詳細了解無線視頻監控的技術發展
視(shi)(shi)頻圖像傳輸(shu)無(wu)(wu)線化打破(po)了(le)傳統同軸電纜和(he)光纖圖像監視(shi)(shi)受制于(yu)硬(ying)件連接的不利局面,具有更(geng)強(qiang)的靈活性和(he)方便性,基(ji)于(yu)無(wu)(wu)線網絡的視(shi)(shi)頻監視(shi)(shi)系統應運而生。無(wu)(wu)線視(shi)(shi)頻傳輸(shu)技(ji)術的發展已對無(wu)(wu)線移動(dong)網絡的架構和(he)協(xie)議產生了(le)深遠的影響(xiang),但由于(yu)無(wu)(wu)線信道帶寬資源(yuan)有限,干(gan)擾因(yin)素(su)多,而視(shi)(shi)頻信號(hao)數據量大(da),實時性要求高(gao)等問(wen)題。
無線視(shi)頻(pin)監控傳(chuan)輸技術
可靠(kao)信(xin)道(dao)(dao)上信(xin)號(hao)傳(chuan)(chuan)(chuan)(chuan)(chuan)(chuan)(chuan)輸(shu)研究的(de)(de)(de)目的(de)(de)(de)是(shi)充分利(li)用信(xin)道(dao)(dao)的(de)(de)(de)帶寬資源;而對于(yu)不(bu)可靠(kao)信(xin)道(dao)(dao),傳(chuan)(chuan)(chuan)(chuan)(chuan)(chuan)(chuan)輸(shu)中(zhong)研究的(de)(de)(de)重點(dian)則是(shi)充分利(li)用帶寬資源來實現可靠(kao)傳(chuan)(chuan)(chuan)(chuan)(chuan)(chuan)(chuan)輸(shu),即(ji)容(rong)錯傳(chuan)(chuan)(chuan)(chuan)(chuan)(chuan)(chuan)輸(shu)技(ji)(ji)術(shu)。這(zhe)里討(tao)論(lun)在(zai)無線(xian)信(xin)道(dao)(dao)上的(de)(de)(de)視頻(pin)傳(chuan)(chuan)(chuan)(chuan)(chuan)(chuan)(chuan)輸(shu)機(ji)(ji)制(zhi)(zhi),其主要的(de)(de)(de)研究點(dian)是(shi)容(rong)錯傳(chuan)(chuan)(chuan)(chuan)(chuan)(chuan)(chuan)輸(shu)控(kong)制(zhi)(zhi)。容(rong)錯傳(chuan)(chuan)(chuan)(chuan)(chuan)(chuan)(chuan)輸(shu)控(kong)制(zhi)(zhi)技(ji)(ji)術(shu)根據(ju)其控(kong)制(zhi)(zhi)方式的(de)(de)(de)不(bu)同可以分為三大類:即(ji)前向(xiang)錯誤控(kong)制(zhi)(zhi)、基(ji)于(yu)反(fan)饋(kui)的(de)(de)(de)ARQ和(he)信(xin)源信(xin)道(dao)(dao)聯合編(bian)碼。前向(xiang)錯誤控(kong)制(zhi)(zhi)(Forward Error Control,FEC)包(bao)(bao)括信(xin)道(dao)(dao)糾錯編(bian)碼技(ji)(ji)術(shu)、交織打包(bao)(bao)技(ji)(ji)術(shu)和(he)優化的(de)(de)(de)包(bao)(bao)調度機(ji)(ji)制(zhi)(zhi)等。基(ji)于(yu)反(fan)饋(kui)的(de)(de)(de)ARQ技(ji)(ji)術(shu)包(bao)(bao)括利(li)用多(duo)幀參考機(ji)(ji)制(zhi)(zhi)的(de)(de)(de)參考幀選擇(Reference Picture Selection,RPS)機(ji)(ji)制(zhi)(zhi)、混合ARQ(Hybrid,HARQ)機(ji)(ji)制(zhi)(zhi)和(he)基(ji)于(yu)ARQ的(de)(de)(de)反(fan)饋(kui)錯誤跟蹤技(ji)(ji)術(shu)。由于(yu)基(ji)于(yu)ARQ的(de)(de)(de)容(rong)錯傳(chuan)(chuan)(chuan)(chuan)(chuan)(chuan)(chuan)輸(shu)控(kong)制(zhi)(zhi)技(ji)(ji)術(shu)具(ju)有優良的(de)(de)(de)性能,所以在(zai)此重點(dian)介紹(shao)ARQ相關(guan)的(de)(de)(de)傳(chuan)(chuan)(chuan)(chuan)(chuan)(chuan)(chuan)輸(shu)控(kong)制(zhi)(zhi)技(ji)(ji)術(shu),并(bing)討(tao)論(lun)現有視頻(pin)容(rong)錯傳(chuan)(chuan)(chuan)(chuan)(chuan)(chuan)(chuan)輸(shu)機(ji)(ji)制(zhi)(zhi)存(cun)在(zai)的(de)(de)(de)不(bu)足。
前(qian)(qian)(qian)向(xiang)(xiang)錯(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)誤(wu)(wu)(wu)控(kong)(kong)制(zhi)(zhi)采(cai)用(yong)(yong)前(qian)(qian)(qian)向(xiang)(xiang)糾(jiu)(jiu)錯(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)編(bian)碼(ma)(ma)(ma)的(de)(de)(de)(de)(de)(de)方(fang)式來(lai)(lai)(lai)克服信(xin)(xin)(xin)道錯(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)誤(wu)(wu)(wu)。在(zai)信(xin)(xin)(xin)道出錯(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)概率波動比較劇烈的(de)(de)(de)(de)(de)(de)情況(kuang)下(xia)(如現(xian)有(you)的(de)(de)(de)(de)(de)(de)移(yi)動信(xin)(xin)(xin)道),為(wei)(wei)了獲得(de)一(yi)定的(de)(de)(de)(de)(de)(de)傳(chuan)輸(shu)(shu)質量(liang)(liang),前(qian)(qian)(qian)向(xiang)(xiang)糾(jiu)(jiu)錯(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)編(bian)碼(ma)(ma)(ma)必(bi)須根(gen)(gen)據(ju)(ju)當前(qian)(qian)(qian)估計的(de)(de)(de)(de)(de)(de)最(zui)差情況(kuang)來(lai)(lai)(lai)增加(jia)冗余校驗比特,這(zhe)會導致(zhi)(zhi)帶(dai)寬(kuan)資(zi)源的(de)(de)(de)(de)(de)(de)浪(lang)費(fei)。對帶(dai)寬(kuan)資(zi)源本來(lai)(lai)(lai)就有(you)限(xian)的(de)(de)(de)(de)(de)(de)無(wu)線(xian)信(xin)(xin)(xin)道而言,顯然是不能(neng)(neng)(neng)滿足要(yao)求(qiu)的(de)(de)(de)(de)(de)(de)。為(wei)(wei)此,考慮把ARQ技術和前(qian)(qian)(qian)向(xiang)(xiang)錯(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)誤(wu)(wu)(wu)控(kong)(kong)制(zhi)(zhi)結(jie)合起來(lai)(lai)(lai),稱為(wei)(wei)HARQ技術。HARQ分為(wei)(wei)兩類(lei)(lei):I類(lei)(lei)HARQ中,發(fa)(fa)(fa)(fa)送(song)(song)(song)端(duan)的(de)(de)(de)(de)(de)(de)前(qian)(qian)(qian)向(xiang)(xiang)編(bian)碼(ma)(ma)(ma)要(yao)具有(you)一(yi)定的(de)(de)(de)(de)(de)(de)糾(jiu)(jiu)錯(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)能(neng)(neng)(neng)力,當接(jie)收(shou)(shou)端(duan)發(fa)(fa)(fa)(fa)現(xian)錯(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)誤(wu)(wu)(wu)后(hou),首先利用(yong)(yong)前(qian)(qian)(qian)向(xiang)(xiang)糾(jiu)(jiu)錯(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)編(bian)碼(ma)(ma)(ma)來(lai)(lai)(lai)糾(jiu)(jiu)正(zheng)(zheng)錯(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)誤(wu)(wu)(wu)。如果錯(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)誤(wu)(wu)(wu)被糾(jiu)(jiu)正(zheng)(zheng),則向(xiang)(xiang)發(fa)(fa)(fa)(fa)送(song)(song)(song)端(duan)傳(chuan)送(song)(song)(song)一(yi)個(ge)(ge)當前(qian)(qian)(qian)包接(jie)收(shou)(shou)成功(gong)的(de)(de)(de)(de)(de)(de)反(fan)饋(kui)信(xin)(xin)(xin)息(ACK),反(fan)之則發(fa)(fa)(fa)(fa)送(song)(song)(song)接(jie)收(shou)(shou)失敗消(xiao)息(NACK)。發(fa)(fa)(fa)(fa)送(song)(song)(song)端(duan)如果收(shou)(shou)到ACK,則繼續發(fa)(fa)(fa)(fa)送(song)(song)(song)下(xia)一(yi)個(ge)(ge)數(shu)據(ju)(ju)包,否則,則重(zhong)(zhong)發(fa)(fa)(fa)(fa)出錯(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)的(de)(de)(de)(de)(de)(de)數(shu)據(ju)(ju)包。由此可(ke)(ke)(ke)(ke)見(jian)I類(lei)(lei)ARQ需要(yao)較強的(de)(de)(de)(de)(de)(de)前(qian)(qian)(qian)向(xiang)(xiang)糾(jiu)(jiu)錯(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)編(bian)碼(ma)(ma)(ma),在(zai)錯(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)誤(wu)(wu)(wu)率較低(di)的(de)(de)(de)(de)(de)(de)應(ying)用(yong)(yong)場合會導致(zhi)(zhi)帶(dai)寬(kuan)資(zi)源的(de)(de)(de)(de)(de)(de)浪(lang)費(fei),但(dan)在(zai)錯(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)誤(wu)(wu)(wu)率高的(de)(de)(de)(de)(de)(de)環(huan)境下(xia)能(neng)(neng)(neng)夠(gou)獲得(de)比其(qi)他類(lei)(lei)型(xing)ARQ機制(zhi)(zhi)更好的(de)(de)(de)(de)(de)(de)吞吐效(xiao)率。Ⅱ類(lei)(lei)ARQ中只要(yao)求(qiu)前(qian)(qian)(qian)向(xiang)(xiang)糾(jiu)(jiu)錯(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)編(bian)碼(ma)(ma)(ma)具有(you)檢錯(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)能(neng)(neng)(neng)力即可(ke)(ke)(ke)(ke),根(gen)(gen)據(ju)(ju)關于信(xin)(xin)(xin)道編(bian)碼(ma)(ma)(ma)糾(jiu)(jiu)錯(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)能(neng)(neng)(neng)力的(de)(de)(de)(de)(de)(de)理論可(ke)(ke)(ke)(ke)知,這(zhe)可(ke)(ke)(ke)(ke)以(yi)起到節約帶(dai)寬(kuan)的(de)(de)(de)(de)(de)(de)作用(yong)(yong)。當接(jie)收(shou)(shou)端(duan)發(fa)(fa)(fa)(fa)現(xian)錯(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)誤(wu)(wu)(wu)后(hou),發(fa)(fa)(fa)(fa)送(song)(song)(song)重(zhong)(zhong)傳(chuan)請求(qiu);發(fa)(fa)(fa)(fa)送(song)(song)(song)端(duan)只傳(chuan)送(song)(song)(song)出錯(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)數(shu)據(ju)(ju)對應(ying)的(de)(de)(de)(de)(de)(de)具有(you)糾(jiu)(jiu)錯(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)能(neng)(neng)(neng)力的(de)(de)(de)(de)(de)(de)校驗碼(ma)(ma)(ma)。當接(jie)收(shou)(shou)端(duan)收(shou)(shou)到后(hou),如果仍然不能(neng)(neng)(neng)糾(jiu)(jiu)正(zheng)(zheng)錯(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)誤(wu)(wu)(wu),則繼續發(fa)(fa)(fa)(fa)送(song)(song)(song)重(zhong)(zhong)傳(chuan)請求(qiu),發(fa)(fa)(fa)(fa)送(song)(song)(song)端(duan)可(ke)(ke)(ke)(ke)以(yi)選擇重(zhong)(zhong)傳(chuan)整體出錯(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)數(shu)據(ju)(ju)和校驗碼(ma)(ma)(ma),也可(ke)(ke)(ke)(ke)以(yi)選擇發(fa)(fa)(fa)(fa)送(song)(song)(song)更強糾(jiu)(jiu)錯(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)能(neng)(neng)(neng)力的(de)(de)(de)(de)(de)(de)校驗碼(ma)(ma)(ma),具體因控(kong)(kong)制(zhi)(zhi)策(ce)略不同可(ke)(ke)(ke)(ke)有(you)所(suo)調(diao)整。鑒于無(wu)線(xian)信(xin)(xin)(xin)道錯(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)誤(wu)(wu)(wu)率高,具有(you)反(fan)饋(kui)信(xin)(xin)(xin)道的(de)(de)(de)(de)(de)(de)無(wu)線(xian)傳(chuan)輸(shu)(shu)通(tong)常采(cai)用(yong)(yong)HARQ-I。圖(tu)2顯示了采(cai)用(yong)(yong)HARQ-I的(de)(de)(de)(de)(de)(de)無(wu)線(xian)視頻傳(chuan)輸(shu)(shu)系統(tong),圖(tu)中虛線(xian)框(kuang)代表了傳(chuan)輸(shu)(shu)中錯(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)誤(wu)(wu)(wu)控(kong)(kong)制(zhi)(zhi)的(de)(de)(de)(de)(de)(de)流程。根(gen)(gen)據(ju)(ju)HARQ-I的(de)(de)(de)(de)(de)(de)設計原(yuan)理,接(jie)收(shou)(shou)端(duan)發(fa)(fa)(fa)(fa)現(xian)錯(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)誤(wu)(wu)(wu)后(hou),首先進(jin)(jin)行前(qian)(qian)(qian)向(xiang)(xiang)錯(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)誤(wu)(wu)(wu)糾(jiu)(jiu)正(zheng)(zheng)(圖(tu)中第一(yi)層(ceng)錯(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)誤(wu)(wu)(wu)屏障),如果不能(neng)(neng)(neng)糾(jiu)(jiu)正(zheng)(zheng)且當前(qian)(qian)(qian)系統(tong)滿足時延(yan)限(xian)制(zhi)(zhi),則發(fa)(fa)(fa)(fa)送(song)(song)(song)ACK請求(qiu)來(lai)(lai)(lai)讓(rang)發(fa)(fa)(fa)(fa)送(song)(song)(song)端(duan)重(zhong)(zhong)傳(chuan)出錯(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)部(bu)分的(de)(de)(de)(de)(de)(de)數(shu)據(ju)(ju)(第二層(ceng)錯(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)誤(wu)(wu)(wu)屏障)。這(zhe)樣的(de)(de)(de)(de)(de)(de)重(zhong)(zhong)傳(chuan)可(ke)(ke)(ke)(ke)以(yi)重(zhong)(zhong)復到接(jie)收(shou)(shou)端(duan)收(shou)(shou)到正(zheng)(zheng)確的(de)(de)(de)(de)(de)(de)數(shu)據(ju)(ju)或者(zhe)重(zhong)(zhong)傳(chuan)延(yan)遲(chi)超(chao)出系統(tong)時延(yan)限(xian)制(zhi)(zhi)為(wei)(wei)止。如果重(zhong)(zhong)傳(chuan)結(jie)束后(hou)仍然不能(neng)(neng)(neng)得(de)到正(zheng)(zheng)確的(de)(de)(de)(de)(de)(de)數(shu)據(ju)(ju)包,在(zai)接(jie)收(shou)(shou)端(duan)就會用(yong)(yong)錯(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)誤(wu)(wu)(wu)隱藏(zang)技術來(lai)(lai)(lai)進(jin)(jin)行錯(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)誤(wu)(wu)(wu)恢(hui)復(第三層(ceng)錯(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)誤(wu)(wu)(wu)屏障)。可(ke)(ke)(ke)(ke)以(yi)看(kan)出,這(zhe)種機制(zhi)(zhi)的(de)(de)(de)(de)(de)(de)基本思想是出錯(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)后(hou)盡量(liang)(liang)使(shi)用(yong)(yong)ARQ技術來(lai)(lai)(lai)恢(hui)復錯(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)(cuo)誤(wu)(wu)(wu),所(suo)以(yi)這(zhe)里將其(qi)命名為(wei)(wei)“盡力而為(wei)(wei)”ARQ機制(zhi)(zhi)(Best Effort ARQ,BEA,RQ)。
無線視頻監控三階段
根據(ju)近年來(lai)網(wang)絡視(shi)(shi)頻(pin)監控(kong)業務(wu)運營實(shi)踐、無(wu)(wu)線網(wang)絡視(shi)(shi)頻(pin)監控(kong)技(ji)術的(de)發(fa)展及(ji)不同用戶群對無(wu)(wu)線視(shi)(shi)頻(pin)監控(kong)的(de)需求程度的(de)發(fa)展,筆(bi)者認為,今后國內無(wu)(wu)線網(wang)絡視(shi)(shi)頻(pin)監控(kong)業務(wu)的(de)發(fa)展將會經歷以下三(san)個階段(duan):
第一階(jie)(jie)段:以(yi)行(xing)(xing)業大客戶無線視頻監(jian)控應用(yong)為主的行(xing)(xing)業典型(xing)應用(yong)階(jie)(jie)段
目前,高端行業用戶的監(jian)(jian)控系統(tong)如國(guo)內的平安工(gong)程(cheng)、交通的道路監(jian)(jian)控、檢驗檢疫(yi)的電(dian)子監(jian)(jian)管(guan)視(shi)(shi)頻(pin)(pin)監(jian)(jian)控等(deng),多為大型化的城(cheng)域性甚至(zhi)全(quan)國(guo)性的行業視(shi)(shi)頻(pin)(pin)監(jian)(jian)控系統(tong)。高端行業用戶現在(zai)(zai)大多處在(zai)(zai)建設(she)大型視(shi)(shi)頻(pin)(pin)監(jian)(jian)控項目的初期,其對監(jian)(jian)控系統(tong)的要求很(hen)高,不僅包括了有線側圖像能夠實(shi)時看得(de)清、錄像存得(de)好、云臺控制等(deng)指令響應(ying)得(de)快等(deng),同(tong)時還增加了對無線視(shi)(shi)頻(pin)(pin)采集(如交通巡邏、平安城(cheng)市(shi)移(yi)(yi)動(dong)巡邏、城(cheng)管(guan)移(yi)(yi)動(dong)巡邏與執法等(deng))及移(yi)(yi)動(dong)視(shi)(shi)頻(pin)(pin)觀(guan)看和控制的應(ying)用要求。
由于(yu)當前能夠實現盈利的(de)運營商視(shi)(shi)頻(pin)(pin)監(jian)控(kong)平臺基本都處于(yu)第一階段行(xing)業用戶上,政府、金融(rong)和電(dian)信仍是視(shi)(shi)頻(pin)(pin)監(jian)控(kong)主要(yao)的(de)應(ying)用領域,無線網(wang)絡(luo)視(shi)(shi)頻(pin)(pin)監(jian)控(kong)與具體行(xing)業的(de)深(shen)度(du)融(rong)合將成為(wei)網(wang)絡(luo)視(shi)(shi)頻(pin)(pin)監(jian)控(kong)市場發展(zhan)的(de)必(bi)然趨勢。
第二階段(duan):以商業監控(kong)的創新性應(ying)用為主和部分家庭推(tui)廣的小眾化應(ying)用階段(duan)
中(zhong)小型(xing)商(shang)業用(yong)(yong)戶(hu)(hu)(hu)不僅是傳統有(you)線(xian)網(wang)絡(luo)視頻(pin)監(jian)控業務的(de)另(ling)一個潛在的(de)大(da)規模用(yong)(yong)戶(hu)(hu)(hu)群(qun),也(ye)是無(wu)線(xian)網(wang)絡(luo)視頻(pin)監(jian)控應(ying)用(yong)(yong)的(de)另(ling)一重要(yao)領(ling)域。這類用(yong)(yong)戶(hu)(hu)(hu)是指有(you)分布式(shi)監(jian)控訪問要(yao)求(qiu)的(de)小型(xing)商(shang)店、中(zhong)等規模連鎖商(shang)業組織(zhi)、醫療、教育(yu)機構等。由于用(yong)(yong)戶(hu)(hu)(hu)具(ju)有(you)移(yi)動(dong)性、遠程移(yi)動(dong)接入及對工作(zuo)效率高要(yao)求(qiu)等特(te)點(dian),無(wu)線(xian)網(wang)絡(luo)視頻(pin)監(jian)控業務在該類應(ying)用(yong)(yong)中(zhong)的(de)滲(shen)透(tou)率將有(you)較高的(de)起點(dian)和較大(da)的(de)提(ti)升空間。
商業(ye)(ye)用(yong)戶對無線視頻監(jian)(jian)(jian)控的業(ye)(ye)務(wu)(wu)需求除(chu)了移(yi)動(dong)視頻查看等(deng)基礎的監(jian)(jian)(jian)控業(ye)(ye)務(wu)(wu)需求外,往往還需要監(jian)(jian)(jian)控系統與企業(ye)(ye)的業(ye)(ye)務(wu)(wu)系統相結(jie)合,比(bi)如(ru)醫療有可(ke)能會(hui)利用(yong)視頻監(jian)(jian)(jian)控平臺(tai)(tai)開展移(yi)動(dong)遠程(cheng)醫療服務(wu)(wu)(如(ru)救護(hu)車上的應急診斷與救護(hu))、銀行(xing)會(hui)利用(yong)運鈔車的移(yi)動(dong)視頻監(jian)(jian)(jian)控進行(xing)管控、學校會(hui)利用(yong)監(jian)(jian)(jian)控平臺(tai)(tai)進行(xing)無線電化(hua)教學、無線電子監(jian)(jian)(jian)考等(deng)應用(yong)。
對(dui)商(shang)(shang)業用(yong)戶來說,與(yu)自身業務(wu)結合良好(hao)的(de)無線視頻(pin)監(jian)控平臺是很好(hao)的(de)擴展(zhan)業務(wu)的(de)手(shou)段,因此運營商(shang)(shang)對(dui)商(shang)(shang)業客戶的(de)引導策略應該是搭建平臺,尋找(zhao)廣泛的(de)集成商(shang)(shang)共(gong)同開發面(mian)向客戶的(de)商(shang)(shang)業應用(yong)。如果電信(xin)運營商(shang)(shang)積極引導開發適應商(shang)(shang)業用(yong)戶的(de)殺(sha)手(shou)級(ji)監(jian)控應用(yong),用(yong)戶群的(de)規(gui)模將很快得到拓(tuo)展(zhan)。
第三階段:以廣泛的個人和家庭應用、商業(ye)(ye)和行業(ye)(ye)應用全(quan)面開花,無(wu)線(xian)視頻監控與視頻的其它應用如(ru)IPTV、視頻會議和語音業(ye)(ye)務(wu)等(deng)應用相融(rong)合的大眾化普遍應用階段。
無(wu)線監控(kong)應(ying)用范圍
1、民用小范(fan)圍(wei)應用
目(mu)前(qian)在(zai)(zai)民(min)用(yong)(yong)(yong)領域應(ying)用(yong)(yong)(yong)的無線(xian)監(jian)控系(xi)統,多(duo)在(zai)(zai)辦(ban)公(gong)場所、廠區(qu)等小范圍中使用(yong)(yong)(yong),以(yi)WLAN、WiFi網絡(luo)方(fang)式(shi)為主。在(zai)(zai)這些已建(jian)(jian)建(jian)(jian)筑(zhu)(zhu)群中,若采用(yong)(yong)(yong)有(you)(you)(you)線(xian)監(jian)控,則(ze)有(you)(you)(you)可(ke)能對原有(you)(you)(you)建(jian)(jian)筑(zhu)(zhu)造成破壞,需要挖槽、埋線(xian)等,因(yin)此不便(bian)于采用(yong)(yong)(yong)傳統有(you)(you)(you)線(xian)監(jian)控。據(ju)天地偉業陳虹旭介(jie)紹(shao),該種(zhong)方(fang)式(shi)布(bu)網簡單(dan),只需一個無線(xian)路由(you)器,即可(ke)進行傳輸(shu),且無網絡(luo)附加費用(yong)(yong)(yong),在(zai)(zai)一些區(qu)域較小又需要使用(yong)(yong)(yong)監(jian)控的場合(he),采用(yong)(yong)(yong)此種(zhong)方(fang)式(shi)來(lai)傳輸(shu)視頻,不失為一個比較好的方(fang)式(shi)。
但此種(zhong)方式應用范圍(wei)有限(xian),在完全(quan)無障礙的空曠場所,其(qi)傳(chuan)輸(shu)距(ju)離可(ke)達到200米。而在相距(ju)較近的建筑群(qun)中也可(ke)實現視頻(pin)傳(chuan)輸(shu),但相對來說(shuo),其(qi)傳(chuan)輸(shu)質量會(hui)受到影響,還(huan)需要有待改(gai)進(jin)。
2、自建無線網絡應用(yong)
在(zai)森林(lin)防火(huo)、偏遠(yuan)(yuan)山區(qu)、油田、風景區(qu)、電力、水利、環保等(deng)大范圍(wei)、長距離(li)固定點(dian)的監控(kong)應(ying)用(yong)中(zhong),采用(yong)無(wu)(wu)線(xian)監控(kong)是(shi)較好的解決方法。在(zai)此類(lei)應(ying)用(yong)中(zhong),因(yin)受范圍(wei)廣、地理位置偏遠(yuan)(yuan)、不(bu)易布(bu)線(xian)等(deng)因(yin)素的制約(yue),如(ru)果(guo)采用(yong)傳統有線(xian)監控(kong)方式會(hui)使線(xian)路敷設和維護成本非常高,因(yin)此通常建議采用(yong)無(wu)(wu)線(xian)監控(kong),如(ru)微波。
建設無線網其(qi)造價一(yi)般受距離(li)的遠(yuan)近(jin)和(he)(he)基站點數(shu)量的制(zhi)約,也(ye)有前期(qi)一(yi)次性投入和(he)(he)后期(qi)維護(hu)的費(fei)用,但(dan)帶(dai)寬有保(bao)障,圖像質量較(jiao)好(hao),可滿足遠(yuan)程監控(kong)的要求。因此有業內(nei)人士說,行業自建無線網應屬公建設施,由政府進行投資較(jiao)合理。
3、使用(yong)運(yun)營商網(wang)絡
移動(dong)、電信、聯通等運營商,會(hui)提(ti)供一些無線傳(chuan)輸(shu)網絡,如2.75G、3G等。可(ke)應(ying)用(yong)(yong)于各類需無線監控(kong)應(ying)用(yong)(yong)的場合,如公交(jiao)車載監控(kong)、出(chu)租車監控(kong)、地(di)鐵高鐵監控(kong)等應(ying)用(yong)(yong)領域(yu)。此(ci)種應(ying)用(yong)(yong)一般租用(yong)(yong)運營商網絡,其特點是空間范圍非(fei)常廣,只(zhi)要運營商網絡所達的區域(yu)均可(ke)使用(yong)(yong)。但其需每月(yue)支付給運營商一定的租賃費,且目前價格較(jiao)為昂貴,帶寬(kuan)與傳(chuan)輸(shu)速率也(ye)有待進一步提(ti)高。
北京攜遠(yuan)天成技術(shu)有(you)限(xian)(xian)公司產品部總監石朝兆認為,無(wu)(wu)線監控(kong)的(de)(de)應(ying)用(yong)前景與(yu)無(wu)(wu)線技術(shu)特別是無(wu)(wu)線寬帶(dai)技術(shu)的(de)(de)發展緊密相(xiang)關,隨著WiFi、3G等(deng)無(wu)(wu)線高(gao)寬帶(dai)技術(shu)的(de)(de)成熟,今后越來越多的(de)(de)行業會采用(yong)無(wu)(wu)線方式。深圳黃河數(shu)字技術(shu)有(you)限(xian)(xian)公司市場(chang)部經(jing)理楊林則認為,采用(yong)無(wu)(wu)線監控(kong)系統與(yu)否,很大程度(du)上是由項目復雜的(de)(de)地理環境(jing)、布線的(de)(de)成本、實施項目的(de)(de)實際需求所決定(ding)(ding)的(de)(de),主要(yao)應(ying)用(yong)于(yu)不方便(bian)布線或沒有(you)障礙物的(de)(de)場(chang)合中(zhong),但其(qi)仍(reng)然(ran)存在(zai)不穩定(ding)(ding)、不可靠、帶(dai)寬低、無(wu)(wu)線網絡覆(fu)蓋有(you)限(xian)(xian)等(deng)缺點,因此在(zai)一定(ding)(ding)程度(du)上,其(qi)仍(reng)只(zhi)是有(you)線監控(kong)的(de)(de)補充角色,還(huan)有(you)待(dai)在(zai)技術(shu)上進(jin)一步提升(sheng)。
跨(kua)時代步進安防監控領域
安防(fang)行業(ye)每當提到(dao)發展(zhan)趨勢時,出(chu)現(xian)(xian)(xian)頻率最高的(de)詞必定是(shi)高清、數字、智能(neng),這已(yi)經是(shi)被公認的(de)三個發展(zhan)趨向(xiang)。可是(shi)在(zai)實現(xian)(xian)(xian)高清化(hua)、數字化(hua)、智能(neng)化(hua)的(de)過(guo)程中視(shi)頻無線傳輸起(qi)著橋梁作用,無線傳輸的(de)便利及(ji)靈活緊(jin)密將三者聯系起(qi)來實現(xian)(xian)(xian)在(zai)安防(fang)行業(ye)的(de)應用。
隨著WIFI、WIMAX、3G等(deng)無(wu)(wu)線寬帶接(jie)入(ru)(ru)技術,覆蓋整個(ge)城市(shi)或城市(shi)的主要地區,為個(ge)人(ren)、企(qi)業、政府乃至整個(ge)社會提供寬帶無(wu)(wu)線接(jie)入(ru)(ru)服務。隨著城市(shi)無(wu)(wu)線化不(bu)停(ting)擴(kuo)展時,三星泰科株式(shi)會社研發首席預測,無(wu)(wu)線視頻監控業務也必將是其重要組成部分,相(xiang)關城市(shi)將掀(xian)起(qi)一(yi)個(ge)無(wu)(wu)線監控的高(gao)潮。
無線(xian)監(jian)(jian)控(kong)由于種種因素特別是帶寬(kuan)的(de)(de)制約只能實(shi)現(xian)局(ju)域(yu)(yu)的(de)(de)監(jian)(jian)控(kong),設備(bei)與(yu)無線(xian)直接(jie)對接(jie),監(jian)(jian)控(kong)區(qu)域(yu)(yu)成功從(cong)局(ju)域(yu)(yu)邁入了(le)城域(yu)(yu)。并(bing)且,相(xiang)對于定點(dian)監(jian)(jian)控(kong),其對實(shi)現(xian)公交(jiao)車(che)、出(chu)租車(che)等移(yi)動監(jian)(jian)控(kong)時,其助推力非常(chang)明顯。之前,無線(xian)監(jian)(jian)控(kong)主(zhu)要依靠移(yi)動、聯通等小帶寬(kuan)網(wang)(wang)絡來實(shi)現(xian),這樣容易造成延時、誤碼等。“無線(xian)城市”依托Wi-Fi作為無線(xian)傳(chuan)輸(shu)方(fang)式的(de)(de)多(duo)模塊網(wang)(wang)狀(zhuang)網(wang)(wang)格無線(xian)網(wang)(wang)絡系統(tong),相(xiang)對于移(yi)動和聯通,網(wang)(wang)絡帶寬(kuan)有了(le)大幅度的(de)(de)改善,穩定性(xing)也更高。另外,如何實(shi)現(xian)對布(bu)線(xian)難(nan)或(huo)者無法布(bu)線(xian)的(de)(de)區(qu)域(yu)(yu)實(shi)施監(jian)(jian)控(kong)一直是傳(chuan)統(tong)監(jian)(jian)控(kong)的(de)(de)一大難(nan)題,城市實(shi)現(xian)全城的(de)(de)網(wang)(wang)絡覆蓋后,為上(shang)述區(qu)域(yu)(yu)不再是監(jian)(jian)控(kong)盲(mang)區(qu)。
不過,也有(you)業(ye)界人士認為網(wang)絡(luo)(luo)寬(kuan)帶(dai)對無(wu)線監(jian)控(kong)(kong)的(de)(de)影響非常(chang)有(you)限(xian),認為盡管有(you)些城(cheng)市實(shi)現了網(wang)絡(luo)(luo)的(de)(de)全城(cheng)覆(fu)蓋(gai),但這種網(wang)絡(luo)(luo)主(zhu)要(yao)用(yong)于通信(xin),與(yu)無(wu)線監(jian)控(kong)(kong)所需要(yao)的(de)(de)網(wang)絡(luo)(luo)有(you)所不同,用(yong)于定(ding)(ding)(ding)(ding)點(dian)監(jian)控(kong)(kong)價格過于昂貴(gui),帶(dai)寬(kuan)也受到限(xian)制。同時(shi),現在(zai)還(huan)處于試行階(jie)段,網(wang)絡(luo)(luo)的(de)(de)穩(wen)定(ding)(ding)(ding)(ding)性還(huan)有(you)待驗(yan)證。而(er)且(qie)是(shi)(shi)與(yu)否采用(yong)無(wu)線監(jian)控(kong)(kong)系(xi)統,很大程(cheng)度上是(shi)(shi)由(you)項目復雜的(de)(de)地理環境(jing)、布(bu)線的(de)(de)成本、實(shi)施項目的(de)(de)實(shi)際需求所決定(ding)(ding)(ding)(ding)的(de)(de),主(zhu)要(yao)應用(yong)于不方便布(bu)線或沒(mei)有(you)障礙物(wu)的(de)(de)場合中,但其(qi)仍然(ran)存在(zai)不穩(wen)定(ding)(ding)(ding)(ding)、不可(ke)靠、帶(dai)寬(kuan)低、無(wu)線網(wang)絡(luo)(luo)覆(fu)蓋(gai)有(you)限(xian)等(deng)缺點(dian),因此在(zai)一(yi)定(ding)(ding)(ding)(ding)程(cheng)度上,其(qi)仍只是(shi)(shi)有(you)線監(jian)控(kong)(kong)的(de)(de)補(bu)充(chong)角色,還(huan)有(you)待在(zai)技術上進一(yi)步(bu)提升。
安防行業(ye)發(fa)展的(de)(de)趨勢(shi)(shi)在(zai)不斷變(bian)化,當高清、數字、智逐漸發(fa)展成(cheng)熟時,會(hui)出(chu)現越(yue)來越(yue)多的(de)(de)聲音(yin)提出(chu)新的(de)(de)趨勢(shi)(shi),如:視頻智能分析、無線傳(chuan)輸、兼容性、攝像機(ji)DSP處理(li)芯片等(deng)還(huan)沒有成(cheng)熱門的(de)(de)領域會(hui)不斷被(bei)關注(zhu)。
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