碎形壓縮應用於遙測影像之研究

A Study on Fractal Compression for Remotely Sensed Images

蔡宗哲(Tzong-Jer Tsai) ； 史天元(Tian-Yuan Shih)

《航測及遙測學刊》 2卷3期 (1997/09) Pp. 25-35

https://doi.org/10.6574/JPRS.1997.2(3).3

摘要

本研究探討碎形壓縮於遙測影像之應用。研究中，分別使用碎形壓縮及傳統JPEG壓縮對兩幅SPOT-2全色態影像進行壓縮，針對各壓縮影像計算與原始影像間之關聯係數、均方根誤差、像元灰度值差異、及訊號雜訊比等統計指標，以比較其差異性。並嘗試利用碎形壓縮過程中區塊的分類，辨識出影像的特徵。成果顯示，碎形壓縮可得到較JPEG為大之壓縮比例，當壓縮比例達到一定程度時，碎形壓縮影像之品質將會優於JPEG。而較為均調的影像區域於壓縮後回復程度較佳。影像中灰值相近的大區域物件則較易分辨出其邊界。

關鍵字

碎形 ； 影像壓縮

並列摘要

Two fractal-based compression procedures are investigated and compared with the conventional JPEG procedure for remotely sensed images. All three algorithms are applied to two panchromatic subscenes from SPOT. The performances are evaluated with the indices including entropy, correlation coefficient, root mean square error, pixel value differences, and signal noise ratio, which are computed from the differences between the compressed and the original images. The results indicate that fractal compression methods provide higher potential compression ratio. In general, when the compression ratio is larger than 50, fractal-based approaches have better performance than JPEG. Regarding feature analysis, edges of large and homogeneous areas can be recognized easier.

並列關鍵字

fractal ； image compression