The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences. Vol. XXXVII. Part B5. Beijing 2008 
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(a) Matte black target 
3.2 Precision assessment 
The residual plots of two targets, matte black and white targets, 
are shown in Figure 4 with respect to the range from the centre, 
which is defined as the distance of a point from the centre of a 
test flat target. The nominal distance between the range camera 
and the targets is 50cm. These figures show that the precision of 
the measure points are decreased as the range from the centre 
increases. In addition, the rate of the decrement for the matte 
black target is larger than that of the matte white target. The 
maximum residuals of the first order least-squares fitting are 
8cm and 4cm for the matte black and whites targets, 
respectively. In addition, a larger number of gross outliers are 
observed in the boundaries of both targets. This demonstrates 
that the precision performance of this range camera is largely 
dependent on the radiometric characteristics of an object, i.e. 
the strength of the returned intensity by the object. 
The residuals of the first order plane fitting are also presented in 
Figure 5 with respect to the x-axis of the measurement, which is 
parallel to the surface of the flat test targets. These patterns 
again show the same result as Figure 4. In particular, a large 
amount of gross outliers were observed from the residual 
pattern at the centre of the matte white target, i.e. Figure 5b. 
This is resulted from a strong intensity return from the centre of 
the target because of the nominal incidence angle at this part of 
90° and its colour, i.e. white. 
(a) Matte black target 
(b) Matte white target 
Figure 5. Residual vs. the x-axis that is parallel to the tangential 
surface of the test target. 
3.3 Residual pattern analysis 
In this section, as another tool for the precision assessment, 
two-dimensional (2D) colour plots of the residual patterns are 
presented in Figure 6. In other words, the residual of the first 
order plane fitting were transformed to the 2D image space of 
the range camera, i.e. 176x144. 
(a) Matte black target 
(b) Matte white target 
Figure 6. Residual pattern plots (matte white), (a) The nominal 
distance between the range camera and the matte black target is 
25cm. (b) The distance of the matte white target from the 
camera is approximately 50cm. The unit of colour bar is metres. 
(b) Matte white target 
Figure 4. Residual vs. the range from the centre which is 
defined as the distance of a point from the centre of the target.