My experience is with CCD used in broadcast TV cameras. In this area, the CCDs normally have the dead pixels very early in their use. It is something that we check right out of the box. After first use, they tend to be fairly stable. However, it is not unheard of as a CCD is an analog device after all and it may deteriorate like any analog device does.
A second thought is that the dead pixel was there all the time and that the firmware in the camera was able to compensate for it. Then, after constant use, it became worse and the firmware was no longer able to eliminate its effects.
A third thought is that it is not a dead pixel at all. Often, the black paint inside the lens delaminates with varying temperature changes over time. Maybe it is a spot on the optics or on the CCD faceplate. I do not recall off the top of my head right now, but I think that dead pixels are white and dirt, dust and marks are black. I may have it reversed. Maybe someone more expert can offer a thought or clarification here?
In any case, a visit to the manufacturer sounds warranted. |
