Package boofcv.alg.fiducial.qrcode

Class ReedSolomonCodes_U8

java.lang.Object

boofcv.alg.fiducial.qrcode.ReedSolomonCodes_U8

public class ReedSolomonCodes_U8
extends Object

TODO Summarize

Code and code comments based on the tutorial at [1].

[1] Reed-Solomon Codes for Coders Viewed on September 28, 2017

Constructor Summary

Constructors

Constructor	Description
ReedSolomonCodes_U8(int numBits, int primitive, int generatorBase)

Method Summary

Modifier and Type	Method	Description
void	computeECC(DogArray_I8 input, DogArray_I8 output)	Given the input message compute the error correction code for it
boolean	correct(DogArray_I8 input, DogArray_I8 ecc)	Decodes the message and performs any necessary error correction
boolean	findErrorLocations_BruteForce(DogArray_I8 errorLocator, int messageLength, DogArray_I32 locations)	Creates a list of bytes that have errors in them
void	generator(int degree)	Creates the generator function with the specified polynomial degree.
int	getTotalErrors()	Number of bit errors

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

ReedSolomonCodes_U8

public ReedSolomonCodes_U8(int numBits,
 int primitive,
 int generatorBase)

Parameters:

numBits - Number of bits in each word

primitive - Primitive polynomial

generatorBase - Base for generator polynomial. 0 or 1

Method Details

computeECC

public void computeECC(DogArray_I8 input,
 DogArray_I8 output)

Given the input message compute the error correction code for it

Parameters:

input - Input message. Modified internally then returned to its initial state

output - error correction code

correct

public boolean correct(DogArray_I8 input,
 DogArray_I8 ecc)

Decodes the message and performs any necessary error correction

Parameters:

input - (Input) Corrupted Message (Output) corrected message

ecc - (Input) error correction code for the message

Returns:

true if it was successful or false if it failed

findErrorLocations_BruteForce

public boolean findErrorLocations_BruteForce(DogArray_I8 errorLocator,
 int messageLength,
 DogArray_I32 locations)

Creates a list of bytes that have errors in them

Parameters:

errorLocator - (Input) Error locator polynomial. Coefficients from small to large.

messageLength - (Input) Length of the message + ecc.

locations - (Output) locations of bytes in message with errors.

generator

public void generator(int degree)

Creates the generator function with the specified polynomial degree. The generator function is composed of factors of (x-a_n) where a_n is a power of 2.
if generatorFamily = 0 then:
g₄(x) = (x - α0) (x - α1) (x - α2) (x - α3) = 01 x4 + 0f x3 + 36 x2 + 78 x + 40

Parameters:

degree - Number of words in ECC. Larger values mean more error correction

getTotalErrors

public int getTotalErrors()

Number of bit errors