For the unrelated piece of technology, please see pattern enhancer.
The molecular pattern enhancer was a part of Geordi La Forge's VISOR. It permitted objects' molecules to be scanned in minute detail.
In 2368, when Hannah Bates claimed there was a breach in Genome colony's biosphere, La Forge told her that the VISOR's molecular pattern enhancer would have picked up even the smallest crack, and literally saw through Bates' lie. (TNG: "The Masterpiece Society")