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成千上万的人物同时出场似乎已经成了大制作电影的必备镜头,比如《魔戒》里的决斗场面、《英雄》里的秦军队伍等等,那么这些场景是如何拍摄的呢?难道真的要去拉数十车的演员来同时表演!能够请到这么多的演员已经很不容易了,再加上堆积成山的服装、化装道具……再想想,这简直就是一场恶梦! 仔细观察电影中的这种场面,会发现大多数演员的穿着都差不多,表情也不能全部看清楚,其实这种大型场面多半都是用数字技术合成的,很少有导演真正去请大批的演员来表演。在影视行业中,如果要将人物与背景分离开,大多数情况都是采用色键抠像法即让演员在蓝色幕布或者绿色幕布前表演,然后使用后期软件将背景的色彩去掉,这种方法既简单又实在,效果很好,许多电视台的新闻节目就是使用的这种方法,但是这种方法有很大局限性,其中最大的问题就是受场地的限制,导演不可能在沙漠里挂一块巨大的蓝布,然后再进行拍摄。遇到这种大型场景的抠像,就得使用“差异抠像”技术了,这种技术的原理是使用两段素材进行对比,分析像素的差别后,将同等位景的像素去掉,留下特别的像素,由干这种技术很特殊,所以现在很多后期软件的处理结果都不太理想,但是作为电影高端合成软件Digital Fusion却可以轻松地、高质量地完成这项任务。
The appearance of thousands of people at the same time seems to have become an essential lens for major productions, such as duel scenes in Lord of the Rings, Qin troops in Heroes, etc. How are these scenes shot? Is it really going to pull tens of car actors to perform at the same time! To get so many actors is not easy, plus the mountains of costumes, costume props ... think about it, it is simply an evil Dream! Careful observation of this scene in the movie, you will find that most actors are wearing the same, the expression can not all see clearly, in fact, most of this large-scale scenes are synthesized using digital technology, very few directors really want to please Actor to perform. In the film and television industry, if you want to separate the characters from the background, in most cases, the color key is used to allow the actor to perform in front of the blue curtain or the green curtain, and then use the late software to remove the background color. The method is simple and real, the effect is very good, many television news programs are using this method, but this method has great limitations, the biggest problem is that the venue constraints, the director can not hang a piece in the desert Huge blue cloth, and then shoot. Encountered such a large scene keyer, you have to use “differential keying” technology, the principle of this technology is to use two clips to compare, after analyzing the pixel difference, the pixels of the same scene removed, leaving Special pixels, made by dry technology, are so special that many late-stage software are less than ideal, but Digital Fusion, the movie’s high-end synthesis software, can do it easily and with high quality.