FaceRecognizer | Face Recognition Application

I'm following an older tutorial on face recognition based on OpenCV in C++ and have an error I can't resolve. The relevant code snippet:

I am trying to pass a value from C++ header file named recognizer.h to Android through my JNI implementation in jni_face_rec.cpp.

recognizer.h

In my app I'm trying to do face recognition on a specific image using Open CV, here first I'm training one image and then after training that image if I run face recognition on that image it successfully recognizes that trained face. However, when I turn to another picture of the same person recognition does not work. It just works on the trained image, so my question is how do I rectify it?

Update: What i want to do is that user should select image of a person from storage and then after training that selected image i want to fetch all images from storage which matches face of my trained image

Here is my activity class:

I am working on Face Recognition java project using OpenCV 3.4.0. For that using createFisherFaceRecognizer(0,1500) method but OpenCV doesn't contain this class and method. Does anyone know about OpenCV? Please let me know how to use it.

These are imports

The picture linked below shows the specific exception I'm getting. I'm not quite sure why I'm having this particular issue as I've built everything in the same directory, so the library file is there. From what I understand this has something to do with what I'm returning to my main method from my c++ function.

What I'm essentially trying to do is pass the name (printId) of the recognized person, as a string, from my c++ function to java.

Picture of command line:

Here's my C++ code:

I'm working on a university project combining MQTT and Face recognition, using a raspberry pi. First of all I want to say that face recognition works normally when it's being run on its own but I have something that bugs me when applying it with MQTT.

Inside the Try section, when a person is being recognized or unknown it publishes really fine every 3 secs. The strange thing is that if I put my hand in front of the camera or if I get out of range, it keeps on sending the ID of the last person it had recognized.

I want it either do nothing or publish none.

Any idea or suggestion to fix this? Thanks in advance

EDIT 1: Basically as I figured out, it has to do more with the face recognition part. When using just a face recognition code using opencv it runs smoothly. But the thing complicates when I put my hand in front of the camera or go away, because the capture freezes at the last thing it sees so it keeps on printing/publishing the same thing. Haven't figured out a way to avoid this yet. Any help would be appreciated

Here is my code below:

/* * Copyright (c) 2011. Philipp Wagner . * Released to public domain under terms of the BSD Simplified license. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions are met: * * Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * * Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * Neither the name of the organization nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * See http://www.opensource.org/licenses/bsd-license */

I'm working on doing some Face, Gender, and Age detection using OpenCV. I have a bunch of images I use to train the models, Essentally I currently have the following:

I'm using the facial recognition from videos by Philipp Wagner ,i updated the code to work with opencv 3.2 ,i had after that a real hard time to create the appropriate face database ,but then my question is how can i give a value for the unknown persons?So far when i run my code it gives the unknown person a value from my database i'am using "0" for myself and "1" for another person. how can i set it to be "-1" for example for unknown subjects ? Here is my code so far, I tried to use threshold but didn't get any results.