According to Wikipedia OpenCV contains 2D and 3D feature toolkits, Egomotion estimation, Facial recognition system, Gesture recognition, Human–computer interaction (HCI), Mobile robotics, Motion understanding, Object identification, Segmentation and recognition, Stereopsis stereo vision: depth perception from 2 cameras, Structure from motion (SFM), Motion tracking, and Augmented reality. OpenCV also includes a statistical machine learning library with things like Boosting (meta-algorithm), Decision tree learning, Gradient boosting trees, Expectation-maximization algorithm, k-nearest neighbor algorithm, Naive Bayes classifier, Artificial neural networks, Random forest, Support vector machine (SVM).
The Delphi OpenCV version which is over on Github contains mainly VCL demos but it does have a Firemonkey demo for Windows (called cFMXCameracapture) and Firemonkey components. The core of Delphi OpenCV contains the Winapi.Windows unit so it does not support Android, IOS, and MacOS at the moment (there is another OpenCV header translation which is less Windows centric). OpenCV itself which is written in C and C++ supports all four platforms and more. Additionally, Delphi OpenCV provides a lot of code for accessing the FFMPEG library. Delphi OpenCV does use some VCL units which means it currently does not support Appmethod without probably significant changes.