电子科发女学光电科学与工程学院 SCHOOL OF OPTOELECTRONIC SCIENCE AND ENGINEERING OF UESTC 2.Spatial and Temporal Redundancy 几k P,() FIGURE 8.2 The intensity histogram of the image in Fig.8.1(b). 1 256 256 0 0 50 100150 200 250 256×256×8 Run Length Coding: C= =128 (256+256)×8
2. Spatial and Temporal Redundancy Run Length Coding： 256 256 8 128 (256 256) 8 C
电子科发女学光电科学与工程学院 SCHOOL OF OPTOELECTRONIC SCIENCE AND ENGINEERING OF UESTC 3.Irrelevant Information ● Information that is ignored by the human visual system or is extraneous to the intended use of an image are obvious candidates for omission. 33K C① AUdI 15K C00 AudI 双 山。 S2 3
3. Irrelevant Information Information that is ignored by the human visual system or is extraneous to the intended use of an image are obvious candidates for omission. 33K 15K
电子科技女学光电科学与工程学院 SCHOOL OF OPTOELECTRONIC SCIENCE AND ENGINEERING OF UESTC 4.Measuring Image Information a random event E with probability P(E)is said to contain this units of information: I(E)=log P(E) =-log P(E) ● a discrete set of possible fa,a2,....a}with associated probabilities [P(a),P(a),...,P(a)},the average informa- tion per source output,called the entropy of the source: H=-∑P(a,)logP(a,)
a random event E with probability P(E) is said to contain this units of information: a discrete set of possible {a1, a2,…, aJ} with associated probabilities {P(a1), P(a2),…, P(aJ)}，the average information per source output, called the entropy of the source： 1 ( ) log log ( ) ( ) I E PE P E 1 log J j j j H Pa Pa 4. Measuring Image Information
电子科技女学光电科学与工程学院 SCHOOL OF OPTOELECTRONIC SCIENCE AND ENGINEERING OF UESTC 4.Measuring Image Information Example: 4收 5,4,⅓，⅓ HP(a,)losP(@,)-2
4 1 7 log 4 j j j H Pa Pa 1234 1111 248 8 ,,, ,,, aaaa A Example: 4. Measuring Image Information
电子科技女学光电科学与工程学院 SCHOOL OF OPTOELECTRONIC SCIENCE AND ENGINEERING OF UESTC 4.Measuring Image Information Image Entropy: i=-p.G)leg,p.)】 k=0 Tk P 87=87 0.25 7128=128 0.47 /186=186 0.25 25=255 0.03 fork≠87,128,186.255 0 i=-[0.251og20.25+0.471og20.47+0.251og20.25+0.03log20.03] ≈-[0.25(-2)+0.47(-1.09)+0.25(-2)+0.03(-5.06)] ≈1.6614bits/pixel
4. Measuring Image Information Image Entropy: 2222 [0.25log 0.25 0.47log 0.47 0.25log 0.25 0.03lo g 0.03] [0.25( 2) 0.47( 1.09) 0.25( 2) 0.03( 5.06)] 1.6614 / H bits pixel 1 2 0 log L rk rk k H pr pr