1. A method comprising: identifying a plurality of first data points in a lookup table, the lookup table being stored in memory, the lookup table including a plurality of second data points associated with respective values, the plurality of first data points each being associated with respective values that are associated with each other using a table gradient constraint, the plurality of first data points each being located in a location that does not correspond to a location of any of the plurality of second data points, and the identifying being performed by a processor executing stored instructions; generating, using interpolation and based on the plurality of first data points and the plurality of second data points, a surface, the generated surface including the plurality of first data points, and the generating being performed by the processor executing the stored instructions; estimating a plurality of interpolated values, each of the plurality of interpolated values being estimated using the generated surface including the plurality of first data points, and the estimating being performed by the processor executing the stored instructions the; establishing a first boundary, the first boundary including a first set of the plurality of first data points, the first set of the plurality of first data points including less than all of the plurality of first data points, and the establishing the first boundary being performed by the processor executing the stored instructions; establishing a second boundary, the second boundary including a second set of the plurality of first data points, the second set of the plurality of first data points including less than all of the first set of the plurality of first data points, and the establishing the second boundary being performed by the processor executing the stored instructions; applying the table gradient constraint to the second set of the plurality of first data points included in the second boundary to generate constrained values, the table gradient constraint constraining the second set of the plurality of first data points included in the second boundary to maintain variation among the second set of the plurality of first data points included the second boundary, the applying being performed by the processor executing the stored instructions; and storing the generated constrained values, the storing being performed by the processor executing the stored instructions.