User Guide

RH-51/52, RH-67/68 Company Confidential

6(a) - Baseband Troubleshooting Nokia Customer Care

Camera module troubleshooting

A fault associated to camera operation can be roughly categorized to three subgroups:

43 Camera is not functional at all, no image can be obtained.

44 Images can be taken but there is nothing recognizable in them.

45 Images can be taken and they are recognizable but for some reason the quality of

images is seriously degraded.

Image quality is very hard to measure quantitatively, and even comparative measure-

ments are difficult (comparing two images) if the difference is small. Especially, if the

user is not satisfied with his/her device’s image quality, and tells e.g. that the images are

not sharp, it is very difficult to test the device and get an exact figure which then would

tell if the device is OK or not.

Most often, subjective evaluation has to be used for finding out if a certain property of

the camera is acceptable or not. Some training and a correctly operating reference

device maybe needed in order to detect what actually is wrong, or is there anything

wrong at all. It is easy for the user to take bad looking images in bad conditions; thus the

camera operation has to be checked always in constant conditions (lighting, tempera-

ture) or by using a second, known to be good device as a reference. Experience signifi-

cantly helps in analysing image quality.

Terms

Dynamic range: The camera’s ability to capture details in dark and bright areas of the

scene simultaneously.

Exposure time: The camera modules use silicon sensor to collect light and for forming

an image. The imaging process roughly corresponds to traditional film photography, in

which exposure time means the time during which the film is exposed to the light com-

ing through optics. Increasing the time will allow for more light hitting the film and thus

results in brighter image. The operation principle is exactly the same with silicon sensor,

but the shutter functionality is handled electronically, i.e. there is no mechanical moving

parts like in film cameras.

Flicker: A phenomenon, which is caused by pulsating in scene lighting, typically appear-

ing as wide horizontal stripes in image.

Noise: Variation of response between pixels with the same level of input illumination.

See e.g. Figure “Noisy image taken in +70deg” for an example of a noisy image.