### ODDEVEN

Removes odd-even defects from a one-dimensional NDF

#### Description:

This application forms a smoothed signal for a one-dimensional NDF whose elements have oscillating biases. It averages the signal levels of alternating pixels. Both elements must be good and not deviate from each other by more than a threshold for the averaging to take place.

This application is intended for images exhibiting alternating patterns in columns or rows, the so called odd-even noise, arising from electronic interference or readout through different channels. However, you must supply a vector collapsed along the unaffected axis, such that the vector exhibits the pattern. See task COLLAPSE using the Mode or Median estimators. The smoothed image is then subtracted from the supplied vector to yield the odd-even pattern.

#### Usage:

oddeven in out [thresh]

#### Parameters:

The one-dimensional NDF containing the input array to be filtered.
##### OUT = NDF (Write)
The NDF to contain the filtered image.
The maximum difference between adjacent elements for the averaging filter to be applied. This allows anomalous pixels to be excluded. If null, !, is given, then there is no limit. [!]
The title of the output NDF. A null (!) value means using the title of the input NDF. [!]

#### Examples:

oddeven raw clean
The one-dimensional NDF called raw is filtered such that adjacent pixels are averaged to form the output NDF call clean.
oddeven out=clean in=raw thresh=20
As above except only those adjacent pixels whose values differ by no more than 20 are averaged.

#### Related Applications

KAPPA: BLOCK, CHPIX, FFCLEAN, GLITCH, ZAPLIN; FIGARO: BCLEAN, CLEAN, ISEDIT, TIPPEX.