使用闪光灯图像对的闪光灯阴影检测

Flash Shadow Detection Using Flash Image Pairs

人们在光线较暗的环境拍摄照片时,经常使用闪光灯来增强光照。但闪光灯的使用会引起一些不良效应,如红眼和闪光灯阴影。检测并去除闪光灯图像中的闪光灯阴影区域,会显著提高对象检测和识别等视觉任务的性能。提出了一种使用闪光灯图像对的闪光灯阴影检测算法。它基于以下假设:闪光灯阴影边缘点只会出现在闪光灯图像中,并且闪光灯阴影区域的灰度值低于非闪光灯图像对应区域的灰度值。所提算法包括三个步骤:预处理、闪光灯阴影边缘点检测和闪光灯阴影检测。仿真结果和与已有方法的比较都验证了所提方法的有效性。

When photographers taking pictures in low-light environments,they normally use flash light to enhance the illuminate. However,the use of flash may introduce unwanted artifacts,such as red-eyes and flash shadows. Detection and removal flash shadows from flash images can significantly improve the performance of several vision tasks such as object detection and recognition. A practical algorithm is proposed to detection flash shadows by using flash image pairs. The key hypothesis is that flash shadow edges appear only in flash images and the intensity values of flash shadow regions are much lower than corresponding regions in no-flash images. The developed algorithm consists of a three-tier process including preprocessing,flash shadow edge detection,and flash shadow detection. Experimental results demonstrate the effectiveness of the presented method as compared to previous methods.