Viec san bang luoc do duoc thuc hien theo thuat toan:

/*

Ima: anh goc can can bang

Histo: l­uoc do xam cua anh

Transfo: bang san bang luoc do

BatDau, KetThuc : diem bat dau va diem ket thuc moi dai? xet

Bande, CentreBande: do rong bang va trung diem cua dai

Nl: so muc xam cua anh goc

Nf: so muc xam cua anh ket qua */

a. Khoi tao

TBLituong <-- pxp/NF;

Bande <-- NI/NF;

CentreBande <-- Bande/2;

BatDau, KetThuc <-- 0;

b. Tinh va bien doi luoc do

While KetThuc < Nl do

Begin Tong <-- 0;

While (Tong < TBLituong) and(KetThuc < NI ) do

Begin Tong <-- Tong + Histo(KetThuc);

Inc(KetThuc)

End;

For i := BatDau to KetThuc -1 do Trandfo[i] <-- CentreBande;

CentreBande <- - CentreBande + Bande;

Debut <-- KetThuc;

End

c. Tinh anh ket qua

For i := 1 to N do

For j :=1 to N do Begin

Pic <-- Ima[i,j];

Ima[i,j] <-- Transfo[Pic]

End