goimagehash

README

goimagehash

Inspired by imagehash

A image hashing library written in Go. ImageHash supports:

• Average hashing
• Difference hashing
• Perception hashing
• Wavelet hashing [TODO]

Installation

go get github.com/corona10/goimagehash

Special thanks to

• Haeun Kim

Usage

func main() {
        file1, _ := os.Open("sample1.jpg")
        file2, _ := os.Open("sample2.jpg")
        defer file1.Close()
        defer file2.Close()

        img1, _ := jpeg.Decode(file1)
        img2, _ := jpeg.Decode(file2)
        hash1, _ := goimagehash.AverageHash(img1)
        hash2, _ := goimagehash.AverageHash(img2)
        distance, _ := hash1.Distance(hash2)
        fmt.Printf("Distance between images: %v\n", distance)

        hash1, _ = goimagehash.DifferenceHash(img1)
        hash2, _ = goimagehash.DifferenceHash(img2)
        distance, _ = hash1.Distance(hash2)
        fmt.Printf("Distance between images: %v\n", distance)
}

Release Note

v0.3.0

• Support DifferenceHashExtend.
• Support AverageHashExtend.
• Support PerceptionHashExtend by @TokyoWolFrog.

v0.2.0

• Perception Hash is updated.
• Fix a critical bug of finding median value.

v0.1.0

• Support Average hashing
• Support Difference hashing
• Support Perception hashing
• Use bits.OnesCount64 for computing Hamming distance by @dominikh
• Support hex serialization methods to ImageHash by @brunoro

Documentation

Index

• type ExtImageHash
  • func AverageHashExtend(img image.Image, hashSize int) (*ExtImageHash, error)
  • func DifferenceHashExtend(img image.Image, hashSize int) (*ExtImageHash, error)
  • func ExtImageHashFromString(s string) (*ExtImageHash, error)
  • func NewExtImageHash(hash []uint64, kind Kind) *ExtImageHash
  • func PerceptionHashExtend(img image.Image, hashSize int) (*ExtImageHash, error)
  • func (h *ExtImageHash) Distance(other *ExtImageHash) (int, error)
  • func (h *ExtImageHash) GetHash() []uint64
  • func (h *ExtImageHash) GetKind() Kind
  • func (h *ExtImageHash) ToString() string
• type ImageHash
  • func AverageHash(img image.Image) (*ImageHash, error)
  • func DifferenceHash(img image.Image) (*ImageHash, error)
  • func ImageHashFromString(s string) (*ImageHash, error)
  • func NewImageHash(hash uint64, kind Kind) *ImageHash
  • func PerceptionHash(img image.Image) (*ImageHash, error)
  • func (h *ImageHash) Distance(other *ImageHash) (int, error)
  • func (h *ImageHash) GetHash() uint64
  • func (h *ImageHash) GetKind() Kind
  • func (h *ImageHash) Set(idx int)
  • func (h *ImageHash) ToString() string
• type Kind

Types

type ExtImageHash

type ExtImageHash struct {
	// contains filtered or unexported fields
}

ExtImageHash is a struct of big hash computation.

func AverageHashExtend

func AverageHashExtend(img image.Image, hashSize int) (*ExtImageHash, error)

AverageHashExtend function returns ahash of which the size can be set larger than uint64 Support 64bits ahash (hashSize=8) and 256bits ahash (hashSize=16)

func DifferenceHashExtend

func DifferenceHashExtend(img image.Image, hashSize int) (*ExtImageHash, error)

DifferenceHashExtend function returns dhash of which the size can be set larger than uint64 Support 64bits dhash (hashSize=8) and 256bits dhash (hashSize=16)

func ExtImageHashFromString

func ExtImageHashFromString(s string) (*ExtImageHash, error)

ExtImageHashFromString returns a big hash from a hex representation

func NewExtImageHash

func NewExtImageHash(hash []uint64, kind Kind) *ExtImageHash

NewExtImageHash function creates a new big hash

func PerceptionHashExtend

func PerceptionHashExtend(img image.Image, hashSize int) (*ExtImageHash, error)

PerceptionHashExtend function returns phash of which the size can be set larger than uint64 Some variable name refer to https://github.com/JohannesBuchner/imagehash/blob/master/imagehash/__init__.py Support 64bits phash (hashSize=8) and 256bits phash (hashSize=16)

func (*ExtImageHash) Distance

func (h *ExtImageHash) Distance(other *ExtImageHash) (int, error)

Distance method returns a distance between two big hashes

func (*ExtImageHash) GetHash

func (h *ExtImageHash) GetHash() []uint64

GetHash method returns a big hash value

func (*ExtImageHash) GetKind

func (h *ExtImageHash) GetKind() Kind

GetKind method returns a kind of big hash

func (*ExtImageHash) ToString

func (h *ExtImageHash) ToString() string

ToString returns a hex representation of big hash

type ImageHash

type ImageHash struct {
	// contains filtered or unexported fields
}

ImageHash is a struct of hash computation.

func AverageHash

func AverageHash(img image.Image) (*ImageHash, error)

AverageHash fuction returns a hash computation of average hash. Implementation follows http://www.hackerfactor.com/blog/index.php?/archives/432-Looks-Like-It.html

func DifferenceHash

func DifferenceHash(img image.Image) (*ImageHash, error)

DifferenceHash function returns a hash computation of difference hash. Implementation follows http://www.hackerfactor.com/blog/?/archives/529-Kind-of-Like-That.html

func ImageHashFromString

func ImageHashFromString(s string) (*ImageHash, error)

ImageHashFromString returns an image hash from a hex representation

func NewImageHash

func NewImageHash(hash uint64, kind Kind) *ImageHash

NewImageHash function creates a new image hash.

func PerceptionHash

func PerceptionHash(img image.Image) (*ImageHash, error)

PerceptionHash function returns a hash computation of phash. Implementation follows http://www.hackerfactor.com/blog/index.php?/archives/432-Looks-Like-It.html

func (*ImageHash) Distance

func (h *ImageHash) Distance(other *ImageHash) (int, error)

Distance method returns a distance between two hashes.

func (*ImageHash) GetHash

func (h *ImageHash) GetHash() uint64

GetHash method returns a 64bits hash value.

func (*ImageHash) GetKind

func (h *ImageHash) GetKind() Kind

GetKind method returns a kind of image hash.

func (*ImageHash) Set

func (h *ImageHash) Set(idx int)

Set method sets a bit of index.

func (*ImageHash) ToString

func (h *ImageHash) ToString() string

ToString returns a hex representation of the hash

type Kind

type Kind int

Kind describes the kinds of hash.

const (
	// Unknown is a enum value of the unknown hash.
	Unknown Kind = iota
	// AHash is a enum value of the average hash.
	AHash
	//PHash is a enum value of the perceptual hash.
	PHash
	// DHash is a enum value of the difference hash.
	DHash
	// WHash is a enum value of the wavelet hash.
	WHash
)