CCD數位相機漏光現象之研究與改善

Abstract

我們常常可以發現，當我們使用數位相機在有高輝度光源的場景進行錄影時，我們可以在錄影檔畫面上看到一個筆直的光線，也就是我們所謂的漏光(Smear)，而這現象也是CCD影像感測器所特有的問題，以目前一般我們抑制漏光的方式，大多以調整光圈、調整曝光時間或者鏡頭上增加減光鏡(Neutral Density Filter；ND Filter)，但以上的方式，均會造成影像品質變差，以及製造成本的上升，所以筆者希望能藉由探討此現象的過程中，了解造成此現象的主要原因，進而找出以不影響畫質且又可以改善漏光的方式。 本論文使用機械快門，在不影響原先的訊號下改善漏光現象，雖然此方式可以改善，但要實際應用在商品上，仍然會有其他問題需要解決，筆者利用此次實驗的結果，提出一個用影像處理的方法來改善漏光現象，但此方式需要軟體人員協助，所以僅提供給後續研究人員參考。

When using a CCD image detector, it is usually found that a straight optical line(smear), which is displayed on video when using a digital camera to record under a lighting source with high brightness. The method we usually use to eliminate the smear is to adjust aperture, the time length of exposure or add Neutral Density Filter on the lens. However, all of the above will reduce the quality of image and increase the production cost. As a result , a method to improve the smear while still maintaining the quality of image is planned to be explained through my further study of this problem and its causes. The method used to improve smear without affecting original signal is mechanical shutter operation detailed in this dissertation, which although is feasible cannot be applied on products without other issues. A new method of image process to improve smear is proposed with the support from the result of this experiment. Nevertheless, this method will require a lot of resources of software programming; this is only of reference to people studying further in this field.