Using the mobile phone as Munsell soil-colour sensor: An experiment under controlled illumination conditions
Using the mobile phone as Munsell soil-colour sensor: An experiment under controlled illumination conditions
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DOI：
10.1016/j.compag.2013.10.002
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发表时间：
2013-11-01
影响因子：
8.3
通讯作者：
Sanchez-Maranon, Manuel
中科院分区：
文献类型：
--
作者：
Gomez-Robledo, Luis;Lopez-Ruiz, Nuria;Sanchez-Maranon, Manuel
在大多数情况下，土壤颜色是通过使用孟塞尔土壤颜色图来确定的，有时使用分光计，有时使用数码相机。这里的目的是评估移动电话是否也能够在受控照明下提供对土壤颜色的客观评估，因为移动电话具有捕捉和处理数字图像的所有要求。为此，我们开发了一个Android应用程序，它可以拍摄土壤样本的照片，允许用户选择感兴趣的区域，然后，经过RGB图像处理和颜色空间之间的多项式处理转换，孟塞尔(HVC)和CIE(XYZ)坐标显示在手机屏幕上。通过这种方式，HTC的一款商用智能手机估计了60个碎土样本的颜色，范围在2.9年到2.3年之间，平均误差为3.75+/-1.81 CIELAB单位，并参考了光谱仪进行的颜色测量。孟塞尔色调的估计最差(平均误差为2.72+/-1.61个孟塞尔单位)，因为它与RGB颜色空间几何不匹配，并且被定义为光源C，不同于手机相机拍摄照片的D65光源。由于测量误差低于文献中描述的土壤颜色视觉测定的误差，并且该应用程序也在与其开发中使用的智能手机不同的智能手机上成功运行，因此我们认为，目前的实验结果鼓励了将智能手机用作土壤颜色传感器的期望。(C)2013爱思唯尔B.V.保留所有权利。
Soil colour has been determined in most cases by using Munsell soil-colour charts, sometimes with spectrometers, and occasionally with digital cameras. The objective here is to assess whether a mobile phone, which has all the requirements to capture and process digital images, might also be able to provide an objective evaluation of soil colour under controlled illumination. For this, we have developed an Android application that takes a picture of a soil sample, allowing the user to select the region of interest and then, after a RGB image-processing and a polynomial process transform between colour spaces, the Munsell (HVC) and CIE (XYZ) coordinates appear on the screen of mobile phone. In this way, a commercial HTC smartphone estimated the colour of 60 crumbled soil samples between 2.9YR and 2.3Y with a mean error of 3.75 +/- 1.81 CIELAB units, taking as a reference the colour measurements performed with a spectroradiometer. The Munsell hue had the worst estimates (mean error of 2.72 +/- 1.61 Munsell units) because of its geometric mismatch with the RGB colour space and for being defined to illuminant C, different of the D65 source under which the phone camera took the pictures. Because the measuring errors were lower than those described in the literature for the visual determination of soil colour, and the application also worked successfully in a different smartphone than the one used in its development, we think that current experimental results encourage the expectations of using smartphones in the field as soil-colour sensors. (C) 2013 Elsevier B.V. All rights reserved.