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arXiv 1403.4359stat.CO
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图像分析中近似贝叶斯计算的预处理

Pre-processing for approximate Bayesian computation in image analysis

Matthew T. Moores, Christopher C. Drovandi, Kerrie Mengersen, Christian P. Robert

摘要:

现有的近似贝叶斯计算(ABC)算法大多假设在每次迭代中从模型中模拟伪数据是可行的。然而,这些模拟的计算成本对于高维数据可能是过高的。一个重要的例子是Potts模型,它通常用于图像分析。在现实世界的应用中遇到的图像可能有数百万像素,因此可扩展性是一个主要问题。我们将ABC与合成似然应用于具有加性高斯噪声的隐藏Potts模型。使用预处理步骤,我们拟合绑定函数来模拟模型参数和合成似然参数之间的关系。我们的数值实验表明,预先计算的绑定函数大大提高了ABC的可扩展性,将模型拟合所需的平均运行时间从71小时减少到仅7分钟。我们还说明了遥感卫星图像的平滑参数估计的方法。没有预先计算,贝叶斯推断对于这种规模的数据集是不切实际的。

英文摘要:

Most of the existing algorithms for approximate Bayesian computation (ABC) assume that it is feasible to simulate pseudo-data from the model at each iteration. However, the computational cost of these simulations can be prohibitive for high dimensional data. An important example is the Potts model, which is commonly used in image analysis. Images encountered in real world applications can have millions of pixels, therefore scalability is a major concern. We apply ABC with a synthetic likelihood to the hidden Potts model with additive Gaussian noise. Using a pre-processing step, we fit a binding function to model the relationship between the model parameters and the synthetic likelihood parameters. Our numerical experiments demonstrate that the precomputed binding function dramatically improves the scalability of ABC, reducing the average runtime required for model fitting from 71 hours to only 7 minutes. We also illustrate the method by estimating the smoothing parameter for remotely sensed satellite imagery. Without precomputation, Bayesian inference is impractical for datasets of that scale.

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