* Ignore: To completely disregard or pay no attention to.
* Overlook: To fail to notice or consider.
* Miss: To fail to see or understand.
* Disregard: To pay no attention to.
* Neglect: To fail to care for or attend to.
* Dismiss: To reject or put aside without consideration.
* Oblivious: Unaware of or not noticing.
* Indifferent: Not caring or interested.
* Unconcerned: Not worried or troubled.
* Unmindful: Not paying attention.
The best antonym depends on the specific context in which "envision" is used.