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Front. Inform. Technol. Electron. Eng.  2010, Vol. 11 Issue (9): 690-698    DOI: 10.1631/jzus.C1000067
    
Harmonic coordinates for real-time image cloning
Rui Wang, Wei-feng Chen*, Ming-hao Pan, Hu-jun Bao
State Key Laboratory of CAD &CG, Zhejiang University, Hangzhou 310027, China
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Abstract  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.

Key wordsSeamless cloning      Poisson’s equation      Harmonic coordinates (HCs)      Mean-value coordinates (MVCs)      GPU acceleration     
Received: 19 March 2010      Published: 07 September 2010
CLC:  TP391.41  
Fund:  Project  supported  in  part  by  the  National  Natural  Science Foundation  of  China  (No.   60903037)  and  the  National  Basic
Research Program (973) of China (No.  2009CB320803)
Cite this article:

Rui Wang, Wei-feng Chen, Ming-hao Pan, Hu-jun Bao. Harmonic coordinates for real-time image cloning. Front. Inform. Technol. Electron. Eng., 2010, 11(9): 690-698.

URL:

http://www.zjujournals.com/xueshu/fitee/10.1631/jzus.C1000067     OR     http://www.zjujournals.com/xueshu/fitee/Y2010/V11/I9/690


Harmonic coordinates for real-time image cloning

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.

关键词: Seamless cloning,  Poisson’s equation,  Harmonic coordinates (HCs),  Mean-value coordinates (MVCs),  GPU acceleration 
[1] Jun-jie CAO, Zhi-xun SU, Xiu-ping LIU, Hai-chuan BI. Measured boundary parameterization based on Poisson’s equation[J]. Front. Inform. Technol. Electron. Eng., 2010, 11(3): 187-198.