next up previous contents index
Next: rotaffin Up: Reference Previous: prolate   Contents   Index

resthline

$ \bigcirc$Name


resthline Restore infrared-type images by suppressing horizontal line effects




$ \bigcirc$Command Synopsis


resthline input output



input : input image

output : output image




$ \bigcirc$Function Summary


void resthline (u , v )

Cimage u , v ;




$ \bigcirc$Description


This module removes artefacts due to grey-level shifts between horizontal lines. This problem often ocuurs with infrared images, when the captors have not been equalized. The correction is simple : from an input image u, we find the parameter k(y) so that the total variation of the output image v(x, y) = u(x, y) + k(y) is as small as possible. The algorithm minimizes the quantity $ \sum_{x}^{}$| u(x, y + 1) + $ \delta$(y) - u(x, y)| with respect to $ \delta$ along each line, then retrieves k(y) by k(y + 1) = k(y) + $ \delta$(y), and chooses k(0) in order to preserve the global mean of the input image u.




$ \bigcirc$Version 1.0


Last Modification date : Thu Nov 29 20:23:56 2001


$ \bigcirc$Author


Lionel Moisan






next up previous contents index
Next: rotaffin Up: Reference Previous: prolate   Contents   Index
mw 2004-05-05