## Facts

- LizardTech, Inc. asserted U.S. Patent No. 5,710,835, directed to performing discrete wavelet transforms (DWT) on large tiled digital images in a memory-efficient manner while producing a “seamless” transform without tile-boundary artifacts.
- The patent described achieving seamlessness by computing coefficients outside a tile and maintaining/combining “updated sums” of coefficients in overlapping regions across tile boundaries.
- Earth Resource Mapping’s ER Mapper software performed a memory-efficient seamless DWT using a different approach, processing the full image by rows and columns while keeping limited data in memory, without using the patent’s “updated sums” technique.
- LizardTech sued ERM in the Western District of Washington for infringement of several claims, including claims directed to the seamless DWT approach.
- The district court granted summary judgment to ERM, finding noninfringement and invalidity for certain claims based on failure to satisfy the written description requirement.
- LizardTech appealed to the Federal Circuit.

## Issues

1. Whether ER Mapper infringed the asserted patent claims, either literally or under the doctrine of equivalents.
2. Whether broad claims (including claim 21 and dependent claims) were invalid under 35 U.S.C. § 112 for lack of written description where the specification disclosed only one method of achieving a seamless DWT.

## Decision

- The Federal Circuit affirmed summary judgment of noninfringement.
- The court held ER Mapper did not literally infringe because it did not practice the claimed “maintaining updated sums” method across tile boundaries.
- The court rejected infringement under the doctrine of equivalents where applying equivalence would effectively extend the claims to cover any seamless DWT method untethered to the disclosed algorithm.
- The Federal Circuit affirmed invalidity of claim 21 and dependent claims for lack of written description under 35 U.S.C. § 112.

## Legal Principles

- Written description is a distinct requirement from enablement and demands that the specification demonstrate the inventor’s possession of the claimed invention as of the filing date.
- A specification that discloses a single specific method for achieving a result does not, without additional disclosure, support claims drafted to cover all methods of achieving that result.
- A patentee cannot claim a broad functional genus when only a single species is described, absent disclosure indicating possession of other implementations within the claimed scope.
- The doctrine of equivalents cannot be used to effectively obtain coverage broader than what the specification supports under § 112.

## Conclusion

The Federal Circuit affirmed that ERM’s different seamless DWT technique did not infringe and held broad “seamless DWT” claims invalid because the patent’s disclosure showed possession only of a particular “updated sums” approach, not all ways of producing a seamless result.


LizardTech, Inc. v. Earth Res. Mapping, Inc., 424 F.3d 1336 (Fed. Cir. 2005)