基于图像增强处理的CDVS匹配算法

Image enhancement based on CDVS matching algorithm

紧凑型视觉描述子(CDVS)的目标是针对移动端的图像检索以及匹配应用提供一套标准化的比特流语法。CDVS标准算法对于光照条件良好的图像具有很好的匹配效果,但是对于昏暗条件下拍摄的图像,匹配的准确度表现不足。因此提出一种基于直方图均衡化的CDVS匹配算法,对昏暗条件下的图像通过直方图均衡算法进行质量提升,增加关键点匹配数,然后再利用CDVS标准算法对图像进行匹配。另一方面,提出一种基于同态滤波的CDVS匹配算法,对昏暗图像进行频域变换,突出高频信号,抑制低频信号,增加图像对比度。实验对比了昏暗条件下图像匹配结果与处理之后图像匹配结果,验证了本算法的有效性。

Compact descriptor for visual search(CDVS)provides a standardized bitstream syntax for mobile image retrieval and matching applications.Although the standard CDVS algorithm has significant advances in the images with the good lighting condition,this approach often fails on dealing with the low-light images.A CDVS matching algorithm based on image enhancement is proposed.Firstly,a histogram equalization method is used for improving the quality of the pictures on low-light conditions to increase the matching number of the key points.Then,a same image enhancement method,which is mainly according to the homomorphic filtering,is adopt as the preprocessing for enhancing the contrast of the image with suppressing the low frequency signal and highlighting the high frequency signal to better extract the descriptors.The experimental results are compared with the image matching results under dim conditions and the image matching results after processing,and the effectiveness of the algorithm is verified.