các kĩ thuật nâng cao chất lượng và nén hình ảnh

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+|q1+>+,$'()* * !"+,$$-* G +*|q1+>+,$$-* ./ !0123 )4+& * G +. !")/ !0123 )4+& . 561+7819:11+;($<9. G +5|q1+>A61+7819:11+;($<9.  G +X}7!q+,$L~TFV5    !" G +?39+'=9A+B ))@ ? 5=9',$$> & +? @=9A+B ))@ 17C D +E %=9A+B ))@ 4+17C E 9=91F7 )%G +E H=91+B )1+I4$J 1K LMN 5=9L:9 O1& +N @=91+B )9@(N %=91K LM1PA+B ))@ Q #$%&%'()*+",  !"#  $%&'( G +E|2i )%_ 9•@& +Q * 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9CVX -.%/@%3#:%&%ABC%D2"E X\/+(]H^@1F_ 4+O4% !"S? G +*3!q$/+b@[,)&$/Hx )% !"Sz.{? @ !"S1+78 [, )+>9+? G +.]9%2o99•@€7]1FG +$/+b@% !"S!M[oA+Mz.{E %2` )1a[,)&'2` )1aN 9\/+b@[,)&$/N Xc1+781$/+(]%d )9( Q @e12f )$/+(]%d )9( Q %\/+(]%d )9( Q G +5@Vd )'=94+# D9+•%V@%0'=91+B )1+I4[,1+B )9@(9VZ+K [x )1F( )$J 1K LM• HVd )'=91" )+`4 X* !"g@[;';11F( ) O & + @ !"g@[;';1hS* G +X3!qA+M4+# D9+D +p7$<9s* G +?3!q% !" )2`9g@[;';1$<9s. % !"g@[;';1FiFj9hS. G +E3!q4+# D9+g@[;';1FiFj9hS5 % !" )2`9g@[;';1hS5 G +N3!q% !" )2`9g@[;';1FiFj9hS5 EF+G2" klmZRnmZRQQQ  X H8I- o1+p7L3'2`9X  !"#  $%&'( 3!qA+M? G +Q3!qA+M%0$/+b@[,)&$/mZRH^@1F_ % !"S? H8I-,,,J o1+p7L3'2`9E 3!qA+M%0$/+b@[,%0)&$/mZRQQQE G +3!qA+M%0$/+b@[,%0)&$/mZRQQQE H8I-0(H8I-,,,K G +(L] +mZR‚mZRQQQN & )M%1$ƒ4W;'*Q G +*„'p O 9•@mZRQQQ[,mZR*Q G +.\ ++(jD + d )U* *  * 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.Q G +*?T@V… +)M9†T%V… +)/ !0123 )4+& .Q t61+7819:11+;($<9. G +*ET@V… +)M9†T%V… +9:11+;($<9A+B ) J †T9V… +9:11+;($<99b J . *# %u )$<9W]$. G +*NT@V… +)M9†T%V}7!q& +)M9†T9V… +9# %u )†THV}7!q9•@& +9# %u ). **(L] +$<9W]$. G +*Q@& +W]$)K )M ) +@7.  !"#  $%&'( G +*… +W]$1+7!2`91F2o9[,L@7A+9# %u )T1P1F]€7@4+&V.* *.+v  +w7.* G +*T@V… +)M9†T%V… +9+v  +w7L@'t‡4;44;F.* *5=9& + G +**@(Hp 9+23 )1FG +$B4+ˆ )9]94+23 )4+]49+v  +w7[,'=9 +w7.5 @=9',$$> & +.5 & )*]9%0'=9!‰9%p1.5 G +*.T@V… +)M9†T%V… +9+v  +w7L@'1‡4;44;F†T9V… +'=9LaHr )$@1F8 †THV… + '=9LaHr )%0'=91F7 )%G +.? G +*5T@V… +)M9†T%V… +1+7!2`9 +i%0'=9@4'@9;9b)]1F>h.f9+Š +)‹@†T9V… +1+7 !2`9 +i%0'=9@4'@9;9b)]1F>hEf9+Š +)‹@.E G +*XT@V… +)M9†T%V… +9+v  +w7L@'1‡4;44;F†T9V… +'=9A+B ))@ 4+17C .N G +*?T@V… +)M9†T%V… +9+v  +w7L@'1‡4;44;F†T9V… +'=91F7 )[>*W*5Q G +*ET@V… +)M9†T%V… +9+v  +w7†T9V… +'=91F7 )%G +5Q G +*NT@V… +)M9†T%V… +9+v  +w7L@'1‡4;44;F†T9V… +'=91+B )1+I45 %=9L:9 O1& +5 G +*QT@V… +)M9†T%V… +9+v  +w74(LL( †T9V… +'=91+B )9@(93%& 5 G +*T@V… +)M9†T%V… +9+v  +w7L@'1‡4;44;F†T9V… +'=9;$4+@LL9@(1K †THV… +'=9 L@7A+9# %u )$<9W]$5 G +*T@V… +)M9†T%V… +9+v  +w74(LL( †T9V… +'=91K LM1PA+B ))@ 5* *X]9A61+781',$ "!2i )%_ & +5* U2" **O & +Hx )$/+b@7y$@ 5. **O & +Hx )$/H^!(] A+B )1" 1+I15. ***O & +mZRHx )% !"S5. G +**@(Hp  O & +mZR[,mZRQQQ55 **.mZRQQQ55 *** 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!"+,$$-* G +*|q1+>+,$$-* ./ !0123 )4+& * G +. !")/ !0123 )4+& . 561+7819:11+;($<9. G +5|q1+>A61+7819:11+;($<9.  G +X}7!q+,$L~TFV5    !" G +?39+'=9A+B ))@ ? 5=9',$$> & +? @=9A+B ))@ 17C D +E %=9A+B ))@ 4+17C E 9=91F7 )%G +E H=91+B )1+I4$J 1K LMN 5=9L:9 O1& +N @=91+B )9@(N %=91K LM1PA+B ))@ Q #$%&%'()*+", G +E|2i )%_ 9•@& +Q  !"#  $%)*)+ *  Q 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9CVX -.%/@%3#:%&%ABC%D2"E X\/+(]H^@1F_ 4+O4% !"S? G +*3!q$/+b@[,)&$/Hx )% !"Sz.{? @ !"S1+78 [, )+>9+? G +.]9%2o99•@€7]1FG +$/+b@% !"S!M[oA+Mz.{E %2` )1a[,)&'2` )1aN 9\/+b@[,)&$/N Xc1+781$/+(]%d )9( Q @e12f )$/+(]%d )9( Q %\/+(]%d )9( Q G +5@Vd )'=94+# D9+•%V@%0'=91+B )1+I4[,1+B )9@(9VZ+K [x )1F( )$J 1K LM• HVd )'=91" )+`4 X* !"g@[;';11F( ) O & + @ !"g@[;';1hS* G +X3!qA+M4+# D9+D +p7$<9s* G +?3!q% !" )2`9g@[;';1$<9s. % !"g@[;';1FiFj9hS. G +E3!q4+# D9+g@[;';1FiFj9hS5 % !" )2`9g@[;';1hS5 G +N3!q% !" )2`9g@[;';1FiFj9hS5 EF+G2" klmZRnmZRQQQ  X H8I- o1+p7L3'2`9X 3!qA+M?  !"#  $%)*)+ G +Q3!qA+M%0$/+b@[,)&$/mZRH^@1F_ % !"S? H8I-,,,J o1+p7L3'2`9E 3!qA+M%0$/+b@[,%0)&$/mZRQQQE G +3!qA+M%0$/+b@[,%0)&$/mZRQQQE H8I-0(H8I-,,,K G +(L] +mZR‚mZRQQQN & )M%1$ƒ4W;'*Q G +*„'p O 9•@mZRQQQ[,mZR*Q G +.\ ++(jD + d )U* *  * / /- 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t61+7819:11+;($<9. G +*ET@V… +)M9†T%V… +9:11+;($<9A+B ) J †T9V… +9:11+;($<99b J . *# %u )$<9W]$. G +*NT@V… +)M9†T%V}7!q& +)M9†T9V… +9# %u )†THV}7!q9•@& +9# %u ). **(L] +$<9W]$. G +*Q@& +W]$)K )M ) +@7. G +*… +W]$1+7!2`91F2o9[,L@7A+9# %u )T1P1F]€7@4+&V.*  !"#  [...]... – (c) Ảnh lọc trung bình 50 Hình 3.19 (a) Ảnh gôc – (b) Ảnh chèn nhiễu salt & pepper– (c) Ảnh lọc thông thấp 51 b Lọc sắc nét ảnh 51 Hình 3.20 (a) Ảnh gôc – (b) Ảnh chèn nhiễu poisson – (c) Ảnh lọc thông cao cơ bản 51 Hình 3.21 (a) Ảnh gôc – (b) Ảnh chèn nhiễu salt & pepper – (c) Ảnh lọc emphasis cao tần – (d) Ảnh lọc sau khi cân bằng mức xám 52 Hình 3.22... 47 Hình 3.15 (a) Ảnh gôc – (b) Ảnh thu được nhờ bộ lọc Laplace có giá trị -4 ở chính giữa – (c) Ảnh thu được nhờ bộ lọc Laplace có giá trị -8 ở chính giữa 48 Hình 3.16 (a) Ảnh gôc – (b) Ảnh chèn nhiễu salt & pepper – (c) Ảnh lọc không gian phi tuyến 49 Hình 3.17 (a) Ảnh gôc – (b) Ảnh chèn nhiễu salt & pepper – (c) Ảnh lọc trung vị 3x3 50 Hình 3.18 (a) Ảnh gôc – (b) Ảnh chèn... Hình 3.22 (a) Ảnh gôc – (b) Ảnh chèn nhiễu poisson – (c) Ảnh lọc tần sô từ không gian 53 3.2.2.6 Các kĩ thuật làm nổi đường biên ảnh 53 3.2.3 Nén ảnh 54 3.2.3.1 Nén ảnh dùng mã hóa Huffman 54 3.2.3.2 Nén ảnh dùng mã dự đoán không tổn thất 54 3.2.3.3 Nén ảnh JPEG dùng biến đổi DCT .54 Hình 3.23 Giao diện nén ảnh JPEG và... trên mạng một cách dễ dàng và nhanh chóng Ngoài ra, các thuật toán nhằm nâng cao chất lượng ảnh cũng là một vấn đề đòi hỏi sự đầu tư nghiên cứu Các thuật toán, các phép biến đổi nâng cao chất lượng ảnh mà chúng ta đã biết như tạo ảnh âm bản, chèn nhiễu, tăng, giãn độ tương phản, biến đổi logic số học, phép lọc… Các kỹ thuật nén sư dụng phép biến đổi Fourier (FT), biến... trình mô phỏng, minh họa cho các kĩ thuật nâng cao chất lượng và nén ảnh, em quyết định chọn đề tài này để làm đồ án tốt nghiệp Đồ án của em chia làm 3 chương: - Chương 1 giới thiệu tổng quan về ảnh số và các kĩ thuật nâng cao chất lượng ảnh như biến đổi ảnh xám, biến đổi âm bản, các phương pháp lọc ảnh nhiễu - Chương 2 giới thiệu về kĩ thuật nén ảnh và đi sâu vào... Nâng cao chất lượng ảnh CHƯƠNG 1 TỔNG QUAN ẢNH SỐ VÀ CÁC KĨ THUẬT NÂNG CAO CHẤT LƯỢNG ẢNH Lịch sư của xư lí ảnh bắt nguồn từ việc nâng cao chất lượng hình ảnh được truyền qua giữa đường cáp London và NewYork vào năm 1920 Lúc ấy xư lí ảnh chỉ đơn giản là xư lí phân bố các mức sáng (mức xám và độ phân giải của ảnh) Việc nâng cao chất lượng ảnh bằng các phương pháp xư lí... sau đó Do kỹ thuật máy tính ngày càng phát triển, nên xư lí ảnh và nâng cao chất lượng ảnh cũng phát triển rất nhanh Trong chương này, ta tìm hiểu về một số kĩ thuật nâng cao chất lượng ảnh như biến đổi ảnh xám, các phương pháp lọc nhiễu, làm nổi đường biên ảnh Các kĩ thuật này hiện nay đang được ứng dụng rộng rãi trong nhiều lĩnh vực 1.1 Tổng quan về ảnh sô Hình ảnh tĩnh... 43 Hình 3.12 (a) Ảnh gôc – (b) Ảnh chèn nhiễu salf & pepper 43 3.2.2.5 Lọc ảnh 44 Hình 3.13 Giao diện chương trình mô phỏng các phương pháp chèn nhiễu và lọc nhiễu 45 a Lọc làm mịn ảnh 45 Bảng 3.1 Các bộ lọc đặc biệt 45 Hình 3.14 (a) Ảnh gôc – (b) Ảnh chèn nhiễu salt & pepper – (c) Ảnh lọc sử dụng ma trận H – (d) Ảnh lọc sử... chương 1, một số kĩ thuật nâng cao chất lượng ảnh như biến đổi ảnh xám (biến đổi âm bản, biến đổi hàm log, hàm mũ), lọc nhiễu (lọc thông thấp, thông cao, lọc phi tuyến, tuyến tính, lọc trung vị,…), làm nổi biên ảnh đã được đề cập đến Nguyễn Phương Hiền – D04VT2 10 Đồ án tốt nghiệp đại học Chương 1: Nâng cao chất lượng ảnh Trên thực tế, nâng cao chất lượng ảnh còn rất nhiều... mã đã giảm xuống Nguyễn Phương Hiền – D04VT2 19 Đồ án tốt nghiệp đại học Chương 2: Các kĩ thuật nén ảnh Các hệ số thu được sau khi lượng tư hoá sẽ được sắp xếp thành một chuỗi các ký hiệu theo kiểu “zig-zag” (theo đường zig-zag trong hình 2.4) để đặt các hệ số có tần số thấp lên trước các hệ số tần số cao Các hệ số này sẽ được mã hoá dựa trên bảng mã Huffman sao cho chiều dài trung