An Experimental Alteration to the CUPID:FINDBACK Algorithm
An alternative form of the basic FINDBACK algorithm can be used by setting the (undocumented) parameter NEWALG to TRUE when running FINDBACK. The new algorithm is currently being assessed to see if it gives an improvement over the basic algorithm.
The problem addressed by the algorithm change is that, when processing high signal-to-noise data, the original algorithm can over-estimate the background in the vicinity of a narrow trough (more narrow than the box size). This is illustated in the following pair of images, in which the data is shown in white and the background estimate produced by the original algorithm (with box size 20 pixels) is shown in red. The right image shows the same data, but is restricted to the lower data values.
