1. A method comprising: receiving a first set of measurement signals associated with measurements of a first plurality of small metrology targets and a plurality of large metrology targets associated with a plurality of metrology target pairs located on a surface of a specimen, wherein each of the metrology target pairs includes one or more small metrology targets and one or more large metrology targets located in close proximity to one another, and wherein each small metrology target occupies a smaller area than each large metrology target; training a signal reconstruction model that maps the measurement signals collected from the first plurality of small metrology targets to the measurement signals collected from the plurality of large metrology targets; receiving a second set of measurement signals associated with measurements of a second plurality of small metrology targets located on the surface of the specimen; and determining reconstructed measurement signals for each small metrology target of the second plurality of small metrology targets based on the second set of measurement signals and the trained signal reconstruction model.