Hierarchical Error Diffusion (HED) developed in  yields high-quality color halftone by explicitly designing three
critical factors: dot overlapping, positioning, and coloring. However, HED requires more error memory buffer than the
conventional error diffusion algorithms since the pixel error is diffused in dot-color domain, instead of colorant domain.
This can potentially be an issue for certain low-cost hardware implementation. This paper develops a memory-efficient
HED algorithm (MEHED). To achieve this goal, the pixel error in dot-color domain is converted backward and diffused
to future pixels in input colorant domain, say, CMYK for print applications. Since the error-augmented pixel value is no
longer bounded within the range [0, 1.0], the dot overlapping control algorithm developed in  needs to be
generalized to coherently handle the pixel density of outside the normal range. The key is to carefully split the modified
pixel density into three parts: negative, regular, and surplus densities. The determination of regular and surplus densities
needs to be dependent on the density of K channel, in order to maintain local color and avoid halftone texture artifact.
The resulting dot-color densities are serves as the input to hierarchical thresholding and coloring steps to generate final
halftone output. Experimental results demonstrate that MEHED achieves similar image quality compared to HED.