監視攝影機的失焦偵測

Abstract

本論文提出一個應用在TI DM368系統上的監視攝影機對於當前影像是否在適當的焦距上的方法。現今許多攝影機都有自動對焦的功能，可以利用硬體的協助達成主動自動對焦，或者在軟體影像處理的部分計算焦點特徵值，配合搜尋演算法來達成被動自動對焦，這些方法通常需要馬達來調整鏡頭的焦距來達成自動對焦的目的。而本論文所提供的方法，是希望不使用搜尋演算法去比對前後焦點特徵值，而是藉由當前影像焦點特徵值間的相對關係，來達成判定當前影像是否在適當焦距上的功能。

Nowadays most of surveillance cameras have autofocus functionality. It can be classified into two types of methods: active autofocus with auxiliary hardware device and passive autofocus with image processing by calculating focus value and searching algorithm. Both of these methods need a motor on camera to control the focal length. In this thesis, we propose a new method applying to TI DM368 to detect out-of-focus situation without searching algorithm but only using some mathematical features on focus values.