Department of Electronic and Computer Engineering, National Taiwan University of Science and Technology, Taipei 106, Taiwan.
Department of Computer Science and Information Engineering, National Taiwan University of Science and Technology, Taipei 106, Taiwan.
Sensors (Basel). 2021 Jun 16;21(12):4136. doi: 10.3390/s21124136.
Photographic reproduction and enhancement is challenging because it requires the preservation of all the visual information during the compression of the dynamic range of the input image. This paper presents a cascaded-architecture-type reproduction method that can simultaneously enhance local details and retain the naturalness of original global contrast. In the pre-processing stage, in addition to using a multiscale detail injection scheme to enhance the local details, the Stevens effect is considered for adapting different luminance levels and normally compressing the global feature. We propose a modified histogram equalization method in the reproduction stage, where individual histogram bin widths are first adjusted according to the property of overall image content. In addition, the human visual system (HVS) is considered so that a luminance-aware threshold can be used to control the maximum permissible width of each bin. Then, the global tone is modified by performing histogram equalization on the output modified histogram. Experimental results indicate that the proposed method can outperform the five state-of-the-art methods in terms of visual comparisons and several objective image quality evaluations.
由于在输入图像动态范围压缩的过程中需要保留所有的视觉信息，因此照片的复制和增强具有挑战性。本文提出了一种级联结构类型的复制方法，它可以同时增强局部细节并保留原始全局对比度的自然度。在预处理阶段，除了使用多尺度细节注入方案来增强局部细节外，还考虑了史蒂文斯效应，以适应不同的亮度水平并正常压缩全局特征。我们在复制阶段提出了一种改进的直方图均衡化方法，其中首先根据整体图像内容的特性调整各个直方图-bin 的宽度。此外，还考虑了人眼视觉系统 (HVS)，以便使用亮度感知的阈值来控制每个-bin 的最大允许宽度。然后，通过对输出修改后的直方图进行直方图均衡化来修改全局色调。实验结果表明，与五种最先进的方法相比，所提出的方法在视觉比较和几种客观图像质量评估方面都具有优势。
