為何 HDR 影像看起來如此鮮明？(Why HDR image looks so vivid?)
文/ Jacky Liu 2016/07/31 HDR 影像 High-dynamic-range imaging (HDRI) 較 LDR 影像 Low-dynamic-range imaging (LDRI) 有更高的動態範圍(Dynamic range)，也就是在單一 Channel 中更精細的記錄影像內容。 Comparing with LDR image (Low-dynamic-range), HDR image (High-dynamic-range) has larger dynamic range, which means that HDR image can record image more precisely. 乍看之下「 HDR 影像格式比起 LDR 有更精細記錄影像的能力」似乎就是其影像更加鮮明的原因，不過這樣的想法存在著問題。 At first glance, “HDR image format has more precise recording ability than LDR image” seems to be the reason why HDR image looks so vivid. However, it contains logically defect. 查看 Wikipedia HDR 頁面後，會發現有更精細的記緣能力只說了一半的故事，另一半同等重要的是顯示，由於傳統顯示器無法完全顯示HDR影像的高對比度，HDR影像必需經過 Tone mapping ，把高動態範圍映射到較窄的動態範圍上。不過在同樣的傳統顯示器上，為何 HDR 影像經過 Tone mapping ，看起來還是比 LDR 影像來的鮮明？ After look up Wikipedia HDR pages, you will find that “more precise recording ability” is only half the story. Another equivalently important part is image display. Because traditional monitor cannot fully display high contrast of HDR image, H