《冰河时代3》的3D原理

时间: 2009/07/09, 01:18, 作者: 封俊, 分类: 电影. 已浏览：163次

看过《冰河时代3》3D版，笑点还可以，故事一般，3D技术的应用为大场景增加了不少临场感。

点击图片看大图

这部电影的3D技术使用的是RealD投影技术，在查看一些资料以后，归结为以下三点：

与以前的3D电影所采用的线极化（垂直极化波和水平极化波）不同，这里使用的是圆极化光波(circularly polarized)，右旋极化光波进入右眼，左旋极化光波进入左眼，使用3D眼镜进行选择及过滤。
在投影仪上，使用被称为ZScreen的模块来对投影仪输出的光进行极化处理后，再投到银幕上。
投影仪每秒输出左旋极化光波和右旋极化光波各72帧图像，共144帧图像。平时所看的电影每秒是24帧图像。

需要较为详细的了解的话可以看下面的介绍及文档。

在维基上有如下的概要介绍：

RealD uses circularly polarized light to produce stereoscopic images. Hence the performance is better than with linearly polarizing systems which suffer from visible double imaging if the head is tilted to the side.^[1]

The projector alternately projects the right-eye frame and left-eye frame, and circularly polarizes these frames, clockwise for the right eye and counterclockwise for the left eye. A push-pull electro-optical modulator called a ZScreen is placed immediately in front of the projector lens to switch polarization. The audience wears disposable circularly polarized glasses (see circular dichroism) to make sure each eye sees only “its own” picture, even if the head is tilted . The very high framerate, which is 72 frames per second per eye, makes sure the image looks continuous. In RealD Cinema, each frame is projected three times to reduce flicker. The source video is usually only 24 frames per second (which can result in a subtle ghosting and stuttering on horizontal camera movements). A special cinema screen is used to minimize depolarization and to reflect back as much light as possible to counter polarization losses. The result is a 3D picture that seems to extend behind and in front of the screen itself.^[2]