臺灣博碩士論文加值系統

給予感興趣區域較高的權重，是近來影像編碼常用到的技術。我們提出一個快速、簡單的方法來動態地偵測人臉，並將這區域視為感興趣區域。我們採用R, G, B 及 Cr的資訊來定義出屬於膚色的像素，因為RGB及YCbCr這兩個色彩系統，廣泛的被硬體或影像編碼標準所採用，這樣的好處是不需要其他的前處理且偵測效果更精確。在定義出感興趣區域後，我們使用低通濾波器來減少非感興趣區域所需使用的位元。
我們的系統架構在H.263+上，並配合其中的一個附加選項：Modified Quantiaztion，我們調整各區域巨集區塊(macroblock)的失真權重及變異數，並藉此來控制其所產生出的影像品質。在我們的實驗結果顯示，我們的方法有顯著的提升感興趣區域的品質。我們的方法非常適用於即時系統的應用上。

The ability to give higher priority to Region-of-Interest(ROI) is the emerging functionality for nowadays video coding. A simple and fast method of face detection is proposed to dynamically define ROI in real time application. We use the color information R,G,B and Cr to determine the skin-color pixels. We don’t need any preprocessing, because these two color spaces are used in most hardware and video codec standards. Then, we use low-pass filters for background to reduce used bits.
For video coding system, a region-based video codec based on the H.263+ with the option mode of modified quantization is set up. We adjust the distortion weight parameter and variance at macroblock layer to control the qualities at different regions. From experimental results, the proposed method can significantly improve quality at ROI. Our method is suitable for real time videoconferencing.

ABSTRACT
CHAPTER 1 INTRODUCTION
1.1 BACKGROUND
1.2 REGION OF INTEREST VIDEO CODING
1.3 ORGANIZATION OF THE THESIS
CHAPTER 2 OVERVIEW OF EXISTING METHODS
2.1 OVERVIEW OF ROI
2.2 OVERVIEW OF FACE DETECTION
2.2.1 Face Detection using Skin-color
CHAPTER 3 PROPOSED METHOD
3.1 FACE DETECTION
3.2 BLURRING
3.3 VIDEO CODING
CHAPTER 4 EXPERIMENTAL RESULTS
CHAPTER 5 CONCLUSION
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