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height 
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Pickup et al. (1995) indicated that a single equation, based on 
view angle, can be used for scene-brightness normalisation. 
Their findings show that this produces results better than the 
commonly used band-ratio techniques. This method was tried 
with data collected at another minesite but to date the results 
have not been thoroughly analysed. 
The mining industry is vital to the Australian economy, but 
mining activity inevitably causes environmental impacts. 
Usually the miner must rehabilitate areas of disturbance to a 
condition satisfactory to the relevant government legislation. In 
Comalco’s bauxite mines at Weipa and Andoom, North 
Queensland, Australia, DMSV data were collected by 
SpecTerra Systems (STS) in November, 1994. This system was 
chosen because it gives a non-invasive, high-resolution, timely 
and cost-effective method of quantitatively monitoring a large- 
scale rehabilitation operations. 
À total of 196 frames of DMSV data, each being approximately 
1x1.5 kilometre. with 2 metre spatial resolution, were collected 
over the Weipa and Andoom minesites on the 12th, 13th and 
14th of November, 1994. The objective was to produce digital 
and photographic mosaics for quantitative measurement of the 
vegetation status. Before this could be achieved, it was 
necessary to remove ‘artefacts’ inherent in the DMSV data, of 
which shading is the most significant. 
For this work spaceborne data, acquired at about the same time 
(10th November, 1994) as the DMSV image, were used as 
uniformly illuminated ‘flat’ image to derive a shading surface 
for correcting the DMSV data. Landsat TM bands 1, 2, 3, and 
4 have band-centres close to the band-centres of the DMSV 
(Table 1). The correction method exploits this similarity by 
correlating the DMSV data with the near-simultaneously 
acquired TM imagery. The wavebands of the field radiometer, 
used for the calibration of the DMSV images, are also included 
in Table 1. 
  
  
Methods 
Table 1: Wavelengths of Landsat TM, DMSV and Exotech Radiometer bands 
| Sensor band 1 band 2 band 3 band 4 
Landsat TM 450 - 520 (nm) 520 - 600 (nm) 600 - 690 (nm) 760 - 900 (nm) 
DMSV 438 - 462 (nm) 538 - 562 (nm) 638 - 762 (nm) 758 - 782 (nm) 
Exotech | -..450 - 480 (nm) 500 - 600 (nm) 600 - 700 (nm) 700 - 800 (nm) 
  
  
  
  
  
  
  
  
All solar-illuminated remotely sensed data exhibit some amount 
of differential shading. However, it is assumed for this 
correction method, that the shading variation is insignificant in 
the portion of the Landsat TM image used for correcting the 
DMSV dataset. Figure 2 illustrates a hypothetical illumination 
curve across a Landsat TM image. Although this differential 
Grey 
Level 
   
  
i 
shading would be significant were the whole of this image used 
in the analysis, for a small portion of it the shading can be 
assumed negligible. Figure 3 compares the Landsat TM subset 
used with a DMSV frame. As illustrated, the area used for the 
correction is small and the shading is negligible therefore the 
shading curve across this subset is assumed to be “flat”. 
Sun 
  
Hot 
Spot 
i 
Distance across track 
7 
Figure 2. Shading across a Landsat TM frame, for a given sun elevation angle 6°. 
283 
International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B2. Vienna 1996