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第三次作业 140705010030 李蓥

2.(a)

答:

图像名称压缩前压缩后压缩比
Sena64kb56.1kb0.88
Sensin64kb60.2kb0.94
Omaha64kb57.0kb0.89 

4.(a)

H=-P(a1)*log2* P(a1)- P(a2)*log2* P(a2)-P(a3)*log2* P(a3)-P(a4)*log2* P(a4)-P(a5)*log2* P(a5

=-0.15* log2*0.15-0.04* log2*0.04-0.26* log2*0.26-0.05* log2*0.05-0.50* log2*0.50=1.818bit

  (b)

编码为:

a1:110

a2:1111

a3:10

a4:1110

a5:0

  (c)

平均码长:L=0.15*3+0.04*4+0.26*2+0.05*4+0.50*1

=1.83 bits/symbol

冗余度: N=H/L*100%=1.818/1.83*100%=99.3%

           v=1-N=0.0066

 

第三次作业 140705010030 李蓥