? ? 【城銘科技】采(cai)(cai)(cai)用(yong)常規(gui)的(de)(de)可見光(guang)照明，不僅(jin)不能(neng)隱(yin)(yin)蔽(bi)，反而更(geng)加暴露監(jian)(jian)控(kong)(kong)(kong)目(mu)標(biao)，在(zai)居民小區還有(you)擾民問題。隱(yin)(yin)蔽(bi)的(de)(de)夜視(shi)監(jian)(jian)控(kong)(kong)(kong)，目(mu)前都是采(cai)(cai)(cai)用(yong)紅(hong)(hong)外(wai)攝像(xiang)技(ji)術。紅(hong)(hong)外(wai)攝像(xiang)技(ji)術分為被動紅(hong)(hong)外(wai)攝像(xiang)技(ji)術和主(zhu)動紅(hong)(hong)外(wai)攝像(xiang)技(ji)術。在(zai)夜視(shi)系統中經常采(cai)(cai)(cai)用(yong)主(zhu)動紅(hong)(hong)外(wai)攝像(xiang)技(ji)術， 即采(cai)(cai)(cai)用(yong)紅(hong)(hong)外(wai)輻射“照明”，產生人眼(yan)看不見而普通攝像(xiang)機能(neng)捕捉到(dao)的(de)(de)紅(hong)(hong)外(wai)光(guang)，輻射“照明”景物和環(huan)境。夜間監(jian)(jian)控(kong)(kong)(kong)中，選擇使(shi)用(yong)合(he)適的(de)(de)紅(hong)(hong)外(wai)燈才能(neng)獲得到(dao)良(liang)好的(de)(de)監(jian)(jian)控(kong)(kong)(kong)效果。
紅(hong)(hong)(hong)外燈的(de)(de)(de)選擇最重要(yao)的(de)(de)(de)問(wen)題是成套(tao)(tao)(tao)性，即紅(hong)(hong)(hong)外燈與攝像機(ji)、鏡頭(tou)、防護罩、供電電源等的(de)(de)(de)成套(tao)(tao)(tao)性。在設計(ji)方案時對所有器材綜合考慮(lv)設計(ji)，把(ba)它作為一個紅(hong)(hong)(hong)外低照度(du)夜視(shi)監控系統工程來考慮(lv)設計(ji)。有的(de)(de)(de)人買完了攝像機(ji)、鏡頭(tou)、防護罩、電源之后(hou)(hou)甚至安裝之后(hou)(hou)才去(qu)考慮(lv)購買紅(hong)(hong)(hong)外燈，這是不正確的(de)(de)(de)，在考慮(lv)成套(tao)(tao)(tao)性時，特(te)別(bie)要(yao)注意以下幾個問(wen)題。
一(yi)、用黑(hei)白攝像機或特殊(shu)彩(cai)色攝像機
CCD 圖(tu)像(xiang)傳感(gan)器(qi)具有很寬(kuan)的感(gan)光(guang)(guang)光(guang)(guang)譜(pu)范圍，其感(gan)光(guang)(guang)光(guang)(guang)譜(pu)不(bu)但包括可見光(guang)(guang)區(qu)(qu)(qu)域，還延(yan)長到紅外區(qu)(qu)(qu)域，利(li)用此特性，可以在夜(ye)間無可見光(guang)(guang)照明(ming)的情況下，用輔助紅外光(guang)(guang)源照明(ming)也(ye)可使CCD圖(tu)像(xiang)傳感(gan)器(qi)清(qing)晰的成(cheng)像(xiang)。而普通彩(cai)色攝像(xiang)機為了(le)能傳輸彩(cai)色信(xin)號(hao)，從 CCD器(qi)件的輸出信(xin)號(hao)中分離出綠藍(lan)紅三種基色視頻信(xin)號(hao)，然后(hou)合成(cheng)彩(cai)色電視信(xin)號(hao)，其感(gan)光(guang)(guang)光(guang)(guang)譜(pu)只在可見光(guang)(guang)區(qu)(qu)(qu)域。
隨著(zhu)技術的(de)(de)(de)(de)進步出現白(bai)(bai)天彩(cai)色(se)(se)/晚(wan)上黑白(bai)(bai)攝像(xiang)機(ji)， 它采用(yong)兩個(ge) CCD進行切換或采用(yong)一個(ge)CCD 利用(yong)數字電路的(de)(de)(de)(de)切換來實(shi)現，但是存在黑白(bai)(bai)照度(du)偏(pian)高、有的(de)(de)(de)(de)對彩(cai)色(se)(se)色(se)(se)彩(cai)的(de)(de)(de)(de)不(bu)利影響等缺點。而紅外低照度(du)彩(cai)色(se)(se)攝像(xiang)機(ji)紅外感度(du)比一般攝像(xiang)機(ji)高 4 倍(bei)以(yi)上，隨著(zhu)成本的(de)(de)(de)(de)降低，會成為(wei)發展趨勢(shi)的(de)(de)(de)(de)。
二、要求選用低照度攝像機(ji)
攝(she)像機的(de)最低照(zhao)度(du)(du)是當被攝(she)景物的(de)光亮度(du)(du)低到(dao)一定(ding)程度(du)(du)而(er)使攝(she)像機輸出的(de)視頻信號電平低到(dao)某(mou)一規定(ding)值(zhi)時的(de)景物光亮度(du)(du)值(zhi)。測定(ding)此參(can)數時，還應特別注明鏡頭的(de)光圈 F的(de)大小。
例如(ru)使(shi)用 F1.2 的(de)(de)(de)(de)(de)鏡頭，當(dang)被攝(she)(she)(she)影景(jing)物(wu)的(de)(de)(de)(de)(de)照(zhao)(zhao)度(du)(du)(du)(du)值低(di)(di)到 0.02Lux 時，攝(she)(she)(she)像(xiang)(xiang)(xiang)機(ji)(ji)輸出(chu)的(de)(de)(de)(de)(de)視頻信號幅值為標準幅值 700mv 的(de)(de)(de)(de)(de) 50%-33%，則稱(cheng)此攝(she)(she)(she)像(xiang)(xiang)(xiang)機(ji)(ji)的(de)(de)(de)(de)(de)最(zui)(zui)低(di)(di)照(zhao)(zhao)度(du)(du)(du)(du)為 0.02Lux/F1.2。有的(de)(de)(de)(de)(de)攝(she)(she)(she)像(xiang)(xiang)(xiang)機(ji)(ji)生產(chan)廠(chang)家給出(chu)不(bu)同光(guang)圈 F 時的(de)(de)(de)(de)(de)最(zui)(zui)低(di)(di)照(zhao)(zhao)度(du)(du)(du)(du)。當(dang)選擇攝(she)(she)(she)像(xiang)(xiang)(xiang)機(ji)(ji)最(zui)(zui)低(di)(di)照(zhao)(zhao)度(du)(du)(du)(du)高于紅外(wai)燈(deng)(deng)要(yao)求時，紅外(wai)燈(deng)(deng)的(de)(de)(de)(de)(de)有效距離將受(shou)到一定影響。 應當(dang)提醒用戶的(de)(de)(de)(de)(de)是市(shi)(shi)場上(shang)(shang)出(chu)售的(de)(de)(de)(de)(de)攝(she)(she)(she)像(xiang)(xiang)(xiang)機(ji)(ji)技術性(xing)能(neng)標出(chu)的(de)(de)(de)(de)(de)最(zui)(zui)低(di)(di)照(zhao)(zhao)度(du)(du)(du)(du)有兩種不(bu)正常情(qing)況，一種是攝(she)(she)(she)像(xiang)(xiang)(xiang)機(ji)(ji)制(zhi)造(zao)(zao)商(shang)所標的(de)(de)(de)(de)(de)最(zui)(zui)低(di)(di)照(zhao)(zhao)度(du)(du)(du)(du)是所謂(wei)的(de)(de)(de)(de)(de)靶面照(zhao)(zhao)度(du)(du)(du)(du)，即(ji) CCD圖像(xiang)(xiang)(xiang)傳感器(qi)上(shang)(shang)的(de)(de)(de)(de)(de)光(guang)照(zhao)(zhao)度(du)(du)(du)(du)，? 它比(bi)景(jing)物(wu)照(zhao)(zhao)度(du)(du)(du)(du)低(di)(di) 10 倍左右；另一種是有個別攝(she)(she)(she)像(xiang)(xiang)(xiang)機(ji)(ji)制(zhi)造(zao)(zao)商(shang)或銷售商(shang)虛報最(zui)(zui)低(di)(di)照(zhao)(zhao)度(du)(du)(du)(du)。目前市(shi)(shi)場上(shang)(shang)比(bi)較經濟的(de)(de)(de)(de)(de)黑白攝(she)(she)(she)像(xiang)(xiang)(xiang)機(ji)(ji)，有的(de)(de)(de)(de)(de)最(zui)(zui)低(di)(di)照(zhao)(zhao)度(du)(du)(du)(du)標為 0.01～0.02lux，它們(men)的(de)(de)(de)(de)(de)實際最(zui)(zui)低(di)(di)照(zhao)(zhao)度(du)(du)(du)(du)僅為 0.1～0.2Lux，如(ru)果，使(shi)用的(de)(de)(de)(de)(de)紅外(wai)燈(deng)(deng)要(yao)求攝(she)(she)(she)像(xiang)(xiang)(xiang)機(ji)(ji)的(de)(de)(de)(de)(de)最(zui)(zui)低(di)(di)照(zhao)(zhao)度(du)(du)(du)(du)為0.02Lux，必然(ran)影響紅外(wai)燈(deng)(deng)的(de)(de)(de)(de)(de)有效照(zhao)(zhao)射距離，而購買(mai)最(zui)(zui)低(di)(di)照(zhao)(zhao)度(du)(du)(du)(du) 0.02Lux 的(de)(de)(de)(de)(de)攝(she)(she)(she)像(xiang)(xiang)(xiang)機(ji)(ji)，價(jia)格可能(neng)比(bi) 0.1～0.2Lux 攝(she)(she)(she)像(xiang)(xiang)(xiang)機(ji)(ji)最(zui)(zui)少高一倍左右。
三、要求(qiu)攝像機的尺寸(cun)規格
攝(she)像(xiang)(xiang)機(ji)標稱尺(chi)(chi)(chi)寸日趨小(xiao)型(xing)化，目前市場(chang)上的(de)(de)攝(she)像(xiang)(xiang)機(ji)尺(chi)(chi)(chi)寸規格(ge)有(you) 1/2“、1/3”、1/4“，攝(she)像(xiang)(xiang)機(ji)尺(chi)(chi)(chi)寸大(da)，接(jie)收的(de)(de)光(guang)通量(liang)(liang)(liang)大(da)，攝(she)像(xiang)(xiang)機(ji)尺(chi)(chi)(chi)寸小(xiao)，接(jie)受(shou)的(de)(de)光(guang)通量(liang)(liang)(liang)少，如紅(hong)外燈(deng)標稱的(de)(de)有(you)效(xiao)距離是(shi)1/2”攝(she)像(xiang)(xiang)機(ji)條件下試(shi)驗(yan)的(de)(de)，如采用(yong) 1/3“或者 1/4”攝(she)像(xiang)(xiang)機(ji)，有(you)效(xiao)距離也(ye)將受(shou)到一(yi)定影(ying)響。1/3“攝(she)像(xiang)(xiang)機(ji)光(guang)通量(liang)(liang)(liang)只(zhi)有(you) 1/2”攝(she)像(xiang)(xiang)機(ji)光(guang)通量(liang)(liang)(liang)的(de)(de) 44%。
四、鏡頭的尺寸規格
與攝像(xiang)機的(de)尺寸規格同理，不再贅述。需(xu)要(yao)注意的(de)是紅(hong)外(wai)(wai)光源(yuan)由(you)于波長長，反映(ying)到普通非(fei)紅(hong)外(wai)(wai)鏡頭(tou)上(shang)會比可見(jian)光焦點略(lve)深一些，所(suo)以(yi)在用了紅(hong)外(wai)(wai)燈夜(ye)間成像(xiang)時(shi)，會感覺焦距稍微模糊一點。
五(wu)、攝(she)像機和(he)鏡頭的功能要求
攝像機有自動電子快(kuai)門功(gong)能，AGC 自動增益(yi)控制(zhi)功(gong)能，鏡(jing)頭有自動光(guang)圈，以適應晝(zhou)夜照度很大的變(bian)化。
六、電源供應
電(dian)(dian)(dian)(dian)(dian)視(shi)監控系統前端設備的(de)(de)電(dian)(dian)(dian)(dian)(dian)源供(gong)(gong)應(ying)要統一(yi)考(kao)慮設計(ji)。紅(hong)(hong)(hong)(hong)外(wai)(wai)(wai)(wai)燈(deng)(deng)(deng)的(de)(de)電(dian)(dian)(dian)(dian)(dian)源供(gong)(gong)應(ying)，考(kao)慮到(dao)紅(hong)(hong)(hong)(hong)外(wai)(wai)(wai)(wai)管(guan)的(de)(de)工作電(dian)(dian)(dian)(dian)(dian)流(liu)對(dui)供(gong)(gong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)壓(ya)十(shi)分敏感(gan)，而(er)電(dian)(dian)(dian)(dian)(dian)纜長(chang)度(du)不同(tong)對(dui)直(zhi)(zhi)(zhi)流(liu)電(dian)(dian)(dian)(dian)(dian)壓(ya)衰減不同(tong)。在(zai)多個紅(hong)(hong)(hong)(hong)外(wai)(wai)(wai)(wai)燈(deng)(deng)(deng)距(ju)(ju)控制室(shi)的(de)(de)距(ju)(ju)離(li)相差(cha)較(jiao)大(da)時(shi)，采(cai)用 DC12V集中(zhong)供(gong)(gong)電(dian)(dian)(dian)(dian)(dian)可(ke)能(neng)使距(ju)(ju)控制室(shi)近的(de)(de)紅(hong)(hong)(hong)(hong)外(wai)(wai)(wai)(wai)燈(deng)(deng)(deng)供(gong)(gong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)壓(ya)高，距(ju)(ju)控制室(shi)遠的(de)(de)紅(hong)(hong)(hong)(hong)外(wai)(wai)(wai)(wai)燈(deng)(deng)(deng)供(gong)(gong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)壓(ya)低。加之電(dian)(dian)(dian)(dian)(dian)源電(dian)(dian)(dian)(dian)(dian)壓(ya)調整上(shang)的(de)(de)偏差(cha)，可(ke)能(neng)造成電(dian)(dian)(dian)(dian)(dian)壓(ya)過(guo)高的(de)(de)紅(hong)(hong)(hong)(hong)外(wai)(wai)(wai)(wai)燈(deng)(deng)(deng)壽命縮短甚(shen)至(zhi)燒壞，電(dian)(dian)(dian)(dian)(dian)壓(ya)低的(de)(de)紅(hong)(hong)(hong)(hong)外(wai)(wai)(wai)(wai)燈(deng)(deng)(deng)發射功率不足。因(yin)此(ci)建議盡可(ke)能(neng)采(cai)用 AC22V供(gong)(gong)電(dian)(dian)(dian)(dian)(dian)或配一(yi)對(dui)一(yi)的(de)(de)直(zhi)(zhi)(zhi)流(liu)穩壓(ya)電(dian)(dian)(dian)(dian)(dian)源，這種(zhong)直(zhi)(zhi)(zhi)流(liu)穩壓(ya)電(dian)(dian)(dian)(dian)(dian)源有(you)的(de)(de)在(zai)電(dian)(dian)(dian)(dian)(dian)網電(dian)(dian)(dian)(dian)(dian)壓(ya)波動在(zai) AC100V-245V時(shi)輸(shu)出直(zhi)(zhi)(zhi)流(liu)電(dian)(dian)(dian)(dian)(dian)壓(ya)都是穩定的(de)(de)，保證紅(hong)(hong)(hong)(hong)外(wai)(wai)(wai)(wai)燈(deng)(deng)(deng)紅(hong)(hong)(hong)(hong)外(wai)(wai)(wai)(wai)輻(fu)射功率都是穩定可(ke)靠的(de)(de)。
防護(hu)罩對紅外(wai)燈的效果也(ye)有(you)影響，紅外(wai)光在傳輸過程(cheng)中，通過不(bu)同介質，透射(she)(she)率(lv)和(he)反射(she)(she)率(lv)也(ye)不(bu)同。不(bu)同的視窗玻(bo)璃(li)，特別是(shi)自動(dong)除(chu)霜鍍膜玻(bo)璃(li)，對紅外(wai)光的衰減也(ye)不(bu)同。
如果您對我們的LED紅外燈感興趣或有疑問，請點擊聯系我們左側、右側客服或致電：400-988-6577，城銘科技-專注于視頻監(jian)控(kong)領域的LED補光燈第一品牌.
