Use of A Portable Camera for Proximal Soil Sensing with Hyperspectral Image Data

In soil proximal sensing with visible and near-infrared spectroscopy, the currently available hyperspectral snapshot camera technique allows a rapid image data acquisition in a portable mode. This study describes how readings of a hyperspectral camera in the 450–950 nm region could be utilised for estimating soil parameters, which were soil organic carbon (OC), hot-water extractable-C, total nitrogen and clay content; readings were performed in the lab for raw samples without any crushing. As multivariate methods, we used PLSR with full spectra (FS) and also combined with two conceptually different methods of spectral variable selection (CARS, “competitive adaptive reweighted sampling” and IRIV, “iteratively retaining informative variables”). For the accuracy of obtained estimates, it was beneficial to use segmented images instead of image mean spectra, for which we applied a regular decomposing in sub-images all of the same size and k-means clustering. Based on FS-PLSR with image mean spectra, obtained estimates were not useful with RPD values less than 1.50 and R2 values being 0.51 in the best case. With segmented images, improvements were marked for all soil properties; RPD reached values ≥ 1.68 and R2 ≥ 0.66. For all image data and variables, IRIV-PLSR slightly outperformed CARS-PLSR.

[1]  Kenshi Sakai,et al.  A ground-based hyperspectral imaging system for characterizing vegetation spectral features , 2008 .

[2]  S. Buckley,et al.  Close-range hyperspectral imaging for geological field studies: workflow and methods , 2013 .

[3]  J. A. Hartigan,et al.  A k-means clustering algorithm , 1979 .

[4]  E. Ben-Dor,et al.  Laboratory, field and airborne spectroscopy for monitoring organic carbon content in agricultural soils , 2007 .

[5]  José A. M. Demattê,et al.  Variation of Routine Soil Analysis When Compared with Hyperspectral Narrow Band Sensing Method , 2010, Remote. Sens..

[6]  A F Goetz,et al.  Imaging Spectrometry for Earth Remote Sensing , 1985, Science.

[7]  Zou Xiaobo,et al.  Variables selection methods in near-infrared spectroscopy. , 2010, Analytica chimica acta.

[8]  H. Ramon,et al.  On-line measurement of some selected soil properties using a VIS–NIR sensor , 2007 .

[9]  W. Amelung,et al.  Sensing of Soil Organic Carbon Using Visible and Near‐Infrared Spectroscopy at Variable Moisture and Surface Roughness , 2014 .

[10]  Michael Vohland,et al.  Determination of soil properties with visible to near- and mid-infrared spectroscopy: Effects of spectral variable selection , 2014 .

[11]  Hongdong Li,et al.  Key wavelengths screening using competitive adaptive reweighted sampling method for multivariate calibration. , 2009, Analytica chimica acta.

[12]  Dong-Sheng Cao,et al.  A strategy that iteratively retains informative variables for selecting optimal variable subset in multivariate calibration. , 2014, Analytica chimica acta.

[13]  R. J. Hanks,et al.  REFLECTION OF RADIANT ENERGY FROM SOILS , 1965 .

[14]  M. Steffens.  Laboratory imaging spectroscopy of a stagnic Luvisol profile - high resolution soil characterisation , 2013 .

[15]  Liang Gao,et al.  Snapshot advantage: a review of the light collection improvement for parallel high-dimensional measurement systems , 2012, Optical engineering.

[16]  Yiyun Chen,et al.  Estimating Soil Organic Carbon Using VIS/NIR Spectroscopy with SVMR and SPA Methods , 2014, Remote. Sens..

[17]  A. McBratney,et al.  Near-infrared (NIR) and mid-infrared (MIR) spectroscopic techniques for assessing the amount of carbon stock in soils – Critical review and research perspectives , 2011 .

[18]  Martin Körschens,et al.  Turnover of soil organic matter (SOM) and long‐term balances — tools for evaluating sustainable productivity of soils , 1998 .

[19]  R. V. Rossel,et al.  Using data mining to model and interpret soil diffuse reflectance spectra. , 2010 .

[20]  A. Ashworth,et al.  Organic substrate, clay type, texture, and water influence on NIR carbon measurements , 2016 .

[21]  P. Geladi,et al.  Linearization and Scatter-Correction for Near-Infrared Reflectance Spectra of Meat , 1985 .

[22]  Juliane Bendig,et al.  Low-weight and UAV-based Hyperspectral Full-frame Cameras for Monitoring Crops: Spectral Comparison with Portable Spectroradiometer Measurements , 2015 .

[23]  M. Schaepman,et al.  Spectral reflectance based indices for soil organic carbon quantification , 2008 .

[24]  P. Magnan.  Detection of visible photons in CCD and CMOS: A comparative view , 2003 .

[25]  R. Barnes,et al.  Standard Normal Variate Transformation and De-Trending of Near-Infrared Diffuse Reflectance Spectra , 1989 .

[26]  Nigel P. Fox,et al.  Progress in Field Spectroscopy , 2006, 2006 IEEE International Symposium on Geoscience and Remote Sensing.

[27]  L. Hoffmann,et al.  Measuring soil organic carbon in croplands at regional scale using airborne imaging spectroscopy , 2010 .

[28]  Michael Vohland,et al.  The Use of Laboratory Spectroscopy and Optical Remote Sensing for Estimating Soil Properties , 2010 .

[29]  Lutgarde M. C. Buydens,et al.  The potential of field spectroscopy for the assessment of sediment properties in river floodplains , 2003 .

[30]  Alex B. McBratney,et al.  Laboratory evaluation of a proximal sensing technique for simultaneous measurement of soil clay and water content , 1998 .

[31]  Gilles Rabatel,et al.  Potential of field hyperspectral imaging as a non destructive method to assess leaf nitrogen content in Wheat , 2011 .

[32]  Edward J. Milton,et al.  Principles of field spectroscopy , 1987 .

[33]  Wouter Saeys,et al.  Potential for Onsite and Online Analysis of Pig Manure using Visible and Near Infrared Reflectance Spectroscopy , 2005 .

[34]  P. Lagacherie,et al.  Estimation of soil clay and calcium carbonate using laboratory, field and airborne hyperspectral measurements , 2008 .

[35]  S. Wold,et al.  PLS-regression: a basic tool of chemometrics , 2001 .

[36]  Eyal Ben-Dor,et al.  Near-Infrared Analysis as a Rapid Method to Simultaneously Evaluate Several Soil Properties , 1995 .

[37]  T. Jarmer,et al.  Quantitative analysis of soil chemical properties with diffuse reflectance spectrometry and partial least-square regression: A feasibility study , 2003, Plant and Soil.

[38]  Antoine Stevens,et al.  Assessment and monitoring of soil quality using near‐infrared reflectance spectroscopy (NIRS) , 2009 .

[39]  Suzelle Barrington,et al.  Shadow analysis: A method for measuring soil surface roughness , 2008 .

[40]  Michael Vohland,et al.  Snapshot Hyperspectral Imaging for Soil Diagnostics – Results of a Case Study in the Spectral Laboratory , 2014 .