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首页> 外文会议>Air and Waste Management Association annual conference and exhibition >Wavelength-Dependent Opacity Measurement and Uncertainty Using Digital Cameras and Smartphones
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Wavelength-Dependent Opacity Measurement and Uncertainty Using Digital Cameras and Smartphones

机译：使用数码相机和智能手机的与波长相关的不透明度测量和不确定性

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In the U.S., opacities of plumes emitted to the atmosphere from point sources are measured using U.S. Environmental Protection Agency (U.S. EPA) Method 9. In 2012, the use of digital still cameras to measure plume opacity was approved by U.S. EPA as an alternative method (ALT 082) that is based on the ASTM D7520-09 standard. Plume opacity values obtained from pictures taken by digital still cameras is determined using the Digital Optical Method (DOM). Previous research has shown that this method can be applied to manual and automatic exposure controlled cameras and smartphones, using the greyscale pixel values (PVs) provided in the digital images. In this research, opacity values were determined for plumes generated by an Illinois EPA (D3PA) smoke generator in Springfield, IL during July 2013. Pictures were taken by a manual exposure controlled and a smartphone camera. Opacity values measured by a transmissometer in the smoke generator's stack were used as the reference values to compare with the camera/ smartphone results. New results presented here include opacity values that are calculated from PVs measured in red, green, and blue channels in addition to greyscale, using the DOM contrast model. The three-color PV analysis allows us to study the wavelength dependence of measured opacity values. Uncertainties are also quantified by performing error propagation with DOM's contrast model and considering the uncertainty of exposure due to PV averaging. Both cameras were certified for opacity measurements based on Method 9 criteria, using greyscale measurements. Opacity values measured by smartphone in red wavelengths are on average smaller than in greyscale by 5.8% for white plume and 19.1% for black plume. Conversely, opacity values measured by smartphone in blue wavelengths are on average larger than in greyscale by 8.3% for white plume and 4.0% for black plume. The extinction Angstrom exponent (a) for white plume is 1.6+1.5 (mean+standard deviation) from smartphone and 1.2±1.6 from manual exposure controlled camera; a for black plume is -0.1+0.7 from smartphone and 0.3 ±0.6 from manual exposure controlled camera. The uncertainty in opacity values due to PV averaging for the red wavelengths is the highest and for the blue wavelength lowest.
机译：在美国，使用美国环境保护署（US EPA）方法9测量从点源排放到大气中的羽流的不透明度。2012年，美国环境保护署批准使用数码相机测量羽流的不透明度是一种替代方法。 （ALT 082）基于ASTM D7520-09标准。使用数字光学方法（DOM）确定从数码相机拍摄的照片中获得的羽毛不透明度值。先前的研究表明，使用数字图像中提供的灰度像素值（PV），可以将该方法应用于手动和自动曝光控制的相机和智能手机。在这项研究中，确定了伊利诺伊州斯普林菲尔德市2013年7月伊利诺伊州EPA（D3PA）烟雾发生器产生的烟流的不透明度值。通过手动曝光控制和智能手机相机拍摄照片。由烟雾发生器烟囱中的透射仪测量的不透明度值用作参考值，以与相机/智能手机的结果进行比较。此处显示的新结果包括不透明度值，该值是使用DOM对比模型从灰度，红色，绿色和蓝色通道中测量的PV计算得出的。三色PV分析使我们能够研究测得的不透明度值的波长依赖性。还可以通过使用DOM的对比模型执行错误传播并考虑由于PV平均导致的曝光不确定性来量化不确定性。根据方法9的标准，使用灰阶测量对两台相机进行了不透明度测量的认证。通过智能手机在红色波长下测得的不透明度值平均比灰度级小白色羽流的5.8％和黑色羽流的19.1％。相反，智能手机在蓝色波长下测得的不透明度值平均比灰度级大，白羽为8.3％，黑羽为4.0％。白羽的消光埃斯通指数（a）与智能手机相比为1.6 + 1.5（均值+标准差），与手动曝光控制相机相比为1.2±1.6;对于黑羽来说，智能手机的-a为-0.1 + 0.7，手动曝光控制的相机为0.3±0.6。红色波长的PV平均导致的不透明度值的不确定性最高，蓝色波长的不确定性最高。

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