This document provides an overview and instructions for making a hand detector on Android using OpenCV. It discusses calculating a skin color histogram, detecting skin areas in an image, finding the largest skin area, and matching histograms using Histograms of Oriented Gradients (HoG). Steps include converting to HSV, generating a histogram in H-S space, applying the histogram to detect skin pixels, filtering and finding contours, labeling connected areas, and getting the largest. HoG extracts gradient features from blocks for matching.