Annual Report 2011–12

24 開拓人類知識的版圖 Motion blur is the result of the relative motion between the camera and the object during the integration time of a digital image which is built by pixels, each representing a tiny point on the object’s surface. As a result, a point on the object will become a line in the image. That means instead of corresponding to only a point on the object, now each pixel in the image represents more than one tiny dot on it, thus making the image blurry. And those lines depict the motion paths. The software developed by Professor Jia and Dr. Xu can backtrack the blurring process by means of mathematical derivation and computer algorithms. The deblurring process involves two steps: first, estimating the direction of motion; second, using proper mathematical models to fix the problem. Their software can do these two steps automatically. The software can recover about 50% of blurry photos. Besides fixing professional or amateur photographers’ photos, this new technology can be useful for recognizing license plates in surveillance images or restoring blurred medical images. 在正常情況下，構成數碼照片像素的小點 應與被攝物體相對位置的點相對應。但若 拍攝時相機與被攝物體之間產生相對運 動，被攝物體的某一點就會在照片中擴散 為一條線，也就是說，照片中每一個像素包 含了被攝物體多個點的信息，不再對應於 被攝物體相對的點，導致圖像模糊，而那條 線也反映出運動的軌跡。 賈教授與徐博士靠着數學推導和計算機演 算法，把引致模糊的過程倒回去，從而化模 糊為清晰。解決相機震動導致的模糊，主要 牽涉兩個步驟：首先是要知道照片拍攝時 相機發生了怎麼樣的運動，然後就可以利用 數學模型來解決問題，得出一張比較清晰 的照片。他們研發的軟件能自動處理這兩 個步驟，現時約五成的模糊相片能夠用這個 軟件修復。 這套軟件用途甚廣，除能協助一般使用者 修復照片外，還能用於保安，如把監視器影 片內模糊的車牌變清晰，或修復超聲波或 其他醫療造影的模糊照片。 賈佳亞教授（右）及徐立博士 Prof. Jia Jiaya (right) and Dr. Xu Li