CAJ | 학술논문

为降低背景光噪声对数字摄像法夜间能见度测量的不确定性影响，对双光源法能见度测量系统进行改进。该系统利用避光筒限制CCD相机视场角，拍摄2个位于不同距离的LED背光源，然后对摄取到的图像进行处理得到光源图像的灰度值，再根据阿拉德定律求得大气消光系数，计算出大气能见度值。通过在无背景光、有背景光未加避光筒和加避光筒3种条件下的比对实验，分析光源图像的灰度信息，并将实验结果进行处理，得出有避光筒和无避光筒时测得的能见度值与无背景光下测量结果的相关系数分别是0．9113和0．3227，均方根相对偏差分别是6．87％和23．38％。结果表明：系统抑制背景光噪声的能力明显增强，能较准确地测量夜间能见度。
위강저배경광조성대수자섭상법야간능견도측량적불학정성영향，대쌍광원법능견도측량계통진행개진。해계통이용피광통한제CCD상궤시장각，박섭2개위우불동거리적LED배광원，연후대섭취도적도상진행처리득도광원도상적회도치，재근거아랍덕정률구득대기소광계수，계산출대기능견도치。통과재무배경광、유배경광미가피광통화가피광통3충조건하적비대실험，분석광원도상적회도신식，병장실험결과진행처리，득출유피광통화무피광통시측득적능견도치여무배경광하측량결과적상관계수분별시0．9113화0．3227，균방근상대편차분별시6．87％화23．38％。결과표명：계통억제배경광조성적능력명현증강，능교준학지측량야간능견도。
In order to reduce the uncertainty caused by background light noise w hen measuring nighttime visibility using digital photogrammetric method ,the system based on double light sources was improved .An effective method was adopted to limit CCD field angle by using the shading cylinder .For obtaining the grayscales of the double LED backlights at different dis‐tances taken by CCD ,computerized image processing was applied for captured images .Then the visibility was derived from extinction coefficient acquired by Allard's law .The contrast test was done to analyze the gray information in three conditions:in dark background ,with or without shading cylinder in light background . Taken the visibility measured in dark back‐ground as the standard value ,compared with the results from using shading cylinder ,the corre‐lation coefficient and average relative errors are 0 .911 3 and 6 .87% ,w hile they are 0 .322 7 and 23 .38% without shading cylinder .It can be seen that ,the ability of restraining interference from background noise is enhanced by using shading cylinder ,thus more accurate results can be got with measuring nighttime visibility .