Image Quality Analysis; Testing For Dust In Camera Module - Nokia RM-51 Service Manual

RM-51
Nokia Customer Care Camera module troubleshooting
Examples of good quality images
Figure 167 Good image taken indoors
Figure 168 Good image taken outdoors

Image quality analysis

Testing for dust in camera module

Context
For detecting these kinds of problems, take an image of a uniform white surface and analyse it in full resolution.
A good quality PC monitor is preferred for analysis. Search carefully, since finding these defects is not always
easy. Figure Effects of dust on optical path (Page 8–11) is an example of an image containing easily detectable
dust problems.
When taking a white image, use uniformly lightened white paper or white wall. One possibility is to use uniform
light but in this case make sure that the camera image is not flickering when taking the test image. In case
flickering happens, try to reduce illumination level. Use JPEG image format for analysing, and set the image
quality parameter to 'High Quality'.
Black spots in an image are caused by dirt particles trapped inside the optical system. Clearly visible and sharp
edged black dots in an image are typically dust particles on the image sensor. These spots are searched for in
the manufacturing phase, but it is possible that the camera body cavity contains a particle, which may move
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