要產生大螢幕，一種經濟的方法是使用多部投影機去拼接，但是由於不同的電子元件及燈泡的緣故，使得每一部投影機都有它個別的亮度及色彩特性，整個拼接螢幕就顯示出不均勻的色彩及亮度。 在這篇研究中，我們使用一台攝影機去捕捉這個拼接螢幕，並提出兩個自動校正的方法，以解決色彩及亮度不均勻的問題。最後，我們產生回授控制信號到多台投影機，並經由 RS-232 通訊埠自動調整投影機。 我們提出兩種方法做為自動色彩匹配的解決方案，第一種方法是gamma 曲線調整法，它依照亮度最低的投影機，產生己知的 gamma 對照表，再個別地把其他台投影機的 gamma 曲線調整成一樣；第二種方法是色座標調整法，藉由調整每個投影單元的色座標，而達到色彩匹配的目的。使用 gamma 曲線調整法需要調整每一階的 gamma 對照表；而使用色座標調整法則是需要利用晶片內建功能，可攜性較差。兩種方法各有優缺點，所以需要看應用於何種顯示技術以決定採用何種方法。 To produce a large screen, one economical way is using multiple projectors to tile. However, each projector has its individual luminance and color characteristics due to different electronic components and light bulbs. The tiled screen then appears the non-uniform color and luminance and has blocking effect. In this study, we use a camera to capture the tiled screen, and propose two automatic calibration methods to resolve the non-uniform color and luminance problems. At last, we generate the feedback control signal to the multiple projectors through the RS-232 port to automatically adjust the projectors. The first method is gamma curve adjusting method, it uses lowest lightness projector to produce known gamma lookup table, and then use this table to individually adjust the gamma curve of each projector; the second method is color coordinate adjusting method, it adjusts color coordinate of primary color of each projector directly. The first method needs to adjust every step of gamma lookup table, it seems hard; the second method needs to use integrated circuit built-in feature, the portability is not so good. Each method has both advantages and disadvantages. Users need to decide what method will be adopted by their application.
