光学技术, 2023, 49 (6): 750, 网络出版: 2023-12-05
自适应加权直方图均衡化的红外图像增强
Infrared image enhancement based on adaptive weighted histogram equalization
红外图像增强 直方图均衡化 自适应加权数 信息熵 infrared image enhancement histogram equalization adaptive weighting coefficient information entropy
摘要
鉴于现有的红外图像增强方法存在欠增强、过增强和放大噪声等缺陷, 提出了自适应加权直方图均衡化的红外图像增强方法。该方法提出了直方图的自适应加权系数, 其反比于每个灰度级对应直方图频次的平方根, 适当地提升频次较小的直方图, 而适当压制频次较大的直方图。用自适应加权系数对各个灰度级的直方图频次进行加权后, 进行直方图均衡化处理, 最后经灰度级映射得到增强图像。实验结果显示, 相对于现有的方法, 本方法的增强图像对比度更高, 边缘细节信息更丰富, 信息熵、平均梯度和标准差分别比现有方法高出0.23、2.2和3.7以上。因此, 本文方法的红外图像增强效果优于最新提出的现有方法。
Abstract
In view of the fact that the existing infrared image enhancement methods suffer from under enhancement, over enhancement and noise amplification, an adaptive weighted histogram equalization method for infrared image enhancement is proposed. In the proposed method, the adaptive weighting coefficient of histogram is put forward, which is inversely proportional to the square root of the histogram frequency corresponding to each gray level, appropriately increases the histogram with smaller frequency, and appropriately suppresses the histogram with larger frequency. After the histogram frequency of each gray level is weighted processed with adaptive weighting coefficient, the weighted histogram is equalized, and finally, the enhanced image is achieved by gray level mapping. Experimental results show that compared with existing methods, the enhanced image by this method has higher contrast, is more rich in edge and detail information, its entropy, average gradient and standard deviation are 0.23, 2.2 and 3.7 higher than those of existing methods, respectively. Therefore, this method outperforms the latest proposed existing methods in image enhancement effect.
周辉奎, 顾牡丹. 自适应加权直方图均衡化的红外图像增强[J]. 光学技术, 2023, 49(6): 750. ZHOU Huikui, GU Mudan. Infrared image enhancement based on adaptive weighted histogram equalization[J]. Optical Technique, 2023, 49(6): 750.