IEEE Trans Image Process. 2017 Nov;26(11):5381-5394. doi: 10.1109/TIP.2017.2724241. Epub 2017 Jul 7.
Near-infrared gray images captured along with corresponding visible color images have recently proven useful for image restoration and classification. This paper introduces a new coloring method to add colors to near-infrared gray images based on a contrast-preserving mapping model. A naive coloring method directly adds the colors from the visible color image to the near-infrared gray image. However, this method results in an unrealistic image because of the discrepancies in the brightness and image structure between the captured near-infrared gray image and the visible color image. To solve the discrepancy problem, first, we present a new contrast-preserving mapping model to create a new near-infrared gray image with a similar appearance in the luminance plane to the visible color image, while preserving the contrast and details of the captured near-infrared gray image. Then, we develop a method to derive realistic colors that can be added to the newly created near-infrared gray image based on the proposed contrast-preserving mapping model. Experimental results show that the proposed new method not only preserves the local contrast and details of the captured near-infrared gray image, but also transfers the realistic colors from the visible color image to the newly created near-infrared gray image. It is also shown that the proposed near-infrared coloring can be used effectively for noise and haze removal, as well as local contrast enhancement.
最近，近红外灰度图像与相应的可见彩色图像一起被证明对图像恢复和分类很有用。本文提出了一种新的着色方法，基于保对比度映射模型为近红外灰度图像添加颜色。一种简单的着色方法是直接将可见彩色图像中的颜色添加到近红外灰度图像中。然而，由于捕获的近红外灰度图像和可见彩色图像之间的亮度和图像结构存在差异，这种方法会导致图像不真实。为了解决差异问题，我们首先提出了一种新的保对比度映射模型，以创建一个在亮度平面上与可见彩色图像外观相似的新的近红外灰度图像，同时保留捕获的近红外灰度图像的对比度和细节。然后，我们开发了一种方法，根据所提出的保对比度映射模型，从可见彩色图像中提取可添加到新创建的近红外灰度图像的逼真颜色。实验结果表明，所提出的新方法不仅保留了捕获的近红外灰度图像的局部对比度和细节，还将逼真的颜色从可见彩色图像传输到新创建的近红外灰度图像。还表明，所提出的近红外着色可有效用于噪声和雾去除以及局部对比度增强。
