How to detect faces in images using Java OpenCV library?-javaTutorial-php.cn

The CascadeClassifier class is used to load the classifier file and detect the required objects in the image.

The detectMultiScale() method of this class can detect multiple objects of different sizes. This method accepts −

A Mat class object used to save the input image.
A MatOfRect class object used to store detected faces.

To get the number of faces in the image −

Use the CascadeClassifier class to load the lbpcascade_frontalface.xml file.
Call the detectMultiScale() method.
Convert the MatOfRect object to an array.
The length of the array is the number of faces in the image.

Example

import org.opencv.core.Core; import org.opencv.core.Mat; import org.opencv.core.MatOfRect; import org.opencv.core.Point; import org.opencv.core.Rect; import org.opencv.core.Scalar; import org.opencv.imgcodecs.Imgcodecs; import org.opencv.imgproc.Imgproc; import org.opencv.objdetect.CascadeClassifier; public class FaceDetection { public static void main (String[] args) { //Loading the OpenCV core library System.loadLibrary( Core.NATIVE_LIBRARY_NAME ); //Reading the Image from the file String file ="D:\Images\faces.jpg"; Mat src = Imgcodecs.imread(file); //Instantiating the CascadeClassifier String xmlFile = "lbpcascade_frontalface.xml"; CascadeClassifier classifier = new CascadeClassifier(xmlFile); //Detecting the face in the snap MatOfRect faceDetections = new MatOfRect(); classifier.detectMultiScale(src, faceDetections); System.out.println(String.format("Detected %s faces", faceDetections.toArray().length)); //Drawing boxes for (Rect rect : faceDetections.toArray()) { Imgproc.rectangle( src, new Point(rect.x, rect.y), new Point(rect.x + rect.width, rect.y + rect.height), new Scalar(0, 0, 255), 3 ); } //Writing the image Imgcodecs.imwrite("D:\Images\face_Detection.jpg", src); System.out.println("Image Processed"); } }

Copy after login

Input

如何使用Java OpenCV库在图像中检测人脸？

Output

No of faces detected: 3

Copy after login

The above is the detailed content of How to detect faces in images using Java OpenCV library?. For more information, please follow other related articles on the PHP Chinese website!