一、我國(guo)安防視頻監(jian)控(kong)系統歷史

視(shi)頻(pin)(pin)監(jian)(jian)(jian)控(kong)(kong)系(xi)(xi)(xi)統(tong)(tong)(tong)(tong)發(fa)(fa)(fa)展(zhan)了(le)短短二(er)(er)十幾年時間，從(cong)最早模擬(ni)監(jian)(jian)(jian)控(kong)(kong)到前些年火熱(re)數字監(jian)(jian)(jian)控(kong)(kong)再到現在(zai)方(fang)興(xing)未艾網絡(luo)視(shi)頻(pin)(pin)監(jian)(jian)(jian)控(kong)(kong)，發(fa)(fa)(fa)生了(le)翻(fan)天覆(fu)地(di)變化。在(zai)IP技術(shu)逐步統(tong)(tong)(tong)(tong)一全球的今(jin)天，我(wo)們有(you)必要重(zhong)新認識(shi)視(shi)頻(pin)(pin)監(jian)(jian)(jian)控(kong)(kong)系(xi)(xi)(xi)統(tong)(tong)(tong)(tong)發(fa)(fa)(fa)展(zhan)歷史(shi)以及現在(zai)和發(fa)(fa)(fa)展(zhan)趨勢。從(cong)技術(shu)角度出發(fa)(fa)(fa)，視(shi)頻(pin)(pin)監(jian)(jian)(jian)控(kong)(kong)系(xi)(xi)(xi)統(tong)(tong)(tong)(tong)發(fa)(fa)(fa)展(zhan)劃分為第一代(dai)模擬(ni)視(shi)頻(pin)(pin)監(jian)(jian)(jian)控(kong)(kong)系(xi)(xi)(xi)統(tong)(tong)(tong)(tong)（CCTV），到第二(er)(er)代(dai)基于(yu)“PC＋多媒體卡”數字視(shi)頻(pin)(pin)監(jian)(jian)(jian)控(kong)(kong)系(xi)(xi)(xi)統(tong)(tong)(tong)(tong)（DVR），到第三代(dai)完全基于(yu)IP網絡(luo)視(shi)頻(pin)(pin)監(jian)(jian)(jian)控(kong)(kong)系(xi)(xi)(xi)統(tong)(tong)(tong)(tong)（IPVS）。

第一代視頻(pin)監(jian)控(kong)：傳(chuan)統(tong)模(mo)擬閉路視監(jian)控(kong)系統(tong)（CCTV）：

依賴攝像(xiang)(xiang)機(ji)、纜、錄(lu)像(xiang)(xiang)機(ji)和(he)監視(shi)器(qi)(qi)等(deng)專(zhuan)用設備(bei)。例如，攝像(xiang)(xiang)機(ji)通過專(zhuan)用同軸纜輸出(chu)視(shi)頻(pin)信號。纜連接到專(zhuan)用模擬視(shi)頻(pin)設備(bei)，如視(shi)頻(pin)畫(hua)面分割器(qi)(qi)、矩陣(zhen)、切換器(qi)(qi)、卡帶式錄(lu)像(xiang)(xiang)機(ji)（VCR）及視(shi)頻(pin)監視(shi)器(qi)(qi)等(deng)。模擬CCTV存在大量局限性：

有限監(jian)控能力只支持(chi)本地監(jian)控，受到模擬視頻纜(lan)(lan)傳輸長度和纜(lan)(lan)放大器限制。

有限(xian)可擴(kuo)展性系統(tong)通常受到視頻畫面(mian)分割器、矩(ju)陣和(he)切(qie)換器輸(shu)入容量(liang)限(xian)制。

錄(lu)像(xiang)(xiang)負載重用戶必須從(cong)錄(lu)像(xiang)(xiang)機中取出或(huo)更換新錄(lu)像(xiang)(xiang)帶保(bao)存，且錄(lu)像(xiang)(xiang)帶易(yi)于丟失、被盜或(huo)無意中被擦(ca)除。

錄像(xiang)質量(liang)不高錄像(xiang)是(shi)主(zhu)要(yao)限(xian)制因素(su)。錄像(xiang)質量(liang)隨拷(kao)貝(bei)數量(liang)增加(jia)而(er)降低(di)。

第二代視頻(pin)監控：當前“模(mo)擬(ni)-數字”監控系統(tong)（DVR）：

“模(mo)擬(ni)-數(shu)字(zi)(zi)”監控系(xi)統(tong)(tong)(tong)是(shi)以數(shu)字(zi)(zi)硬盤錄(lu)像機DVR為核心(xin)半(ban)模(mo)擬(ni)-半(ban)數(shu)字(zi)(zi)方案(an)，從(cong)攝像機到DVR仍采用(yong)同(tong)軸纜輸出視頻信號，通(tong)過DVR同(tong)時支持錄(lu)像和(he)回放，并可(ke)支持有限IP網絡訪問，由于DVR產品五花(hua)八(ba)門，沒有標準(zhun)，所以這一代(dai)系(xi)統(tong)(tong)(tong)是(shi)非標準(zhun)封閉系(xi)統(tong)(tong)(tong)，DVR系(xi)統(tong)(tong)(tong)仍存在大量局限：

“模擬(ni)-數(shu)字”方案(an)仍(reng)需要在每個攝像機上安裝單獨視頻纜(lan)，導致布線(xian)復(fu)雜(za)性。

有(you)限可擴展(zhan)性DVR典型(xing)限制是一次最多(duo)只(zhi)能擴展(zhan)16個攝像機(ji)。

有限可(ke)管(guan)理性您需要外部服務(wu)器(qi)和管(guan)理軟(ruan)件來(lai)控(kong)制多個DVR或監控(kong)點(dian)。

有限遠程監視(shi)/控制能(neng)力您不能(neng)從任意客戶機訪問任意攝像(xiang)機。您只能(neng)通過DVR間接訪問攝像(xiang)機。

磁盤發(fa)生故(gu)障(zhang)風險(xian)與RAID冗余和磁帶相比，“模擬-數(shu)字(zi)”方案(an)錄像沒有保(bao)護，易于丟失。