trained_classifier_location = "C:/opencv/sources/data/haarcascades/haarcascade_frontalface_alt.xml";//Defining the location our XML Trained Classifier in a string//
CascadeClassifier faceDetector;//Declaring an object named 'face detector' of CascadeClassifier class//
faceDetector.load(trained_classifier_location);//loading the XML trained classifier in the object//
vector<Rect>faces;//Declaring a rectangular vector named faces//
faceDetector.detectMultiScale(image_with_humanface, faces, 1.1, 4, CASCADE_FIND_BIGGEST_OBJECT);//Detecting the faces in 'image_with_humanfaces' matrix//
Rect maxRect;//Declaring a rectangle. By default the size is zero pixel//
for (int i = 0; i < faces.size(); i++){ //Initiating for loop to detect the largest face//
if (faces[i].area() > maxRect.area()){ //Calculating the area of face and comparing it with area of maxRect//
maxRect = faces[i];//storing the largest rectangle in MaxRect according to size of largest face//
}
}
for (size_t i = 0; i < faces.size(); i++){ //Loop to draw rectangle around the faces//
Mat faceROI = image_with_humanface(maxRect);//Storing the face in a matrix having size equal to maxRect//
int x = maxRect.x;//Getting the initial row value of face rectangle's starting point//
int y = maxRect.y;//Getting the initial column value of face rectangle's starting point//
int h = y + maxRect.height;//Calculating the height of the rectangle//
int w = x + maxRect.width;//Calculating the width of the rectangle//
rectangle(image_with_humanface, Point(x, y), Point(w, h), Scalar(255, 0, 255), 3, 6, 0);//Drawing a rectangle using around the largest//
}
imshow("Face Detection",image_with_humanface);//Showing the largest face face//
waitKey(0);//To wait for keystroke to terminate the program
return 0;
}输出
更新时间: 10-3-2021
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