Graduate Institute of Automation Technology, National Taipei University of Technology, Taipei 106, Taiwan.
Department of Computer Science and Information Engineering, National Taiwan University of Science and Technology, Taipei 106, Taiwan.
Sensors (Basel). 2021 Sep 9;21(18):6038. doi: 10.3390/s21186038.
A desirable photographic reproduction method should have the ability to compress high-dynamic-range images to low-dynamic-range displays that faithfully preserve all visual information. However, during the compression process, most reproduction methods face challenges in striking a balance between maintaining global contrast and retaining majority of local details in a real-world scene. To address this problem, this study proposes a new photographic reproduction method that can smoothly take global and local features into account. First, a highlight/shadow region detection scheme is used to obtain prior information to generate a weight map. Second, a mutually hybrid histogram analysis is performed to extract global/local features in parallel. Third, we propose a feature fusion scheme to construct the virtual combined histogram, which is achieved by adaptively fusing global/local features through the use of Gaussian mixtures according to the weight map. Finally, the virtual combined histogram is used to formulate the pixel-wise mapping function. As both global and local features are simultaneously considered, the output image has a natural and visually pleasing appearance. The experimental results demonstrated the effectiveness of the proposed method and the superiority over other seven state-of-the-art methods.
一种理想的摄影再现方法应该有能力将高动态范围图像压缩到低动态范围显示器，以真实地保留所有视觉信息。然而，在压缩过程中，大多数再现方法在保持全局对比度和保留真实场景中大多数局部细节之间存在着平衡的挑战。为了解决这个问题，本研究提出了一种新的摄影再现方法，可以平滑地考虑全局和局部特征。首先，使用高光/阴影区域检测方案来获取先验信息以生成权重图。其次，进行相互混合的直方图分析以并行提取全局/局部特征。第三，我们提出了一种特征融合方案来构建虚拟组合直方图，通过根据权重图使用高斯混合自适应地融合全局/局部特征来实现。最后，使用虚拟组合直方图来制定像素级映射函数。由于同时考虑了全局和局部特征，因此输出图像具有自然和令人愉悦的外观。实验结果表明了所提出方法的有效性，并优于其他七种最先进的方法。
