Abstract: This study proposed to identify and investigate optimality of Discrete Cosine Transform (DCT) based Gradient Vector Flow (GVF) active contours and this research is expected to yield a robust technique which can be used to boundary map chromosome images having variability in shape and size, from chromosome spread images. Weak edges are also manifested here. GVF field active contours are found to have good convergence properties. The energy compaction is enhanced by incorporating the DCT into the segmentation scheme. A unique set of parameter values for the technique is required for boundary mapping every chromosome image. Characterization studies have shown that an optimal range of values exists for each parameter within which good boundary mapping results can be obtained for various chromosomes in similar class of images.