Method for formatting partially overlapping holograms

DETAILED DESCRIPTION In one embodiment of the present invention, a method of writing holograms includes: numbering sections in sequence, where each section has a spatial projection onto a holographic medium; and writing at least one hologram in each of the sections in sequence.
Writing in two sections with adjacent spatial projections provides a substantially uniform exposure level for a sequentially subsequent section with a spatial projection that overlaps the two sections.
According to one aspect, one or more holograms can be tested to determine the available dynamic range for recording additional holograms.
For example, a test hologram can be measured to determine its efficiency from which an available dynamic range can be estimated for the corresponding location in the holographic medium.
An exposure schedule at that location then can be correspondingly adjusted.
Similarly, multiple test holograms can be measured to determine available dynamic ranges and exposure schedules at multiple locations.
According to another aspect, additional sections of the holographic medium can be exposed just for the purpose of maintaining a substantially uniform exposure level when sequentially writing holograms in the numbered sections.
For example a bookend of additional sections near a boundary of a shelf of the numbered sections can be exposed to provide a substantially uniform exposure level when writing holograms in the shelf in sequence near the boundary.
Each additional section similarly has a spatial projection onto the holographic medium and overlaps at least one section of the shelf.
In another embodiment of the present invention, a holographic medium tangibly embodies holograms in a sectional format.
The format includes: multiple sections, where each section has a spatial projection onto the holographic medium and each section has a sequence number for storing holograms in sections; and at least one hologram in at least one section, where each section has an exposure level corresponding to holograms therein