摘要
用数字相机拍摄时,不恰当的光源常导致图像中的不均匀光照,用扫描仪获取图像时也有同样问题.不规则照明对图像质量造成严重损害,用光照平衡技术可消除图像中的这种不均匀照明.该文针对文字图像提出一种光照平衡的改进方法,利用对比度加权来扩大文字和背景之间的差异,使直方图更为均衡,降低不成比例的光强分布引起的对比度不均匀性.实验结果表明,新方法可有效改进失真文字图像的质量,提高文档的可读性.
With digital cameras, an inappropriate light source often leads to uneven illumination of the picture. The same problem also occurs when capturing an image via digital scanners; irregular illumination seriously distorts the image quality. Light balancing can eliminate such uneven illumination in multimedia. In this paper, we provide an improved version of this technique for text images. The new version adopts a contrast weight to amplify distinction between the text and the background. This can equalize the histogram and reduce uneven contrast of the disproportionate light distribution. The simulator shows that the new version can effectively improve the distorted documents with satisfactory quality and readability.
出处
《应用科学学报》
CAS
CSCD
北大核心
2008年第5期499-505,共7页
Journal of Applied Sciences
关键词
光照平衡
照度
数字化
对比度增强
light balancing, illumination, digitization, contrast enhancement
