Migrating from OpenCV 2.x to 3.x

Init library

OpenCVLoader.initAsync(OpenCVLoader.OPENCV_VERSION_2_4_13, this, mLoaderCallback);

OpenCVLoader.initAsync(OpenCVLoader.OPENCV_VERSION_3_1_0, this, mLoaderCallback);

Highgui -> Imgcodecs / Videoio

The functionality in Highgui has been split into two additional modules:

• Imgcodecs (imread / imwrite...).
• Videoio (VideoCapture, VideoWriter).

Highgui.imread(fileName, Highgui.CV_LOAD_IMAGE_GRAYSCALE)
Highgui.imread(fileName)
Highgui.imwrite(photoPath, mBgr);
Highgui.imencode(".bmp", frame, mem);
...

Imgcodecs.imread(fileName, Imgcodecs.CV_LOAD_IMAGE_GRAYSCALE)
Imgcodecs.imread(fileName)
Imgcodecs.imwrite(photoPath, mBgr);
Imgcodecs.imencode(".bmp", frame, mem); 
...

Drawing functions: Core -> Imgproc

Core.circle(..); 
Core.line(...);

Imgproc.circle(..);
Imgproc.line(..);