Chen Yen-Yu
Department of Information Management, ChengChou Institute of Technology, 6, Line 2, Sec 3, Shan-Chiao Rd., Yuanlin, Changhwa, Taiwan.
Int J Med Inform. 2007 Oct;76(10):717-25. doi: 10.1016/j.ijmedinf.2006.07.002. Epub 2006 Aug 23.
The work proposed a novel bit-rate-reduced approach for reducing the memory required to store a remote diagnosis and rapidly transmission it.
In the work, an 8x8 Discrete Cosine Transform (DCT) approach is adopted to perform subband decomposition. Modified set partitioning in hierarchical trees (SPIHT) is then employed to organize data and entropy coding. The translation function can store the detailed characteristics of an image. A simple transformation to obtain DCT spectrum data in a single frequency domain decomposes the original signal into various frequency domains that can further compressed by wavelet-based algorithm. In this scheme, insignificant DCT coefficients that correspond to a particular spatial location in the high-frequency subbands can be employed to reduce redundancy by applying a proposed combined function in association with the modified SPIHT.
Simulation results showed that the embedded DCT-CSPIHT image compression reduced the computational complexity to only a quarter of the wavelet-based subband decomposition, and improved the quality of the reconstructed medical image as given by both the peak signal-to-noise ratio (PSNR) and the perceptual results over JPEG2000 and the original SPIHT at the same bit rate. Additionally, since 8x8 fast DCT hardware implementation being commercially available, the proposed DCT-CSPIHT can perform well in high speed image coding and transmission.
本研究提出了一种新颖的降低比特率的方法,以减少存储远程诊断所需的内存并实现快速传输。
在本研究中,采用8×8离散余弦变换(DCT)方法进行子带分解。然后采用改进的分层树集合划分(SPIHT)算法进行数据组织和熵编码。平移函数可以存储图像的详细特征。通过在单频域中进行简单变换以获得DCT频谱数据,将原始信号分解为多个频域,这些频域可以通过基于小波的算法进一步压缩。在该方案中,通过应用所提出的组合函数并结合改进的SPIHT算法,可以利用高频子带中对应于特定空间位置的无关紧要的DCT系数来减少冗余。
仿真结果表明,嵌入式DCT-CSPIHT图像压缩算法将计算复杂度降低至基于小波的子带分解算法的四分之一,并且在相同比特率下,与JPEG2000和原始SPIHT算法相比,通过峰值信噪比(PSNR)和感知结果衡量,其重建医学图像的质量得到了提高。此外,由于8×8快速DCT硬件实现已有商用产品,因此所提出的DCT-CSPIHT算法在高速图像编码和传输方面表现良好。