262 CHAPTER 8. APPLICATIONS
be pointed out that in dye-mixing processes, the desired color match is obtained
by systematically adding the colorants until the desired color is obtained. Since
adjustments in color cannot be made by removing the colorant once it has been
applied to a sample, the initial concentrations of the colorant need to be less
than those specified by the standard to assure an additive mixing process.
Figure 8.11. Convergence of the tristimulus values of the sample to the desired
X 0 ,Y 0 ,andZ 0
Another important issue in dye mixing processes is that other additives
are required for pH control, mixture consistency, etc., and to develop proper
bonding characteristics between the colorant mixture and the sample substrate.
To include the effect of these additives, an additional set of FAMs similar to
that shown in Table 8.3 should be incorporated into the schematic shown in
Figure 8.9.
In the simulation study, no attempts were made to optimize the performance
of the fuzzy controller to yield a ìcriticalî response in the color matching process.
This can be achieved by adjusting the membership functions appropriately to
produce a faster convergence and thereby minimizing the number of samples
that need to be examined under a spectrophotometer.
The proposed methodology can be easily implemented using commercially
available fuzzy rule chips that include appropriate AID and DIA converters and
other associated electronic components. The fuzzy logic hardware, the dye-
mixing process, and spectrophotometerand associated accessories can all be
integrated into a single color mixing and matching unit.
8.4 Identification of trash in cotton
In order to maintain uniform cotton quality, the cotton industry adheres to
standards for cotton classification based on several quality factors. The pres-
ence of any extraneous material adversely affects some of these quality factors.
Mechanically harvested cotton contains large quantities of trash in addition to
useful cottonfiber. The ginning process separates cottonfiber from trash mate-
rial, and various cleaning machines are used to remove the trash. Classification
of trash objects at critical locations in the ginning process can be used for the