Blockhash Core

This is the core implementation of the blockhash perceptual image hashing algorithm.

Look at the main blockhash package if you want a higher level api.

Installation

npm install --save blockhash-core

Usage

const { bmvbhash } = require('blockhash')
 
const image = new ImageData(/* ... */)
const result = bmvbhash(image, 16)
 
console.log(result)
//=> f81bf99ffb803400e07f8c5d849f049707033a033fe33fe1bfe00e618ee30ca7

API

bmvbhash(data, bits)

• data (ImageData, required) - The input image data
• bits (number, required) - Create hash of size N^2 bits
• returns string - The resulting hash in hex format

Precise but slower, non-overlapping blocks.

This method is recommended as a good tradeoff between speed and good matches on any image size.

bmvbhashEven(data, bits)

• data (ImageData, required) - The input image data
• bits (number, required) - Create hash of size N^2 bits
• returns string - The resulting hash in hex format

Quick and crude, non-overlapping blocks.

This method is only advisable when the image width and height are an even multiple of the number of blocks used.