For the unrelated piece of technology, please see pattern enhancer.
The molecular pattern enhancer was a facility 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, enabling him literally to see through her lie. (TNG: "The Masterpiece Society")