Counter - propagation network for character recognition

Abstract

Abstract,Much effort has been extended in making computer recognize characters automatically, Methods currently widely used for character recognition are mainly involved in pattern marching using image processing techniques. One limitation of such methods is their inability to respond to variations. This paper presents the use of counter -propagation network based on Kohonen network for character recognition. A first attempt at recognizing 37 symbols has been carried out. Obtained results showed that the system is very robust, stable and still capable to retrieve correctly characters for 25% corrupted images. MO DAUNhan dang la Iinh VIl'C duce ap dung rong rai trong thirc te, trong do nhan dang chir la van d~duce quan tarn ngay cang can do nhu eau dich va xir Iy cac van ban mot each tu dong. Qua trinh xir Iy van ban g0111cac buoc eo ban sau: -So hoa van ban bang scanner, sau do luu trit du6'i dang tep anh -Xu ly sa bo nhir tang cuong anh, tach vung chir ra khoi van ban, sau do tach tirng ky tu ra duoi dang cac ma tran diem anh.-Nhan dang tirng ky tu.'-Luu trfr trc lai diroi dang text ASCII, Trong cac biroc tien hanh 6 tren, giai dean nhan dang ky tu quyet dinh den toe d(> va d(> chfnh xac ClW cac h~nhan dang xir Iy ,5n ban. Cac phuong phap truyen thongMet trong nhirng thu tuc quan trong va tieu ten nhieu thoi gian cua cac phuong phap truyen thong la lam manh ky tu Thu tuc nay Iamgiam d(> rong cac net cua ky tu xuong con met diem nham phat hien bo khung xuong r':a ky tu. D(> phirc tap cua thuat toan ty l~voi d(> day cua ky tu. Thu tuc nay tao dieu kien cho viec tim kiem cac dau hieu dac tnrng cua ky tu, song no cling lam cho mot s6 ky tu tro nen giong nhau hon. Do do, gay kho khan cho cac thu tuc ra quyet dinh sau nay. Thu tuc nay se khong lam viec tot khi chat lUQ11gquet cua scanner toi hoac ban than ky tu diroc lay tu van ban mo eo net dirt. Do do no can duoc cac thu tue tien xir ly nhir lam tron duong bien, khu nhiet. tro giup.Cac phirong phap ra quyet dinh trong phuong .phap nhan dang truyen thong duoc cai dat tinh trong chuong trinh. Cac phirong phap nay dua vao viec nghien CUll truce cac dac tnrng cua cac ky tu nhu s6 giao diem hoac eau true cac ky tu nhu so' di~m ket thuc, s6 elm trinh, s6 thanh i Vien Cong nghe Xa hiem, Ha Noi 2 Diii hoc Bach khoa, Ha Noi. 13•