An Algorithm for Light Compensation

數位攝影系統在今天已經是很普遍的電子產品，其內建的功能也為了因應各種拍攝環境與使用者的需求而愈來愈完備。然而目前的數位攝影系統在某些光照環境，如背光，暗光，側光等，容易出現不令人滿意的影像。例如在主體背光的情況下容易因測光系統的誤判而產生背景曝光正常而主體卻昏暗的影像;在暗光的環境下因為光線的不足而產生整體畫面皆昏暗的影像;在側光情況下，主體的左右兩側會呈現一邊明亮而另一邊昏暗的結果。在許多應用上會希望主體能夠以明亮且清晰的畫面呈現出來。本論文提出一個光源補償的方法來改善在這些光照環境下所產生的影像。Digital camera systems often produce undesired result when working with improper light conditions such as dim light, side light, and back light. Images captured at those environments often tend to deteriorate the subject appearance. The details of dark region are too obscure to be recognized, and it will not be a happy experience when these faults happen on the subject.e enhance the image quality by adjusting the brightness of the image by applying log curve to each pixel, and then we reduce the brightness with amount proportional to each pixel’s brightness value of original image. Our results show that we can light up the dark regions, meanwhile, keep the bright regions from being overexposure.摘要 iibstract ivontents vist of Figures vihapter 1 Introduction 1hapter 2 Related Work 3hapter 3 Light Compensation 10.1 Overview 10.2 Brightness Enhancement 10.3 Brightness decreasing 12hapter 4 Experiments and Results 15hapter 5 Conclusion 24ibliography 2