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A Research on Fractal Image Coding for Mobile Image Communications

移动图像通信中的分形图像编码研究

基本信息

批准号：
13450154
负责人：
TANIMOTO Masayuki
金额：
$ 3.97万
依托单位：
Nagoya University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2002
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-13450154/
关键词：
Fractal Correlation Collage theorem Error resilience Picture coding Mobile communication

项目摘要

Through this research, the following results were obtained :1. In fractal image decoding process, we investigated theoretically the mechanism of the propagation of image degradation caused by errors of received compressed data. We found that the propagated errors are about 2.4 times as the errors of compressed data regardless of the search area in encoding process.2. We proposed a new coding method for error resilience by sending the image twice with the same amount of data as the single image. This is realized by using double-sized range blocks and a new criterion to determine the domain block.3. In the proposed method, we determined the optimal shape of enlarged range blocks from the mean square error between range blocks and domain blocks. We confirmed the results from the viewpoint of the coding efficiency.4. We also investigated the mechanism of the error detection in the decoding process. We found that the error detection using threshold sometimes fails, and this hampers error recovering and causes image degradation.5. To prevent misdetection of error as 4, we introduced a pre-processing in the encoder, which selects only domain blocks that causes no error misdetection.6. Using encoder and decoder based on 5, we succeeded to suppress the misdetection of errors.We confirmed that the proposed method outperforms the conventional method with 2-3 dB gain of PSNR in an erroneous channel environment.

通过本研究，取得了以下成果：1.在分形图像解码过程中，我们从理论上研究了由于接收到的压缩数据的错误而引起的图像退化的传播机理。我们发现，在编码过程中，无论搜索区域如何，传播的误差都是压缩数据误差的2.4倍.我们提出了一种新的编码方法，通过发送图像两次相同的数据量的单张图像的错误恢复。这是通过使用双倍大小的范围块和一个新的标准来确定域块来实现的。在该方法中，我们确定了最佳形状的扩大范围块之间的范围块和域块的均方误差。我们从编码效率的角度证实了这一结果.我们还研究了解码过程中的错误检测机制。我们发现使用阈值的错误检测有时会失败，这会妨碍错误恢复并导致图像退化.为了防止错误误检4，我们在编码器中引入了预处理，只选择不会导致错误误检的域块。6.使用基于5的编解码器，成功地抑制了误检，在错误信道环境下，该方法的峰值信噪比比传统方法提高了2- 3dB。