Content area
Full Text
Abstract - Due to the uneven distribution of light at night, the quality of the night color image is usually unsatisfactory. To solve this problem, in this paper, we propose a new statistical method based on the retinex. The algorithm analyzes the transformation relationship between the nighttime image and illumination image by the algorithm of Michael Elad and MSRCR algorithm. Through this transformation, we can accurately and quickly get the illumination image. Then, we can get the resulting image successfully based on the retinex. Our algorithm can greatly enhance the image contrast and brightness, recover image details, eliminate the "halo effect" efficiently, and accelerate the computational speed remarkably. Experiments on different nighttime images demonstrate the effectiveness of our approach.
Keywords: statistical law; image enhancement; night color image
(ProQuest: ... denotes formulae omitted.)
1 Introduction
The night color image enhancement is of great importance in both the computational photography and computer vision. First, it can effectively increase the visibility and surrealism of the scene. Second, artificial illumination light distributes unevenly at night leading to weakening the quality of monitoring photos and increasing the difficulty of surveillance. Thus, the night color image enhancement can promote the video surveillance .Last, the input images of most computer vision algorithms (e.g., the photometric analysis algorithm) are daytime images. Thus, the night color image enhancement can increase the scope of such algorithms by enhancing nighttime images.
However, the night color image enhancement is a challenging task. Currently, the main techniques for the night image enhancement are the image fusion and image enhancement. Image fusion techniques include two categories: one is the fusion of the nighttime image and visible image [1,2] and another is the fusion of the nighttime image and infrared image [3, 4], These methods require multiple different spectral images collected in the same scene and have high computational complexity .The main techniques for the image enhancement include contrast stretching, slicing, histogram equalization, and some algorithms based on the retinex [5-11], etc. Of all those algorithms, the algorithm based on the retinex has acceptable results, but it will produce the "halo effect" and high time complexity.
In this paper, we propose a novel algorithm for enhancing the night color image based on the statistical law and the retinex....