OpenCV (Open Source Computer Vision Library) is an open source
computer vision and machine learning software library.  OpenCV was
built to provide a common infrastructure for computer vision
applications and to accelerate the use of machine perception in the
commercial products.  Being a BSD-licensed product, OpenCV makes it
easy for businesses to utilize and modify the code.

The library has more than 2500 optimized algorithms, which includes
a comprehensive set of both classic and state-of-the-art computer
vision and machine learning algorithms.  These algorithms can be
used to detect and recognize faces, identify objects, classify human
actions in videos, track camera movements, track moving objects,
extract 3D models of objects, produce 3D point clouds from stereo
cameras, stitch images together to produce a high resolution image
of an entire scene, find similar images from an image database,
remove red eyes from images taken using flash, follow eye movements,
recognize scenery and establish markers to overlay it with augmented
reality, etc.

WWW: https://www.opencv.org/