快速DCT區塊之壓縮域全域影像強化

Global Image Enhancement in DCT-Based Domain

陳彣(Wen Chen)

指導教授 ： 郭忠民

義守大學/電機資訊學院/資訊工程學系/碩士(2015年)

https://doi.org/10.6343/ISU.2015.00149

摘要

本篇文章提出了一個在壓縮域進行影像強化的方法，並且發展了快速的計算，直接將空間域方法於壓縮域當中有效的執行。由於現代人對於儲存空間的需求，通常人們都會對影像進行壓縮，來降低影像的儲存空間，但是影像在空間域進行強化之後再壓縮，極為繁複，所以本篇文章提出簡單快速的方法可以直接在壓縮域當中進行影像強化。
本篇文章同時提出了一種新的Haar transform，可以快速的將原本進行餘弦轉換之後產生的8×8矩陣，直接向下分解成1×1的類空間域，或者是向上合併成256×256的矩陣，以前的Haar transform
需要一步一步慢慢累加，計算過程非常的繁瑣沒有效率，我們所提出的新Haar transform只需要一步即可合併或分解成自己所指定的矩陣大小，不用逐步向下分解或向上合併。並且此文章也針對分解或合併之後的壓縮域矩陣提出了不同的壓縮域強化方法，使影像能夠在壓縮域也能有效的使用空間域的方法來強化，而且不會有嚴重的區塊效應產生，也能有效的保持影像的亮度。

關鍵字

DCT域 ； 影像強化

並列摘要

In this paper, a new method that enhances the images in DCT domain with low computational complexity is proposed. Nowadays, huge amounts of images have been produced by the electronic devices. For storage or transmission, people usually compression images to save more space. But to enhance image in spatial domain after decompressing seems very complicated. Therefore, the proposed can enhance images in DCT domain directly.
In this thesis, a new fast Haar transform that decomposes the DCT coefficients into qusi-spatial domain is developed. In order to use spatial domain techniques, the decomposition procedure is very useful. Because the decomposition is fast thus the proposed method is very computational efficiency. We combine the characteristics in frequency domain and the histogram equalization to enhance images. Results indicate that the method can enhance images very well.

並列關鍵字

DCT frequency domain ； Haar transform ； Image enhancement

參考文獻

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