图片相似度计算（直方图、峰值信噪比、结构相似性、感知哈希算法）、轮廓检测、直线检测、圆检测、角点检测、直线交点计算、旋转角度矫正、图像匹配的对应相似处连线、灰度、二值化、直方图均衡化。

Calculate PhotoDNA hashes using Python

CLI Java wrapper for the PhotoDNA library

Perceptual hashing command-line tool

Perceptual Hash in J

A library of perceptual hash algorithms (aHash, dHash, pHash, wHash).

audio perceptual hash extraction library

Here will be C++ library for perceptual image hashes.

Android librarry (kotlin) : Image (JPEG, BMP) comparison (perceptual hash algorithm)

Let's find out duplicate images with Perceptual Hashing algorithms

Generate content-based image hashes on Node.js.