阈值差分灰度文本图像压缩

Gray Document Image Compression with Thresholding and Differencing

提出一种灰度文本图像压缩方案.该方案充分考虑灰度文本图像的特征,用阈值差分算法将灰度文本图像分解为黑白图像和灰度残差图像,然后采用JBIG(joint bi-level image group)和LZW(Lempel-Ziv-Welch)压缩算法分别对黑白图像和灰度残差图像进行压缩.试验表明:视觉效果优于GIF、JPEG压缩方案,且压缩效率比GIF平均提高了55%.

A compression method for gray document image is presented in the paper. Firstly, gray document image is decomposed into a black white image and a residual gray image with thresholding and differencing algorithm, then the decomposed ones are compressed using JBIG and LZW. The experiment concludes that the ratio of compression is increased 55% more than GIF′s and there is better visual effect than GIF′s and JPEG′s.