QRDecoders

BerlekampMassey <: ReedSolomonAlgorithm

Berlekamp-Massey algorithm for error correction.

DecodeError <: Exception

The data part of QR-matrix contains error.

Euclidean <: ReedSolomonAlgorithm

Euclidean algorithm for error correction.

InfoError <: Exception

The non-data part of QR-matrix contains error.

For example, Finder pattern, Alignment pattern, Timing pattern, Format information, Version information, matrix size and etc.

ReedSolomonAlgorithm

An abstract type for error correction algorithm of Reed Solomon code.

ReedSolomonError <: Exception

An error occurs during error-correction.

block2bits(blocks::AbstractVector)

Convert a block to bits.

correct_message(msgblock::AbstractVector
               , ecblock::AbstractVector
               , alg::ReedSolomonAlgorithm
               ; noerror::Bool=false)

Error correction of the message block using the given algorithm.

Throw DecodeError if the value noerror is true and the message need error correction.

decodedata(bits::AbstractVector, msglen::Int, ::Mode)

Decode message from bits without checking the pad_bits.

decodemode(bits::AbstractVector)

Decode mode from the bits of length 4. Note: the Byte mode and the UTF8 mode use the same mode indicator(0100).

deinterleave(bytes::AbstractVector, ec::ErrCorrLevel, version::Int)

De-interleave the message, i.e. sperate msgblocks and ecblocks from data bits.

extract_databits(mat::AbstractMatrix, datapos::AbstractMatrix)

Extract data bits from the QR-Code.(Inverse procedure of placedata!)

getalterpos(array::AbstractVector)

Get the switch-value indexes of the input array. It can be used for detecting the finder patterns.

Examples

julis> using QRDecoders: getalterpos
julia> array = Bool[1,1,0,0,0,1,1,0]
julia> getalterpos(array)
3-element Vector{Int64}:
 2
 5
 7

getqrmatrix(img)

Get the QR-code matrix from an image.

Note that the input must be a standard QR-code image with or without white border, i.e. the image should not contain any other non-QR-Code information.

hamming_distance(x, y)

Calculate the Hamming distance between two elements.

hamming_distance(C::AbstractVector)

Hamming distance of a linear code.

hamming_weight(x::Poly)

Calculate the Hamming weight of a polynomial.

qrdecode(mat::AbstractMatrix
        ; noerror::Bool=false
        , preferutf8::Bool=true
        , alg::ReedSolomonAlgorithm=Euclidean()
        )::QRInfo

QR code decoder.

If noerror is true, the decoder will raise an Exception(ReedSolomonError/InfoError) when the QR code mat needs error correction.

If preferutf8 is true, the decoder will try to decode the message by UTF8 mode when dealing with Byte mode.

The error correction algorithm is specified by the variable alg(default: Euclidean).

qrdecode(path::AbstractString; keywords...)

QR code decoder.

For more information of the keywords, see qrdecode(mat::AbstractMatrix; keywords...).

qrdecode_format(mat::AbstractMatrix; noerror=false)

Return the format of the QR-Code(ErrCorrLevel + mask).

qrdecode_format(fmt::Int)::Int

Decode format information.

qrdecode_version(mat::AbstractMatrix; noerror=false)

Return the version of the QR-Code.(Matrix to Integer)

qrdecode_version(version::Int)

Decode version information.(Interger to Integer)

qrdecompose(mat::AbstractMatrix, noerror=false)

Decompose the QR-Code into its constituent parts.

trybyte(bits::AbstractVector, msglen::Int)

Try decoding message by Byte mode, where bits = message_bits + pad_bits. Return true if the pad_bits is correct.

tryutf8(bits::AbstractVector, msglen::Int)

Try decoding message by utf-8 mode.