基于T i n y O S 的無線傳感器網(wǎng)絡(luò)體系結(jié)構(gòu)
無線傳感器網(wǎng)絡(luò)WSN(Wireless Sensor Network) 由部署在監(jiān)測(cè)區(qū)域內(nèi)大量廉價(jià)的傳感器節(jié)點(diǎn)組成,通過
無線通信方式形成multi2hop 自組織的網(wǎng)絡(luò)系統(tǒng),其目的是協(xié)作地感知、采集和處理網(wǎng)絡(luò)覆蓋區(qū)域中感知
對(duì)象的信息,并發(fā)送給觀察者。本文從分析無線傳感器節(jié)點(diǎn)Mica 和其上運(yùn)行的操作系統(tǒng)TinyOS 出發(fā),
著重描述無線傳感器網(wǎng)絡(luò)節(jié)點(diǎn)應(yīng)用程序體系結(jié)構(gòu)和消息通信機(jī)制。
OTSU Gray-level image segmentation using Otsu s method.
Iseg = OTSU(I,n) computes a segmented image (Iseg) containing n classes
by means of Otsu s n-thresholding method (Otsu N, A Threshold Selection
Method from Gray-Level Histograms, IEEE Trans. Syst. Man Cybern.
9:62-66 1979). Thresholds are computed to maximize a separability
criterion of the resultant classes in gray levels.
OTSU(I) is equivalent to OTSU(I,2). By default, n=2 and the
corresponding Iseg is therefore a binary image. The pixel values for
Iseg are [0 1] if n=2, [0 0.5 1] if n=3, [0 0.333 0.666 1] if n=4, ...
[Iseg,sep] = OTSU(I,n) returns the value (sep) of the separability
criterion within the range [0 1]. Zero is obtained only with images
having less than n gray level, whereas one (optimal value) is obtained
only with n-valued images.
