Package boofcv.alg.fiducial.qrcode

Class GaliosFieldTableOps_U8

java.lang.Object
boofcv.alg.fiducial.qrcode.GaliosFieldTableOps
boofcv.alg.fiducial.qrcode.GaliosFieldTableOps_U8
public class GaliosFieldTableOps_U8 extends GaliosFieldTableOps
Precomputed look up table for performing operations on GF polynomials of the specified degree.

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

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

  • Constructor Details

    • GaliosFieldTableOps_U8

      public GaliosFieldTableOps_U8(int numBits, int primitive)
      Specifies the GF polynomial
      Parameters:
      numBits - Number of bits needed to describe the polynomial. GF(2**8) = 8 bits
      primitive - The primitive polynomial

  • Method Details

    • polyScale

      public void polyScale(DogArray_I8 input, int scale, DogArray_I8 output)
      Scales the polynomial.

      Coefficients for largest powers are first, e.g. 2*x**3 + 8*x**2+1 = [2,8,0,1]

      Parameters:
      input - Input polynomial.
      scale - scale
      output - Output polynomial.

    • polyAdd

      public void polyAdd(DogArray_I8 polyA, DogArray_I8 polyB, DogArray_I8 output)
      Adds two polynomials together. output = polyA + polyB

      Coefficients for largest powers are first, e.g. 2*x**3 + 8*x**2+1 = [2,8,0,1]

      Parameters:
      polyA - (Input) First polynomial
      polyB - (Input) Second polynomial
      output - (Output) Results of addition

    • polyAdd_S

      public void polyAdd_S(DogArray_I8 polyA, DogArray_I8 polyB, DogArray_I8 output)
      Adds two polynomials together.

      Coefficients for smallest powers are first, e.g. 2*x**3 + 8*x**2+1 = [1,0,2,8]

      Parameters:
      polyA - (Input) First polynomial
      polyB - (Input) Second polynomial
      output - (Output) Results of addition

    • polyAddScaleB

      public void polyAddScaleB(DogArray_I8 polyA, DogArray_I8 polyB, int scaleB, DogArray_I8 output)
      Adds two polynomials together while scaling the second.

      Coefficients for largest powers are first, e.g. 2*x**3 + 8*x**2+1 = [2,8,0,1]

      Parameters:
      polyA - (Input) First polynomial
      polyB - (Input) Second polynomial
      scaleB - (Input) Scale factor applied to polyB
      output - (Output) Results of addition

    • polyMult

      public void polyMult(DogArray_I8 polyA, DogArray_I8 polyB, DogArray_I8 output)

      Coefficients for largest powers are first, e.g. 2*x**3 + 8*x**2+1 = [2,8,0,1]

    • polyMult_flipA

      public void polyMult_flipA(DogArray_I8 polyA, DogArray_I8 polyB, DogArray_I8 output)

    • polyMult_S

      public void polyMult_S(DogArray_I8 polyA, DogArray_I8 polyB, DogArray_I8 output)
      Identical to polyMult(DogArray_I8, DogArray_I8, DogArray_I8)

      Coefficients for smallest powers are first, e.g. 2*x**3 + 8*x**2+1 = [1,0,2,8]

    • polyEval

      public int polyEval(DogArray_I8 input, int x)
      Evaluate the polynomial using Horner's method. Avoids explicit calculating the powers of x.

      01x**4 + 0fx**3 + 36x**2 + 78x + 40 = (((01 x + 0f) x + 36) x + 78) x + 40

      Coefficients for largest powers are first, e.g. 2*x**3 + 8*x**2+1 = [2,8,0,1]

      Parameters:
      input - Polynomial being evaluated
      x - Value of x
      Returns:
      Output of function

    • polyEval_S

      public int polyEval_S(DogArray_I8 input, int x)
      Evaluate the polynomial using Horner's method. Avoids explicit calculating the powers of x.

      01x**4 + 0fx**3 + 36x**2 + 78x + 40 = (((01 x + 0f) x + 36) x + 78) x + 40

      Coefficients for smallest powers are first, e.g. 2*x**3 + 8*x**2+1 = [1,0,2,8]

      Parameters:
      input - Polynomial being evaluated
      x - Value of x
      Returns:
      Output of function

    • polyEvalContinue

      public int polyEvalContinue(int previousOutput, DogArray_I8 part, int x)
      Continue evaluating a polynomial which has been broken up into multiple arrays.
      Parameters:
      previousOutput - Output from the evaluation of the prior part of the polynomial
      part - Additional segment of the polynomial
      x - Point it's being evaluated at
      Returns:
      results

    • polyDivide

      public void polyDivide(DogArray_I8 dividend, DogArray_I8 divisor, DogArray_I8 quotient, DogArray_I8 remainder)
      Performs polynomial division using a synthetic division algorithm.

      Coefficients for largest powers are first, e.g. 2*x**3 + 8*x**2+1 = [2,8,0,1]

      Parameters:
      dividend - (Input) Polynomial dividend
      divisor - (Input) Polynomial divisor
      quotient - (Output) Division's quotient
      remainder - (Output) Divisions's remainder

    • polyDivide_S

      public void polyDivide_S(DogArray_I8 dividend, DogArray_I8 divisor, DogArray_I8 quotient, DogArray_I8 remainder)
      Performs polynomial division using a synthetic division algorithm.

      Coefficients for smallest powers are first, e.g. 2*x**3 + 8*x**2+1 = [1,0,2,8]

      Parameters:
      dividend - (Input) Polynomial dividend
      divisor - (Input) Polynomial divisor
      quotient - (Output) Division's quotient
      remainder - (Output) Divisions's remainder