一种空域和变换域相结合的图像增强算法

An Image Enhancement Algorithm Based on Space Domain and Transform Domain

针对传统图像增强算法只使用空域或变换域处理策略的不足,提出一种空域和变换域相结合的处理方法。首先通过使用高斯/拉普拉斯金字塔分解技术将原始灰度图像细分成不同频带,然后在各个频带上分别使用伽玛校正实现对比度均衡化,最后将均衡化结果再利用高斯/拉普拉斯金字塔重构技术进行恢复,即可达到图像增强的目的。实验结果表明,与传统图像增强算法相比,该算法不但能够提高欠曝光区域的对比度,而且能够对过曝光区域实现有效抑制,达到很好的视觉均衡。

Considering the shortage of the traditional image enhancement algorithms that it can only use space-domain or transform-domain processing strategy separately,a novel processing method combining space domain with transform domain was proposed.Firstly,the original gray images were decomposed into different frequency bands by using Gaussian/Laplacian pyramid transform.Secondly,gamma correction was employed to achieve contrast equalization in each band.Finally,the enhanced images were reconstructed from the equalized one by means of inverse pyramid transform.Experimental results indicated that：Compared with traditional image enhancement algorithms,the proposed one can not only increase the contrast of underexposure regions,but also effectively suppress the luminance of overexposure regions,and achieve a good visual balance.