Technical Abstract: Sorting pistachio kernels from in-shell pistachios currently requires automated and hand sorting, an expensive and labor-intensive two-stage process. This paper examines the feasibility and effectiveness of using color imaging as a basis for identifying both regular and small in-shell pistachio nuts from kernels in the pistachio nut process stream. Color imaging would provide the basis for a low cost, high speed sorting device. Two methods were used to distinguish the images of in-shell and small in-shell nuts from kernels. The first method was a discriminant analysis (DA) algorithm, and resulted in a 98.7% overall accuracy for separating regular in-shell pistachio nuts and kernels. The errors were exclusively false negatives (fn), no false positives (fp) were made. Small in-shell pistachio nuts were harder to discriminate from kernels, resulting in an overall accuracy of 80.7%, with 1.99% fp and 17.31% fn. The second method used a k-nearest neighbors (knn) algorithm. The overall accuracy for knn was 96.2% for kernels and 95.8% for small in-shell nuts. With careful selection of features this method shows promise for providing a cheaper, high speed method for sorting kernels from in-shell pistachio nuts.