With the increasing use of digital imagery that is independent of TV, new methods are continually being introduced. Just as in halftoning, coding schemes that exploit the lowpass spatial response of the eye have been suggested for image coding. In subband coding [313], the image is split into orthogonal subbands with varying frequency content. The subbands are then quantized with fewer bits allocated to higher frequency components. VQ techniques, similar to those described in the earlier section on palettization, can be used for the quantization. Known anisotropy in the eye's spatial response can also be utilized. The lower sensitivity of the eye along the 45 angle, permits fewer bits to be allocated to frequency bands located on the diagonal. This idea is easily extended to color images. However, complete **data** on the spatial frequency response of the eye to spatial color (chromatic) frequencies has only recently been published. The combination of subband coding with color spatial frequency response was presented in [314] and [315].