Correction of random noise

Periodic line dropouts and striping are forms of non-random noise that may be recognized and restored by simple means. Random noise, on the other hand, requires a more sophisticated restoration method, such as filter operations.

Random noise or spike noise may be caused by errors during transmission of data or a temporary disturbance. Here, individual pixels acquire DN values that are much higher or lower than the surrounding pixels. In the image, these pixels produce bright and dark spots that interfere with information extraction procedures.

A spike noise can be detected by mutually comparing neighbouring pixel values. If neighbouring pixel values differ by more than a specific threshold margin, it is designated as spike noise and the DN is replaced by an interpolated DN.