pHash

A Clojure library for computing perceptual hashes. Currently aHash, dHash, wHash and pHash are supported.

Requirements

Java 1.8 is required to run this program. Leiningen is required for building and deploying the library.

Usage

1. Deploy the library to your local repository (~/.m2) via lein install -h
2. Include [de.nihas101/phash "0.10.0"] in the dependencies of your project.clj
3. Require the necessary namespaces:

(ns example
  (:require
   [de.nihas101.phash.core :as core]
   [de.nihas101.phash.a-hash :as ah]    ; If you plan to use aHash
   [de.nihas101.phash.d-hash :as dh]    ; If you plan to use dHash
   [de.nihas101.phash.p-hash :as ph]))  ; If you plan to use pHash

4. Use the desired functionality:

;; Calculate the perceptual hash of image img using aHash
(core/perceptual-hash (ah/a-hash) img)

;; Calculate the hamming distance of the perceptual hash (computed using dHash) between images img-a and img-b
(core/image-distance (dh/d-hash) img-a img-b)

;; Returns true if img-a's and img-b's perceptual hashes (computed using pHash) differ in less than 5 bits
(core/eq-images? (ph/p-hash) img-a img-b 5)

To set the number of bits used for the hash, simply pass the size to the corresponding hashing function. Note that hash sizes should always be a powers of 2 (i.e. size = 2^n). By default the hash will always have 64 bits.

;; Calculate the perceptual hash (of 16 bits) of image img using aHash
(core/perceptual-hash (ah/a-hash 16) img)

Images can be loaded from a file-system via imagez with:

(:require
  [de.nihas101.phash.utils :as u])

(u/load-image "path/to/image")

Alternatively other libraries that output java.awt.Image instances can be used.

License

Copyright © 2021 nihas101

This program and the accompanying materials are made available under the terms of the Eclipse Public License 2.0 which is available at http://www.eclipse.org/legal/epl-2.0.

This Source Code may also be made available under the following Secondary Licenses when the conditions for such availability set forth in the Eclipse Public License, v. 2.0 are satisfied: GNU General Public License as published by the Free Software Foundation, either version 2 of the License, or (at your option) any later version, with the GNU Classpath Exception which is available at https://www.gnu.org/software/classpath/license.html.