You can download the CVImage library here.
This will be the series of tutorials to elaborate the OpenCV face swap example. The 1st one is a demonstration of the face detection of the Face module, instead of using the Object Detection module. The sample program will detect faces from 2 photos, using the Haar Cascades file, haarcascade_frontalface_default.xml, located in the data folder of the Processing sketch.
The major command is
Face.getFacesHAAR(im.getBGR(), faces, dataPath(faceFile));
where im.getBGR() is the photo Mat returned from the CVImage object, im, faces is a MatOfRect variable returning the rectangle of all faces detected, and faceFile is a string variable containing the file name of the Haar Cascades XML file.
Complete source code is in the website GitHub repository, ml20180818a.