Data.Blockhash

Perceptual image hash calculation tool based on algorithm descibed in Block Mean Value Based Image Perceptual Hashing by Bian Yang, Fan Gu and Xiamu Niu.

Documentation

data Image

Constructors

Image

Fields

• imageWidth :: Int
• imageHeight :: Int
• imagePixels :: Vector Word8

Instances

Show Image

Methods

showsPrec :: Int -> Image -> ShowS

show :: Image -> String

showList :: [Image] -> ShowS

newtype Hash

Constructors

Hash

Fields

• unHash :: Vector Char

Instances

Show Hash

Methods

showsPrec :: Int -> Hash -> ShowS

show :: Hash -> String

showList :: [Hash] -> ShowS

hammingDistance :: Hash -> Hash -> Int

Calculate the hamming distance for two hashes in hex format

blockhash

Arguments

:: Image

RGBA image data

-> Int

The number of blocks to divide the image by horizontally and vertically

-> Method

Method

-> Hash

The result

Calculate perceptual hash for an RGBA image

data Method

Constructors

Precise

Precise method puts weighted pixel values to blocks according to pixel area falling within a given block and provides more accurate results in case width and height are not divisible by the number of bits.

Quick

Quick method uses rounded block sizes and is less accurate in case image width and height are not divisible by the number of bits.

Instances

Bounded Method

Methods

minBound :: Method

maxBound :: Method

Enum Method

Methods

succ :: Method -> Method

pred :: Method -> Method

toEnum :: Int -> Method

fromEnum :: Method -> Int

enumFrom :: Method -> [Method]

enumFromThen :: Method -> Method -> [Method]

enumFromTo :: Method -> Method -> [Method]

enumFromThenTo :: Method -> Method -> Method -> [Method]

Eq Method

Methods

(==) :: Method -> Method -> Bool

(/=) :: Method -> Method -> Bool

Show Method

Methods

showsPrec :: Int -> Method -> ShowS

show :: Method -> String

showList :: [Method] -> ShowS