The current version of omcomb combines the four image segments generated by the full-frame low resolution mode into a single image, which the OM imaging chain task, OMICHAIN, can then process.
This task was originally written for use by the OM slew-chain task in the process of building a complete OM flat-field: there it combined the 4 science windows from a single exposure, to produce 1/4 of a complete OM flat-field. Subsequently, a new, full-frame low-resolution OM science mode has been introduced, (also known as Engineering-2 mode), in which a single exposure of the whole field of view is acquired at low resolution using BPE (electronic) binning. The resulting image, 1024x1024 pixels, is telemetered as a sequence of four separate, but adjacent rectangular segments, each 256x1024 pixels in size. A requirement therefore arose for a task in the OM imaging-chain to recombine the four full-frame low-resolution mode image segments into a single image, and since at the present time the OM slew-chain task is disabled, omcomb has been modified to perform this task. As and when slew processing is again needed to produce flat-fields, that functionality will be re-instigated in omcomb so that it can perform either task.