Sample_of_dlib-jni.cpp

extern "C" JNIEXPORT jbyteArray JNICALL
JNI_METHOD(detectFacesAndLandmarks)(JNIEnv *env,
                                    jobject thiz,
                                    jobject bitmap) {
    if (sFaceDetector.num_detectors() == 0) {
        LOGI("L%d: sFaceDetector is not initialized!", __LINE__);
        throwException(env, "sFaceDetector is not initialized!");
        return NULL;
    }
    if (sFaceLandmarksDetector.num_parts() == 0) {
        LOGI("L%d: sFaceLandmarksDetector is not initialized!", __LINE__);
        throwException(env, "sFaceLandmarksDetector is not initialized!");
        return NULL;
    }

    // Profiler.
    Profiler profiler;
    profiler.start();

    // Convert bitmap to dlib::array2d.
    dlib::array2d<dlib::rgb_pixel> img;
    convertBitmapToArray2d(env, bitmap, img);

    double interval = profiler.stopAndGetInterval();

    const float width = (float) img.nc();
    const float height = (float) img.nr();
    LOGI("L%d: input image (w=%f, h=%f) is read (took %.3f ms)",
         __LINE__, width, height, interval);

    profiler.start();

    // Now tell the face detector to give us a list of bounding boxes
    // around all the faces in the image.
    std::vector<dlib::rectangle> dets = sFaceDetector(img);
    interval = profiler.stopAndGetInterval();
    LOGI("L%d: Number of faces detected: %u (took %.3f ms)",
         __LINE__, (unsigned int) dets.size(), interval);

    // Protobuf message.
    FaceList faces;
    // Now we will go ask the shape_predictor to tell us the pose of
    // each face we detected.
    for (unsigned long j = 0; j < dets.size(); ++j) {
        profiler.start();
        dlib::full_object_detection shape = sFaceLandmarksDetector(img, dets[j]);
        interval = profiler.stopAndGetInterval();
        LOGI("L%d: #%lu face, %lu landmarks detected (took %.3f ms)",
             __LINE__, j, shape.num_parts(), interval);

        profiler.start();

        // To protobuf message.
        Face* face = faces.add_faces();
        // Transfer face boundary.
        Rectangle* bound = face->mutable_bound();
        bound->set_left((float) dets[j].left() / width);
        bound->set_top((float) dets[j].top() / height);
        bound->set_right((float) dets[j].right() / width);
        bound->set_bottom((float) dets[j].bottom() / height);
        // Transfer face landmarks.
        for (u_long i = 0 ; i < shape.num_parts(); ++i) {
            dlib::point& pt = shape.part(i);

            Landmark* landmark = face->add_landmarks();
            landmark->set_x((float) pt.x() / width);
            landmark->set_y((float) pt.y() / height);
        }
        interval = profiler.stopAndGetInterval();
        LOGI("L%d: Convert #%lu face to protobuf message (took %.3f ms)",
             __LINE__, j, interval);
    }

    profiler.start();

    // Prepare the return message.
    int outSize = faces.ByteSize();
    jbyteArray out = env->NewByteArray(outSize);
    jbyte* buffer = new jbyte[outSize];

    faces.SerializeToArray(buffer, outSize);
    env->SetByteArrayRegion(out, 0, outSize, buffer);
    delete[] buffer;

    interval = profiler.stopAndGetInterval();
    LOGI("L%d: Convert faces to protobuf message (took %.3f ms)",
         __LINE__, interval);

    return out;
}