以影像處理及決策樹技術作名片內容之自動分析

Abstract

在本論文中我們利用影像分析的技巧，提出一些可以自動分析名片影像的方法。影像分析的主要工作，是希望能取出名片有用的資訊。在我們的方法中，有五個階段：基本區塊的抽取、商標的抽取、名片型別的分類、文字列型別的分類，以及名片影像的重建展示。在基本區塊的抽取階段，我們使用邊緣偵測及區塊生長演算法來找出基本區塊，再用矩量保持二值化來減少基本區塊裡的顏色。在商標的抽取階段，我們利用區塊的顏色以及相關資訊，判斷這些區塊為商標或是文字區塊。在名片型別的分類階段，我們利用文字區塊寬與高的比例來區分名片的型別，分成中文名片和英文名片。在文字列型別的分類階段，在中文名片中我們處理九種文字列型別，分別是姓名、公司名稱、電子信箱、網頁位址、行動電話、傳真電話，電話號碼、統一編號、地址。英文名片中的文字列型別除了統一編號之外與中文名片的相同。我們利用適當的決策樹提出對中文名片和英文名片的文字列的型別作分類的分法。最後，我們利用一個適當的技術來壓縮名片影像中的組成成分，以降低儲存空間。良好的實驗結果，顯示了我們所提出方法的可行性。

A system for automatic analysis of various contents of name card images using decision-tree classification techniques is proposed. Five major phases of name card content analysis are identified, including basic block extraction, logo extraction, card type classification, text line classification, and card image reconstruction. In the phase of basic block extraction, edge detection and region-growing techniques are applied to extract basic blocks in name card images. Then, a moment-preserving thresholding technique is used to reduce the colors in each basic block. In the phase of logo extraction, several effective features are proposed to classify extracted blocks into logo blocks and text blocks. In the phase of card type classification, the width/height radios of text blocks are used to classify card types into Chinese and English. In the phase of text line type classification for Chinese name cards, nine types of text lines are recognized, including name line, title line, e-mail line, web address line, mobile phone number line, fax number line, phone number line, government publications number line, and address line. And text line types in English name cards identical to those in Chinese name cards except the government publications number line are also recognized. Adaptive decision-tree methods for classifying these text line types both in Chinese and in English name cards are proposed. Finally, a suitable compression method is proposed to reduce the data volumes of the recognized name card contents to save storage space and display time. Good experimental results reveal the feasibility of the proposed methods.