An Instantaneous-Profile Laser Scanner to Measure Soil Surface Microtopography
Frédéric Darboux*,a and
Chi-hua Huangb
a Purdue University, presently at: INRA-Science du sol, B.P. 20619, F-45166 Olivet Cedex, France
b USDAARS, National Soil Erosion Research Laboratory, 1196 Soil Bldg., Purdue University, West Lafayette, IN 47907-1196

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Fig. 1. Layout of the instantaneous profile laser scanner.
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Fig. 2. Position of calibration and validation points viewed by the camera in (a) the (x, z) geometric coordinate, and (b) (column, row) camera pixel coordinate.
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Fig. 3. Position of the measured and estimated points in the laser-beam plane for the calibration and validation points.
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Fig. 4. Resolutions of the laser scanner in millimeters, shown as contours, for (a) horizontal direction (with width of the profile) and (b) vertical direction (with height of the profile from the bottom edge of the picture).
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Fig. 5. Frequency distribution of the accuracy/resolution ratio for the calibration (a and b) and validation (c and d) points in the x and z directions.
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Fig. 6. Distribution of static noise at an acquisition rate of (a) 6.5 Hz and (b) 0.15 Hz.
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Fig. 7. Accuracy analysis of the laser scanner showing (a) absolute accuracy from the distribution of measured heights obtained using a stairlike shape object with 5-mm high steps; and (b) relative accuracy from the distribution of height differences form two digital elevation models (DEMs) of the same soil surface.
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Fig. 8. Successive laser-scanned surface topography displaying the progression of a head cut from an area 35 cm wide by 70 cm long. Heights are represented in gray levels with darker tones for lower elevations (maximal height range: 44 mm). The black areas are missing values because of the shadow effect.
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Copyright © 2003 by the Soil Science Society of America.