近年來，伴隨CCD和DSP技術的日趨進步，低照度攝像機雖然日趨成熟穩定，并在不少領域中使用，但行業專家認為低照度攝像機并非是市場主流，只有在一些特定的情況下被應用，如添加光源成本較高或不便于安裝光源的情況下，低照度攝像機才能發揮作用。所為何故?目前低照度攝像機發展遭遇哪些困境?如何才能實現破繭成蝶? 

　　曲高和寡

    2011年作為“十二五”開局之年，中國安防行業發展將依舊波瀾壯闊。據了解，除了直接投資近1000億元的全國城市報警與監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" 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title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" 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title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控" title="監控">監控系統建設試點工程(即“3111”試點工程)進入整體推進階段外，安防在高鐵建設、高速公路建設、地鐵城軌、城市智能交通、校園監控、社區家庭等細分行業中的需求也在增長。此外，大型活動帶動的需求同樣不容忽視，即將迎來8月12日第26屆世界大學生運動會的深圳，其供大運會使用的智能交通系統、信息網絡系統和安保系統等，就將投入30多億元。

    然而，作為前端監控的一份子——低照度攝像機并沒有跟上安防的大跨步節奏。據CantronicSystems市場營銷執行副總裁JonChynoweth稱，就全球市場來看，低照度攝像機的市場規模僅有3億美元左右，這些攝像機也主要用于特殊場合或者偏遠區域，如一些機要區域、關鍵基礎設施、化工廠、邊檢控制、港口入境和邊防。

    尋根認祖

    除了最原始的增加補光燈或紅外燈、選用大靶面CCD(該方法百萬像素攝像機普遍采用)外，長期來改善低照度成像效果的手段不外乎下面幾種。

    選用高靈敏度CCD，目前攝像機大多采用兩大系列CCD,一是索尼的SUPPERHADCCD系列，另一是索尼的EX-VIEWHADCCD系列。EXVIEWHADCCD將CCD每一像素的開口率提高，進而達到更低照度。技術資料介紹EXVIEWHADCCD的低照效果是SUPPERHADCCD的4~6倍，實際上確實有提升;

    ·彩轉黑技術，目前采用這一技術甚多，可配合使用紅外燈。轉換技術有兩種，一是采用紅外濾光片和切換電路來進行彩色/黑白轉換;另一種利用電子電路將彩色信號濾除掉，無需紅外濾光片。高端彩轉黑攝像機多采用前一種切換技術，以保證顏色還原度和清晰度;

    ·幀累積(慢快門)技術，但慢快門的啟動使得圖像實時性變差，造成嚴重的拖尾現象，所以只適用于靜態場所的監視，不宜監控目標移動速度較快的場合;

    ·數字降噪技術，從一些高檔低照攝像機的數字降噪表現來看，能在低照的噪點過多的情況下(特別是AGC啟動時)，較好地改善圖像的潔凈度和清晰度，從而提升低照成像效果，但很多攝像機在降噪功能啟動后還是會出現拖尾和動畫感問題。

    從上述簡單羅列，可歸納出提升低照度下成像效果的途徑主要還是從兩方面入手：一是提高CCD自身性能;二是增加內部軟硬件的圖像處理能力。

    遭遇軟肋

    近年來，低照度攝像機盡管已有長足進步，但隨著應用要求的不斷提高，或說用戶日益的“挑剔”，也暴露出種種弊端，并制約著其進一步發展，這主要表現在感光器件靈敏度還不能真正滿足全天候監控的需求、產品價格的劣勢，以及需求本身的強度不高。所以說，靈敏度、價格、需求強度便成了其阻礙壯大的軟肋。 

　　感光器件靈敏度

    感光器件在近幾年雖然發展迅速，但仍然與人們的期望值有較大的差距。浙江大華技術股份有限公司產品中心產品經理江用也表示，從技術上來看制約低照度攝像機發展的最主要的因素仍是感光器件的靈敏度。如果感光器件的靈敏度不夠高，在非常微弱的自然光且不借助其他光源的情況下就會導致圖像噪點增多、清晰度不高、層次感不強。感光器件性能不穩定將導致攝像機對被攝物體的細節分辨能力下降。所以，為了在底光照環境下也能獲得較理想的圖像效果，采用“超感度”的低照CCD是提高攝像機低照度性能、獲得理想圖像效果的最關鍵因素。

    價格劣勢

    其次是產品價格。神州數碼(中國)有限公司AMPON事業部產品經理蘭柳表示，低照度攝像機器件品質選擇要比普通攝像機高，還會應用一些獨特的技術來進一步提升低照度性能，因此低照度攝像機的成本較高。因為不僅需要采用低照度性能優秀的CCD，而且在產品設計上，要有專門的低照度電路，并采用ICR機械彩轉黑(即步進電機驅動的雙濾光片設計)等。再者，低照度攝像機的核心器件超感度CCD依然被索尼等幾家半導體巨頭壟斷，所以，產品價格仍舊居高不下。

    此外，其他監控攝像機對低照度產品也有一定的影響，如紅外一體機。實際上這兩種產品是互相補充的關系。一般地，紅外一體機定位在中低價位，而低照度攝像機成本較高，占據中高價位。這樣就使得既可以選擇紅外一體機，也可以選擇低照度攝像機的場合，用戶又沒有專門要求時，如果預算不足，用戶往往會更傾向于采用價格更低廉的紅外一體機產品。

    市場需求強度不高

    伴隨著CCD和DSP技術的日趨進步，低照度攝像機雖然日趨成熟穩定，也在不少領域中使用，但行業專家認為低照度攝像機并非是市場主流，只有在一些特定區域如添加光源成本較高或不便于安裝光源的情況下，低照度攝像機才能發揮重要的作用。據統計，超過半數以上的應用環境，對監控強度的要求不是特別高，要求攝像機24小時保持高品質監控的場合并不多，普通攝像機就能滿足大多數應用領域的監控需求。由此可見，低照度攝像機的應用還需要克服選用上的人為因素，才能取得較大突破。