Referencing in multi-acquisition slide imaging

Referencing of image acquired in multiple rounds of imaging is disclosed. In certain implementations, a baseline round of images are acquired and registered to one another to establish a global transformation matrix. In a subsequent round of image acquisition, a limited number of field of view images are initially acquired and registered to the corresponding baseline images to solve for translation, rotation, and scale. The full set of baseline images is then acquired for the subsequent round and each image is pre-rotated and pre-scaled based on the transform determined for the subset of images. The pre-rotated, pre-scaled images are then registered using a translation-only transform.