Harmonic coordinates for real-time image cloning

摘要

Traditional gradient domain seamless image cloning is a time consuming task, requiring the solving of Poisson’s equations whenever the shape or position of the cloned region changes. Recently, a more efficient alternative, the mean-value coordinates (MVCs) based approach, was proposed to interpolate interior pixels by a weighted combination of values along the boundary. However, this approach cannot faithfully preserve the gradient in the cloning region. In this paper, we introduce harmonic cloning, which uses harmonic coordinates (HCs) instead of MVCs in image cloning. Benefiting from the non-negativity and interior locality of HCs, our interpolation generates a more accurate harmonic field across the cloned region, to preserve the results with as high a quality as with Poisson cloning. Furthermore, with optimizations and implementation on a graphic processing unit (GPU), we demonstrate that, compared with the method using MVCs, our harmonic cloning gains better quality while retaining real-time performance.