  The Pan-STARRS1 Science Consortium have carried out a set of imaging surveys
using the 1.4 giga-pixel GPC1 camera on the PS1 telescope. As this camera is
composed of many individual electronic readouts, and covers a very large field
of view, great care was taken to ensure that the many instrumental effects were
corrected to produce the most uniform detector response possible. We present
the image detrending steps used as part of the processing of the data contained
within the public release of the Pan-STARRS1 Data Release 1 (DR1). In addition
to the single image processing, the methods used to transform the 375,573
individual exposures into a common sky-oriented grid are discussed, as well as
those used to produce both the image stack and difference combination products.
