色彩影像初階校正與縮放技術研究

Color Image Preliminary Calibration and Resizing Technique

蔡孟達(Meng-Ta Tsai)

指導教授 ： 張元翔

中原大學/工學院/資訊工程研究所/碩士(2005年)

https://doi.org/10.6840/cycu200500362

摘要

隨著影像技術與資訊技術的發展，數位影像已遍及每一個地方，影像色彩亦從灰階影像進展到彩色影像，因此數位色彩裝置(如掃描器)也就越來越普遍。除了效率之外，消費者最重視的就是色彩品質，顏色是否接近真實色彩相當重要，而色彩校正就是修正色彩特性的技術。一般而言，色彩校正過程繁複，因此一般使用者不容易進行色彩校正，本研究嘗試發展一套簡易色彩校正程序，能夠協助使用者自行校正色彩且達到一定程度的校正效果。利用校色稿之色彩線性分佈的特性，修正影像於掃描過程中所產生的非線性反應誤差，在實驗結果中可以看出本研究已達到初步的校正效果，然而為了追求更近一步的效能，仍需深入研究並改進校正程序。
基礎的影像處理技術(如縮放、分割)通常是醫學影像、多媒體技術等的基本運算，若基礎處理效果不佳使得影像失真，接下去的後續處理就是對錯誤的資料做處理。本論文針對色彩影像縮放進行研究，影像縮放大多採用內插法來處理，傳統內插法包括：最近鄰內插法、雙線性內插法、雙立方內插法，傳統內插法的縮放效果並未達到高水準，本論文研究另一種內插法─斜角投射B-Spline內插法。分別以主觀與客觀(訊號雜訊比)的方式來評估各個內插法的縮放效果，以實驗結果來看，不論主觀或客觀的評估方式皆指出斜角投射B-Spline內插法對色彩影像有較佳的縮放效果，但考慮執行速率，斜角投射B-Spline內插法並非最有效率的影像縮放處理法。

關鍵字

色彩影像 ； 色彩校正 ； 色彩影像縮放 ； 內插法技術

並列摘要

With the advance of imaging and information techniques, digital images are popular everywhere. The color of image has also been developed from achromatic to chromatic. So, color imaging device (ex. scanner) has become more and more popular. Except for efficiency, consumers respect color quality. It is very important that digital color data represent original color. Calibration is a technique of correcting color characteristics. In general, calibration process is not tedious. So, general users can not easily calibrate themselves. This thesis tried to develop one simple calibration process. It could help users calibrate themselves and achieve certain degree of calibration. Using the property of linear distribution of standard color chart, we fixed the non-linear response error during scanning process. Experimental results show that the process we proposed achieved preliminary success. However, for better results, more research effort is desired.
Basic technique of image processing (e.g. resizing, segmentation etc.) is usually the basic operator of medical image and digital multimedia. If the results of fundamental processing are performed badly, this could cause distortion such that the follow-up step will be processing wrong data. This thesis is to study the color image resizing. Image resizing was generally processed by interpolation. The conventional interpolation included: Nearest Neighbor Interpolation, Bilinear Interpolation, and Bicubic Interpolation. The conventional interpolation could not achieve high quality of image resizing. This thesis is an attempt to overcome the deficiency of conventional methods and to study another method, namely oblique projection of B-Spline interpolation. Both subjective and objective (Signal to Noise Ratio) methods are used to estimate the quality of resized images. Experimental results show that the oblique projection of B-Spline interpolation has achieved best results. However, the oblique projection of B-Spline interpolation was not the most efficient image resizing processing method.

並列關鍵字

calibration ； interpolation technique ； color images ； image resizing

參考文獻

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