Jab to RGB multidimensional lookup tables

The CIECAM color appearance space (Jab) is widely used in color science. The relationship between XYZ and Jab is defined by a set of equations. For ease of computation and architectural flexibility, it is desirable to implement these relationships in multi-dimensional lookup table form. Unfortunately, for some colors just outside the sRgb gamut, these equations give complex numbers. Furthermore, to include colors that printers can produce, a transformation between Jab and a wider gamut RGB is necessary. Such a table would contain problematical colors. To solve this problem we accurately reproduce the CIECAM results within a gamut of reasonable colors. Nodes just outside the gamut are used when interpolating to find colors just inside the gamut so they are also affected by the accuracy constraint. All the nodes outside the gamut are also subjected to a smoothness constraint. Both RGB to Jab and Jab to RGB tables have been produced for a wide gamut RGB, and give quite accurate results.