Nokia NHL-10 Baseband Troubleshooting And Manual Tuning Manual page 35

NHL-10
Baseband Troubleshooting CCS Technical Documentation
scene objects. In practice, the operation is such that close objects may be noticed to get more
blurred when the distance to them is shortened from 40 cm. Lack of sharpness will be first vis-
ible in full resolution (VGA) images. If observing just the viewfinder, even very close objects
may seem to appear sharp.
Sharpness of picture edges:
Lens performance degrades in image edges, and generally the image is sharpest in centre
part. This applies particularly to distant objects (> 1 meter).
See below:
Figure 26: Sharpness of picture is worse in edge than in centre
Geometrical distortion:
The camera lens will cause some amount of so called barrel distortion in images. In practice,
this appears as bending of straight objects in edges of the image.
See the following figure. Note the geometrical barrel distortion in background, for example (wall
in the background).
Amount of light available:
In dim condition camera runs out of sensitivity. Exposure time is long (especially in night mode)
and the risk of getting shaken images grows. Image noise level grows. The maximum exposure
time in night mode is approximately ¼ seconds, so images need to be taken with extreme care
when the amount of light reflected from the target is low.
ISSUE 2 01/2004 COMPANY CONFIDENTIAL 35
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