OpenCV Java createFisherFace Ptr

Question

I have been developing with OpenCV (Java) on Eclipse. I am now to the point that I need to create a FisherFace for my FaceRecognizer class. Based on my searches, I found out that there doesn't seem to be any support for this. According to this question, it seems like it has to do with the Ptr class. Is it that Java doesn't have a Ptr class to handle the returned Ptr value? If so, then will this Java Ptr class handle it? If this is not a solution, is there any tutorials that can guide me on making the FaceRecognizer class? Thank you!

Answer 1

the whole problem is on the c++ side, so your java Ptr class won't help.

with opencv 2.4.8, you could try to rebuild the jni-adapter:

(note, that the cv::Ptr class in opencv3.0 won't be compatible with that)

---

// facerec.dll
#include "jni.h"
#include "opencv2/contrib/contrib.hpp"


extern "C" {


JNIEXPORT jlong JNICALL Java_org_matxx_n_createLBPHFaceRecognizer(JNIEnv* env, jclass, jint);

JNIEXPORT jlong JNICALL Java_org_matxx_n_createLBPHFaceRecognizer(JNIEnv* env, jclass, jint)
{
    try {

        cv::Ptr<cv::FaceRecognizer> ptr = cv::createLBPHFaceRecognizer();
        cv::FaceRecognizer * pf = ptr.get();
        ptr.addref(); //don't let it self-destroy here..
        return (jlong) pf;
    } catch (...) {
        jclass je = env->FindClass("java/lang/Exception");
        env->ThrowNew(je, "sorry, dave..");
    }
    return 0;
}
} // extern "C"

---

and a java 'factory' for that :

---

// LBPHFaceRecognizer.java

import org.opencv.contrib.FaceRecognizer;
import org.opencv.core.Core;


public class LBPHFaceRecognizer extends FaceRecognizer
{
    static{ System.loadLibrary("facerec.dll"); }

    private static native long n_createLBPHFaceRecognizer();

    public LBPHFaceRecognizer()
    {
        super(n_createLBPHFaceRecognizer());
    }
}

---

later, you can create a face reco:

---

FaceRecognizer facerec = new LBPHFaceRecognizer();