Transcript Improved Gray Scale (IGS) Code

Improved Gray Scale (IGS) Code
Exercise 2
M023010098
謝芷瑜
Processing
 Implement 4-bit IGS code, LSB is
 Zero
 Random
 Myself
 Transmission error
 1%, 5%, 10%, 15%
 Error correction
 Used Hamming code, correction one bit
Design LSB by Myself
𝑖𝑓 𝑖 = 0 𝑡ℎ𝑒𝑛
𝐿𝑆𝐵𝑖 = 𝐼𝐺𝑆𝑖
else
𝐿𝑆𝐵𝑖 =
𝐼𝐺𝑆𝑖−1 +𝐼𝐺𝑆𝑖
2
(7, 4)Hamming code
6
h6
5
h5
4
h4
3
2
1
0
IGS bit 3 IGS bit 2 IGS bit 1 IGS bit 0
h4 = 𝐵𝑖𝑡0
 h5 = 𝐵𝑖𝑡0
h6 = 𝐵𝑖𝑡0
𝐵𝑖𝑡1
𝐵𝑖𝑡2
𝐵𝑖𝑡1
𝐵𝑖𝑡2
𝐵𝑖𝑡3
𝐵𝑖𝑡3
𝑃𝐴 = 𝐵𝑖𝑡4
 𝑃𝐵 = 𝐵𝑖𝑡5
𝑃𝐶 = 𝐵𝑖𝑡6
𝐵𝑖𝑡0
𝐵𝑖𝑡0
𝐵𝑖𝑡0
𝐵𝑖𝑡1
𝐵𝑖𝑡2
𝐵𝑖𝑡1
𝐵𝑖𝑡2
𝐵𝑖𝑡3
𝐵𝑖𝑡3
3 Types
1) No Error, No Protect
2) Error, No Protect
3) Error, Protect
No Error No Protect
Zero
31.9082
Random
27.354
Myself
27.5911
Compression：LSB Method
No Error No Protect
P
S
N
R
34
32
30
28
26
24
22
20
LSB_0
LSB_random
LSB_myself
Method
1% Error - Zero
No Protect
23.9821
Protect
30.6509
1% Error - Myself
No Protect
22.8602
Protect
27.0754
5% Error - Zero
No Protect
17.7702
Protect
22.4141
5% Error - Myself
No Protect
17.3933
Protect
21.6115
Compression：with/without protect
LSB : 0
P
S
N
R
35
30
25
20
15
10
5
0
Protect
No Protect
1
5
10
Bit Error Rate(%)
15
Compression：with/without protect
LSB : Random
P
S
N
R
35
30
25
20
15
10
5
0
Protect
No Protect
1
5
10
Bit Error Rate(%)
15
Compression：with/without protect
LSB : Myself
P
S
N
R
35
30
25
20
15
10
5
0
Protect
No Protect
1
5
10
Bit Error Rate(%)
15
Conclusion
 對於改善4-bit IGS code，LSB使用Myself方法稍微優於
Random，而其中Zero的效果最好(PSNR最高)。
 由於Error Protection採用(7, 4)Hamming code，只能更
正one bit。當發生1% Error時，能被更正96%~98%的
錯誤；若為5% Error，更正率降為70%~79%，代表
錯誤發生2 bits以上的機率提升許多。
Correction-BER Relational Graph
Correction Ratio(%)
100%
90%
80%
70%
LSB_0
60%
LSB_Random
50%
LSB_Myself
40%
1
5
10
Bit Error Rate(%)
15